Power Supply IC Series for TFT-LCD Panels
Single-channel Source Voltage
Output Power Supply + Gamma Buffer Amp ICs
BD8151EFV,BD8157EFV
No.09035EBT11
●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
BD8151EFV
BD8157EFV
−40 to +85
Topr
℃
−40 to +125
Storage temperature range
Tstg
−55 to +150
℃
Switching pin current
Isw
1.5**
A
Switching pin voltage
Vsw
15
V
VS voltage
Maximum junction temperature
VS
15
V
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
Limit
Unit
Min.
Typ.
Max.
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
5
9
14
V
Power supply voltage BD8151EFV
VS pin voltage
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1/17
2009.07 - Rev.B
BD8151EFV, BD8157EFV
Technical Note
●Electrical Characteristics BD8151EFV (Unless otherwise specified, Ta = 25℃; Vcc = 3.3V, ENB = 3.3V)
Limit
Parameter
Symbol
Unit
Conditions
Min.
Typ.
Max.
[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
ISW
—
2
—
A
ISO
6
10
14
µA
[Overcurrent protection circuit]
Overcurrent limit
[Soft start circuit]
SS source current
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 on voltage
VON
Vcc × 0.7
Vcc
—
V
ENB off voltage
VOFF
—
0
Vcc × 0.3
V
Standby current
ISTB
—
0
10
μA
VENB = 0 V
Average consumption current
ICC
—
1.2
2.4
mA
no switching
Ibo
−1
0
1
μA
IN += 4.5 V
[ENB]
[Overall]
[Amp]
Input bias current
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.)
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2/17
2009.07 - Rev.B
BD8151EFV, BD8157EFV
Technical Note
●Electrical Characteristics BD8157EFV (Unless otherwise specified, Ta = 25℃; Vcc = 2.5V, ENB = 2.5V)
Limit
Parameter
Symbol
Unit
Conditions
Min.
Typ.
Max.
[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
ISW
—
2
—
A
ISO
6
10
14
µA
[Overcurrent protection circuit]
Overcurrent limit
[Soft start circuit]
SS source current
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 on voltage
VON
Vcc × 0.7
Vcc
—
V
ENB off voltage
VOFF
—
0
Vcc × 0.3
V
Standby current
ISTB
—
0
10
μA
VENB = 0 V
Average consumption current
ICC
—
1.2
2.4
mA
no switching
Ibo
−1
0
1
μA
IN += 4.5 V
[ENB]
[Overall]
[Amp]
Input bias current
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.)
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3/17
2009.07 - Rev.B
BD8151EFV, BD8157EFV
Technical Note
●Reference Data (Unless otherwise specified, Ta = 25℃)
2.0
1.25
-40℃
1.00
25℃
0.75
0.50
150℃
0.25
0.00
1.0
125℃
0.5
0.0
25℃
-0.5
-1.5
2
3
4
5
0
6
1.245
1.240
1.235
1
2
3
-40
4
2.0
-8
-12
-16
BD8157EFV
1.5
1.0
0.5
0.0
-20
0
0.5
1
1.5
2
0
2 .4
Fig. 4 SS Source Current
ENB CURRENT : ENB[μA] .
25℃
5
-40℃
0.5
1.0
1.5
2.0
2.5
3
4.5
6
7.5
1000
VFCLK=GND
500
0
-40
-15
10
125℃
10
25℃
5
-40℃
Fig. 7 FCLK Pin Current
0.5
1.0
1.5
2.0
2.5
0
-50
1.1
1.2
VCC=3.3V f=600kHz
EFFICIENCY [%]
EFFICIENCY [%]
Max Duty [%]
80
VCC=2.5V f=1200kHz
70
80
VCC=3.3V f=1200kHz
70
60
BD8157EFV
BD8151EFV
50
40
80
120
125
Fig. 10 Max. Duty Ratio Temperature
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1.5
90
60
0
1.4
100
90
AMBIENT TEMPERATURE : Ta[℃]
1.3
Fig. 9 COMP Sinking vs Source
Current
VCC=2.5V f=600kHz
80
-40
110
COMP VOLTAGE : VCOMP[V]
100
85
85
50
-100
1.0
3.0
Fig. 8 ENB Pin Current
90
60
Fig. 6 Switching Frequency
Temperature
ENB VOLTAGE : VENB[V]
95
35
AMBIENT TEMPERATURE : Ta[℃]
15
FCLK VOLTAGE : FCLK[V]
100
110
100
0
0.0
3.0
85
VFCLK=VCC
Fig. 5 Reference Voltage
Temperature
125℃
10
0
0.0
1.5
20
15
60
1500
SUPPLY VOLTAGE : VCC[V]
SS VOLTAGE : VSS[V]
20
35
2000
SWITCHING FREQUENCY : FSW[kHz]
REFERENCE VOLTAGE : VREF[V]
-4
10
Fig. 3 Reference Voltage
Temperature
Fig. 2 Standby Current
0
-15
AMBIENT TEMPERATURE : Ta[℃]
SUPPLY VOLTAGE : VCC[V]
Fig. 1 Total Supply Current
SS CURRENT : ISS[μA]
1.250
1.230
-2.0
0 0.5 1
SUPPLY VOLTAGE : VCC[V]
FCLK CURRENT : FCLK[μA] .
