PC1935 DC-DC CONVERTER CONTROL DESCRIPTION PC1935 low-v

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PC1935 DC-DC CONVERTER CONTROL DESCRIPTION PC1935 low-v

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BiCMOS INTEGRATED CIRCUIT
PC1935
DC-DC CONVERTER CONTROL
DESCRIPTION
PC1935 low-voltage input DC-DC converter control that configure three-output (step-up inverted output DC-DC converter input voltage 3.3, Because wide operating voltage range, this also used control DC-DC converters using adapter input.
FEATURES
supply voltage: (MIN.) Operating voltage range: (breakdown voltage: control three output channels. Timer latch circuit short-circuit protection. Ceramic capacitor with capacitance (0.1 used short-circuit protection. Dead times channels (step-up) (inverted output) from external resistors. Dead time channel (step-up) internally fixed Soft start each channel independently. Each channel turned ON/OFF independently.
ORDERING INFORMATION
Part Number Package 16-pin plastic TSSOP (5.72 (225))
PC1935GR
information this document subject change without notice. Before using this document, please confirm that this latest version.
devices/types available every country. Please check with local representative availability additional information.
Document G13418EJ3V0DS00 (3rd edition) Date Published March 2000 Printed Japan
mark shows major revised points. 1998
PC1935
BLOCK DIAGRAM
Channel inversion DTC3 OUT3 DTC2 Channel step-up OUT2
Internal fixed voltage
Internal fixed voltage
Soft start select switch
Internal fixed voltage
Reference voltage section
Oscillation section
Timer latch short-circuit protection section
Internal fixed voltage Channel step-up OUT1
VREF
Data Sheet G13418EJ3V0DS00
PC1935
CONFIGURATION (Top view)
16-pin plastic TSSOP (5.72 (225)) PC1935GR
VREF OUT1
DTC3 OUT3 DTC2 OUT2
FUNCTIONS
Symbol VREF Power supply Reference voltage output Frequency setting resistor connection Ground Short-circuit protection/channel soft start capacitor connection OUT1 Channel error amplifier inverted input Channel error amplifier output Channel open-drain output DTC3 Channel error amplifier output Channel error amplifier inverted input Channel dead time setting Function Symbol OUT2 DTC2 OUT3 Function Channel open-drain output Channel error amplifier output Channel error amplifier inverted input Channel dead time setting Channel open-drain output
Data Sheet G13418EJ3V0DS00
PC1935
CONTENTS ELECTRICAL SPECIFICATIONS CONFIGURATION OPERATION EACH BLOCK.
Reference Voltage Generator Oscillator Under Voltage Lock-out Circuit Error Amplifiers.12 Comparators.12 Timer Latch-Method Short Circuit Protection Circuit Output Circuit.13
NOTES USE.
Setting Output Voltage Setting Oscillation Frequency Preventing Malfunction Timer Latch-Method Short Circuit Protection Circuit.15 Connecting Unused Error Amplifiers ON/OFF Control.17 3.5.1 Channel (for step-up) 3.5.2 Channel (for step-up) 3.5.3 Channel (for inverted output) Maximum Duty Limit Notes Actual Pattern Wiring.20
APPLICATION EXAMPLE
Application Example.21 List External Parts
PACKAGE DRAWING RECOMMENDED SOLDERING CONDITIONS
Data Sheet G13418EJ3V0DS00
PC1935
ELECTRICAL SPECIFICATIONS
Absolute Maximum Ratings (unless otherwise specified,
Parameter Supply voltage Output voltage Output current (open drain output) Total power dissipation Operating ambient temperature Storage temperature Symbol Tstg Ratings Unit
Caution
Product quality suffer absolute maximum rating exceeded even momentarily parameter. That absolute maximum ratings rated values which product verge suffering physical damage, therefore product must used under conditions that ensure that absolute maximum ratings exceeded.
