ROHM BD6072HFN

LED Drivers for LCD Backlights
White Backlight LED Drivers
for Small to Medium LCD Panels
(Switching Regulator Type)
BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN
No.11040ECT19
●Description
Switching Regulator type LED Driver Series for small LCD backlight are boost DC/DC converters possible to drive the white
LEDs at constant. It is possible that turning on white LED steadily by a series connection which has no current variation, and
by a fast transient response with current mode. And, BD6069GUT/BD6071HFN/BD6072HFN are white LED driver ICs with
synchronous rectification. With synchronous rectification (no external schottky diode required) and small package, they can
save mount space. BD6071HFN suited over voltage and over current limit from BD6069GUT/BD6072HFN.
●Features
1) Boost DC/DC converter
2) Adjustment of brightness by external PWM pulse
3) Possible to driving 3 LEDs (BD6071HFN )
4) Possible to driving 4 LEDs (BD6069GUT, BD6072HFN)
5) Possible to driving 8 LEDs (BD6067GU)
6) Soft start function (BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN)
7) Synchronous rectification Boost DC/DC converter (BD6069GUT, BD6071HFN, BD6072HFN)
8) No external schottky diode required (BD6069GUT, BD6071HFN, BD6072HFN)
9) Output Open • Short protect (BD6069GUT, BD6071HFN, BD6072HFN)
●Applications
These drivers are applicable for various fields such as mobile phones, portable game machines, Inter-phone camera,
audio player, portable DVD player, back light for printer display etc… and support light of the camera for the mobile phone,
simple flash. And, these can use power supply for OEL.
●Line up matrix
Input
voltage range
Switching
frequency
BD6067GU
2.7 ~ 5.5V
0.8 ~ 1.2MHz
5 ~
BD6069GUT
2.7 ~ 5.5V
0.8 ~ 1.2MHz
BD6071HFN
2.7 ~ 5.5V
BD6072HFN
2.7 ~ 5.5V
Parameter
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© 2011 ROHM Co., Ltd. All rights reserved.
White LED
number
Operating
temperature range
Package
-30 ~ +85℃
VCSP85H1
4
-30 ~ +85℃
VCSP60N1
0.8 ~ 1.2MHz
3
-30 ~ +85℃
HSON8
0.8 ~ 1.2MHz
4
-30 ~ +85℃
HSON8
1/29
8
2011.01 - Rev.C
BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN
Technical Note
►BD6067GU
●Absolute maximum ratings (Ta=25℃)
Parameter
Symbol
Ratings
Unit
Power supply voltage 1
VMAX1
7 *1
V
Applicable to Vin, EN,
Vfb and VDAC pins
Power supply voltage 2
VMAX2
40 *1
V
Applicable to SW and Vout pins
Operating temperature range
Topr
-30 ~ +85
℃
Storage temperature range
Tstg
-55 ~ +150
℃
Pd
800 *2
mW
Power dissipation
Conditions
50mm×58mm×1.75mm
Glass epoxy PCB mounting
*1 This value is based on GND.
*2 This loss decreases approximate 6.4mW/℃ when Ta is 25℃ or more.
●Recommended Operation Range (Ta=-30℃ to +85℃)
Parameter
Operating supply voltage
Symbol
Ratings
Unit
VCC
2.7 ~ 5.5
V
●Electrical characteristics (Unless otherwise stated, Ta is 25℃ and Vin is 3.6V.)
Limits
Parameter
Symbol
Min.
Min.
Min.
Conditions
Vin pin
Unit
Conditions
<EN pin>
‘L’ level input voltage
VthL
-
-
0.4
V
‘H level input voltage
VthH
1.4
-
-
V
‘H’ level input current
IIH
-
18.3
30.0
μA
EN=5.5V
‘L’ level input current
IIL
-2.0
-0.1
-
μA
EN=0V
VDAR
56
112
168
kΩ
Input voltage range
Vin
3.1
-
5.5
V
Quiescent current
Iq
-
0.1
2.0
μA
EN=0V
Operating current
Idd
-
0.9
1.4
mA
EN=3.6V, Vfb=1.0V
VFB pin control voltage
Vfb
0.18
0.20
0.22
V
Over current limit
Icoil
450
600
750
mA
SW transistor ON resistance
Ronn
-
0.5
1.4
Ω
Switching frequency
fSW
0.8
1.0
1.2
MHz
Maximum duty
Duty
92.5
95.0
-
%
Vo
-
-
30.0
V
Over voltage protection
Ovp
30.0
31.0
32.0
V
Output open protection
Ovl
-
0.7
1.4
V
Startup time
Ts
-
0.5
1.0
ms
<DAC control pin>
VDAC-Vfb resistance
<Switching regulator>
Output voltage range
*1
Isw=200mA
Vfb=0V
Vfb=0V
Vout=24V
*1 The DC current is measured in this item.