-40℃
-1.0
1.255
COMP CURRENT : ICOMP[uA] .
SUPPLY CURRENT: ICC[mA] .
1.50
1.260
1.5
REFERENCE VOLTAGE : VREF[V] .
STANDBY CURRENT : ICC[μA] .
1.75
50
0
0.05
0.1
0.15
0.2
0.25
OUTPUT CURRENT : IO[A]
Fig. 11 Vcc = 2.5 V Power
Efficiency
4/17
0.3
0 0.02
0.15
0.3
0.45
0.6
OUTPUT CURRENT : IO[A]
Fig. 12 Vcc = 3.3 V Power
Efficiency
2009.07 - Rev.B
BD8151EFV, BD8157EFV
Technical Note
●Reference Data (Unless otherwise specified, Ta = 25℃)
0.8
MAXIMUM CURRENT : IOMAX[A] .
100
EFFICIENCY [%]
90
80
70
60
BD8157EFV
50
2.0
2.5
3.0
3.5
BD8157EFV
F=600kHz
0.4
VO
F=1200kHz
0.2
100mV/div
0
2.1
4.0
2.4
SUPPLY VOLTAGE : VCC[V]
2.7
3.0
3.3
3.6
10
9
OUTPUT VOLTAGE : VO[V]
10
VS CURRENT : IS[mA]
0.1
6
4
2
0.01
0
0.1
5
Fig. 16 SS Capacitance vs
Delay Time
OUTPUT VOLTAGE : VOUT[V]
5
0
-5
-10
-15
-20
15
3
4
5
6
9
8
8
7
-40℃
6
5
4
25℃
125℃
3
2
1
7
8
9
0
8
8
OUTPUT VOLTAGE : VOUT[V] .
9
7
6
5
-40℃
3
2
1
0
0
50
100
150
200
250
50
75
100 125 150 175 200
300
OUTPUT CURRENT : IOUT[mA] .
Fig. 22 VCOM Sinking Current
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7
6
-40℃
25℃
1.0
7
6
5
-40℃
25℃
125℃
4
3
2
1
0
-200 -175 -150 -125 -100 -75 -50 -25
0
OUTPUT CURRENT : IOUT[mA] .
Fig. 20 Buffer Sinking Current
9
25℃
25
OUTPUT CURRENT : IOUT[mA] .
Fig. 19 Buffer Voltage
125℃
0.1
Fig. 18 Output voltage
Load Regulation 1
9
BUFFER INPUT VOLTAGE:VIN[V]
4
8.2
LOAD CURRENT : IO[A]
0
2
8.4
Fig. 17 VS Pin Current
10
1
8.6
VS VOLTAGE : VS[V]
SS CAPACITANCE [μF]
OFFSET VOLTAGE:VOFFSET[mV
10
8.8
8
0.0
0
0.01
0.001
OUTPUT VOLTAGE : VOUT[V]
DELAY TIME [ms]
8
OUTPUT VOLTAGE : VOUT[V] .
Fig. 15 Load Response
Waveform
Fig. 14 Max. Load Current vs
Power Supply Voltage
Fig. 13 Power Efficiency vs
Power Supply Voltage
20us/div
3.9
SUPPLY VOLTAGE : VCC[V]
1
Io=100mA
Io=0mA
0.6
Fig. 21 Buffer Source Current
IN
125℃
5
4
3
OUT
2
1us/div
1
0
-300
2V/div
-250
-200
-150
-100
-50
0
OUTPUT CURRENT : IOUT[mA]
Fig. 23 VCOM Source Current
5/17
Fig. 24 Slew Rate Waveform
2009.07 - Rev.B
Technical Note
BD8151EFV, BD8157EFV
●Pin Assignment Diagram
●Block Diagram
SW
VCC
1
CURRENT
SENSE
2
SLOPE
PGND
GND
FB
COMP
SS
VCOM
OUT1
OUT2
OUT3
SW
VCC
ENB
FCLK
VS
COMIN
IN1
IN2
IN3
IN4
20
PGND
19
GND
+
DRV
ENB
FCLK
3
OSC
SET
RESET SDWN
OCP
18
ERR
+ 1.245V
4
UVLO
TSD
VS
LOGIC
5
BUFFER SUPPLY
COMIN 6
FB
17
COMP
16
SS
PWM
+ SOFT
START
15 VCOM
OUT4
IN1
7
14
OUT1
IN2
8
13
OUT2
IN3
9
12
OUT3
IN4
10
11
OUT4
TOP VIEW
Fig. 25 Pin Assignment Diagram and Block Diagram
●Pin Assignment Diagram and Pin Functions
Pin No.