Recommended Operating Conditions
Parameter Supply voltage Output voltage Output current Operating temperature Oscillation frequency Symbol fOSC MIN. TYP. MAX. Unit
Caution
recommended operating range exceeded without causing problems provided that absolute maximum ratings exceeded. However, device operated that exceeds recommended operating conditions, margin between actual conditions absolute maximum ratings small, therefore thorough evaluation necessary. recommended operating conditions imply that device used with values their maximum values.
Data Sheet G13418EJ3V0DS00
PC1935
Electrical Characteristics (unless otherwise specified, fOSC kHz)
Block Under voltage lock-out section Reference voltage section Parameter Start-up voltage Operation stop voltage Hysteresis voltage Reset voltage (timer latch) Reference voltage Line regulation Load regulation Temperature coefficient Oscillation section fOSC setting accuracy fOSC total stability Symbol (L-H) (H-L) VCCR VREF REGIN REGL VREF/T fOSC fOSC Conditions IREF IREF IREF IREF IREF VVCC20 mAIREF1 °CTA+85 IREF °CTA+85 Duty setting section Input bias current Channel maximum duty Channel soft start time Low-level threshold voltage DMAX. CDLY Duty (channels and2) Duty (channel High-level threshold voltage Duty (channel Duty (channel Error amplifier section Input threshold voltage Input bias current Open loop gain Unity gain Maximum output voltage Maximum output voltage Maximum sink current Output source current Output section Output voltage Rise time Fall time Short-circuit protection section sense voltage Source current short-circuiting Delay time Overall Circuit operation current Input sense voltage VITH funity
MIN.
TYP. 1.57
MAX.
Unit
12.5
VVCC20
(Channels only)
0.285 -100
0.315 +100
Channels Channel 1.75
0.02 0.63 2.05 0.75 0.85
IOsink IOsource VTH1, VTH2 VTH3 IOUV tDLY
CDLY
Caution Connect capacitor 0.01 VREF pin.
PC1935
CREF 0.01
Data Sheet G13418EJ3V0DS00
Timing Charts (sequence operation power application channel channel channel
Channel
OUT1 Channel starts.
Data Sheet G13418EJ3V0DS00
Channel DTC2
OUT2 Channel starts.
DTC3
Channel
OUT3 Channel starts.
PC1935
PC1935
Typical Characteristic Curves (unless otherwise specified, fOSC kHz, (Nominal)
Total power dissipation
VREF
Reference voltage VREF
IREF
312.5 °C/W
Operating ambient temperature (°C)
Supply voltage
VREF 2.13
Reference voltage VREF
fOSC 1000
Oscillation frequency fOSC (kHz)
IREF
2.12 2.11 2.10 2.09 2.08 2.07 Operating ambient temperature (°C) fOSC
Timing resistance
Output voltage
Oscillation frequency accuracy fOSC
Operational ambient temperature (°C)
Output current (mA)
Data Sheet G13418EJ3V0DS00
PC1935
DMAX.
Channel maximum duty DMAX.
Output voltage
Operating ambient temperature (°C)
Timing resistance
High-level threshold voltage
1.62
Low-level threshold voltage
1.64
1.24 1.22
1.60
1.20
1.58
1.18
1.56 Operating ambient temperature (°C) CDLY
1.16 Operating ambient temperature (°C) tDLY CDLY
Short-circuit protection circuit delay time tDLY (ms)
Channel soft start time (ms)
capacitor capacitance CDLY
capacitor capacitance CDLY
Data Sheet G13418EJ3V0DS00
PC1935
tDLY CDLY
Delay time tDLY (ms)
Operating ambient temperature (°C)
Gain (dB)
Frequency (Hz)
Circuit operation (mA)
Circuit operation (mA)
Operating ambient temperature (°C)
Supply voltage
Data Sheet G13418EJ3V0DS00
Phase (deg)
PC1935
CONFIGURATION OPERATION EACH BLOCK
Figure Block Diagram
(common each channel)
Oscillation section Error amplifier DTC2 Error amplifier DTC3 Error amplifier VREF
OUT1
comparator
Output section
OUT2
comparator
Output section
OUT3
comparator Under voltage lock-out section
Output section
Reference voltage section
Dead time setting: (internally fixed)
comparator 0.63
Soft start select switch CDLY
Timer latch short-circuit protection section
Data Sheet G13418EJ3V0DS00
PC1935
Reference Voltage Generator
reference voltage generator comprised band-gap reference circuit, outputs temperature-compensated reference voltage (2.1 reference voltage used power supply internal circuits, reference voltage, also accessed externally VREF (pin
Oscillator
oscillator self-oscillates timing resistor attached (pin This oscillator waveform input inverted input pins (channel non-inverted input (channel three comparators determine oscillation frequency.