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© 2011 ROHM Co., Ltd. All rights reserved.
2/29
2011.01 - Rev.C
BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN
Technical Note
►BD6067GU
●Electrical characteristic curves (Reference data)
5.0
4.0
1.0
1.4
0.9
1.3
Switching freqency [MHz]
0.8
0.7
0.6
Iq [µA]
Ta=85℃
2.0
Ta=25℃
0.5
Ta=85℃
0.4
Ta=25℃
0.3
1.0
3
3.5
4
Vin [V]
4.5
5
0.0
2.5
5.5
3
100
4
Vin [V]
4.5
5
Vin=5.5V
Efficiency [%]
Vin=3.6V
70
Vin=3.1V
60
Vin=5.5V
15
25
ILED [mA]
35
80
Vin=3.6V
70
Vin=3.1V
45
35
3.5
4
Vin [V]
4.5
5
5.5
Fig.7 Output Voltage vs.
Power Supply Voltage
(8LED)
15
25
ILED [mA]
35
45
25
Ta=25℃
20
200
170
2.5
Vin=3.6V
Ta=-30℃
15
10
Ta=85℃
Vin=3.1V
5
180
3
Vin=3.6V
Vin=3.1V
(8LED) (Ta=25℃)
Ta=85℃
500
70
Fig.6 Efficiency vs. LED Current
190
1000
5.5
Vin=5.5V
5
ILED [mA]
Vfb [mV]
1500
5
(7LED) (Ta=25℃)
210
2000
4.5
Fig.5 Efficiency vs. LED Current
220
Ta=-30℃
4
Vin [V]
80
45
Ta=25℃
2500
0
2.5
25
ILED [mA]
230
3000
3.5
50
15
(6LED) (Ta=25℃)
3500
3
60
5
Fig.4 Efficiency vs. LED Current
Ta=85℃
0.8
90
50
5
0.9
Fig.3 Oscillation Frequency vs.
Power Supply Voltage
60
50
1
100
90
80
1.1
0.6
2.5
5.5
100
90
Output power [mW]
3.5
Fig.2 Quiescent current vs. Power
Supply Voltage
Fig.1 Operating current vs. Power
Supply Voltage
Ta=-30℃
0.7
0.1
Ta=-30℃
0.0
2.5
Efficiency [%]
Ta=-30℃
0.2
Efficiency [%]
Idd [mA]
3.0
Ta=25℃
1.2
Vin=2.7V
0
3
3.5
4
Vin [V]
4.5
5
5.5
0
20
40
60
EN Duty [%]
80
100
Fig.8 VFB Pin Control Voltage vs.
Power Supply Voltage
Fig.9 EN Pin
PWM Brightness Control Characteristic
(8LED) (ILED=20mA)
(f=100Hz, Ta=25℃)
25
Vin=3.6V
ILED [mA]
20
15
10
Vin=3.1V
5
0
0.0
Vin=2.7V
0.5
1.0
VDAC [V]
1.5
2.0
Fig.10 DAC
Brightness Control Characteristic
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© 2011 ROHM Co., Ltd. All rights reserved.
3/29
2011.01 - Rev.C
BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN
Technical Note
►BD6067GU
●Block Diagram and Recommended Circuit Example
L1
22µH
Vin
Cin
1µF
Vin
D1
Over voltage
protect
Thermal
Shutdown
PWMcomp
S
Q
Current
Sence
ERRAMP
+
14kΩ
VFB
98kΩ
+
OSC
300kΩ
GND GNDA
20mA
+
-
+
Control
R
+
-
Output open
protect
TSD
Q1
Cout
1µF
Vout
SW
VDAC
R1
10Ω
EN
OFF
ON
Fig.11 Block Diagram and Recommended Circuit Example
C1
C2
B3
B1
A1
C3
A2
A3
Fig.12 Pin location diagram VCSP85H1 (Bottom view)
●Pin assignment table
Pin
Pin name
number
In/Out
Function
A1
GNDA
-
Analog GND
A2
EN
In
Enable control (pull-down by internal resistance)
A3
VDAC
In
Analog signal input for current adjustment
B1
Vin
-
Supply voltage input
B3
VFB
In
Feedback voltage input
C1
VOUT
In
Over voltage protection input SBD open protection input
C2
SW
In
Switching pin
C3
GND
-
Power GND
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© 2011 ROHM Co., Ltd. All rights reserved.
