ROHM BD8157EFV Technical data
Power Supply IC Series for TFT-LCD Panels
ingleS -channel Source Voltage
Output Power Supply + Gamma Buffer Amp ICs
BD8151EFV,BD8157EFV
●Description
The BD8151EFV,BD8157EFV power supply IC are designed for use with TFT-LCD panels. It incorporates a built-in source
voltage step-up switching regulator and gamma correction buffer amp. The combination of a source power supply and
gamma correction buffer on a single chip delivers significant cost savings.
Compatible with input voltages from 2.5 V to 5.5 V (BD8151EFV), 2.1 V to 4.0 V (BD8157EFV), the IC supports low-voltage
operation and reaches over 85% efficiency with a 2.5 V input, contributing to low power consumption designs.
●Features
1) Single-chip implementation of a source power supply and gamma correction buffer
2) Support for low-voltage operation, with input voltages from 2.5 V to 5.5 V (BD8151EFV)
2.1 V to 4.0 V (BD8157EFV)
3) Built-in 1.4 A, 0.2 low-voltage FET
4) Switchable step-up DC/DC switching frequencies: 600 kHz/1.2 MHz
5) Current mode PWM control
6) Under-voltage lockout protection circuit
7) Built-in overcurrent protection circuit
8) Built-in thermal shutdown circuit
●Applications
Satellite navigation systems, laptop PC TFT LCD panels
LCD monitor panels
●Absolute maximum ratings (Ta = 25℃)
Parameter Symbol Limit Unit
Power supply voltage Vcc 7 V
Power dissipation Pd 1000* mW
Operating temperature range
Storage temperature range Tstg −55 to +150 ℃
Switching pin current Isw 1.5** A
Switching pin voltage Vsw 15 V
VS voltage VS 15 V
Maximum junction temperature Tjmax 150 °C
* Reduced by 8 mW/℃ over 25℃, when mounted on a glass epoxy board (70 mm x 70 mm x 1.6 mm).
** Must not exceed Pd.
●Recommended Operating Ranges (Ta = 25℃)
Parameter Symbol
Power supply voltage BD8151EFV Vcc 2.5 3.3 5.5 V
Power supply voltage BD8157EFV Vcc 2.1 2.5 4.0 V
Switching current ISW — — 1.4 A
Switching pin voltage VSW — — 14 V
VS pin voltage VS 5 9 14 V
BD8151EFV
BD8157EFV −40 to +125
Topr
Min. Typ. Max.
−40 to +85
Limit
No.09035EBT11
℃
Unit
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1/17
2009.07 - Rev.B
BD8151EFV, BD8157EFV
●Electrical Characteristics BD8151EFV (Unless otherwise specified, Ta = 25℃; Vcc = 3.3V, ENB = 3.3V)
Parameter Symbol
[Triangular waveform oscillator]
Oscillating frequency 1 FOSC1 540 600 660 kHz FCLK = 0 V
Oscillating frequency 2 FOSC2 1.08 1.20 1.32 MHz FCLK = Vcc
[Overcurrent protection circuit]
Overcurrent limit ISW — 2 — A
[Soft start circuit]
SS source current ISO 6 10 14 µA Vss = 0.5 V
[Under-voltage lockout protection circuit]
Off threshold voltage VUTOFF 2.1 2.2 2.3 V
On threshold voltage VUTON 2.0 2.1 2.2 V
[Error amp]
Input bias current IB — 0.1 0.5 µA
Feedback voltage VFB 1.232 1.245 1.258 V Buffer
[Output]
On resistance RON — 200 300 mΩ *Isw = 1 A
Max. duty ratio DMAX 72 80 88 % RL = 100 Ω
[ENB]
ENB on voltage VON Vcc × 0.7 Vcc — V
ENB off voltage VOFF — 0 Vcc × 0.3 V
[Overall]
Standby current ISTB — 0 10 μA VENB = 0 V
Average consumption current ICC — 1.2 2.4 mA no switching
[Amp]
Input bias current Ibo −1 0 1 μA IN += 4.5 V
Drive current 1 IOO1 50 70 140 mA OUT1 to OUT4
Drive current 2 IOO2 150 200 400 mA VCOM
Max. output current Voho VS-0.16 VS-0.1 — V Io = −5 mA, IN += VS
Min. output current Vohl — 0.1 0.16 V Io = 5 mA, IN += 0 V
This product is not designed for protection against radio active rays.
* Design guarantee (No total shipment inspection is made.)
Min. Typ. Max.