Pin name
Function
1
SW
2
VCC
Power supply input pin
3
ENB
Control input pin
4
FCLK
Frequency switching pin
N-channel power FET drain output
5
VS
6
COMIN
VCOM input pin
Buffer power supply input pin
7
IN1
Amp input pin 1
8
IN2
Amp input pin 2
9
IN3
Amp input pin 3
10
IN4
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
17
COMP
18
FB
19
GND
Ground pin
20
PGND
Ground pin
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Amp input pin 4
Soft start current output pin
Error amp output pin
Error amp inversion input pins
6/17
2009.07 - Rev.B
Technical Note
BD8151EFV, BD8157EFV
●Description of Operation of Each Block
10uH
Vo
RB161M-20
1
20
SW
VCC
2.5V
10uF
PGND
CURRENT
SENSE
2
SLOPE
VCC
10uF
19
GND
+
100kΩ
DRV
3
OSC
ENB
SET
LOGIC
RESET SDWN
OCP
18
ERR
+ 1.245V
FB
15kΩ
4
UVLO
TSD
FCLK
5
20kΩ
17
PWM
+ -
16
SS
VS
20kΩ
6
VCOM
IN1
OUT1
OUT2
IN2
OUT3
IN3
10
IN4
V3
12
9
20kΩ
V2
13
8
20kΩ
V1
14
7
20kΩ
0.01uF
VCOM
15
COMIN
20kΩ
5.1kΩ 3300pF
COMP
SOFT
START
BUFFER SUPPLY
V4
11
OUT4
TOP VIEW
20kΩ
Fig. 26 Application Circuit Diagram
Error amp (ERR)
This is the circuit to compare the reference voltage 1.245 V (Typ.) and the feedback voltage of output voltage. The COM
pin voltage resulting from this comparison determines the switching duty. At the time of start, since the soft start is
operated by the SS pin voltage, the COMP pin voltage is limited to the SS pin voltage.
Oscillator (OSC)
This block generates the oscillating frequency. Either a 600 kHz or 1.2 MHz (Typ.) frequency can be selected with the
FCLK pin.
SLOPE
This block generates the triangular waveform from the clock generated by OSC. Generated triangular waveform is sent to
the PWM comparator.
PWM
The COMP pin voltage output by the error amp is compared to the SLOPE block's triangular waveform to determine the
switching duty. Since the switching duty is limited by the maximum duty ratio which is decided internally, it does not
become 100%.
Reference voltage (VREF)
This block generates the internal reference voltage of 1.245 V (Typ.).
Protection circuit (UVLO/TSD)
UVLO (under-voltage lockout protection circuit) shuts down the circuits when the voltages are 2.2 V (Typ.BD8151EFV)
1.8 V (Typ.ND8157EFV) or lower. Thermal shutdown circuit shuts down IC at 175°C (Typ.) and recovers at 160°C (Typ.).
Overcurrent protection circuit (OCP)
Current flowing to the power FET is detected by voltage at the CURRENT SENSE and the overcurrent protection operates
at 3 A (Typ.). When the overcurrent protection operates, switching is turned off and the SS pin capacity is discharged.
Soft start circuit
Since the output voltage rises gradually while restricting the current at the time of startup, it is possible to prevent the
output voltage overshoot or the inrush current.
Buffer amp and VCOM
This buffer amp is used to set the gamma correction voltage, which can be set in from 0.2 V to (VOUT - 0.2 V). Use the
VOUT resistance division to set the gamma correction voltage. The VCOM voltage is set similarly.
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7/17
2009.07 - Rev.B
Technical Note
BD8151EFV, BD8157EFV
●Timing Chart
Startup sequence
VCC
ENB
SS
SW
VO
Fig. 27 Startup sequence
Overcurrent protection operating
2.5V
VCC,ENB
SS
SW
VO
IO
Fig. 28 Overcurrent protection operating
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8/17
2009.07 - Rev.B
BD8151EFV, BD8157EFV
Technical Note
●Selecting Application Components
(1) Setting the output L constant
The coil L to use for output is decided by the rating current ILR and input current maximum value IINMAX of the coil.
Vcc
IINMAX+ ∆IL should not reach
the rating value level
IL
L
INMAX
I
current
IL
Vo
average
Co
t
Fig. 30 Output Application Circuit Diagram
Fig. 29 Coil Current Waveform
Adjust so that IINMAX + ∆IL does not reach the rating current value ILR. At this time, ∆IL can be obtained by the following
equation.
1
Vo-Vcc
1
Vcc
[A]
Where, f is the switching frequency.
∆IL =
L
Vcc
f
Set with sufficient margin because the coil L value may have the dispersion of approx. 30%. If the coil current exceeds
the rating current ILR of the coil, it may damage the IC internal element.
BD8157EFV uses the current mode DC/DC converter control and has the optimized design at the coil value. The following
coil values are recommended from the aspects of power efficiency, response and safety. When the coil out of this range is
selected, the stable continual operation is not guaranteed such as the switching waveform becomes irregular. Please pay
attention to it.
Switching frequency: L = 10 µH to 22 µH at 600 kHz
Switching frequency: L = 4.7 µH to 15 µH at 1,200 kHz
(2) Setting the output capacitor
For the capacitor C to use for the output, select the capacitor which has the larger value in the ripple voltage VPP allowance
value and the drop voltage allowance value at the time of sudden load change. Output ripple voltage is decided by the
following equation.
