ABSTRACT With continuous growth rate year, electronic lamp ballasts wi

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AN1543/D Electronic Lamp Ballast Design
ABSTRACT With continuous growth rate year, electronic lamp ballasts widely spread over world. Even though light fluorescent tube discontinuous spectrum, higher efficiency brought electronic control these lamps make them best choice save energy absorbed lighting systems. years ago, lack reliable efficient power transistors made design such circuits difficult! Today, thanks technology improvements carried Semiconductor, design engineers handle problems linked with power semiconductors without sacrificing global efficiency their circuits. This Application Note reviews basic electronic lamp ballast concepts gives design rules build industrial circuits. SUMMARY MAIN PURPOSE Fluorescent tube basic operation Standard electromagnetic ballast Electronic circuits HALF BRIDGE CIRCUIT DESIGN DIMMABLE CIRCUIT POWER SEMICONDUCTORS CONCLUSIONS APPENDIX ELECTRONIC LAMP BALLAST
Main Purpose
Assure that circuit will remain stable, even under fault conditions. Comply with applicable domestic international regulations (PFC, THD, RFI, safety). Obviously, high electronic lamp ballast will certainly include other features like dimming capability, lamp wear monitoring, remote control, these optional will analyzed separately.
Fluorescent Lamp Operation
When lamp off, current flows apparent impedance nearly infinite. When voltage across electrodes reaches Vtrig value, mixture highly ionized generated across terminals lamp. This behavior depicted typical operating curve shown Figure
Inom
Vstrike
generate light pressure fluorescent lamp, electronic circuit must perform four main functions: Provide start-up voltage across electrodes lamp. Maintain constant current when lamp operating steady state.
Figure Typical Pressure Fluorescent Tube Characteristic
Semiconductor Components Industries, LLC, 2000
September, 2000 Rev.
Publication Order Number: AN1543/D
AN1543/D
value Vstrike function several parameters: filling mixture pressure temperature tube length tube diameter kind electrodes: cold Typical values Vstrike range from 1200 Once tube voltage across drops on-state voltage (Von), magnitude being dependent upon characteristics tube. Typical ranges from value will vary during operation lamp but, order simplify analysis, will assume, first approximation, that on-state voltage constant when tube running steady state. Consequently, equivalent steady state circuit described back back zener diodes shown Figure start-up network being more complex, particularly during ionization. This consequence negative impedance exhibited lamp when voltage across electrodes collapses from Vstrike Von.
BALLAST
operation lamp even under worst case "end life" conditions. consequence, converter will slightly oversized make sure that, after 8000 hours operation, system will still drive fluorescent tube.
Controlling Fluorescent Lamp
already stated, both voltage current must accurately controlled make sure that given fluorescent lamp operates within specifications. most commonly used network built around large inductor, connected series with lamp, associated with bi-metallic switch generally named "the starter". Figure gives typical electrical schematic diagram standard, line operated, fluorescent tube control.
TUBE MAINS
BI-METALLIC TRIGGER
Figure Standard Ballast Circuit Fluorescent Tube
Figure Typical Fluorescent Tube Equivalent Circuit Steady State
now, there model available describe start sequence these lamps. However, since most phenomena dependent upon steady state characteristics lamp, simplify analysis assuming that passive networks control electrical behavior circuit. Obviously, this assumption wrong during time elapsed from Vstrike Von, since this time interval very short, results given proposed simple model accurate enough design converter. When fluorescent tube aging, electrical characteristics degrade from original values, yielding less light same input power, different Vstrike voltages. simple, cost electronic lamp ballast cannot optimize overall efficiency along lifetime tube, circuit must designed guarantee
operation fluorescent tube requires several components around tube, shown Figure mixture enclosed tube ionized means high voltage pulse applied between electrodes. make this start-up easy, electrodes actually made filaments which heated during tube ionization start-up (i.e,. increasing electron emission), their deconnection being automatic when tube goes into steady state mode. this time, tube impedance decreases toward minimum value (depending upon tube internal characteristics), current circuit being limited inductance series with power line. starting element, commonly named "starter", essential part ignite fluorescent tube. made bi-metallic contact, enclosed glass envelope filled with neon based mixture, normally OPEN state. When line voltage applied circuit, fluorescent tube exhibits high impedance, allowing voltage across "starter" high enough ionize neon mixture. bi-metallic contact gets hot, turning contacts which, turn, will immediately de-ionize "starter". Therefore, current flow circuit, heating filaments. When bi-metallic contact cools down, electrical circuit rapidly opened, giving current variation inductance which, turn, generates overvoltage according Lenz's law.
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AN1543/D
Since there synchronization with line frequency (the switch operates random basis), circuit opens current level anywhere between maximum zero. voltage pulse low, tube doesn't turn start-up sequence automatically repeated until fluorescent tube ionizes. that time, tube impedance falls minimum value, yielding voltage drop across electrodes and, hence, across switch. Since starter longer ionized, electrical network filaments remains open until next turn-on circuit. must point that fluorescent tube turns when current zero: this source flickering standard circuit. It's important problem which lead visual problems stroboscopic effect rotating machines computer terminals. take care this phenomena, fluorescent tubes, least those used industrial plants, always dual basis single light spreader, from different phases (real virtual capacitor) order eliminate flickering. value inductor function input line frequency Hz), together with characteristics lamp. impedance given Equation
trigger switch standard device. electromechanical ballast main drawbacks: Ignition lamp controlled. Light lamp flickers same frequency line voltage. But, other hand, magnetic ballast provides very cost solution driving pressure fluorescent tube. overcome flickering phenomenon poor start-up behavior, engineers have endeavored design electronic circuits control lamp operation much higher frequency. efficiency (Pin/Lux) fluorescent lamp increases significantly shown Figure soon current through lamp runs above kiloHertz.
with: 2**F
Herz
Henry
Computing value straightforward. Assuming European line (230 V/50 tube (Von Vtrig then:
IRMS Ptube
Figure Typical Fluorescent Lamp Efficiency Function Operating Frequency
IRMS 0.55
electronic circuit build fluorescent lamp controller divided into main groups: Single switch topology, with unipolar current, (unless circuit operates parallel resonant mode). Dual switch circuit, with bipolar output current. manufacturers fluorescent lamps highly recommend operating tubes with bipolar current. This avoids constant bias electrodes Anode-Cathode pair which, turn, decreases expected lifetime lamp. fact, when unipolar current flows into tube, electrodes behave like diode material cathode side absorbed electron flow, yielding rapid wear filaments. consequence, line operated electronic lamp ballasts designed with either dual switch circuit (the only used Europe), single switch, parallel resonant configuration (mainly used countries with lines), providing current tubes.
limit steady state current, impedance must equal
Line-Von IRMS
(230-100) 0.55
Therefore, inductor must have value (assuming pure Ohmic resistance total circuit being negligible):
2*p*F
0.75
order minimize losses generated into inductor Joule's effect, resistance must kept possible: this achieved selecting current density A/mm2 maximum copper. However, value wire diameter used manufacture inductor will limited cost, size weight expected given inductor.
