Output 0.5A Less High Efficiency Step-down Switching Regulator with Bu

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Output 0.5A Less High Efficiency Step-down Switching Regulator with Bu

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Single-chip Type with built-in Switching Regulator Series
Output 0.5A Less High Efficiency Step-down Switching Regulator with Built-in Power MOSFET
BD9122GUL
No.09027EAT31
Description ROHM's high efficiency step-down switching regulator (BD9122GUL) power supply designed produce voltage including volts from 5/3.3 volts power supply line. Offers high efficiency with original pulse skip control technology synchronous rectifier. Employs current mode control system provide faster transient response sudden change load. Features Offers fast transient response with current mode control system. Offers highly efficiency load range with synchronous rectifier (Nch/Pch FET) SLLM (Simple Light Load Mode) Incorporates soft-start function. Incorporates thermal protection ULVO functions. Incorporates short-current protection circuit with time delay function. Incorporates shutdown function Employs WL-CSP VCSP50L2 Power supply including DSP, Micro computer ASIC Absolute Maximum Ratings (Ta=25) Parameter Voltage PVCC Voltage Voltage SW,ITH Voltage Power Dissipation Operating temperature range Storage temperature range Maximum junction temperature
Symbol PVCC VSW,VITH Topr Tstg Tjmax
Limits -0.3+7 -0.3+7 -0.3+7 -0.3+7 6602 -25+85 -55+150 +150
Unit
should exceeded. Derating done 5.28mW/ temperatures above Ta=25, Mounted Glass Epoxy PCB.
Operating Conditions (Ta=25) Parameter Voltage PVCC Voltage Voltage average output Output voltage Setting Range
Symbol PVCC VOUT
Min. 2.5*4 2.5*4
Limits Typ.
Max.
Unit
should exceeded. case output voltage 1.8V more, VccMin 2.7V.
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1/13
2009.05 Rev.A
BD9122GUL
Electrical Characteristics (Ta=25, VCC=PVCC=3.3V, EN=VCC, R1=20k, R2=10k, unless otherwise specified.) Limits Parameter Symbol Min. Typ. Max. Standby current Bias current voltage High voltage input current Oscillation frequency resistance resistance Voltage Output voltage SInk current Source Current UVLO threshold voltage UVLO release voltage Soft start time Timer latch time Output Short circuit Threshold Voltage ISTB VENL VENH FOSC RONP RONN VADJ VOUT ITHSI ITHSO VUVLO1 VUVLO2 TLATCH VSCP 0.780 2.22 0.800 1.200 2.35 0.820
Technical Note
Unit
Conditions EN=GND Standby mode Active mode VEN=3.3V PVCC=3.3V PVCC=3.3V
VADJ=1.0V VADJ=0.6V VCC=30V VCC=03V SCP/TSD operated VOUT=20V
Block Diagram, Application Circuit
VREF PVCC Current Comp SLOPE Soft Start UVLO RITH CITH PGND Current Sense/ Protect Driver Logic 3.3V Input 10µF
4.7µH 4.7F
Output
Fig.1 Block Diagram
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2/13
2009.05 Rev.A
BD9122GUL
configuration
Technical Note
9122
PGND
(unit
PVcc
View
Fig.2 View number function name PGND PVCC source Ground Enable pinActive High
Fig.3 Physical Dimension VCSP50L2
function
output pin/Connected phase compensation capacitor Pch/Nch drain output source power supply input Output voltage detect
Characteristics data(Reference data)
OUTPUT VOLTAGE:VOUT[V]
OUTPUT VOLTAGE:VOUT[V]
OUTPUT VOLTAGE:VOUT[V]
VOUT=1.5V Ta=25 Io=0A
VOUT=1.5V
VOUT=1.5V
VCC=3.3V Ta=25 Io=0A
VOLTAGE:VEN[V]
VCC=3.3V Ta=25
OUTPUT CURRENT:IOUT
INPUT VOLTAGE:VCC[V]
Fig.4 VOUT
Fig.5 VOUT
Fig.6 IOUT VOUT
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3/13
2009.05 Rev.A
BD9122GUL
Characteristics data(Reference data) Continued
1.55 1.54
OUTPUT VOLTAGE:VOUT[V]
Technical Note
1.53 1.52 1.51 1.50 1.49 1.48 1.47 1.46 1.45
EFFICIENCY:[%]
FREQUENCY:FOSC[MHz]
VOUT=1.5V VCC=3.3V Io=0A
VOUT=1.5V
1.20 1.15 1.10 1.05 1.00 0.95 0.90 0.85 0.80
VCC=3.3V
VCC=3.3V Ta=25
OUTPUT CURRENT:IOUT[mA] 1000
TEMPERATURE:Ta[]
TEMPERATURE:Ta[]
Fig. VOUT
0.35 0.30
RESISTANCE:R
Fig.8 Efficiency
CIRCUIT CURRENT:I