Limit
Unit Conditions
Technical Note
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2/17
2009.07 - Rev.B
BD8151EFV, BD8157EFV
●Electrical Characteristics BD8157EFV (Unless otherwise specified, Ta = 25℃; Vcc = 2.5V, ENB = 2.5V)
Parameter Symbol
[Triangular waveform oscillator]
Oscillating frequency 1 FOSC1 480 600 720 kHz FCLK = 0 V
Oscillating frequency 2 FOSC2 0.96 1.20 1.44 MHz FCLK = Vcc
[Overcurrent protection circuit]
Overcurrent limit ISW — 2 — A
[Soft start circuit]
SS source current ISO 6 10 14 µA Vss = 0.5 V
[Under-voltage lockout protection circuit]
Off threshold voltage VUTOFF 1.7 1.8 1.9 V
On threshold voltage VUTON 1.6 1.7 1.8 V
[Error amp]
Input bias current IB — 0.1 0.5 µA
Feedback voltage VFB 1.232 1.245 1.258 V Buffer
[Output]
On resistance RON — 200 600 mΩ *Isw = 1 A
Max. duty ratio DMAX 75 85 95 % RL = 100 Ω
[ENB]
ENB on voltage VON Vcc × 0.7 Vcc — V
ENB off voltage VOFF — 0 Vcc × 0.3 V
[Overall]
Standby current ISTB — 0 10 μA VENB = 0 V
Average consumption current ICC — 1.2 2.4 mA no switching
[Amp]
Input bias current Ibo −1 0 1 μA IN += 4.5 V
Drive current 1 IOO1 50 70 140 mA OUT1 to OUT4
Drive current 2 IOO2 120 200 400 mA VCOM
Max. output current Voho VS-0.16 VS-0.1 — V Io = −5 mA, IN += VS
Min. output current Vohl — 0.1 0.16 V Io = 5 mA, IN += 0 V
This product is not designed for protection against radio active rays.
* Design guarantee (No total shipment inspection is made.)
Min. Typ. Max.
Limit
Unit Conditions
Technical Note
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© 2009 ROHM Co., Ltd. All rights reserved.
3/17
2009.07 - Rev.B
BD8151EFV, BD8157EFV
●Reference Data (Unless otherwise specified, Ta = 25℃)
1.75
1.50
1.25
1.00
0.75
0.50
SUPPLY CURRENT: ICC[mA] .
0.25
0.00
0.5
0123456
Fig. 1 Total Supply Current
-40℃
SUPPLY VOLT AGE : VCC[ V]
25℃
150℃
2.0
1.5
1.0
0.5
0.0
-0.5
-1.0
-1.5
STANDBY CURRENT : ICC[μA] .
-2.0
01234
25℃
SUPPLY VOLTAGE : VCC[V]
Fig. 2 Standby Current
0
2.0
-4
-8
-12
SS CURRENT : ISS[μA]
-16
-20
00.5 11.52
SS VOLTAGE : VSS[V]
Fig. 4 SS Source Current
20
15
125
2 .4
℃
1.5
1.0
0.5
REFERENCE VOLTAGE : VREF[V]
0.0
0 1.5 3 4.5 6 7.5
SUPPLY VOLT AGE : VCC[V]
Fig. 5 Reference Voltage
Temperature
20
15
125℃
10
25℃
10
25℃
5
FCLK CURRENT : FCLK[μA] .
0
0.0 0.5 1.0 1.5 2.0 2.5 3.0
Fig. 7 FCLK Pin Current
FC LK VOLTAGE : FC LK[V]
-40℃
5
ENB CURRENT : ENB[μA] .
0
0.0 0.5 1.0 1.5 2.0 2.5 3.0
ENB VOLTAGE : VEN B[V]
Fig. 8 ENB Pin Current
100
95
90
Max Duty [%]
85
EFFICIENCY [%]
100
90
80
70
60
VCC=2.5V f=600kHz
VCC=2.5V f=1200kHz
80
-40 0 40 80 120
AMBIENT TEM PERATU RE : Ta[℃]
Fig. 10 Max. Duty Ratio Temperature
125
50
0 0.05 0.1 0.15 0.2 0.25 0.3
OUTPUT CURRENT : IO[A]
Fig. 11 Vcc = 2.5 V Power
125℃
-40℃
BD8157EFV
-40℃
Efficiency
Technical Note
1.260
1.255
1.250
1.245
1.240
1.235
REFERENCE VOLTAGE : VREF[V] .
1.230
-40 -15 10 35 60 85 110
AM BIE NT TE MP ER ATURE : Ta[℃]
Fig. 3 Reference Voltage
Temperature
2000
1500
1000
500
SWITCHING FREQUENCY : FSW[kHz]
0
-40 -15 10 35 60 85 110
AMBIENT TEM PERATU RE : Ta[℃]
VFCLK=VCC
VFCLK=GND
Fig. 6 Switching Frequency
Temperature
100
50
0
-50
COMP CURRENT : ICOMP[uA] .
-100
1.0 1.1 1.2 1.3 1.4 1. 5
COM P VOLTAGE : VC OMP[V]
Fig. 9 COMP Sinking vs Source
Current
100
VCC=3.3V f=600kHz
90
80
70
EFFICIENCY [%]
60
VCC=3.3V f=1200kHz
BD8151EFV
50
0.02
0 0. 15 0.3 0.45 0. 6
OUTPUT CURRENT : IO[A]
Fig. 12 Vcc = 3.3 V Power
Efficiency
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© 2009 ROHM Co., Ltd. All rights reserved.