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AN1543/D
power, battery operated fluorescent tubes driven with single switch flyback topology. But, output transformer coupled tube capacitive network current through lamp alternating. However, filaments any) cannot automatically turned this simple configuration global efficiency downgraded accordingly. dual switch circuits divided into main topologies: Half bridge, series resonant. Current push-pull converter. half bridge far, most widely used Europe (100% so-called Energy Saving Lamps Industrial applications based this topology), while push-pull preferred solution with around electronic lamp ballasts using this scheme today (see typical schematic diagram Figure
LINE FILTER LINE DRIVER NETWORK Itube
Figure Typical Current Fed, Push-Pull Converter
FLUORESCENT TUBE
Both these topologies have their advantages drawbacks, consequence associated power transistors being negligible shown Table
Table 1.Main Characteristics Dual Switches Topologies
Parameters Half Bridge Push-Pull
V(BR)CER Inrush Current window Drive Intrinsic Galvanic Isolation
times Inom** 2.60 -3.60 High side
1100 1600 times Inom** 1.90 -2.30 side only
Notes:* numbers typical operation line.
Inom: current into transistors steady state.
Push Pull Topology main advantage current push-pull converter, besides common grounded Emitter structure, ruggedness this topology since sustain short circuit load without damage semiconductors (assuming they were sized cope with level current voltage generated during such fault condition). This direct benefit current mode brought inductor series with line. However, imbalance both power transistors magnetic circuit leads high voltage spikes that make this topology difficult line voltage above Additionally, practical fluorescent tubes when they driven from push-pull circuit, half bridge, series resonant topology being better solution. push-pull converter designed with either single transformer, shown Figure using separate core build oscillator (see Figure
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AN1543/D
LOAD
LOAD
Figure Basic Single Transformer Circuit
Figure Basic Transformer Circuit
Single Transformer Basic Operation circuit uses same core drive transistors supply power load. Operation based saturation core when magnetic flux exceeds maximum value core sustain. Although this very cost solution, commonly used power above tens watts, because global efficiency downgraded dual mode operation output transformer (i.e., saturable linear). Figure gives typical schematic diagram. Transformer Operation high load currents high frequency, transformer requirements dual role frequency control efficient transformation output voltage becomes difficult problem single transformer design. this reason, transformer design, depicted Figure more advantageous. operation this circuit similar transformer case, except that only small core need saturated. Since magnetization current small, high current levels transformer saturation magnetic flux reduced significantly when compared transformer design. course, stresses applied power semiconductors reduced same ratio. Another major advantage transformer inverter design that operating frequency determined VFB, voltage easily regulated provide constant frequency drive power transformer. Starting Circuit general, basic circuits depicted Figures will oscillate readily, unless some means provided begin oscillation. This especially true full load
temperature. simple, commonly used starting circuit shown Figure this design, resistors form simple voltage divider bias transistors conduction before oscillation starts.
LOAD
Figure Basic Starting Circuit
Sinusoidal Output Inverter basic inverters discussed above have output frequency voltage directly proportional supply voltage, output being square wave. sinusoidal output, tightly controlled frequency together with easily regulated output voltage, inverter must modified from basic circuit. simple efficient way, current topology, with inductor connected between primary output transformer supply line shown Figure When circuit tuned with capacitors then voltage across switches sinusoidal, yielding minimum switching losses into silicon. Typical waveforms given Figure
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AN1543/D
FULL LOAD LOAD
UNLOADED, TRANSFORMER CONVERTER
Figure Typical Current Fed, Sinusoidal Output Converter
*VCC
CURRENT FED, RESONANT CIRCUIT
Figure Typical Push-Pull Waveforms
INPUT RECTIFIER 1N4937 LINE 1N4937
Itube
LINE FILTER
Vtrig
DIAC
FLUORESCENT TUBE
Figure Typical Half Bridge Topology
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Transistor selection criteria: Select Collector current capability sustain peak value during either unloaded short circuit conditions. Select V(BR)CES avoid avalanche under worst case conditions (i.e., high line, unloaded operation). Define storage time window make sure devices will tightly matched, thus minimizing magnetic imbalance into output transformer. Make sure load line never goes outside either FBSOA RBSOA maximum ratings selected transistors. HALF BRIDGE TOPOLOGY ANALYSIS
Basic Circuit
basic schematic diagram half bridge, self oscillant topology given Figure transistors active side bridge, capacitors being passive arm.
Operation Description
other hand, voltage developed across secondaries must limited value lower than V(BR)EBO transistors, otherwise Base-Emitter junction goes avalanche global efficiency downgraded. Moreover, must point that, even transistor sustain Base-Emitter avalanche (assuming that associated energy within V(BR)EBO maximum rating), such continuous mode operation make transient long term behavior converter more difficult predict. However, there problem Base-Emitter junction forced into avalanche mode during start-up because, under these conditions, energy dissipated into junction very absorbed silicon. voltage given another electromagnetic equation:
oscillations generated means saturable transformer Since transistors biased state Base-Emitter impedance provided secondaries transformer this circuit cannot start itself, unless there imbalance between high side side converter. But, such imbalance will severely downgrade operation once converter begins. Therefore, preferable have pair matched transistors start converter with network built around Diac capacitor resistor When line voltage applied, capacitor charges exponentially through resistor When voltage across reaches trig value diac turns discharging into Base-Emitter network This transistor turns change collector current (dI/dt) through primary generates voltage across each secondaries arranging windings depicted Figure voltage negative upper switch positive lower one. This forward biases Collector current this transistor keeps rising until core saturates From electromagnetic circuit theory, magnitude current secondaries given Equation
safety rule thumb, steady state V(BR)EBO. load being highly inductive,the Collector current will rise with slope given Equation
Start-up Sequence
start-up voltage (Vstrike) generated series resonant network built with inductor capacitor behavior this network being predictable with Equations given below. resonant frequency
Quality Factor given
with resistance circuit. This factor also expressed Equation
(10)
resonance, impedance series circuit given Equation
(11)
course, value must large enough fully saturate transistor, even under worst case conditions:
with intrinsic current gain transistor
resonance, term equals cancel each other:
(12)
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Therefore, impedance minimum equals resistance:
(13)
However, simple equivalent circuit given Figure helpful perform first calculations when designing this kind circuit.
Itube
resonance, current circuit maximum follows Ohm's law:
(14)
same time, voltage across capacitor maximum stated Equation
VCC*Q (15)
HALF FLUORESCENT BRIDGE TUBE
behavior R/L/C resonant circuit depicted Figure Depending upon ratio, curve more less flattened. This described selectivity R/L/C network.
Pout Von*Itube
Figure Basic Equivalent Circuit Steady-State
high
Figure Typical R/L/C Series Network Behavior
value dictated needs application, associated components must sized accordingly. Since inductor direct function output power operating conditions, designer other choice than adjust values capacitor resistor Quality factor, keeping mind resistance filaments. HALF BRIDGE DESIGN Note: design proposed herein assumes V-50 input line voltage together with single four foot tube. voltage Vtrig being Nominal operating frequency: kHz. Designing converter lamp ballast application very difficult, there many steps iterations that must performed first. Unfortunately, there accurate simple model available, time this publication, simulate electronic lamp ballast.
first step define chopper frequency, since most critical parameters dependent upon this criteria. topology being self oscillant, Half Bridge will permit design make manufacturing electronic circuit simple possible. selected core used build converter must meet following specifications: core must: saturable exhibit curve square possible available lowest possible cost re-arranging Ampere's equation, compute operating frequency self oscillant converter based saturable core:
(16)
With: voltage across Primary winding
number turns Primary core saturation flux Tesla Core cross section frequency Herz
Care must taken, cost base drive network dynamic parameters power transistors will likely optimized. fact, storage time will probably greater than computed operating chopper frequency. graph given Figure gives typical storage time variation, function bias conditions, bipolar transistor. More detailed information available
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AN1543/D
from designer's data sheet provided Semiconductor.