1
Vcc
∆IL
(ILMAX)
[V] Where, f is the switching frequency.
∆VPP = ILMAX×RESR +
fCo
Vo
2
Perform setting so that the voltage is within the allowable ripple voltage range.
For the drop voltage during sudden load change; VDR, please perform the rough calculation by the following equation.
VDR
=
∆I
Co
10 µ sec
[V]
However, 10 µs is the rough calculation value of the DC/DC response speed. Please set the capacitance considering the
sufficient margin so that these two values are within the standard value range.
(3) Selecting the input capacitor
Since the peak current flows between the input and output at the DC/DC converter, a capacitor is required to install at the
input side. For this reason, the low ESR capacitor is recommended as an input capacitor which has the value more than
10 µF and less than 100 m. If a capacitor out of this range is selected, the excessive ripple voltage is superposed on the
input voltage, accordingly it may cause the malfunction of IC.
However these conditions may vary according to the load current, input voltage, output voltage, inductance and switching
frequency. Be sure to perform the margin check using the actual product.
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9/17
2009.07 - Rev.B
BD8151EFV, BD8157EFV
Technical Note
(4) Selecting the output rectification diode
Schottky barrier diode is recommended as the rectification diode to use at the DC/DC converter output stage. Select the
diode paying attention to the max. inductor current and max. output voltage.
Max. Inductor current
IINMAX + ∆IL < Rating current of diode
Max. output voltage VOMAX
< Rating voltage of diode
Since each parameter has 30% to 40% of dispersion, be sure to design providing sufficient margins.
(5) Design of the feedback resistor constant
Refer to the following equation to set the feedback resistor. As the setting range, 10 k to 330 k is recommended. If the
resistor is set to a 10 k or lower, it causes the reduction of power efficiency. If it is set to 330 k or larger, the offset
voltage becomes larger by the input bias current 0.4 µA (Typ.) in the internal error amplifier.
Step-up
Vo =
R8 + R9
R9
1.245
[V]
Reference voltage 1.245 V
Vo
R8
R9
＋
ERR
－
2
FB
Fig. 31Feedback Resistance Setting
As the capacitance, 0.001 µF to 0.1µF is recommended. If the capacitance is set to
0.001 µF, the overshooting may occur on the output voltage. If the capacitance is
set to 0.1 µF or larger, the excessive back current flow may occur in the internal
parasitic elements when the power is turned OFF and it may damage IC. When the
capacitor of 0.1 µF or larger is used, be sure to insert a diode to Vcc in series, or a
bypass diode between the SS pin and VCC.
Bypass diode
10
DELAY TIME[ms]
(6) Setting the soft start time
Soft start is required to prevent the coil current at the time of startup from increasing
and the overshoot of the output voltage at the starting time. Fig. 32 shows the
relation between the capacitance and soft start time. Please refer to it to set the
capacitance.
1
0.1
0.01
0.001
0.01
0.1
SS CAPACITANCE[uF]
Fig.32 SS Pin Capacitance vs
Delay Time
Back current prevention diode
VCC
Output pin
Fig. 33 Bypass Diode Example
When there is the startup relation (sequences) with other power supplies, be sure to use the high accuracy product (such as X5R).
Soft start time may vary according to the input voltage, output voltage loads, coils and output capacity. Be sure to verify the
operation using the actual product.
(7) Setting the ENB pin
When the ENB pin is set to Hi, the internal circuit becomes active and the DC/DC converter starts operating. When it is set
to Low, the shut down is activated and all circuits will be turned OFF.
(8) Setting the frequency by FCLK
It is possible to change the switching frequency by setting the FCLK pin to Hi or Low. When it is set to Low, the product
operates at 600 kHz (Typ.). When it is set to Hi, the product operates at 1,200 kHz (Typ.).
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10/17
2009.07 - Rev.B
Technical Note
BD8151EFV, BD8157EFV
(9) Setting RC, CC of the phase compensation circuit
In the current mode control, since the coil current is controlled, a pole (phase lag) made by the CR filter composed of the
output capacitor and load resistor will be created in the low frequency range, and a zero (phase lead) by the output
capacitor and ESR of capacitor will be created in the high frequency range. In this case, to cancel the pole of the power
amplifier, it is easy to compensate by adding the zero point with CC and RC to the output from the error amplifier as shown
in the illustration.
Open loop gain
fp =
fp(Min)
A
fp(Max)
fz (ESR) =
0
Gain
1
2 Ro Co
1
2 ESR Co
[Hz]
[Hz]
【dB】
lOUTMin
Pole at the power amplification stage
When the output current reduces, the load resistance
RO increases and the pole frequency lowers.
fz(ESR)
lOUTMax
0
Phase
【deg】
fp(Min) =
-90
fz(Max) =
Error amplifier phase compensation
[Hz]
1
[Hz]
2 RoMin Co
(At light-load)
(At heavy-load)
Zero at the power amplification stage
When the output capacitor is set larger, the pole
frequency lowers but the zero frequency will not
change. (This is because the capacitor ESR
becomes 1/2 when the capacitor becomes 2 times.)