4/17
2009.07 - Rev.B
BD8151EFV, BD8157EFV
V
.
.
Technical Note
●Reference Data (Unless otherwise specified, Ta = 25℃)
100
90
80
70
EFFICIENCY [%]
60
50
2.0 2.5 3.0 3.5 4.0
SUPPLY VOLT AGE : VCC[V]
Fig. 13 Power Efficiency vs
Power Supply Voltage
10
1
BD8157EFV
0.8
BD8157EFV
0.6
0.4
0.2
MAXIMUM CURRENT : IOMAX[A] .
0
2.1 2.4 2.7 3.0 3.3 3.6 3.9
F=600kHz
F=1200kHz
SUPPLY VOLT AGE : VCC[ V]
Fig. 14 Max. Load Current vs
Power Supply Voltage
10
8
6
Io=0mA
VO
100mV/div
Fig. 15 Load Response
Waveform
9
8.8
8.6
Io=100mA
20us/div
0.1
DELAY TIME [ms]
0.01
0.001 0.01 0.1
10
SS CAPAC ITAN CE [μ F]
Fig. 16 SS Capacitance vs
Delay Time
5
0
-5
-10
-15
OFFSET VOLTAGE:VOFFSET[m
-20
123456789
BUF FER INPUT VOLTAGE:VIN[ V]
Fig. 19 Buffer Voltage
9
8
7
6
5
4
125℃
3
2
OUTPU T VOLTAGE : VOUT[V]
1
0
0 50 100 150 200 250 300
OUTPU T CU RRENT : IOU T[mA] .
Fig. 22 VCOM Sinking Current
25℃
-40℃
4
VS CURRENT : IS[mA]
2
0
0 5 10 15
VS VOLTAGE : VS[V]
Fig. 17 VS Pin Current
9
8
OUTPUT VOLTAGE : VOUT[V]
7
6
5
4
3
2
1
0
-40℃
25℃
125℃
0 25 50 75 100 125 150 175 200
OUTPUT CURRENT : IOUT[mA] .
Fig. 20 Buffer Sinking Current
9
8
7
-40℃ 25℃
6
5
4
3
2
OUTPU T VOLTAGE : VOUT[V]
1
0
-300 - 250 -200 -150 - 100 -50 0
OUTPU T CU RRENT : IOU T[mA]
125℃
Fig. 23 VCOM Source Current
8.4
8.2
OUTPUT VOLTAGE : VO[V]
8
0.0 0.1 1.0
LOAD CURRENT : IO[A]
Fig. 18 Output voltage
Load Regulation 1
9
8
7
6
-40℃
5
4
3
2
OUTPUT VOLTAGE : VOUT[V]
1
0
-200 -175 -150 -125 -100 - 75 -50 - 25 0
OUTPUT CURRENT : IOUT[mA] .
25℃
125℃
Fig. 21 Buffer Source Current
IN
OUT
1us/div
Fig. 24 Slew Rate Waveform
2V/div
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5/17
2009.07 - Rev.B
BD8151EFV, BD8157EFV
+
+
●Pin Assignment Diagram ●Block Diagram
SW
1
SW
VCC
ENB
FCLK
COMIN
IN1
IN2
IN3
IN4
VS
PGND
GND
FB
COMP
SS
VCOM
OUT1
OUT2
OUT3
OUT4
VCC
ENB
FCLK
VS
COMIN
IN1
2
3
4
5
6
7
BUFFER SUPPLY
IN2
8
IN3
9
IN4
10
TOP VIEW
Fig. 25 Pin Assignment Diagram and Block Diagram
●Pin Assignment Diagram and Pin Functions
SLOPE
OSC
UVLO
TSD
CURRENT
SENSE
+
Technical Note
20
PGND
DRV
LOGIC
RESET
PWM
-
SDWN
OCP
ERR
SOFT
START
SET
19
GND
-
18
FB
1.245V
COMP
17
SS
16
15
VCOM
14
OUT1
13
OUT2
OUT3
12
11
OUT4
Pin No. Pin name Function
1 SW N-channel power FET drain output
2 VCC Power supply input pin
3 ENB Control input pin
4 FCLK Frequency switching pin
5 VS Buffer power supply input pin
6 COMIN VCOM input pin
7 IN1 Amp input pin 1
8 IN2 Amp input pin 2
9 IN3 Amp input pin 3
10 IN4 Amp input pin 4
11 OUT4 Amp output pin 4
12 OUT3 Amp output pin 3
13 OUT2 Amp output pin 2
14 OUT1 Amp output pin 1
15 VCOM VCOM output pin
16 SS Soft start current output pin
17 COMP Error amp output pin
18 FB Error amp inversion input pins
19 GND Ground pin
20 PGND Ground pin
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6/17
2009.07 - Rev.B
© 2009 ROHM Co., Ltd. All rights reserved.
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