Vclamp
and, consequently, voltage starts drop, yielding less forward bias Base network. Collector current increases, operating point transistor moves along f(IC) curve. meantime, Base current limited NS/NP ratio, stated Equation must remember that voltage function dIC/dt, absolute magnitude Collector current being irrelevant. When voltage drops, available Base drive decreases transistor will rapidly leave saturation region. Consequently, Collector current decreases dIC/dt reverses from positive going slope negative going slope. transistor driven from current transformer, then same mechanism applies available Base current, stated Equation These points cumulative and, soon primary current decreases, core starts recover from flux saturation, voltage magnetically induced Base current) reverses, transistor will rapidly switch Collector current. oscillograms given Figures show typical Base bias standard converter using this technique. Based these oscillograms, it's clear that turn-off mechanism, with typical timing values around negligible must taken into account during design.
Figure Typical Storage Time Variation Function Collector Current
turn-off mechanism transistor twofold: When current increases Primary winding magnetic flux increases accordingly, operating point core moves toward Bsat. this point, core goes into saturation area relative permeability -mr- collapses from nominal value down unity. With typical 6000, this large variation makes Primary/Secondary coupling nearly negligible
STORAGE TIME
s/DIV mA/DIV
COLLECTOR CURRENT
ZERO
s/DIV mA/DIV
Figure Typical Base Current Waveform
Figure Typical Waveform (17)
Therefore, practical operating frequency will dependent upon core used build saturable transformer absolute value Collector current storage time (tsi). This shown Equation
with period depending upon core storage time
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factor stands half bridge topology used. design saturable transformer bounded several parameters: Magnetic material availability Core shapes available (Toroids preferred because they have highest square characteristic) Manufacturing costs typical curves given Figure provided manufacturers cores different material they propose their portfolio products. Most time, data sheets show upper side curves, characteristic being absolutely symmetrical axis. other hand, shape curve, i.e. Bsat value, controlled using increase reluctance core. course, this possible toroidal cores.
course, order with lower cost, it's preferable standard core several iterations above equation, using variable. Since current keeps increasing during storage time transistor, cannot calculated peak value saturate core because, this case, current will much higher than expected one. other hand, it's very easy anticipate tolerance this point design; therefore, rule thumb, first pass made using IP/2 compute oscillator. From toroid data book provided LCC, FT6.3 toroid (external diameter 6.30 with half peak:
1.60 0.40 0.35
1.82 turn
Using next available toroid, FT10 (external diameter
SATURABLE MATERIAL: MAINLY USED BUILD OUTPUT TRANSFORMERS.
2.50 0.40 0.35
2.85 turns
SATURABLE MATERIAL, WITH SQUARE CHARACTERISTIC, USEFUL BUILD OSCILLATORS.
Note:Drawing scale. Figure Typical Curves
build transformer, either data provided manufacturers cores, using B=f(H) curves, pre-define type core that would best application. This derived from Equation which gives minimum electromagnetic field needed saturate given core:
(18)
selection core from `off shelf' standard products (see preferred models given Table depends upon expected frequency, cost, availability. example, select toroid with ferrite material, being higher than 6000. simplify manufacture this transformer will make first iteration with turns, assuming across primary. characteristic curves this core show that saturation flux room temperature +25°C), cross sectional area being 0.08 cm2. These parameters yield theoretical operating frequency
0.51 0.08
20424
with saturation field A/cm number turns primary
current into effective core perimeter
Using, first analysis, storage time power transistors, given data sheet, practical time (ton) switch will
10-6 20424 29.98
Since must higher than (the intrinsic field sustainable material defined data sheet), then compute perimeter core, assuming given number turns, rearranging Equation
(18a)
yielding typical operating frequency
1/(2*ton) 1/(2*29.98*10-6) 16677
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AN1543/D
This below expected operating frequency specified above. Performing same analysis with FT6.3 toroid yields typical operating frequency kHz, with turns, value well within expected range. This toroid will final choice this design.
Table 2.Popular Available Toroids
Toroid FT6.3 FT10 FT16 Ext. Dia. 6.30 10.00 1.60 2.50 4.00 0.032 0.08 0.20
BREAKDOWN VOLTAGE
Even transistors never operate V(BR)CEO(1) mode, must select devices with voltage rating above rectified line voltage:
V(BR)CEO Vline (19)
nominal line, this yields:
V(BR)CEO 1.15 V(BR)CEO (The 1.15 factor stands normalized European line variation).
Based Equation it's clear that storage time (tsi) power transistors plays significant role defining electronic lamp ballast. This dynamic parameter main impacts design: operating frequency converter, hence power delivered load derived from Equations will constant from module another. output inductor driven with other than Duty Cycle, yielding risk saturating core. capacitive side half bridge helps prevent saturation inductor D.C. (point -b-). point float around half value, cannot compensate large variations will have using transistors specifically designed this circuit. other hand, some cost designs single capacitor close loop, yielding high risk saturation which, turn, lead destruction power switches resulting current under fault conditions. Point worse power modules, particularly when line voltage because even small variation frequency either over under drive fluorescent lamp. Consequently, transistors used such designs must have tight dispersion their dynamic parameters, specified min/max window storage time mandatory achieve stable reliable operation. course, this easily done using MOSFET devices, cost increases significantly, keeping losses constant, compared BIPOLAR transistors. However, power/low line voltage applications, MOSFET provide good alternative this kind electronic ballast design. next step selection power semiconductors, main parameters take into account input line voltage, output power operating chopper frequency.
Since such value available standard device, recommended that designer rated transistor. worthwhile point that, assuming freewheeling diodes properly selected (fast ultra-fast type), voltage across Collector-Emitter junction each transistor shall exceed supply, limiting RBSOA(2) operation within this voltage limit. However, simple cost converter doesn't provide well regulated supply and, under transient conditions, voltage rise well above expected maximum value. Depending upon input network, high yielding unexpected stresses into semiconductors. Consequently, power transistors must sized sustain high FBSOA(3) RBSOA generated this transient. Fortunately, stated above, Base-Emitter network open and, impedance during these transients, transistors have breakdown voltage capability extended V(BR)CER(4) V(BR)CES(5) region. Figure gives typical voltage capability modern high voltage transistor, function Base-Emitter impedance. Curves show typical values BUL44 product Tcase +25°C.
1000 BVCER (VOLTS)
Figure Collector-Emitter Breakdown Voltage Function
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AN1543/D
COLLECTOR CURRENT RATING Table 4.Preferred MOSFET Devices Lamp Ballast Applications
Devices MTD3N25E MTD5N25E MTD1N50E MTD2N60E MTP3N50 MTP6N60E MTP8N50 V(BR)DSS RDS(on) 2.00 1.10 8.50 3.80 3.00 1.20 0.80 Package DPAK DPAK DPAK DPAK TO-220 TO-220 TO-220
current capability power transistor defined under conditions: start steady state Since start value, together with Quality factor dependent upon steady state conditions, must first compute steady state value derive start peak. other hand, since start sequence lasts hundredths millisecond, there need select transistor with this inrush current value nominal capability. designer will preferably steady state condition define power semiconductor. steady state, current into lamp will Irms Pout/Von Irms 55/100 peak current
Irms
During start current will (assuming IP*Q 0.77*3 2.31 selected transistor must have operating current between 0.80 1.00 must able sustain peak value 2.50 3.00 range, being high enough saturate transistor even during start keep Base drive simple, minimize losses, 0.80 must high possible. other hand, must remember influence this parameter dynamic behavior bipolar power transistor, make compromises accordingly. this point, make pre-selection among lamp ballast dedicated transistors developed Semiconductor. From preferred devices listed Table we'll select BUL44D2, nominal operating current, this design.