Under Voltage Lock-out Circuit
under voltage lock-out circuit prevents malfunctioning internal circuits when supply voltage low, such when supply voltage first applied, when power supply interrupted. When voltage low, three output transistors same time.
Error Amplifiers
non-inverted input pins error amplifiers E/A1, E/A2, E/A3 connected internally (the input threshold voltages (TYP .)). circuits error amplifiers E/A1, E/A2, E/A3 exactly same. first stage error amplifier P-channel transistor input.
Comparators
output duty controlled according outputs error amplifiers voltage input Dead Time Control (fixed internally channel triangular waveform input inverted pin, error amplifier output Dead Time Control voltage (fixed internally channel input non-inverted pins comparators channel channel Therefore, output transistor period period when triangular waveform lower than error amplifier output Dead Time Control voltage (fixed internally channel Channel logical inverse channel channel Consequently, triangular waveform input noninverted input pin, error amplifier output Dead Time Control voltage input inverted input pins comparator channel Therefore, transistor period period when triangular waveform higher than error amplifier output Dead Time Control voltage (refer Timing Charts).
Data Sheet G13418EJ3V0DS00
PC1935
Timer Latch-Method Short Circuit Protection Circuit
When outputs converters each channel drop, outputs error amplifiers those outputs high (FB3 output goes low). output exceeds timer latch input detection voltage (VTH (FB3 output goes lower than timer latch input detection voltage (VTH 0.63 V)), then output comparator goes low, goes off. When turns OFF, constant-current supply charges CDLY pin. internally connected flip-flop. When voltage reaches detection voltage (VUV (TYP output flip-flop goes .)), low, output stage each channel latched (refer Figure Block Diagram). logic channels reverse that channel Consequently, inverter circuit inserted between output channels comparator input. Make power supply voltage briefly less than reset voltage (VCCR, reset latch circuit when short-circuit protection circuit operated.
Output Circuit
output circuit N-channel open-drain output providing output withstand voltage (absolute maximum rating), output current (absolute maximum rating).
Data Sheet G13418EJ3V0DS00
PC1935
NOTES
Setting Output Voltage
Figure illustrates method setting output voltage. output voltage obtained using formula shown figure. input threshold value error amplifier (TYP error amplifiers, E/A1, E/A2, E/A3. Therefore, select resistor value that gives this voltage.
Figure Setting Output Voltage
When setting positive output voltage using error amplifier E/A1.
VOUT (positive voltage)
VOUT
E/A1
When setting positive output voltage using error amplifier E/A2.
VOUT (positive voltage)
VOUT
E/A2
Data Sheet G13418EJ3V0DS00
PC1935
When setting negative output voltage using error amplifier E/A3.
