BD6077GUT
LED Drivers for LCD Backlights
White Backlight LED Drivers
for Small to Medium LCD Panels
(Switching Regulator Type)
BD6077GUT
No.11040EAT41
●Description
The BD6077GUT is a white LED driver IC with synchronous rectification that can drive up to 3LEDs.
With synchronous rectification (no external schottky diode required) and small package, they can save mount space.
And the brightness of LED can be adjusted by using PWM pulse on EN pin.
●Features
1) Synchronous rectification Boost DC/DC converter
2) No external schottky diode required
3) Driving 3 series white LEDs
4) Over voltage protection
5) Protect open and short output
6) Thermal shut down
7) Brightness adjustment by external PWM pulse
8) Small and Thin CSP package in 8pins
●Applications
White LED Backlight
Torchlight and easy flash for camera of mobile phone
●Absolute
maximum ratings (Ta=25°C)
Parameter
Maximum applied voltage 1
Maximum applied voltage 2
Power dissipation
Operating temperature range
Storage temperature range
Symbol
VMAX1
VMAX2
Pd
Topr
Tstg
Ratings
7 *
1
20 *
1
750 *
2
-30~+85
-55~+150
Unit
V
V
mW
℃
℃
Condition
Vin, EN, VFB, TEST
SW, Vout
*1 These value are based on GND and GNDA pins.
*2 50mm×58mm×1.75mm At glass epoxy board mounting. When it’s used by more than Ta=25
℃,
it’s reduced by 6.0mW/℃.
●Operating
conditions (Ta=25°C)
Parameter
Power supply voltage
Symbol
Vin
Ratings
Min.
2.7
Typ.
3.6
Max.
5.5
Unit
V
Condition
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© 2011 ROHM Co., Ltd. All rights reserved.
1/16
2011.12 - Rev.A
BD6077GUT
●Electrical
characteristics
Unless otherwise specified Ta =-30℃~+85℃, Vin=3.1~5.5V
Limits
Parameter
Symbol
Min.
Typ.
[ EN terminal ]
EN threshold voltage (Low)
EN threshold voltage (High)
EN terminal input current
EN terminal output current
[ Switching regulator ]
Quiescent Current
Current Consumption
Feedback voltage
Inductor current limit
SW saturation voltage
SW on resistance P
Switching frequency
Duty cycle limit
Over voltage limit
1
Technical Note
Max.
Unit
Condition
VthL
VthH
Iin
Iout
-
1.4
-
-2.0
-
-
18.3
-0.1
0.4
-
30.0
-
V
V
µA
µA
EN=5.5V
EN=0
Iq
Idd
Vfb
Icoil
Vsat
Ronp
fSW
Duty
Ovl
-
-
0.47
210
-
-
0.8
82.7
14.0
0.1
1.0
0.50
310
0.245
5.4
1.0
95.0
14.5
2.0
1.5
0.53
410
0.345
7.2
1.2
-
15.0
µA
mA
V
mA
V
Ω
MHz
%
V
EN=TEST=VFB=0V,SW=open
EN=1.4V,TEST=0V,VFB=1.0V,
SW=open
EN=1.4V,TEST=0V
EN=1.2V, TEST=2.9V,
Vin=3.6V,VOUT=9V (*1)
Isw=200mA, Vin=3.6V
Isw=200mA, Vout=10V
EN=1.4V,TEST=0V,VFB=0V,
VOUT=10V,SW=open
EN=1.4V,TEST=0V,VFB=0V,
VOUT=10V,SW=open
EN=1.4V,TEST=0V,VFB=0V,
SW=open
This parameter is tested with DC measurement.
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© 2011 ROHM Co., Ltd. All rights reserved.
2/16
2011.12 - Rev.A
BD6077GUT
●Test
circuit
*Test circuit A (for Inductor current limit, Feedback voltage.)