4/29
2011.01 - Rev.C
BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN
Technical Note
►BD6067GU
●Release Circuit Protection
1) Operation
BD6067GU is a constant frequency PWM current mode DC/DC converter. It is shown in the block diagram of Fig.11. In a
PWM comparator forming one of the PWM current mode features, one is an error element from the error amplifier and
another is an element produced by superimposing the inductor current on a slope waveform that prevents sub-harmonic
oscillation. This output controls Q1 via the RS latch. Energy is stored in an external inductor whileQ1 is ON and then it is
moved to the COUT capacitor via D1 while Q1 is OFF. In this way, voltage Vout higher than input voltage Vin can be
obtained. Because the above operation is performed in a way that the VFB pin voltage equals the Vfb voltage, the boost
voltage is dominantly determined by the expression “Vf × number of LEDs.”
Vout voltage = (Vf × number of LEDs) + Vfb
2) LED current control
The LED current is determined depending on the VFB pin voltage “Vfb” and the resistance connected to VFB.
ILED is given below.
ILED =200mV/ R1
ILED [mA]
5
10
12
15
20
BD6067GU
39
20
16
13
10
R1 [Ω]
3) Dimming control
▪ Control by PWM signal
The startup condition of BD6067GU is controlled via the SHDNB/EN pin. It is powered OFF at 0.4V or less and powered
ON at 1.4V or more.
As shown in Fig.13, brightness is controlled in the BD6067GU via the PWM signal input the SHDNB/EN pin. In this way,
the LED current is controlled in a range from 0 to the maximum current. The average LED current increases in
proportion to the Duty cycle of the PWM signal. In the PWM off cycle, no current dissipation takes place in IC and LEDs,
resulting in high efficiency. Duties below 5% and above 95% must no be used for brightness control because they
significantly affects the leading and trailing edges. BD6067GU standard PWM frequency ranges from 100Hz to 300Hz.
L1
22μH
Vin
Vin
D1
SW
Vout
1μF
BD6067GU
VFB
VDAC
GNDA GND
ILED
EN
PWM
100Hz~300Hz
R1
10Ω
Fig.13 Example of Brightness Control by PWM signal at the EN Pin
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© 2011 ROHM Co., Ltd. All rights reserved.
5/29
2011.01 - Rev.C
BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN
Technical Note
►BD6067GU
▪ Control by DC Voltage
BD067GU has a built-in function for LED current control by DC voltage and can control the current by VDAC pin control
voltage.
L1
22μH
25
Vin
Vin
D1
SW
20
Vout
VFB
ILED [mA]
1μF
BD6067GU
Vfb
VDAC
GNDA GND
EN
15
10
ILED
5
0
DAC
0
0.5
1
1.5
2
2.5
DAC [V] (Vfb=200mV)
R1
10Ω
Fig.15 DAC Constant Current Characteristics by
DAC Control
Fig.14 Brightness Control by BD6067GU DAC
●Over voltage Protection
BD6067GU has an over voltage protection feature. When a fault occurs, for example, IC is disconnected from LED, an
excessive voltage rise may cause the SW pin and VOUT pin to exceed the absolute maximum ratings respectively, resulting
in IC damage. For this reason, when VOUT is 30V or more, over voltage protection is activated to turn Q1 off so that the SW
pin and VOUT pin don’t exceed the absolute maximum ratings.
At this time, the IC state changes from active to inactive and the output voltage drops slowly. Then, when the output voltage
falls below the over voltage protection hysteresis level, the output voltage continues to rise up to 30V again.
This protection circuit is shown in Fig.16.
D1
SW
Q1
Cout
Vout
Driver
OVER Detector
OVER VOLTAGE REF
Control
Fig.16 Block Diagram for Short-circuit Protection and over voltage Protection
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© 2011 ROHM Co., Ltd. All rights reserved.
6/29
2011.01 - Rev.C
BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN
Technical Note
►BD6067GU
●Startup and Rush Current
BD6067GU has a built-in soft start function. This function prevents the rush current from being generated at startup time.