Fig.9 Fosc
VCC=3.3V
VOLTAGE:VEN[V]
VCC=3.3V
VCC=3.3V
0.25 0.20
PMOS
0.15
NMOS
0.10 0.05 0.00
TEMPERATURE:Ta
TEMPERATURE:Ta[]
TEMPERATURE:Ta[]
Fig.10 RONN, RONP
Fig.11
Fig.12
Ta=25
FREQUENCY:FOSC[MHz]
VCC=PVCC
VOUT=1.5V
SLLMcontrol
VOUT=1.5V
VOUT
VOUT VCC=3.3V Ta=25 Io=0A VCC=3.3V Ta=25
INPUT VOLTAGE:VCC
Fig.13 Fosc
control VOUT=1.5V
Fig.14 Soft start waveform
Fig.15 waveform Io=10mA
VOUT=1.8V VOUT VOUT
VOUT=1.8V
VOUT
VCC=3.3V Ta=25
IOUT
IOUT VCC=3.3V Ta=25 VCC=3.3V Ta=25
Fig.16 waveform Io=200mA
Fig.17 Transient Response Io=50125mA(10s)
Fig.18 Transient Response o=12550mA(10s)
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4/13
2009.05 Rev.A
BD9122GUL
Information advantages Advantage 1Offers fast transient response with current mode control system. BD9122GUL(transient response IO=50mA125mA)
VOUT=1.8V VOUT VOUT
Technical Note
VOUT=1.8V
IOUT
IOUT VCC=3.3V Ta=25 VCC=3.3V Ta=25
Io=50125mA Fig.19 Comparison transient response Advantage Offers high efficiency load range.
Io=12550mA
lighter load: Utilizes current mode control mode called SLLM lighter load, which reduces various dissipation such switching dissipation (PSW), gate charge/discharge dissipation, dissipation output capacitor (PESR) on-resistance dissipation (PRON) that otherwise cause degradation efficiency lighter load.
Achieves efficiency improvement lighter load.
Efficiency
SLLM
heavier load: Utilizes synchronous rectifying mode on-resistance FETs incorporated power transistor. resistance P-channel 0.3(Typ.) resistance N-channel 0.2(Typ.)
inprovement SLLM system improvement synchronous rectifier
0.001
0.01 Output current Io[A]
Fig.20 Efficiency Achieves efficiency improvement heavier load. Offers high efficiency load range with improvements mentioned above. Advantage 3Supplied smaller package small-sized power incorporated. Output capacitor required current mode control: ceramic capacitor Inductance required operating frequency MHz: 2.2H inductor Reduces mounting area required.
RITH DC/DC Convertor Controller VOUT CITH CVCC
RITH CITH
Fig.21 Example application
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5/13
2009.05 Rev.A
BD9122GUL
Technical Note
Operation BD9122GUL synchronous rectifying step-down switching regulator that achieves faster transient response employing current mode control system. utilizes switching operation (Pulse Width Modulation) mode heavier load, while utilizes SLLM (Simple Light Load Mode) operation lighter load improve efficiency. Synchronous rectifier does require power dissipated rectifier externally connected conventional DC/DC converter junction shoot-through protection circuit limits shoot-through current during operation, which power dissipation reduced. Current mode control Synthesizes control signal with inductor current feedback loop added voltage feedback. (Pulse Width Modulation) control oscillation frequency MHz. signal form turns P-channel (while N-channel turned OFF), inductor current increases. current comparator (Current Comp) receives signals, current feedback control signal (SENSE: Voltage converted from voltage feedback control signal (FB), issues RESET signal both input signals identical each other, turns P-channel (while N-channel turned rest fixed period. control repeat this operation. SLLM (Simple Light Load Mode) control When control mode shifted from heavier load lighter load vise versa, switching pulse designed turn with device held operated normal control loop, which allows linear operation without voltage drop deterioration transient response during mode switching from light load heavy load vise versa Although control loop continues operate with signal from RESET signal from Current Comp, designed that RESET signal held issued shifted light load mode, with which switching tuned switching pulses thinned under control. Activating switching intermittently reduces switching dissipation improves efficiency.