Table 3.Preferred Bipolar Power Devices Lamp Ballast Applications
Devices BUL35 BUL43B BUD43B BUL44 BUL44D2 BUD44D2 BUL45 BUL146 BUL147 MJE18002 MJE18002D2 MJE18004 MJE18004D2 MJE18006 MJE18204 MJE18604D2 MJE18605D2 V(BR)CEO V(BR)CES 1000 1000 1000 1000 1000 1200 1600 1600 Peak Package TO-220 TO-220 TO-220 TO-220 TO-220 DPAK TO-220 TO-220 TO-220 TO-220 TO-220 TO-220 TO-220 TO-220 TO-220 TO-220 TO-220
Based BUL44D2 data sheet, will forced gain reference value steady state. With collector current this yields Base current minimum. freewheeling diodes will MUR150, UltraFast rectifier. Base drive transistors achieved under modes: current source voltage source Using current source straightforward solution (Figure saturable transformer designed yield Base current, according Equation
NP*IP NS*IS (20)
Since values already defined, compute number turns each secondaries:
turns
must pointed that such circuit will keep forced gain value defined designer this case whatever Collector current Therefore, already stated, must make sure that transistor intrinsic higher than even under high start-up current condition. other hand, difficult improve dynamic behavior transistor when Base driven from such simple current source. voltage mode will preferred improve global efficiency. Driving device from voltage source achieved using capacitor load secondary, Base having been through series resistor depicted Figure windings derived from general Equation used transformers:
(21)
value bound high Base/Emitter breakdown voltage, amount feedback, associated VBE(on), Base/Emitter network end.
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Assuming VBE(on) 1.10 drop Emitter resistor (VEE), value must within limits given here below: (22) RB*IB VBE(on) V(BR)EBO value must small possible minimize losses drive network, must high enough provide feedback oscillator. simple rule selecting this resistor make higher than apparent dynamic impedance Base input:
VBE(on) (23)
This value well below minimum guaranteed V(BR)EBO, round design transformer:
turns
then: 1.10/0.18 select then:
15*0.18+1.10+1 4.80
wire diameter derived from maximum current density 4.50 A/mm2, selected from table given appendix. main advantage associated with voltage mode control capability design more efficient Base drive, thus improving switching performance transistors. This particularly useful high power converters where losses silicon must minimized.
Figure Typical Current Mode Drive
Figure 19.(b) Typical Voltage Mode Drive Circuit
this point, oscillator nearly completed, will necessary refine design based first results coming from prototype. already stated, steady state current fluorescent tube limited external inductance, value derived from impedance must series with lamp right output power:
(24)
must have tightly specified, dispersion storage time from Since assumed have negligible impedance, derive
2*p*F 1.60 30000 (25)
0.35
This represents impedance R/L/C circuit, according Equation given Page Depending upon values assuming resistance negligible operating frequency nominal, current waveform will truncated either peak value sine (worst case) during negative going slope. Obviously, second case, turn switching losses will lower. dynamic behavior transistor must stable make sure that frequency stays within predicted limits. Consequently, power semiconductors
limiting current steady state, inductance, associated capacitor builds resonant circuit during start-up sequence. Prior computing value must make assumptions: storage time will shorter during start-up, consequence lower high current. toroid will saturate more rapidly higher dl/dt. Consequently, operating frequency will higher, resonant network computed accordingly. Assuming
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that start-up frequency kHz, then value derived rearranging Equation
4.39 600002 10-3 (26)
into Collector/Base junction Q1/Q2, yielding uncontrolled charges. Moreover, voltage drop across network higher than V(BR)EBO, Base/Emitter junction will avalanched associated current will generate extra losses into silicon stated Equation
V(BR)EBO*IA*dt*F (27)
This value being standard, will nF/1000 resonant frequency then:
(1.6 10-3 10-9)
capacitors used build passive side half-bridge, associated with must yield resonant frequency well below used steady state. make 5*F, then
From point view, parallel, thus C3+C4:
4.39 60000 10-3
worst case condition will occur when switches off. When voltage node (see Figure negative network time constant large enough, Base/Emitter junction transistor forward biased short circuit generated through Q1/Q2. This instantaneous power much higher than transistors sustain (the FBSOA characteristic) both transistors destroyed microseconds. avoid risks described above, highly recommended that designers freewheeling diodes across each transistor.
Safety Circuit
will closest normalized value start-up network, built around R1/C1/D1/R4, must perform main functions: Provide enough Base current turn transistor. Minimize losses into this circuit. minimize losses, yielding Joule's effect into this resistor. Base current given discharge capacitor into Base/Emitter network. Since this impedance circuit, capacitor must sized yield pulse width large enough significant current into primary rule thumb, time constant shall time, case around yielding
Freewheeling Diodes
Across freewheeling diodes providing path inductive current, these devices clamp spike voltage, stated Lenz's law, when switches off. course, since dV/dt pretty high, must have fast turn-on time make sure that peak voltage will clamped safe value. other hand, these diodes used, then negative going current flows
regulations withstanding, once converter running steady state, safety circuit limited single fuse switch line overload occurs. more sophisticated, much more expensive way, self resetting thermal switch open line temperature inside module becomes higher than safe limit, usually between 85°C 100°C. However, during start-up sequence, must make sure that fluorescent tube turns otherwise converter damaged continuously operating resonant mode. stated Page current very high losses silicon will rapidly exceed maximum ratings power transistors used converter. course, delay must provided yield enough time warm filaments trigger tube. Basically, self oscillant circuit turned grounding Base drive bottom transistor. This accomplished using SCR, small signal transistor, sink Base current ground depicted Figure Base drive also disconnected using extra winding across drive transformer (T1, Figure shunting available current ground: this technique switches both memorize failure mode until user switches mains (see Figure Another open Emitter Ground path bottom transistor depicted Figure this relatively complex cost effective.
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TUBE TUBE
DIAGNOSTIC CIRCUIT
DIAGNOSTIC CIRCUIT
Figure Turning Converter Sinking Base Current Ground
Figure Fault Memorization
+VCC
TUBE
DIAGNOSTIC CIRCUIT
Figure Using Emitter Switch Technique Stop Converter Power Factor Correction
electronic lamp ballasts large bulk reservoir capacitor associated with bridge rectifier, therefore, only draw power from line when instantaneous voltage exceeds charge capacitor. result, power factor (cos around 0.50) harmonic content input current very high. European regulation EEC555-2 specifies both minimum expected value maximum harmonic content curve acceptable kind electronic circuit connected mains. cope with this regulation, either passive network (basically large inductor together with combination rectifiers capacitors) active circuit built around boost converter. passive Power Factor Correction (PFC) economical, bulky (because operates line
frequency) very efficient with typical 0.80. Using active brings, addition high THD, constant voltage across electronic ballast which yields constant power load, regardless line voltage. example, point that European line voltage ranges from this ±15% variation from nominal values. This cause change light intensity large enough sensed human eye.