Vin
Cin
1µF
L1
22µH
Vin
D1
Cout
1µF
Vout
SW
Over voltage
protect
Output open
protect
Thermal
Shutdown
TSD
+
-
ILED
+
-
Soft start circuit
PWMcomp
S
Q1
Q
Control
R
ERRAMP
+
Current
Sence
300kΩ
+
14kΩ VFB
98kΩ
VDAC
0~1.8V
OSC
GND GNDA
R1
10Ω
VDAC
+
EN
OFF
ON
Fig.17 Soft Start Circuit
●Application Circuit Example
The output maximum voltage range of BD6067GU is 30V.
*** When LED has 8 lights, special care should be taken to prevent output voltage (VOUT) from exceeding 30V.
VOUT = (LED vf × number of LED lights) + Vfb
Vin
Cin
1µF
L1
22µH
Vin
D1
Over voltage
protect
Thermal
Shutdown
TSD
Q
Output open
protect
PWMcomp
S
Q1
Cout
1µF
Vout
SW
Control
R
Current
Sence
+
14kΩ
VFB
R1
10Ω
98kΩ
VDAC
1µF
OSC
300kΩ
R2
10kΩ
1kHz
EN
OFF
ILED
+
-
ERRAMP
+
+
GND GNDA
+
-
ON
Fig.18 Example of Dimming Circuit Subject to PWM Control at the VDAC Pin
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© 2011 ROHM Co., Ltd. All rights reserved.
7/29
2011.01 - Rev.C
BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN
Technical Note
►BD6067GU
●External components Selection Method
<<Constants in the standard circuit example>>
R1: Determines the LED current ILED at power ON.
<Recommended parts>
R1[Ω]
ILED (mA)
5
39
15
13
20
10
L1: Coil for boost. The recommended value is 22µH. be sure to use a sufficient DC current permissible value and a sufficient
low DC resistance coil.
<Recommended parts>
Inductance value
Model number/manufacturer
22µH
NR3015T220M / TAIYO YUDEN
Cin: Power supplie bypass capacitor. This capacitor must be provided to remove an instantaneous power supply noise for
stable voltage supply to this IC. To obtain good characteristics, the low ESR parts like the ceramics capacitor must be
used. The recommended capacitance is 1µF or more.
<Recommended parts>
Capacitance value
Model number/manufacturer
1.0µF
GRM188B11A105KA61B / MURATA
C0: Output smoothing capacitor. The capacitance recommended for BD6067GU is 1.0µF.
<Recommended parts>
Capacitance value
Model number/manufacturer
1.0µF
UMK107C105KA-B / TAIYO YUDEN
When selecting capacitors for Cin and C0, special care should be taken for rated voltage. The desirable rated voltage is
about double the voltage actually applied to the capacitor. When the margin for rated voltage is not sufficient, the
capacitance may be a half or less of the nominal value.
D1: Schottky barrier diode (SBD) for output rectification. To achieve high conversion efficiency, use a diode characterized by
of low Vf, low reverse leak and high current capacity.
<Recommended parts>
Model number/manufacturer
RB160M-40 / ROHM
●Recommended PCB layout
When a PCB designed, the power supply line should be wired in a way that the board impedance can be minimized. If
necessary, the bypass capacitor must be connected. In particular, pins around the DC/DC converter must be wired in such a
way that the wiring impedance can be minimized. In addition, when a DC/DC converter using a coil is used, it is necessary to
place the output capacitor Cout, coil L1, rectification diode D1 and bypass capacitor CIN near this IC and keep the GND
impedance low.
To cell voltage source
CIN
EN
GNDA
VDAC
VIN
VOUT
VFB
SW
R1
GND
COUT
D1
To battery GND
L1
Fig.19 PCB Layout Image
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© 2011 ROHM Co., Ltd. All rights reserved.
8/29
2011.01 - Rev.C
BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN
Technical Note
►BD6067GU
Top surface (Top view)
Bottom surface (Top view)
Fig. 20 PCB Layout
***Bypass capacitor and GND
It is necessary to place bypass capacitor CIN, coil L1 and power ground GND near this IC (CIN2 of Fig.20).
To obtain good characteristics, as the need arises power supply, bypass capacitor CIN between analog GNDA must be
added. (at LED8 lights).
When LED has 8 lights, full assessment is required for characteristics prior to usage.