SENSE Current Comp RESET Level Shift Amp. Driver Logic Load VOUT
VOUT
Fig.22 Diagram current mode control
PVCC SENSE IL(AVE) PVCC SENSE
Current Comp
Current Comp
RESET
RESET
VOUT
VOUT(AVE)
VOUT
VOUT(AVE)
switching
Fig.23 switching timing chart
Fig.24 SLLM
switching timing chart
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6/13
2009.05 Rev.A
BD9122GUL
Technical Note
Description operations Soft-start function terminal shifted "High" activates soft-starter gradually establish output voltage with current limited during startup, which possible prevent overshoot output voltage inrush current. Shutdown function With terminal shifted "Low", device turns Standby Mode, function blocks including reference voltage circuit, internal oscillator drivers turned OFF. Circuit current during standby (Typ.). UVLO function Detects whether input voltage sufficient secure output voltage this supplied. hysteresis width (Typ.) provided prevent output chattering.
Hysteresis 50mV
VOUT
Soft start Standby mode Operating mode Standby mode UVLO
Operating mode
Standby mode
Operating mode
Standby mode
UVLO
UVLO
Fig.25 Soft start, Shutdown, UVLO timing chart Short-current protection circuit with time delay function Turns output protect from breakdown when incorporated current limiter activated continuously fixed time(TLATCH) more. output thus held tuned recovered restarting re-unlocking UVLO.
Output latch
Output Short circuit Threshold Voltage VOUT Limit
Standby mode
t1<TLATCH Operating mode
t2=TLATCH
Standby mode
Operating mode
Timer latch
Fig.26 Short-current protection circuit with time delay timing chart
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7/13
2009.05 Rev.A
BD9122GUL
Switching regulator efficiency Efficiency expressed equation shown below: POUT POUT POUT+PD
Technical Note
Efficiency improved reducing switching regulator power dissipation factors follows: Dissipation factors: resistance dissipation inductor FETPD(I Gate charge/discharge dissipationPD(Gate) Switching dissipationPD(SW) dissipation capacitorPD(ESR) Operating current dissipation ICPD(IC)
1)PD(I R)=IOUT (RCOIL[]DC resistance inductor, RON[]ON resistance FET, IOUT[A]Output current.) (Cgs[F]Gate capacitance FET, f[H]Switching frequency, V[V]Gate driving voltage FET) 3)PD(SW)= (CRSS[F]Reverse transfer capacitance FET, IDRIVE[A]Peak current gate.) IDRIVE 4)PD(ESR)=IRMS (IRMS[A]Ripple current capacitor, ESR[]Equivalent series resistance.) (ICC[A]Circuit current.)
Consideration permissible dissipation heat generation this functions with high efficiency without significant heat generation most applications, special consideration needed permissible dissipation heat generation. case extreme conditions, however, including lower input voltage, higher output voltage, heavier load, and/or higher temperature, permissible dissipation and/or heat generation must carefully considered. dissipation, only conduction losses resistance inductor resistance considered. Because conduction losses considered play leading role among other dissipation mentioned above including gate charge/discharge dissipation switching dissipation.
ROHM standard layer board Board j-a=189.4/W
0.66W Power dissipation:Pd
duty (=VOUT/VCC) RCOILDC resistance coil RONPON resistance P-channel RONNON resistance N-channel IOUTOutput current
Ambient temperature:Ta
Fig.27 Thermal derating curve (VCSP50L2) VCC=3.3V, VOUT=1.5V, RONP=0.3, RONN=0.2 IOUT=0.3A, example, D=VOUT/VCC=1.5/3.3=0.45 =0.135+0.11 =0.245[] RONP greater than RONN this dissipation increases duty becomes greater. With consideration dissipation above, thermal design must carried with sufficient margin allowed.
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8/13
2009.05 Rev.A
BD9122GUL
Selection components externally connected Selection inductor
Technical Note
inductance significantly depends output ripple current. seen equation (1), ripple current decreases inductor and/or switching frequency increases. [A](1)
VOUT
Appropriate ripple current output should more less maximum output current. [A](2) [H](3) (IL: Output ripple current, Switching frequency)
Fig.28 Output ripple current Current exceeding current rating inductor results magnetic saturation inductor, which decreases efficiency. inductor must selected allowing sufficient margin with which peak current exceed current rating. Select inductor resistance component (such ACR) minimize dissipation inductor better efficiency. Selection output capacitor (CO)
Output capacitor should selected with consideration stability region equivalent series resistance required smooth ripple voltage. Output ripple voltage determined equation
VOUT
[V](4) (IL: Output ripple current, ESR: Equivalent series resistance output capacitor) Rating capacitor should determined allowing sufficient margin against output voltage. Less allows reduction output ripple voltage.