A
Gain
【dB】
0
Phase
1
2 RoMax Co
0
fp (Amp.) =
【deg】-90
1
[Hz]
2 Rc Cc
Fig. 34 Gain vs Phase
L
VCC
Vcc,PVcc
Cin
Ro
ESR
SW
COMP
Rc
Vo
Co
GND,PGND
Cc
Fig. 35 Application Circuit Diagram
It is possible to realize the stable feedback loop by canceling the pole fp (Min.), which is created by the output capacitor
and load resistor, with CR zero compensation of the error amplifier as shown below.
fz (Amp.) = fp (Min.)
1
2 Rc Cc
1
=
2 Romax Co
[Hz]
As the setting range for the resistor, 1 k to 10 k is recommended. When the resistor is set to 1 k or lower, the effect by
phase compensation becomes low and it may cause the oscillation of output voltage. When it is set to 10 k or larger, the
COMP pin becomes Hi-Z and the switching noise becomes easy to superpose. Therefore the stable switching pulse
cannot be generated and the irregular ripple voltage may be generated on the output voltage.
As the setting range for the capacitance, 3,300 pF to 10,000 pF is recommended. When the capacitance is set to 3,300 pF
or lower, the irregular ripple voltage may be generated on the output voltage due to the effect of switching noise. When it is
set to 10,000 pF or larger, the response becomes worse and the output voltage fluctuation becomes large. Accordingly it
may require the output capacitor which is larger than the necessary value.
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© 2009 ROHM Co., Ltd. All rights reserved.
11/17
2009.07 - Rev.B
Technical Note
BD8151EFV, BD8157EFV
(10) Using the buffer amp and VCOM
The 4-channel buffer amp and 1-channel VCOM output are used to generate the gamma compensation voltage that is
input to the source driver. The VS pin serves as the power supply for the buffer amp and VCOM.
VS
VCOMIN
VCOM voltage output
VIN1
V1
VIN2
V2
VIN3
For gamma correction
Gamma correction voltage output
V3
VIN4
V4
Fig. 36 Example Buffer Amp Circuit
Use caution as the gamma correction buffer amp and VCOM have different output current capacities. A range from I/O
power supply to ground potentials can be set for the built-in buffer amplifier. If output voltage noise becomes problematic,
insert a 0.1 µF capacitor in the output circuit. A capacitance value of 0 pF to 1 µF is recommended for this capacitor. Large
capacitance values of 1 µF or larger may cause back current to flow through internal parasitic diodes in the event of a
supply voltage ground fault, causing damage to internal IC elements. For applications where such modes are anticipated,
implement a bypass diode or other preventive measure.
Wait for trigger
Vs
V1
V2
V3
V4
Fig. 37 Gamma Correction Voltage Startup Waveform
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© 2009 ROHM Co., Ltd. All rights reserved.
12/17
2009.07 - Rev.B
Technical Note
BD8151EFV, BD8157EFV
●Application Examples
* Although ROHM is sure that the application examples are recommendable ones, further check the characteristics of
components that require high precision before using them.When a circuit is used modifying the externally connected circuit
constant, be sure to decide allowing sufficient margins considering the dispersion of values by external parts as well as our
IC including not only the static but also the transient characteristic.
For the patent, we have not acquired the sufficient confirmation. Please acknowledge the status.
(1) When the charge pump is removed from the DC/DC converter to make it 3-channel output mode:
It is possible to create the charge pump by using the switching operation of DC/DC converter. When the application shown
in the following diagram is used, 1-channel DC/DC converter output, 1-channel positive side charge pump and 1-channel
negative side charge pump can be output as a total of 3 channels.
0.1uF
0.1uF
10uH
VOUT
DAN217U
10uF
RB161M-20
1
20
SW
VCC
2.5V
2
10uF
1uF
19
SLOPE
VCC
1uF
PGND
CURRENT
SENSE
2SD2657k
GND
+
DRV
3
SET
OSC
LOGIC
RESET SDWN
ENB
OCP
18
ERR
+ 1.245V
FB
0.1uF
VGH
4
UVLO
TSD
FCLK
5
17
PWM
+ -
COMP
SOFT
START
BUFFER SUPPLY
1uF
DAN217U
16
SS
VS
6
15
7
14
COMIN
VCOM
1uF
VCOM
IN1
V1
2SB1695k
OUT1
V2
13
8
VGL
OUT2
IN2
9
12
10
11
UDZ
Series
V3
OUT3
IN3
IN4
UDZ
Series
1uF
V4
OUT4
TOP VIEW
Fig. 38 3 ch Application Circuit Diagram Example
(2) When the output voltage is set to 0 V:
Since the switch does not exist between the input and output in the application using the step-up type DC/DC converter,
the output voltage is generated even if the IC is turned off. When it is intended to keep the output voltage 0 V until IC
operates, insert the switch as shown in the following circuit diagram.