Circuit Description
proposed circuit based MC34262, dedicated together with power switch, this case MOSFET, arranged boost topology. course, rectified voltage longer filtered large capacitor,
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filter having been designed damp high frequency noise from line (see typical schematic diagram Figure This circuit feeds lamp ballast converter recharges reservoir capacitor (i.e., Figure 11). MC34262 takes care signal controls
MOSFET make envelope high frequency pulsed current close possible sinusoidal waveform. other hand, output voltage regulated (sensing achieved through current flowing into power switch monitored across sense resistor connected between Source/Ground
1N4937
1N4007
MUR150E
+400
MC34262
MTP4N50E
MAINS
Figure Typical Circuit
IEC555-2 SPECIFICATION
LINE INPUT CURRENT
HARMONIC TOTAL HARMONIC DISTORTION
Figure Typical Evaluation Board
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MUR180E 1N4007 DIAC BUL44D2 FT063 1N4148 1N4148 1N4148 1N4148 0.22 MCR26 1200 BUL44D2 Ptube
MUR120 AGND MTP4N50E
MC34262
ZENER
AN1543/D
Figure High Fluorescent Lamp Ballast Demo Board
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FILTER
FUSE
Notes: resistors 0.25 unless otherwise noted. capacitors Polycarbonate, 10%, unless otherwise noted.
AGND
LINE
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performance outstanding, with 0.98 Total Harmonic Distortion (THD) well within EEC555-2 regulations. MC34262 data sheet associated Technical Notes give information required design loaded lamp ballast other type electronic circuit. order make sure that will damaged during start-up sequence lamp ballast, time constant R1/C1 delays operation MC34262 about three seconds, thus yielding safe amount time operate both circuits. course, voltage will constant during start-up, this irrelevant since converter running steady state. demo board, designed Semiconductor, includes circuit which drives converter with constant voltage. circuit uses newly developed BUL44D2 transistors standard self oscillant configuration. performance summarized below, parts list printed circuit board layout available appendix.
Table 5.Test Results Nominal Operating Frequency: Nominal Output Power: Power Transistors Case Temperature: Cos: Global Efficiency: 0.98 65°C (steady state, free air)
mA/DIV
mA/DIV
MS/s
LINE
LOAD
STOPPED
Figure Collector Base Currents Steady State
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LOSSES IC*VCE V/DIV
mA/DIV
MS/s
STOPPED
Figure Switching Losses
V/DIV DYNAMIC VCE(sat)
VIRTUAL VCE(zero)
mA/DIV
MS/s
-5.4
STOPPED
Figure VCE(sat) Losses
Measuring dynamic VCE(sat), under high value, straight forward because input amplifier oscilloscope becomes saturated large voltage cannot accurately sense saturation value when transistor turns example, setting oscilloscope mV/div will yield meaningless results because instrument will
recover from +400 coming from rail voltage, within less than Several techniques exist overcome this problem. used Semiconductor depicted Figure
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+VCC
LOAD VCES(dyn1) DRIVE VCES(dyn2) VCE(sat)dyn DEFINITION MEASUREMENT TECHNIQUE VCES(dyn) OSCILLOSCOPE +Vaux
Figure Dynamic VCE(sat)
Diode must sustain peak voltage developed across device under test (Q1). must also have very fast turn-on time. Vaux value adjusted between (depending upon expected VCE(sat)dyn), diode calibrated current forced resistor (usually mA). VCE(sat)dyn then calculated subtracting forward drop (VF) from voltage sensed oscilloscope. accuracy this method good enough characterize compare behavior several transistors. Additionally, make this test reproducible, dynamic VCE(sat) specified under timing conditions (see Figure microsecond three microseconds after reaches value. HIGH DIMMABLE LAMP BALLAST Since voltage across fluorescent tube lower than value would cause tube turn off, it's practical variations adjust output power. fact, using this basic technique yields limited span dimming effect light output lamp. other hand, Pulse Width Modulation (PWM) current through tube light, care must taken balance magnetic circuit. Another simple, efficient solution, variable frequency (with constant duty cycle) drive converter, keeping series inductance constant. Since impedance output network function frequency (Equation power adjusted from zero 100% using this technique.
already stated, storage time associated with bipolar transistor parameter electronic lamp ballasts. case dimmable circuits, this parameter even more important because will offset operating frequency variable amount. Moreover, since current varies output power adjusted, transistor bias varies well Base drive must designed automatically compensate these variations. There three main keys solving this problem: standard Bipolar transistors with Baker clamp network. high voltage MOSFETs. newly developed H2BIP transistors. Using Baker clamp technique straight forward, shown schematic diagram given Figure there some drawbacks: designer must least three fast diodes (two voltage, high voltage). voltage power transistor longer VCE(sat), increases VCE(sat) VBE(on), yielding much higher losses than those generated with standard circuit. example, nominal VCE(sat) BUL44 0.20 voltage rises when device driven with Baker clamp. It's clear that with five times more power dissipated steady state, heatsink mandatory cool transistor. diodes associated with this solution free they occupy space printed circuit board.
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COLLECTOR VCE(sat)
minimum, devices sustain high voltage needed these applications. H2BIP: product paragraph.
Circuit Analysis
BASE
VBE(on) EMITTER
Figure Typical Baker Clamp Circuit
Although this solution sometimes used, it's preferred build dimmable lamp ballast. MOSFETs solve problems associated with storage time, even when operating Drain current varies over wide range, losses limiting factor. DS(on) MOSFET increases when breakdown voltage V(BR)DSS increases (for given chip size). only reduce RDS(on) increase size, this also increases cost, thus limiting MOSFETs high applications. Additionally, care must taken protect Gate/Source from voltage spikes over H2BIP* device integrates active anti-sat network into Bipolar power transistor, together with antiparallel diode connected across Collector/Emitter. basic concept twofold: Avoid hard saturation, thus making storage time short possible. Avoid storage time variation whatever operating Collector current assuming that intrinsic higher than forced IC/IB. course, cannot zero, small enough make this technology good choice design electronic lamp ballast. Also, voltage very close VCE(sat) more than needed activate anti-saturation network), keeping associated losses
adjust output power fluorescent tube described half bridge design example, will vary frequency from kHz. course, circuit longer self oscillant we'll oscillator drive power stage shown Figure oscillator built with integrated into make this module dimmable with voltage source. flip-flop provides phase signals drive Mosfet which, turn, control power stage Q3/Q4. Transistors respectively connected across Gate/Source Q3/Q4, provide impedance path rapidly discharge input capacitance high voltage devices, avoiding risk associated with poor drive conditions, particularly when converter operates high frequency. results tests performed Toulouse summarized Table
Table 6.Dimmable Lamp Ballast Test Results Pout Pout Fmin Fmax MTP8N50E 0.60 (without network) 0.98 (with MC33262based PFC) 40°C (steady state, free air)
time delays built with R3/CissQ1, R4/CissQ2 R5/CissQ3 R6/CissQ4, make sure that none these circuits will have cross conduction during nominal operation. these reasons, cannot bipolar devices design series inductance resonant capacitor straightforward already described self oscillant circuit. transformer built T1600A toroid (external diameter mm), primary inductance being Assuming 1600, primary secondary windings turns each.