VREF
E/A3
VOUT (negative voltage)
VOUT
VREF
Setting Oscillation Frequency
Choose according oscillation frequency (fOSC) timing resistor (RT) characteristics (refer Typical Characteristics Curves fOSC RT). formula below (3-1) gives approximation fOSC. However, result formula only approximation, value must confirmed actual operation, especially high-frequency operation.
fOSC[Hz] 1.856 109/RT[]
(3-1)
Preventing Malfunction Timer Latch-Method Short Circuit Protection Circuit
timer latch short-circuit protection circuit operates when error amplifier outputs channel channel (pin exceed approximately when error amplifier output channel (pin goes below approximately 0.63 cuts output. However, rise power supply voltage fast, there noise (pin latch circuit malfunction output off. prevent this, keep wiring impedance between (pin low, avoid applying noise pin.
Data Sheet G13418EJ3V0DS00
PC1935
Connecting Unused Error Amplifiers
When unused circuit three control circuits provided internally error amplifier E/A2, connect circuit such make sure that output error amplifier low. When unused circuit error amplifier E/A3, connect circuit such make sure that output error amplifier high. case error amplifier E/A1, Dead Time Control fixed internally, sure always this amplifier. Figure shows examples connect unused error amplifiers.
Figure Examples Connecting Unused Error Amplifiers
Error amplifier E/A2
VREF
E/A2
DTC2
Error amplifier E/A3
VREF
E/A3
DTC3
Data Sheet G13418EJ3V0DS00
PC1935
ON/OFF Control
3.5.1
Channel (for step-up)
ON/OFF signal control method output oscillation channel input ON/OFF signal from shown Figure 3-3. channel soft start timer latch (SCP) internally selected. Soft start executed when first start signal input. When soft start detected, soft start select switch turned timer latch circuit operates.
Figure ON/OFF Control (channel step-up)
(Converter output voltage)
comparator (common each channel) Error amplifier
Dead time setting: (internally fixed) VREF
0.63
output stage comparator
CDLY
Oscillation section (common each channel)
When high: status Q11: pin: level Output duty comparator: D11: pin: High level output: level
When low: status (start Q11: CDLY charged sequence [VREF CDLY] Soft start D11: pin: level output: High level
When goes high again after start (SW: OFF): status Q11: pin: level (Nothing happens because OFF.) D11: pin: High level output: level comparator output duty: Converter output voltage (VO1) drops.
Caution Even start executed making again after (3), soft start executed because soft start select switch (SW) remains OFF. execute soft start channel again, drop once.
Data Sheet G13418EJ3V0DS00
PC1935
3.5.2 Channel (for step-up)
ON/OFF signal control method output oscillation channel input ON/OFF signal from shown Figure 3-4. converter turned ON/OFF controlling level DTC2 pin. However, necessary keep level output (the comparator input high) that timer latch does start when converter OFF. this circuit example, output level controlled controlling level pin.
Figure ON/OFF Control (channel step-up)
(Converter output voltage)
comparator (common each channel)
CDLY
Error amplifier
0.63 VREF DTC2 output stage
comparator
Oscillation section (common each channel)
When high: status Q21: DTC2 pin: level Output duty comparator: D21: pin: High level output: level comparator output: High level Timer latch stops.
When low: status Q21: charged sequence [VREF C21] DTC2 voltage rises Soft start D21: pin: level output: High level comparator output: level Charging CDLY starts (timer latch start).
Caution Keep low-level voltage DTC2 within high-level voltage higher. maximum voltage that applied must equal lower than VREF.
Data Sheet G13418EJ3V0DS00
PC1935
3.5.3 Channel (for inverted output)
ON/OFF signal control method output oscillation channel input ON/OFF signal from shown Figure 3-5. converter turned ON/OFF controlling level DTC3 pin. However, necessary keep level output high that timer latch does start when converter OFF. this circuit example, output level controlled controlling level pin. Because channel supports inverted converter, comparator logic different from that channels
Figure ON/OFF Control (channel inverted output)
VREF
comparator (common each channel)
CDLY
-VO3 (Converter output voltage) VREF DTC3
Error amplifier
0.63
output stage
comparator
Oscillation section (common each channel)
When high: status Q31: Q32: DTC3 pin: High level Output duty comparator: Q33: pin: level output: High level comparator output: High level Timer latch stops.