10uH
Vo
10uF
RB161M-20
1
20
SW
VCC
2.5V
2
10uF
SLOPE
VCC
PGND
CURRENT
SENSE
19
GND
+
DRV
3
OSC
ENB
SET
LOGIC
RESET SDW N
OCP
18
ERR
+ 1.245V
FB
4
UVLO
TSD
FCLK
5
17
PW M
+ -
COMP
SOFT
START
BUFFER SUPPLY
16
SS
VS
6
VCOM
V1
14
7
IN1
OUT1
V2
13
8
OUT2
IN2
V3
12
9
OUT3
IN3
10
IN4
VCOM
15
COMIN
V4
11
OUT4
TOP VIEW
Fig. 39 Switch Application Circuit Diagram Example
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© 2009 ROHM Co., Ltd. All rights reserved.
13/17
2009.07 - Rev.B
Technical Note
BD8151EFV, BD8157EFV
●I/O Equivalent Circuit Diagrams
1.SW
11.OUT4 12.OUT3 13.OUT2 14.OUT1 15.VCOM
VS
3.ENB
4.FCLK
16.SS
Vcc
Vcc
200kΩ
6.COMIN 7.IN1 8.IN2 9.IN3
10.IN4
17.COMP
VS
18.FB
Vcc
Fig.40 I/O Equivalent Circuit Diagrams
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© 2009 ROHM Co., Ltd. All rights reserved.
14/17
2009.07 - Rev.B
Technical Note
BD8151EFV, BD8157EFV
●Notes for use
1) Absolute maximum ratings
Use of the IC in excess of absolute maximum ratings such as the applied voltage or operating temperature range may
result in IC damage. Assumptions should not be made regarding the state of the IC (short mode or open mode) when such
damage is suffered. A physical safety measure such as a fuse should be implemented when use of the IC in a special
mode where the absolute maximum ratings may be exceeded is anticipated.
2) GND potential
Ensure a minimum GND pin potential in all operating conditions.
3) Setting of heat
Use a thermal design that allows for a sufficient margin in light of the power dissipation (Pd) in actual operating conditions.
4) Pin short and mistake fitting
Use caution when orienting and positioning the IC for mounting on an application board. Improper mounting may result in
damage to the IC. Shorts between output pins or between output pins and the power supply and GND pins caused by the
presence of a foreign object may result in damage to the IC.
5) Actions in strong magnetic field
Use caution when using the IC in the presence of a strong magnetic field as doing so may cause the IC to malfunction.
6) Testing on application boards
When testing the IC on an application board, connecting a capacitor to a pin with low impedance subjects the IC to stress.
Always discharge capacitors after each process or step. Ground the IC during assembly steps as an antistatic measure,
and use similar caution when transporting or storing the IC. Always turn the IC's power supply off before connecting it to or
removing it from a jig or fixture during the inspection process.
7) Ground wiring patterns
When using both small signal and large current GND patterns, it is recommended to isolate the two ground patterns,
placing a single ground point at the application's reference point so that the pattern wiring resistance and voltage
variations caused by large currents do not cause variations in the small signal ground voltage. Be careful not to change the
GND wiring patterns of any external components.
8) This monolithic IC contains P+ isolation and P substrate layers between adjacent elements in order to keep them isolated.
P/N junctions are formed at the intersection of these P layers with the N layers of other elements to create a variety of
parasitic elements. For example, when the resistors and transistors are connected to the pins as shown in Fig. 41, a
parasitic diode or a transistor operates by inversing the pin voltage and GND voltage.
The formation of parasitic elements as a result of the relationships of the potentials of different pins is an inevitable result
of the IC's architecture. The operation of parasitic elements can cause interference with circuit operation as well as IC
malfunction and damage. For these reasons, it is necessary to use caution so that the IC is not used in a way that will
trigger the operation of parasitic elements, such as the application of voltages lower than the GND (P substrate) voltage to
Resistor
input and output pins.
Transistor (NPN)
(Pin B)
C
B
E
C
～
～
～
～
(Pin B)
～
～
B
(Pin A)
E
GND
GND
N
P＋
N
N
N
N
Parasitic
element
P
GND
P
P＋
Parasitic
elements
P＋
N
N
(Pin A)
～
～
P
P＋
P substrate
Parasitic elements
Parasitic
element
GND
Fig.41 Example of a Simple Monolithic IC Architecture
GND
9) Overcurrent protection circuits
An overcurrent protection circuit designed according to the output current is incorporated for the prevention of IC
destruction that may result in the event of load shorting. This protection circuit is effective in preventing damage due to
sudden and unexpected accidents. However, the IC should not be used in applications characterized by the continuous
operation or transitioning of the protection circuits. At the time of thermal designing, keep in mind that the current capacity
has negative characteristics to temperatures.
10) Thermal shutdown circuit (TSD)
This IC incorporates a built-in TSD circuit for the protection from thermal destruction. The IC should be used within the
specified power dissipation range. However, in the event that the IC continues to be operated in excess of its power
dissipation limits, the attendant rise in the chip's temperature Tj will trigger the temperature protection circuit to turn off all
output power elements. The circuit automatically resets once the chip's temperature Tj drops.
Operation of the TSD circuit presumes that the IC's absolute maximum ratings have been exceeded. Application designs
should never make use of the TSD circuit.