Fig.29 Output capacitor output rise time must designed fall within soft-start time, capacitance output capacitor should determined with consideration requirements equation (5): Tss: Soft-start time Ilimit: Over current detection level, 1A(Typ) VOUT VOUT=1.5V, IOUT=0.3A, TSS=1ms, Inappropriate capacitance cause problem startup. 100F ceramic capacitor recommended. Selection input capacitor (Cin)
Input capacitor select must capacitor capacitance sufficient cope with high ripple current prevent high transient voltage. ripple current IRMS given equation (6):
VOUT
OUT(VCC-VOUT)
[A](6) IOUT
Worst case IRMS(max.) VCC=3.3V, VOUT=1.5V, IOUTmax.=0.3A 1.5(3.3-1.5) When twice VOUT, IRMS=
Fig.30 Input capacitor
=0.15[ARMS] 10F/10V ceramic capacitor recommended reduce dissipation input capacitor better efficiency.
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9/13
2009.05 Rev.A
BD9122GUL
Technical Note
Determination RITH, CITH that works phase compensator Current Mode Control designed limit inductor current, pole (phase lag) appears frequency area filter consisting output capacitor load resistance, while zero (phase lead) appears high frequency area output capacitor ESR. phases easily compensated adding zero power amplifier output with described below cancel pole power amplifier.
fp(Min.) Gain [dB] fp(Max.) IOUTMin. IOUTMax. fz(ESR)
fz(ESR)= Pole power amplifier When output current decreases, load resistance increases pole frequency lowers. fp(Min.)= [Hz]with lighter load
Phase [deg]
Fig.31 Open loop gain characteristics fp(Max.)= [Hz] with heavier load
Gain [dB]
fz(Amp.)
Zero power amplifier Increasing capacitance output capacitor lowers pole frequency while zero frequency does change. (This because when capacitance doubled, capacitor reduces half.) fz(Amp.)=
Phase [deg]
Fig.32 Error phase compensation characteristics
VOUT VOUT RITH CITH
VCC,PVCC
VOUT
GND,PGND
Fig.33 Typical application Stable feedback loop achieved canceling pole (Min.) produced output capacitor load resistance with zero correction error amplifier. fz(Amp.)= fp(Min.)
Determination output voltage output voltage VOUT determined equation (7): VADJ: Voltage terminal (0.8V Typ.) With adjusted, output voltage determined required.
Output
Adjustable output voltage range 1.0V2.0V k100 resistor resistor resistance higher than used, check assembled carefully ripple voltage etc.
Fig.34 Deter mination output voltage
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10/13
2009.05 Rev.A
BD9122GUL
Cautions Board layout VOUT PVcc Fig.35 Layout diagram PGND CITH RITH
Technical Note
sections drawn with heavy line, thick conductor pattern short possible. input ceramic capacitor closer pins PVCC PGND, output capacitor closer PGND. CITH RITH between pins neat possible with least necessary wiring.
Recommended components Lists above application Symbol Part Value Coil 2.2uH Ceramic capacitor 10uF Ceramic capacitor 10uF VOUT=1.0V VOUT=1.2V CITH Ceramic capacitor VOUT=1.5V VOUT=1.8V VOUT=2.0V VOUT=1.0V VOUT=1.2V RITH Resistance VOUT=1.5V VOUT=1.8V VOUT=2.0V
Manufacturer murata murata 2200pF murata 1000pF 6.8k ROHM 4.7k
Series MIPF2016D2R2 GRM188B30J106ME47B GRM188B30J106ME47B
GRM15 Series
MCR006 6801 MCR006 4701
parts list presented above example recommended parts. Although parts sound, actual circuit characteristics should checked your application carefully before use. sure allow sufficient margins accommodate variations between external devices this when employing depicted circuit with other circuit constants modified. Both static transient characteristics should considered establishing these margins. When switching noise substantial impact system, pass filter should inserted between PVCC pins, schottky barrier diode established between PGND pins.