Procedure
~Inducton current limit~
1. Start to increase Iout from 0mA gradually.
2. You will find that Vout will start to go down and the duty will be decreased.
3. Then, you can measure the coil current as “inductor current limit”
~VFB voltage~
1. Supply 0mA to Iout
2. Then, you can measure the VFB voltage as “Feedback voltage”.
3.1~5.5V
VIN
1µF
Icoil
A
VIN
EN
TEST
GNDA
GND
SW
VOUT
1µF
Iou
t
Technical Note
22µH
monitor
Tall
Ton
Duty=
Ton
Tall
VFB
V
RFB
24Ω
Fig.1 Test Circuit A
*Test circuit B (for Over voltage limit,Duty cycle limit, Switching frequency)
Procedure
~Over voltage limit~
1. Start to increase VOUT from 12V to 16V
2. You will find frequency change from around 1MHz to 0Hz
3. Then,you can measur the VOUT voltage as “Over Voltage limit”
~Duty cycle limit, Switching frequency ~
1. Supply 9V to VOUT terminal
2. Then,you can measure the duty as “Duty cycle limit” and the frequency and “Switching frequency”.
monitor
3.1~5.5V
VIN
1µF
EN
TEST
GNDA
GND
VIN
SW
VOUT
1µF
Tall
Ton
Duty=
Ton
Tall
12V to 16V
VFB
Fig.2 Test Circuit B
*TEST circuit C
(for Quiescent current, current comsumption, EN Terminal input/output current, EN threshold voltage(Low/High))
3.1~5.5V
ICC
A
1uF
A
IEN
0.0~5.5V
TEST
GNDA
TEST
GND VFB
1.0V(current comsumption)
VIN
EN
SW
VOUT
Fig.3 Test Circuit C
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© 2011 ROHM Co., Ltd. All rights reserved.
3/16
2011.12 - Rev.A
BD6077GUT
●Electrical
characteristic curves (Reference data)
5
4
3
2
1
0
1
2
Ta=-30℃
3
4
VIN[V]
5
6
7
1.0
0.8
0.6
0.4
Ta=85℃
0.2
Ta=-30℃
0.0
1
2
3
4
5
VIN[V]
6
7
0.8
2.5
3
Ta=25℃
Frequency [MHz]
Technical Note
1.2
1.1
Ta=-30℃
1.0
IIN[mA]
Ta=85℃
Ta=25℃
IIN[uA]
0.9
Ta=25℃
Ta=85℃
3.5
4
VIN[V]
4.5
5
5.5
Fig.4 Current consumption
vs.
Power supply voltage
Fig.5 Quiescent current
vs.
Power supply voltage
Fig.6 Oscillation frequency
vs.
Power supply voltage
550
450
400
Ta=85℃
Inductor current [mA]
350
300
VIN=3.1V
250
90
85
Murata : LQH32CN53L
525
VFB[mV]
Ta=25℃
VIN=3.6V
VIN=5.5V
Efficiency[%]
80
75
70
65
60
55
TOKO : DB3015CK
500
475
Ta=-30℃
450
2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
Ta[℃]
200
-30
-10
10
30
50
Ta [deg]
70
85
50
10
15
20
25
30
Iout[mA]
35
40
Fig.7 Feedback voltage
vs.
Power supply voltage
Fig.8 Inductor current limit
vs.
Temperature
Fig.9 Efficiency vs. LED current
(4LED=VOUT14V)
90
85
Efficiency [%]
80
VIN=5.5V
1400
1200
Output Power[mW]
Ta=-30℃
Efficiency[%]
Ta=25℃
90
Ta=-30℃
85
80
Ta=85℃
75
Ta=25℃
70
65
60
3.0
3.2
3.4
3.6 3.8
VIN[V]
4.0
4.2
2.7
3.1
3.5
3.9 4.3
VIN[V]
4.7
5.1
5.5
VIN=3.6V
75
70
65
60
10
15
20
25
30
Iout [mA]
35
40
Ta=25℃
VIN=3.1V
VIN=4.2V
1000
800
Ta=85℃
600
400
Fig.10 Efficiency vs. LED current
(3LED=VOUT10.5V)
coil : TOKO DB3015CK
Fig.11 Output power
vs.
Power supply voltage
coil : TOKO DB3015CK
Fig.12 Efficiency
vs.
Power supply voltage
(Load=34mA)
coil : TOKO DB3015CK
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© 2011 ROHM Co., Ltd. All rights reserved.
4/16
2011.12 - Rev.A
BD6077GUT
●Electrical
characteristic curves (Reference data) – Continued
Technical Note
VOUT
VOUT
EN
EN
VOUT
delta=1.68V
VFB
Peak=208mA
Peak=160m
VFB
Iin
Vin=3.6V, Ta=25
o
C
3LED, 34mA Load
Iin
Fig.13 LED Open output voltage
Fig.14 LED brightness adjustment
Fig.15 Soft Start
50
500
40
400
VIN=4.2V
30
300
VFB[mV]
VFB[mV]
VIN=3.9V
VIN=3.1V
VIN=3.6V
10
VIN=3.6V
0
0
0
20
40
60
Duty[%]
80
100
0
2
4
Duty[%]
6
8
10
-20%
0
20
40
60
Duty[%]
80
100
20%
15%
VIN=4.2V
VFB voltage variation
10%
VIN=5.2V
5%
0%
-5%
VIN=3.6V
VIN=5.2V
20
VIN=3.9V
VIN=3.1V
VIN=5.2V
200
VIN=3.1V
VIN=4.2V
100
-10%
-15%
Fig.16 LED brightness adjustment
for PWM control
Fig.17 LED brightness adjustment
for PWM control (Expansion)
Fig.18 LED brightness variation
for PWM control
(comparison of VFB at VIN=3.9V)
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© 2011 ROHM Co., Ltd. All rights reserved.
5/16
2011.12 - Rev.A
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