11) Testing on application boards
At the time of inspection of the installation boards, when the capacitor is connected to the pin with low impedance, be sure
to discharge electricity per process because it may load stresses to the IC. Always turn the IC's power supply off before
connecting it to or removing it from a jig or fixture during the inspection process. Ground the IC during assembly steps as
an antistatic measure, and use similar caution when transporting or storing the IC.
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© 2009 ROHM Co., Ltd. All rights reserved.
15/17
2009.07 - Rev.B
BD8151EFV, BD8157EFV
Technical Note
POWRE
DISSIPATION :
●Power Dissipation Reduction
2000
On 70×70×1.6mm Board
1500
1000
1000
500
BD8151EF
BD8157EF
0
25
50
75 85
100
125
150
AMBIENT MPERATURE :Ta[℃]
Fig.42 Power Dissipation Reduction
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© 2009 ROHM Co., Ltd. All rights reserved.
16/17
2009.07 - Rev.B
BD8151EFV, BD8157EFV
Technical Note
●Ordering part number
B
D
8
Part No.
1
5
1
Part No.
8151
8157
E
F
V
-
Package
EFV : HTSSOP-B20
E
2
Packaging and forming specification
E2: Embossed tape and reel
HTSSOP-B20
6.5±0.1
(MAX 6.85 include BURR)
(4.0)
1
1.0±0.2
(2.4)
6.4±0.2
0.5±0.15
11
4.4±0.1
20
Tape
Embossed carrier tape (with dry pack)
Quantity
2500pcs
Direction
of feed
E2
The direction is the 1pin of product is at the upper left when you hold
( reel on the left hand and you pull out the tape on the right hand
)
10
0.325
1.0MAX
+0.05
0.17 -0.03
0.08±0.05
0.85±0.05
S
0.08 S
0.65
+0.05
0.24 -0.04
1pin
(Unit : mm)
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© 2009 ROHM Co., Ltd. All rights reserved.
Reel
17/17
Direction of feed
∗ Order quantity needs to be multiple of the minimum quantity.
2009.07 - Rev.B
Datasheet
Notice
Precaution on using ROHM Products
1.
Our Products are designed and manufactured for application in ordinary electronic equipments (such as AV equipment,
OA equipment, telecommunication equipment, home electronic appliances, amusement equipment, etc.). If you
(Note 1)
, transport
intend to use our Products in devices requiring extremely high reliability (such as medical equipment
equipment, traffic equipment, aircraft/spacecraft, nuclear power controllers, fuel controllers, car equipment including car
accessories, safety devices, etc.) and whose malfunction or failure may cause loss of human life, bodily injury or
serious damage to property (“Specific Applications”), please consult with the ROHM sales representative in advance.
Unless otherwise agreed in writing by ROHM in advance, ROHM shall not be in any way responsible or liable for any
damages, expenses or losses incurred by you or third parties arising from the use of any ROHM’s Products for Specific
Applications.
(Note1) Medical Equipment Classification of the Specific Applications
JAPAN
USA
EU
CHINA
CLASSⅢ
CLASSⅡb
CLASSⅢ
CLASSⅢ
CLASSⅣ
CLASSⅢ
2.
ROHM designs and manufactures its Products subject to strict quality control system. However, semiconductor
products can fail or malfunction at a certain rate. Please be sure to implement, at your own responsibilities, adequate
safety measures including but not limited to fail-safe design against the physical injury, damage to any property, which
a failure or malfunction of our Products may cause. The following are examples of safety measures:
[a] Installation of protection circuits or other protective devices to improve system safety
[b] Installation of redundant circuits to reduce the impact of single or multiple circuit failure
3.
Our Products are designed and manufactured for use under standard conditions and not under any special or
extraordinary environments or conditions, as exemplified below. Accordingly, ROHM shall not be in any way
responsible or liable for any damages, expenses or losses arising from the use of any ROHM’s Products under any
special or extraordinary environments or conditions. If you intend to use our Products under any special or
extraordinary environments or conditions (as exemplified below), your independent verification and confirmation of
product performance, reliability, etc, prior to use, must be necessary:
[a] Use of our Products in any types of liquid, including water, oils, chemicals, and organic solvents
[b] Use of our Products outdoors or in places where the Products are exposed to direct sunlight or dust
[c] Use of our Products in places where the Products are exposed to sea wind or corrosive gases, including Cl2,
H2S, NH3, SO2, and NO2
[d] Use of our Products in places where the Products are exposed to static electricity or electromagnetic waves
[e] Use of our Products in proximity to heat-producing components, plastic cords, or other flammable items
[f] Sealing or coating our Products with resin or other coating materials
[g] Use of our Products without cleaning residue of flux (even if you use no-clean type fluxes, cleaning residue of
flux is recommended); or Washing our Products by using water or water-soluble cleaning agents for cleaning
residue after soldering
[h] Use of the Products in places subject to dew condensation
4.
The Products are not subject to radiation-proof design.
5.
Please verify and confirm characteristics of the final or mounted products in using the Products.
6.
In particular, if a transient load (a large amount of load applied in a short period of time, such as pulse. is applied,
confirmation of performance characteristics after on-board mounting is strongly recommended. Avoid applying power
exceeding normal rated power; exceeding the power rating under steady-state loading condition may negatively affect
product performance and reliability.