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9/29
2011.01 - Rev.C
BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN
Technical Note
►BD6071HFN
●Absolute maximum ratings (Ta=25℃)
Parameter
Symbol
Ratings
Unit
Power supply voltage 1
VMAX1
7 *1
V
Applicable to Vin,EN,VFB,
TEST pins
Power supply voltage 2
VMAX2
20 *1
V
Applicable to SW,Vout pins
Pd
630 *2
mW
70mm×70mm×1.6mm at
glass epoxy board mounting
Power dissipation
Operating temperature range
Topr
-30 ~ +85
℃
Storage temperature rang
Tstg
-55 ~ +150
℃
Conditions
*1 These values are based on GND and GNDA pins.
*2 When it’s used by more than Ta=25℃, it’s reduced by 5.04mW/℃.
●Recommended operating range (Ta=-30℃ ~+85℃)
Parameter
Ratings
Symbol
Operating supply voltage
Vin
Min.
Typ.
Max.
2.7
3.6
5.5
Unit
Conditions
V
●Electrical characteristic (Unless otherwise specified Ta = +25℃, Vin=3.6V)
Limits
Parameter
Symbol
Min.
Typ.
Max.
Unit
Conditions
<EN Terminal>
EN threshold voltage (Low)
VthL
-
-
0.4
V
EN threshold voltage (High)
VthH
1.4
-
-
V
EN terminal input current
Iin
-
18.3
30.0
μA
EN=5.5V
Iout
-2.0
-0.1
-
μA
EN=0
Input voltage range
Vin
3.1
-
5.5
V
Quiescent Current
Iq
-
0.1
2.0
μA
EN=0V
EN=2.6V,VFB=1.0V,VIN=3.6V
EN terminal output current
<Switching regulator>
Current Consumption
Idd
-
1.1
1.5
mA
Feedback voltage
Vfb
0.47
0.50
0.53
V
Inductor current limit
Icoil
200
265
330
mA
SW saturation voltage
Vsat
-
0.14
0.28
V
Isw=200mA, Vout=13V
SW on resistance P
Ronp
-
2.1
3.2
Ω
Ipch=200mA,Vout=13V
Switching frequency
fSW
0.8
1.0
1.2
MHz
Duty cycle limit
Duty
82.7
85.0
-
%
Output voltage range
Vo
-
-
14.0
V
Over voltage limit
Ovl
14.0
14.5
15.0
V
Start up time
Ts
-
0.5
1.0
ms
Vin=3.6V *1
VFB=0V
VFB=0V
*1 This parameter is tested with dc measurement.
●Electrical characteristic curves (Reference data)
5.0
1.0
1.4
0.9
1.3
Switching freqency [MHz]
0.8
4.0
3.0
Iin [µA]
IIN [mA]
0.7
Ta=85℃
2.0
Ta=25℃
0.6
0.5
0.4
0.3
1.0
0.2
3
3.5
4
Vin [V]
4.5
5
5.5
Fig.21 Current Consumption vs.
power source voltage
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© 2011 ROHM Co., Ltd. All rights reserved.
Ta=-30℃
1.1
Ta=25℃
1
0.9
Ta=85℃
0.8
0.7
0.1
Ta=-30℃
0.0
2.5
Ta=-30, 25, 85℃
1.2
0.0
2.5
3
3.5
4
Vin [V]
4.5
5
5.5
Fig.22 Quiescent current vs.
power source voltage
10/29
0.6
2.5
3
3.5
4
Vin [V]
4.5
5
5.5
Fig.23 Oscillation frequency vs.
power source voltage
2011.01 - Rev.C
BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN
Technical Note
►BD6071HFN
●Electrical characteristic curves (Reference data)
90
90
90
CoilCraft : DO1608C-223
MURATA:LQH32CN220K53
75
TDK:VLCF4020T-220MR56
70
TDK:VLF3012AT-220MR33
65
85
85
80
80
Efficiency [%]
CoilCraft : DO1608C-223
80
Efficiency [%]
Efficiency [%]
85
MURATA:LQH32CN220K53
75
TDK:VLCF4020T-220MR56
70
TDK:VLF3012AT-220MR33
65
60
15
20
25
30
ILED [mA]
35
40
VIN=4.5V
75
VIN=3.6V
VIN=3.1V
70
65
60
10
VIN=5.5V
60
10
15
20
25
30
ILED [mA]
35
40
10
15
20
25
30
ILED [mA]
35
40
Fig.24 Efficiency vs. LED current in each coil Fig.25 Efficiency vs. LED current in each coil Fig.26 Efficiency vs. LED current
< 3LED > (VOUT=10.5V, VIN=3.6V, Ta=25℃)
340
85
320
2000
Ta=-30℃
300
80
VIN=5.5V
75
VIN=4.5V
70
VIN=3.6V
VIN=3.1V
280
260
240
220
60
10
15
20
25
30
ILED [mA]
35
40
Fig.27 Efficiency vs. LED current
< 3LED > (VOUT=10.5V, VIN=3.6V, Ta=25℃)
0.53
Ta=25℃
1000
Ta=85℃
VIN=5.5V
200
-30
-10
10
30
50
Temparature [℃]
70
90
Fig.28 Inductor current limits vs.