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BC557C MTP8N50E 1N4148
BC557C 1N4148
AGND MC14046 MPF960
1N4148
AGND
MC14013
MPF960 FT1603A
1200 MTP8N50E
1N4148
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Figure Dimmable Electronic Lamp Ballast (Demo Version)
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FILTER BRIDGE MC7815 GROUND
AGND
FUSE
LINE
MTP8N50E
V-3.5
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V/DIV
mA/DIV
V/DIV
MS/s
STOPPED
Figure Drain Current Gate Voltage Steady State Pout Pmax
V/DIV
mA/DIV
V/DIV
MS/s
STOPPED
Figure Drain Current Gate Voltage Steady State Pout Pmin
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POWER SEMICONDUCTORS
Integration
Since half bridge based circuits freewheeling diode across Collector Emitter each power switch, first step toward development power devices integrate this diode into silicon Bipolar transistor. Using state technology design power products, Semiconductor taken this opportunity build more features, being make this transistor best choice lamp ballast applications. basic internal circuit given Figure This device includes freewheeling diode active anti-saturation network accurately control dynamic behavior (particularly storage time) die. This concept, patented Semiconductor, been called H2BIP, acronym High frequency, High gain BIPolar transistor. main features this high voltage Bipolar transistor high gain (hFE), short, highly reproducible storage time, monolythic Collector/Emitter diode tailored match needs lamp ballasts. This family includes four standard products: BUL44D2, BUL45D2, MJE18004D2 MJE18604D2, which will extended cope with specific requests. There neither current voltage theoretical limits associated with this concept.
Table 7.Preferred H2BIP Devices Lamp Ballast Applications
Devices BUL44D2 BUL45D2 MJD18002D2 MJE18004D2 MJE18604D2 MJE18605D2 V(BR)CEO V(BR)CBO 1000 1000 1600 1600 Peak (under development)
transistor equal this case, standard transistor will forced hard saturation consequence large Base current used bias junction, yielding large uncontrolled storage time. solve this issue, H2BIP product will sink Emitter node drive current soon voltage difference between Collector/Base main transistor negative enough forward bias connected across Base/Emitter junction. This depicted Figure Using above bias conditions, 1/15 66.6 will sink ground extra 133.4 yielding mode operation quasi saturation region. This results shortest highly reproducible collector current storage time. Since this mechanism will exist Collector current from IB1, dynamic behavior transistor will nearly constant shown Figure
MAIN TRANSISTOR
ANTI-SAT NETWORK
FREE WHEELING DIODE
Figure Basic H2BIP Internal Circuit
Note:The BUL44D2 available DPACK under BUD44D2 name.
These devices used either designs, drop-in replacement parts current designs. existing circuits, designer might have tune Base/Emitter network order full benefit H2BIP. understand operation H2BIP technique, must first assume that forward Base current large enough force equivalent transistor into saturation region given Collector current. example, assume intrinsic
Figure 34.(b) Basic Operation
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Another possibility integration resistor, both (see Figure only problem accuracy these resistors. Semiconductor doesn't perform laser trimming during wafer processing power discrete devices order keep associated costs minimum), accuracy these resistors limited ±30% with temperature coefficient 5000 range. These tolerances incompatible with electronic lamp ballast applications and, unless designer accepts associated drawbacks, further work will carried these kinds devices.
BIAS CONDITIONS:
Figure (IC) Constant
Using feedback resistor Emitter node each transistor yields more stable operation over operating temperature range depicted curves given Figure
INTEGRATION EMITTER FEEDBACK
Figure (TC) Constant
typical application demonstrated Figure
H2BIP
BASE DRIVE NETWORK ADDING BASE BIAS RESISTOR
Figure Bias Resistor Integration
H2BIP
Figure Typical H2BIP Application Circuit
second major integration, already performed Semiconductor, concerns MOSFET. standard converter based such semiconductors, designer must provide during turn-off time impedance path discharge input capacitance (Ciss). Since global efficiency expected high possible, phase shifter network connected Gate/Source, usually relatively high impedance (several switching performance MOSFET might poor enough justify extra components avoid storage time like phenomena achieve fast Drain current fall time. typical schematic diagram Figure
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GATE DRIVE NETWORK 1N4148 INPUT RECTIFIER
LINE FILTER
BC557
1N4148
LINE BC557 FLUORESCENT TUBE
DIAC
Figure Typical MOSFET Application
This circuit works fine, four extra components each power MOSFET (Q3/D3/D4/R2 Q5/D5/D6/R3 take significant space pcb, total cost negligible and, more over, using standard transistors lead uncontrolled operation module consequence very large gain dispersion these parts. using existing process called Smart DiscreteTM, Semiconductor integrated this circuit into MOSFET, making device driveable from high impedance. This family products called ZPCMOS, acronym Zero Power Controlled MOSFET, basic internal circuit shown Figure
DRAIN GATE VGS(Q1)
This device driven from network. turn time independent impedance connected Gate Source, value resistor being large enough keep steady state current below ZPCMOS used existing circuits, assuming that electrical parameters compatible, drop-in replacement solution improve overall efficiency given application. Figure demonstrates savings, terms component counts, brought ZPCMOS lamp ballast application.
ZPCMOS GATE DRIVE NETWORK
ZPCMOS
BASIC ZPCMOSFET CIRCUIT
SOURCE
Figure Basic ZPCMOS Internal Circuit
Figure Typical ZPCMOS Drive
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application assumed same described Figure example, demo board built with ZPCMOS smaller than circuit using standard MTD5N25E devices, saving passive active parts converter. Most electronic lamp ballasts start-up network built around Diac with associated clamp diode. This circuit automatically disconnected once converter running integration these components evaluated bring simple, cost TO92 packaged device perform this function. Figure gives typical circuit.
+VCC
Therefore, even this type power product manufacturable, unlikely that there will many chances develop such devices associated cost will compatible with lamp ballast market.
DRIVE NETWORK
Vout
+VCC
CHANNEL
SINGLE TO92 INTEGRATED CIRCUIT HALF BRIDGE CONVERTER V/0.050 DIAC nF-100 DRIVE NETWORK
Vout
CHANNEL
Figure Start-Up Network Integration Other Configurations Figure Compound Output Basic Circuits High Voltage Integration
compound circuit described Figure example drive transistor half bridge topology (the Gate Base floats several hundredths volt above ground). Unfortunately, much more expensive than usual network used electronic lamp ballasts. reason being, besides extra transistor, there need fast, high voltage P-channel), device nearly times larger than matched NPNs. This consequence lower mobility carriers into material compared that achieved material (everything else being constant).
With product power range from possible design cost effective circuit with power transistors built-in, such would either over-sized power modules, marginal high ones. other hand, since applications electronic lamp ballasts split into main families (Compact Fluo Industrial), much more flexible
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solution make driver intelligent possible, leave power switches outside silicon. Although, already stated, it's probably feasible solution integrate converters industrial applications. output power together with strong trend toward miniaturization, make Compact Fluo Lamp good candidate integrate much possible
+VCC
electronic circuit this type product. However, order keep costs compatible with this market, preferable leave power switches outside half bridge being built either with small footprint packages (DPAK, SOT223), into single SOIC (assuming that losses held minimum, avoiding risk high junction temperature).