7.
De-rate Power Dissipation (Pd) depending on Ambient temperature (Ta). When used in sealed area, confirm the actual
ambient temperature.
8.
Confirm that operation temperature is within the specified range described in the product specification.
9.
ROHM shall not be in any way responsible or liable for failure induced under deviant condition from what is defined in
this document.
Precaution for Mounting / Circuit board design
1.
When a highly active halogenous (chlorine, bromine, etc.) flux is used, the residue of flux may negatively affect product
performance and reliability.
2.
In principle, the reflow soldering method must be used; if flow soldering method is preferred, please consult with the
ROHM representative in advance.
For details, please refer to ROHM Mounting specification
Notice - GE
© 2014 ROHM Co., Ltd. All rights reserved.
Rev.002
Datasheet
Precautions Regarding Application Examples and External Circuits
1.
If change is made to the constant of an external circuit, please allow a sufficient margin considering variations of the
characteristics of the Products and external components, including transient characteristics, as well as static
characteristics.
2.
You agree that application notes, reference designs, and associated data and information contained in this document
are presented only as guidance for Products use. Therefore, in case you use such information, you are solely
responsible for it and you must exercise your own independent verification and judgment in the use of such information
contained in this document. ROHM shall not be in any way responsible or liable for any damages, expenses or losses
incurred by you or third parties arising from the use of such information.
Precaution for Electrostatic
This Product is electrostatic sensitive product, which may be damaged due to electrostatic discharge. Please take proper
caution in your manufacturing process and storage so that voltage exceeding the Products maximum rating will not be
applied to Products. Please take special care under dry condition (e.g. Grounding of human body / equipment / solder iron,
isolation from charged objects, setting of Ionizer, friction prevention and temperature / humidity control).
Precaution for Storage / Transportation
1.
Product performance and soldered connections may deteriorate if the Products are stored in the places where:
[a] the Products are exposed to sea winds or corrosive gases, including Cl2, H2S, NH3, SO2, and NO2
[b] the temperature or humidity exceeds those recommended by ROHM
[c] the Products are exposed to direct sunshine or condensation
[d] the Products are exposed to high Electrostatic
2.
Even under ROHM recommended storage condition, solderability of products out of recommended storage time period
may be degraded. It is strongly recommended to confirm solderability before using Products of which storage time is
exceeding the recommended storage time period.
3.
Store / transport cartons in the correct direction, which is indicated on a carton with a symbol. Otherwise bent leads
may occur due to excessive stress applied when dropping of a carton.
4.
Use Products within the specified time after opening a humidity barrier bag. Baking is required before using Products of
which storage time is exceeding the recommended storage time period.
Precaution for Product Label
QR code printed on ROHM Products label is for ROHM’s internal use only.
Precaution for Disposition
When disposing Products please dispose them properly using an authorized industry waste company.
Precaution for Foreign Exchange and Foreign Trade act
Since our Products might fall under controlled goods prescribed by the applicable foreign exchange and foreign trade act,
please consult with ROHM representative in case of export.
Precaution Regarding Intellectual Property Rights
1.
All information and data including but not limited to application example contained in this document is for reference
only. ROHM does not warrant that foregoing information or data will not infringe any intellectual property rights or any
other rights of any third party regarding such information or data. ROHM shall not be in any way responsible or liable
for infringement of any intellectual property rights or other damages arising from use of such information or data.:
2.
No license, expressly or implied, is granted hereby under any intellectual property rights or other rights of ROHM or any
third parties with respect to the information contained in this document.
Other Precaution
1.
This document may not be reprinted or reproduced, in whole or in part, without prior written consent of ROHM.
2.
The Products may not be disassembled, converted, modified, reproduced or otherwise changed without prior written
consent of ROHM.
3.
In no event shall you use in any way whatsoever the Products and the related technical information contained in the
Products or this document for any military purposes, including but not limited to, the development of mass-destruction
weapons.
4.
The proper names of companies or products described in this document are trademarks or registered trademarks of
ROHM, its affiliated companies or third parties.
Notice - GE
© 2014 ROHM Co., Ltd. All rights reserved.
Rev.002
Datasheet
General Precaution
1. Before you use our Pro ducts, you are requested to care fully read this document and fully understand its contents.
ROHM shall n ot be in an y way responsible or liabl e for fa ilure, malfunction or acci dent arising from the use of a ny
ROHM’s Products against warning, caution or note contained in this document.
2. All information contained in this docume nt is current as of the issuing date and subj ect to change without any prior
notice. Before purchasing or using ROHM’s Products, please confirm the la test information with a ROHM sale s
representative.
3.
The information contained in this doc ument is provi ded on an “as is” basis and ROHM does not warrant that all
information contained in this document is accurate an d/or error-free. ROHM shall not be in an y way responsible or
liable for an y damages, expenses or losses incurred b y you or third parties resulting from inaccur acy or errors of or
concerning such information.
Notice – WE
© 2014 ROHM Co., Ltd. All rights reserved.
Rev.001
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