When low: status Q31: OFF. charged sequence [VREF R34] DTC3 voltage drops. Soft start Q33: pin: High level output: level comparator output: level Charging CDLY starts (timer latch start).
Caution
Keep high-level voltage DTC3 higher low-level voltage within maximum voltage that applied must equal lower than VREF.
Data Sheet G13418EJ3V0DS00
PC1935
Maximum Duty Limit
Channel switched internally between Soft Start Timer Latch. this reason, voltage fixed internally, maximum duty limited 85%. voltage channel channel externally, maximum duty limited.
Notes Actual Pattern Wiring
When actually carrying pattern wiring, necessary separate control-related grounds power-related grounds, make sure that they share impedances possible. addition, make sure high-frequency impedance lowered using capacitors other components prevent noise input VREF pin.
Data Sheet G13418EJ3V0DS00
Application Example
R210 R212 R310 R312
R211
APPLICATION EXAMPLE
3300 1SS220 R213 R311
VR26
VR23
DTC3
3300 R313 VR33 OUT3 DTC2 OUT2
VR36
PC1935
VREF VR13 OUT1
Figure Chopper-Method/Inverting-Type Switching Regulator
Figure shows example circuit obtaining V/50 V/50 from power supply.
Data Sheet G13418EJ3V0DS00
1SS220 R214 R111 ON/OFF R112 ON/OFF R215 R110 3300
R314
ON/OFF
R315
PC1935
PC1935
List External Parts
list below shows external parts.
Table List External Parts
Symbol Parameter Function Output capacitor Schottkey diode Choke inductor Switching transistor Buffer transistor Buffer transistor Switching diode Transistor switch Output capacitor Schottkey diode Choke inductor Switching transistor Buffer transistor Buffer transistor Switching diode Transistor switch Output capacitor Schottkey diode Choke inductor Switching transistor Buffer transistor Buffer transistor Transistor switch Transistor switch Transistor switch Part number 20SA68M D1FS4 636FY-470M 2SD2403 2SA812 2SC1623 1SS220 2SK2158 20SA68M D1FS4 636FY-470M 2SD2403 2SA812 2SC1623 1SS220 2SK2158 20SA68M D1FS4 636FY-470M 2SB1572 2SA812 2SC1623 2SA812 2SC1623 2SC1624 Maker SANYO SHINDENGEN TOKO SANYO SHINDENGEN TOKO SANYO SHINDENGEN TOKO D73F series OS-CON, series D73F series OS-CON, series D73F series Remark OS-CON, series
Remarks capacitors that specified above list multilayer ceramic capacitors. resistors that specified above list 1/4W resistors.
Data Sheet G13418EJ3V0DS00
PC1935
PACKAGE DRAWING
16-PIN PLASTIC TSSOP (5.72 (225))
detail lead
NOTE
Each lead centerline located within 0.10 true position (T.P.) maximum material condition.
ITEM
MILLIMETERS 5.15±0.15 5.0±0.1 0.375 MAX. 0.65 (T.P.) 0.24 +0.06 -0.04 0.09 +0.06 -0.04 1.01 +0.09 -0.06 0.92 6.4±0.2 4.4±0.1 1.0±0.2 0.145+0.055 -0.045 0.10 0.10 0.25 0.6±0.15 S16GR-65-PJG-1
Data Sheet G13418EJ3V0DS00
PC1935
RECOMMENDED SOLDERING CONDITIONS
Recommended solder conditions this product described below. details recommended soldering conditions, refer Information Document "Semiconductor Device Mounting Technology Manual" (C10535E). soldering methods conditions other than those recommended, consult NEC.