INPUT LINE RECTIFIER FILTERING
INITIALIZATION
START-UP MC33262 OSCILLATOR GATE DRIVE
OUTPUT
DIAGNOSTIC
SENSE TUBE STRIKED
Figure Typical Integrated Version Electronic Lamp Ballast
design multi chip package straightforward seems first. depends greatly thermal behavior overall system. example, junction ambient thermal resistance 150°C/W plastic SOIC package ambient temperature being +60°C. maximum losses allowable into silicon given Equation
Tamb Pmax Rthj-a Under above conditions, (150-60)/150 (28)
equally dissipated each power devices, assuming those driver negligible. compact fluo lamps range powered from line, peak current into switches around maximum allowable RDS(on) MOSFET given Equation
RDS(on)(max) IDRMS2 (29)
This value yields zero safety margin because assumes continuously operating maximum temperature. transistor lifetime highly reduced result Arrhenius's (the expected life divided 1000 when temperature increases from +40° +150° more realistic junction temperature +120°C, yielding maximum into silicon under same ambient conditions. course, these losses
this example, RDS(on) 0.2/((0.4/2)2) 2.50 Obviously, this maximum value +120°C, yielding 1.60 +25°C. size rated MOSFET will mils, dimension incompatible with existing cost SOICs. circuit either split into packages (one controller, second power stage), built inside same SOIC depicted dotted line Figure
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+Vbat LINE CONTROLLER FLYBACK +100 V/+400 HIGH PRESSURE LAMP
IGNITION
Figure Fully Integrated Power Electronic Lamp Ballast
Figure Basic High Pressure Lamp Control Circuit (HID Lamp) Static Induction Lamp
Obviously, process used manufacture this type integrated product must able sustain order make compatible with power requirements. time this publication, Semiconductor developing such process target specification already defined cover range power involved these kinds applications. final product will existing high voltage technology, developed line operated battery chargers. However, order make such device flexible possible, power transistors will integrated into structure, giving designer more flexibility. lamp ballast road already includes this development cope with world wide needs. EMERGING APPLICATION
High Pressure Fluorescent Lamp
Using filament, Static Induction Discharge lamp 60,000 hour lifetime, longer than standard fluorescent tubes. Basically, circuit generates field across lamp plasma driven electromagnetic field instead electrostatic one. ignited almost instantaneously (there need pre-heat filaments), thanks high frequencies allowed control these applications, circuit made smaller than more conventional ones. There are, however, number drawbacks; being most critical since will allowed pollute radio frequency bands with thousand converters operating megaHertz range. typical schematic diagram given Figure
Among large number applications being developed lighting field, automotive probably most promising since brings more safety driver yielding much more powerful light without overloading alternator. This achieved using high pressure lamp, with white light, replace existing incandescent bulbs. With efficiency about five times higher, rated high pressure lamp gives twice amount light yielded standard halogen bulbs. cost this approach much higher than price regular bulb, together with relatively complex circuit needed ignite drive lamp. However, addition higher efficiency, high pressure lamp brings lifetime exceeding expected life time car. Figure gives typical block diagram such application.
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FERRITE +VCC DRIVER XTAL LAMP
RESERVED FREQUENCIES: 2.65 13.56 27.12 CLASS AMPLIFIER AVAILABLE BAND: kHz-400 kHz. POWER FERRITE MATERIAL AVAILABLE MHz. LAMP IONIZATION VOLTAGE: V/cm.
Figure Typical Static Induction Discharge Lamp Application
CONCLUSIONS only does save energy, miniaturization electronic ballasts makes them suitable small enclosures. fluorescent lighting
market will continue grow rapidly during next decade, even replacing standard incandescent bulbs designed personal use. Nowadays, engineers have access broad range semiconductors, from which they select best device match their applications. Power transistors, either Bipolar MOSFET, reliable these electronic modules more than years without failure. technology only begun bring more intelligence into silicon, affordable cost, making lighting systems more rugged, with features cannot even imagine with standard electromechanical ballasts: dimming, remote control, real time energy saving, just name few. 1993 electronic lamp ballast market represented around million Compact Energy Saving lamps, million industrials (two, four foot tubes) million voltage Halogen lamps, numbers which expected more than double within five years. addition, applications emerging, like high pressure discharge lamps vehicular induction lamps. main supplier semiconductors, goal develop products make sure that designer world will find optimum solution cope with needs: this benefit electronic lamp ballasts expertise accumulated Semiconductor.
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APPENDIX V(BR)CEO: Collector Emitter Breakdown Voltage, Base open. This minimum guarantee value given transistor. Modern power transistors have wide spread their electrical parameters designer must rely some safety margin older, non-repetitive, semiconductors. RBSOA: Reverse Bias Safe Operating Area. This parameter specifies maximum energy transistor handle when commutating inductive load. RBSOA dynamic parameter which dependent upon Base reverse voltage bias specified Semiconductor designer's data sheets. FBSOA: Forward Bias Safe Operating Area. This parameter specifies maximum power transistor sustain when operating Forward Base bias mode. FBSOA dependent upon power pulse width cannot exceeded under circumstances. V(BR)CER: Collector Emitter Breakdown Voltage, Base connected Emitter impedance. V(BR)CES: Collector Emitter Breakdown Voltage, Base shorted Emitter. V(BR)CBO: Collector Base Breakdown Voltage, Emitter open.
SYMBOLS, UNITS CONVERSION FACTORS
Parameter Magnetic Flux Density Magnetic Field Intensity Permeability (free space) Permeability (relative) Effective Magnetic area Mean Magnetic Path length length Magnetic flux (BdA) Magnetic Potential (Hdl) Inductance Inductance Index Window Area core Wire Cross section Area Number turns Mean Length turn Current Density Resistivity Area Product, Aw*Ae Energy Symbol Units Tesla A-T/m 4*10-7 Weber Amp-Turn Henry turn) A/m2 Joule Gauss Oersted Maxwell Gilbert Henry turn A/cm W-cm Units 10-4 1000/4 4*10-7 10-4 10-2 10-2 10-3 10/4 10-4 10-4 10-2 10-2 10-8 10-7
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WIRE TABLE: Copper Wire, Heavy Insulation
Dia. 2.59 2.31 2.05 1.83 1.63 1.45 1.29 1.15 1.02 0.91 0.81 0.72 0.64 0.57 0.51 0.45 0.40 0/.36 0.32 0.29 0.25 0.23 0.20 0.18 0.16 0.14 0.13 0.11 0.10 0.09 0.08 0.07 Area 5.26 4.17 3.31 2.62 2.08 1.65 1.31 1.03 0.82 0.65 0.52 0.41 0.32 0.26 0.20 0.16 0.13 0.10 0.08 0.06 0.05 0.04 0.03 0.025 0.020 0.016 0.012 0.010 0.008 0.006 0.005 0.004 Dia. Ins. 2.73 2.44 2.18 1.95 1.74 1.56 1.39 1.24 1.11 1.00 0.89 0.80 0.71 0.64 0.57 0.51 0.46 0.41 0.37 0.33 0.30 0.27 0.24 0.22 0.20 0.18 0.16 0.14 0.13 0.12 0.01 0.09 Area 5.85 4.67 3.73 2.98 2.38 1.90 1.52 1.21 0.97 0.78 0.62 0.50 0.40 0.32 0.26 0.21 0.17 0.13 0.11 0.08 0.07 0.06 0.04 0.037 0.300 0.024 0.019 0.016 0.013 0.011 0.008 0.007 20°C 0.0033 0.0041 00.52 0.0066 0.0083 0.0104 0.0132 0.0166 0.0209 0.0264 0.0333 0.0420 0.0530 0.0668 0.0842 0.1062 0.1339 0.1689 0.2129 0.2685 0.3386 0.4269 0.5384 0.6789 0.8560 1.0795 1.3612 1.7165 2.1644 2.7293 3.4417 4.3399 100°C 0.0044 0.0055 0.0070 0.0088 0.0111 0.0140 0.0176 0.0176 0.0280 0.0353 0.0445 0.0561 0.0708 0.0892 0.1125 0.1419 0.1789 0.2256 0.2845 0.3587 0.4523 0.5704 0.7192 0.9070 1.1437 1.4422 1.8186 2.2932 2.8917 3.6464 4.5981 5.7982 Current A/mm2 Amps 23.68A 18.78A 14.90A 11.81A 9.365A 7.43A 5.90A 4.67A 3.70A 2.94A 2.33A 1.85A 1.46A 1.16A 0.92A 0.73A 0.58A 0.46A 0.36A 0.29A 0.23A 0.18A 0.14A 0.11A 0.091A 0.072A 0.057A 0.045A 0.036A 0.028A 0.023A 0.018A
American Wire Gauge Area (*D2)/4 Copper resistivity temperature 1.724*(1 0.0042*(T-20))*10-6 20°C: 1.724*10-6 Current Density Limit:
current density 4.50 A/mm causes approximately 30°C temperature increase with natural cooling transformer inductor whose core area product Aw*Ae) cm4. With larger core, allowable current density decreases because surface usable dissipate heat increases less rapidly than volume producing heat:
4.5*AP-0.125 A/mm2
When frequency increases, skin effect becomes dominant resistance increases:
2*p*r*a
thickness given, Lord Rayleigh's formula:
10-7)
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value derived from Equation
with: Hertz meter 10-7) (30)
resistivity (0.018 copper) permeability copper)
THICKNESS
Table 8.Resistance Function Frequency
Frequency 25kHz 35kHz 50kHz 75kHz 100kHz 200kHz 300kHz 500kHz 1000kHz 0.50 0.1073 0.1314 0.1697 0.2400 1.00 0.0268 0.0328 0.0379 0.0536 0.0657 0.0848 0.1200 2.00 0.0094 0.0112 0.0134 0.0164 0.0189 0.0268 0.0328 0.0424 0.0600 Thickness 0.427mm 0.360mm 0.301mm 0.246mm 0.213mm 0.150mm 0.123mm 0.095mm 0.067mm
FREQUENCY (kHz) NOTE: Curve valid copper only.