equivalent circuit
PVCC PVCC PVCC
Fig.36 equivalent circuit
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11/13
2009.05 Rev.A
BD9122GUL
Technical Note
Cautions Absolute Maximum Ratings While utmost care taken quality control this product, application that exceed some absolute maximum ratings including voltage applied operating temperature range result breakage. broken, short-mode open-mode identified. expected encounter with special mode that exceed absolute maximum ratings, requested take necessary safety measures physically including insertion fuses. Electrical potential must designed have lowest electrical potential operating conditions. Short-circuiting between terminals, mismounting When mounting board, care must taken avoid mistake orientation alignment. Failure result breakdown. Short-circuiting foreign matters entered between output terminals, between output power supply also cause breakdown. 4.Operation Strong electromagnetic field noted that using strong electromagnetic radiation cause operation failures. Thermal shutdown protection circuit Thermal shutdown protection circuit circuit designed isolate from thermal runaway, intended protect guarantee thermal shutdown protection circuit which once activated should used thereafter operation originally intended. Inspection with board capacitor must connected lower impedance during inspection with board, capacitor must discharged after each process avoid stress electrostatic protection, provide proper grounding assembling processes with special care taken handling storage. When connecting jigs inspection process, sure turn power supply before connected removed. Input terminals This monolithic with isolation between P-substrate each element illustrated below. This P-layer N-layer each element form junction, various parasitic element formed. resistor joined transistor terminal shown junction works parasitic diode following relationship satisfied; GND>Terminal resistor side), GND>Terminal transistor side); GND>Terminal transistor side), parasitic transistor activated N-layer other element adjacent above-mentioned parasitic diode. structure inevitably forms parasitic elements, activation which cause interference among circuits, and/or malfunctions contributing breakdown. therefore requested take care device such manner that voltage lower than P-substrate) applied input terminal, which result activation parasitic elements.
Resistor
Transistor (NPN)
Parasitic element
substrate Parasitic element
substrate Parasitic element
Parasitic element
Other adjacent elements
Fig.37 Simplified structure monorisic Ground wiring pattern small-signal large-current provided, will recommended separate large-current pattern from small-signal pattern establish single ground reference point that resistance wiring pattern voltage fluctuations large current will cause fluctuations voltages small-signal GND. attention cause fluctuations wiring pattern external parts well.
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12/13
2009.05 Rev.A
BD9122GUL
Ordering part number
Technical Note
Part 9122
Part
Package GUL: VCSP50L2
Packaging forming specification Embossed tape reel (VCSP50L2)
VCSP50L2 <Dimension>
<Tape Reel information>
Tape Quantity Direction feed Embossed carrier tape 3000pcs
(The direction 1pin product upper left when hold reel left hand pull tape right hand.)
1234
1234
1234
1234
1234
1234
(Unit:mm)
Reel
1Pin
Direction feed
When order please order times amount package quantity.
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13/13
2009.05 Rev.A
Notice
Notes
copying reproduction this document, part whole, permitted without consent ROHM Co.,Ltd. content specified herein subject change improvement without notice. content specified herein purpose introducing ROHM's products (hereinafter "Products"). wish such Product, please sure refer specifications, which obtained from ROHM upon request. Examples application circuits, circuit constants other information contained herein illustrate standard usage operations Products. peripheral conditions must taken into account when designing circuits mass production. Great care taken ensuring accuracy information specified this document. However, should incur damage arising from inaccuracy misprint such information, ROHM shall bear responsibility such damage. technical information specified herein intended only show typical functions examples application circuits Products. ROHM does grant you, explicitly implicitly, license exercise intellectual property other rights held ROHM other parties. ROHM shall bear responsibility whatsoever dispute arising from such technical information. Products specified this document intended used with general-use electronic equipment devices (such audio visual equipment, office-automation equipment, communication devices, electronic appliances amusement devices). Products specified this document designed radiation tolerant. While ROHM always makes efforts enhance quality reliability Products, Product fail malfunction variety reasons. Please sure implement your equipment using Products safety measures guard against possibility physical injury, fire other damage caused event failure Product, such derating, redundancy, fire control fail-safe designs. ROHM shall bear responsibility whatsoever your Product outside prescribed scope accordance with instruction manual. Products designed manufactured used with equipment, device system which requires extremely high level reliability failure malfunction which result direct threat human life create risk human injury (such medical instrument, transportation equipment, aerospace machinery, nuclear-reactor controller, fuel-controller other safety device). ROHM shall bear responsibility Products above special purposes. Product intended used such special purpose, please contact ROHM sales representative before purchasing. intend export ship overseas Product technology specified herein that controlled under Foreign Exchange Foreign Trade Law, will required obtain license permit under Law.
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Output 0.5A Less High Efficiency Step-down Switching Regulator with Bu

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