Surface Mount Type
PC1935GR: 16-pin plastic TSSOP (5.72 (225))
Soldering Method Soldering Conditions Symbol Recommended Conditions Infrared reflow Package peak temperature: Time: seconds MAX. (210 MIN.), Number times: MAX. Package peak temperature: Time: seconds MAX. (200 MIN.), Number times: MAX. Wave soldering Soldering bath temperature: MAX., Time: seconds MAX., Number times: Preheating temperature: MAX. (package surface temperature) WS60-00-1 VP15-00-3 IR35-00-3
Caution more soldering methods combination.
Data Sheet G13418EJ3V0DS00
PC1935
[MEMO]
Data Sheet G13418EJ3V0DS00
PC1935
[MEMO]
Data Sheet G13418EJ3V0DS00
PC1935
NOTES BiCMOS DEVICES
PRECAUTION AGAINST SEMICONDUCTORS Note:
Strong electric field, when exposed device, cause destruction gate oxide ultimately degrade device operation. Steps must taken stop generation static electricity much possible, quickly dissipate once, when occurred. Environmental control
must adequate. When dry, humidifier should used. recommended avoid using insulators that easily build static electricity. Semiconductor devices must stored transported anti-static container, static shielding conductive material. test measurement tools including work bench floor should grounded. operator should grounded using wrist strap. Semiconductor devices must touched with bare hands. Similar precautions need taken boards with semiconductor devices HANDLING UNUSED INPUT PINS Note:
connection device inputs cause malfunction. connection provided input pins, possible that internal input level generated noise, etc., hence causing malfunction. Input levels devices must fixed high using pull-up pulldown circuitry. Each unused should connected with resistor, considered have possibility being output pin. handling related unused pins must judged device device related specifications governing devices.
STATUS BEFORE INITIALIZATION BiCMOS DEVICES Note:
Power-on does necessarily define initial status device. Production process BiCMOS does define initial operation status device. Immediately after power source turned devices with reset function have been initialized. Hence, power-on does guarantee out-pin levels, settings contents registers. Device initialized until reset signal received. Reset operation must executed immediately after power-on devices having reset function.
Data Sheet G13418EJ3V0DS00
PC1935
[MEMO]
information this document subject change without notice. Before using this document, please confirm that this latest version. part this document copied reproduced form means without prior written consent Corporation. Corporation assumes responsibility errors which appear this document. Corporation does assume liability infringement patents, copyrights other intellectual property rights third parties arising from device described herein other liability arising from such device. license, either express, implied otherwise, granted under patents, copyrights other intellectual property rights Corporation others. Descriptions circuits, software, other related information this document provided illustrative purposes semiconductor product operation application examples. incorporation these circuits, software, information design customer's equipment shall done under full responsibility customer. Corporation assumes responsibility losses incurred customer third parties arising from these circuits, software, information. While Corporation been making continuous effort enhance reliability semiconductor devices, possibility defects cannot eliminated entirely. minimize risks damage injury persons property arising from defect semiconductor device, customers must incorporate sufficient safety measures design, such redundancy, fire-containment, anti-failure features. devices classified into following three quality grades: "Standard", "Special", "Specific". Specific quality grade applies only devices developed based customer designated "quality assurance program" specific application. recommended applications device depend quality grade, indicated below. Customers must check quality grade each device before using particular application. Standard: Computers, office equipment, communications equipment, test measurement equipment, audio visual equipment, home electronic appliances, machine tools, personal electronic equipment industrial robots Special: Transportation equipment (automobiles, trains, ships, etc.), traffic control systems, anti-disaster systems, anti-crime systems, safety equipment medical equipment (not specifically designed life support) Specific: Aircraft, aerospace equipment, submersible repeaters, nuclear reactor control systems, life support systems medical equipment life support, etc. quality grade devices "Standard" unless otherwise specified NEC's Data Sheets Data Books. customers intend devices applications other than those specified Standard quality grade, they should contact sales representative advance.

PC1935 DC-DC CONVERTER CONTROL DESCRIPTION PC1935 low-v

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