0.01
1000
1200
Figure Thickness Skin Effect Function Frequency Table 9.Fluorescent Tube Characteristics
Length ft/mm 2400 2400 1800 1800 1800 1500 1500 1200 1200 Dia. mm/T Power Operating Volt/Ampere 0.94 0.89 0.77 0.64 0.70 0.64 0.63 0.42 0.42 0.36 0.38 0.38
values given copper wire meter long, ambient temperature 25°C.
0.07 0.06 0.05 RESISTANCE 0.04 0.03 0.02 0.01 FREQUENCY (kHz) 1000 1200
Table 10.Preferred Core Suppliers
THOMSON SIEMENS PHILIPS VOGT
NOTE: Wire solid copper, meter long, diameter 2.00 temperature 20°C.
Figure Copper Wire Resistance Function Frequency
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Rload IC(sense
FORWARD BIAS REVERSE BIAS BASIC TEST CIRCUIT
IB(sense)
NOTE: Waveforms idealized scaled.
Figure Switching Time Definition
ELECTRONIC LAMP BALLAST PART LIST (Figure 25.)
Index Value F/25 F/450 nF/63 nF/63 nF/25 nF/1200 nF/1200 nF/630 nF/250 nF/630 nF/630 nF/630 MUR120 MUR180E 1N4007 DIAC Zener 1N4007 1N4007 1N4007 1N4007 1N4148 1N4148 Comments pitch mils radial mils pitch mils radial mils pitch mils pitch mils pitch mils pitch mils pitch mils pitch mils pitch mils pitch mils pitch mils pitch mils pitch mils radial mils radial mils MOTOROLA MOTOROLA MOTOROLA MOTOROLA MOTOROLA MOTOROLA MOTOROLA MOTOROLA MOTOROLA Index 1N4148 1N4148 MTP4N50 BUL45D2 BUL45D2 MCR26 MC34262 OSCILLATOR MOTOROLA VOGT VOGT MOTOROLA MOTOROLA MOTOROLA MOTOROLA Value Comments
Total Components Notes: resistors 0.25 unless otherwise noted capacitors polycarbonat, ±10%, unless otherwise noted Transformer Core FT6.3 Ferrite turn turns each
(primary) (secondaries)
Output inductance
Core EF2509 Ferrite equivalent (Operating frequency: min) turns, wire preferably Litz type.
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DIMMABLE ELECTRONIC LAMP BALLAST PART LIST (Figure 31.)
Index Value component pF/1500 pF/1500 nF/400 nF/400 nF/63 nF/63 F/25 F/16 F/385 F/385 nF/630 nF/63 nF/630 F/25 F/16 ZENER 1N4148 1N4148 ZENER 1N4148 1N4148 1N4007 1N4007 1N4007 1N4007 styroflex, AXIAL pitch mils pitch mils pitch mils pitch mils pitch mils pitch mils radial mils pitch mils pitch mils radial mils radial mils radial mils pitch mils pitch mils pitch mils radial mils radial mils MOTOROLA Comments Index MPF960 MPF960 MTP8N50E MTP8N50E BC557-C BC557-C Test Test Test Test Point Point Point Point voltage Clock Drive Voltage GROUND MOTOROLA MOTOROLA T1600A Core, Value Comments EF2509A Core, supplier MOTOROLA MOTOROLA MOTOROLA MOTOROLA MOTOROLA MOTOROLA
MOTOROLA
MOTOROLA MOTOROLA MOTOROLA MOTOROLA BRIDGE
MC14046B MC14013B DRIVER
Total Components Notes: resistors 0.25 unless otherwise noted capacitors polycarbonat, ±10%, unless otherwise noted Transformer Core FT1600A-M01 Ferrite turns, wire dia. Core EF2509 Ferrite equivalent (Operating frequency: min) turns, wire preferably Litz type.
Output inductance
Motorola Available Literature
Motorola, TMOS Power Data DL135 Motorola, Bipolar Power Transistor Data DL111 Motorola, Linear DL128/D Vol. Motorola, Electronic Lamp Ballasts BR480/D Bairanzade, "The Electronic Control Fluorescent Lamps," Motorola, AN1049 Bairanzade, "Basic Electronic Halogen Transformer," Motorola, EB407 Robert Haver, "The ABC's Inverters," Motorola, AN222
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Semiconductor trademarks Semiconductor Components Industries, (SCILLC). SCILLC reserves right make changes without further notice products herein. SCILLC makes warranty, representation guarantee regarding suitability products particular purpose, does SCILLC assume liability arising application product circuit, specifically disclaims liability, including without limitation special, consequential incidental damages. "Typical" parameters which provided SCILLC data sheets and/or specifications vary different applications actual performance vary over time. operating parameters, including "Typicals" must validated each customer application customer's technical experts. SCILLC does convey license under patent rights rights others. SCILLC products designed, intended, authorized components systems intended surgical implant into body, other applications intended support sustain life, other application which failure SCILLC product could create situation where personal injury death occur. Should Buyer purchase SCILLC products such unintended unauthorized application, Buyer shall indemnify hold SCILLC officers, employees, subsidiaries, affiliates, distributors harmless against claims, costs, damages, expenses, reasonable attorney fees arising directly indirectly, claim personal injury death associated with such unintended unauthorized use, even such claim alleges that SCILLC negligent regarding design manufacture part. SCILLC Equal Opportunity/Affirmative Action Employer.
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ABSTRACT With continuous growth rate year, electronic lamp ballasts wi

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