Temperature
EN
5V/div
0
2.5
3
3.5
VIN [V]
4
4.5
Fig.29 Output power vs. power
source voltage
VOUT
1V/div
0.52
⊿V=1.57V
Ta=85℃
0.51
VFB [V]
1500
500
VIN=3.6V
VIN=3.1V
65
< 2LED > (VOUT=7.5V, Ta=25℃)
Output Power [mW]
90
IIN [mA]
Efficiency [%]
< 2LED > (VOUT=7.5V, VIN=3.6V, Ta=25℃)
IIN
100mA/dev
Ta=25℃
0.5
VOUT
10V/div
Ta=-30℃
0.49
10ms
IIN
200mA/div
VFB
0.5V/div
0.48
( 100µs/div )
0.47
2.5
3
3.5
4
4.5
VIN [V]
5
Ave IIN =1.5mA
( 4ms/div )
5.5
Fig.30 Feedback voltage vs.
Power source voltage
Fig.31 Soft Start
Fig.32 LED Open output voltage
( VIN = 3.6V, Ta = 25℃, 3LED, 20mA Load )
EN
2V/div
IIN
200mA/div
ILED
20mA/div
VOUT
5V/div
( 4ms/div )
Fig.33 LED luminance adjustment
( VIN = 3.6V, Ta = 25℃, 3LED, 20mA Load )
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11/29
2011.01 - Rev.C
BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN
Technical Note
►BD6071HFN
●Block diagram, recommended circuit example, pin location diagram
L
22μH
CIN
1μF
VIN
SW
VOUT
over voltage
protect
Q2
short protect
TSD
Q1
PWMcomp
Q
S
Q
R
+
Control
Current
Sence
+
-
COUT
1μF
+
-
white LED
ERRAMP
+
VFB
+
OSC
RFB
24Ω
300kΩ
GND
GNDA
EN
TEST
Fig.34 Block diagram and recommended circuit diagram
8
7
6
5
1
2
3
4
Fig.35 Pin location diagram HSON8 (Top view)
●Pin assignment table
PIN Name
In/Out
Pin number
Function
GNDA
-
1
Analog GND
EN
In
2
Enable control(pull down is integrated on resistance)
TEST
In
3
TEST input (pull down is integrated on resistance)
VIN
In
8
Power supply input
VFB
In
4
Feedback input voltage
VOUT
Out
7
Output
SW
In
6
Switching terminal
GND
-
5
Power GND
●Operation
BD6071HFN is a fixed frequency PWM current mode DC/DC converter, and adopts synchronous rectification architecture.
As for the inputs of the PWM comparator as the feature of the PWM current mode, one is overlapped with error components
from the error amplifier, and the other is overlapped with a current sense signal that controls the inductor current into Slope
waveform for sub harmonic oscillation prevention. This output controls Q1 and Q2 via the RS latch.
Timing of Q1 and Q2 is precisely adjusted so that they will not turn ON at the same time, thus putting them into
non-overlapped relation.
In the period where Q1 is ON, energy is accumulated in the external inductor, and in the period where Q1 is OFF, energy is
transferred to the capacitor of VOUT via Q2.
Further, BD6071HFN has many safety functions, and their detection signals stop switching operation at once.
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© 2011 ROHM Co., Ltd. All rights reserved.
12/29
2011.01 - Rev.C
BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN
Technical Note
►BD6071HFN
●Description of Functions
1) Soft starts and off status
BD6071HFN has soft start function and off status function.
The soft start function and the off status function prevent large current from flowing to the IC via coil.
Occurrence of rush current at turning on is prevented by the soft start function, and occurrence of invalid current at turning
off is prevented by the off status function.
2) Isolation control
BD6071HFN has isolation control to prevent LED wrong lighting at power off.
The cause of the LED wrong lighting is leak current from VIN to the white LED.
Therefore, when BD6071HFN gets in power off (EN = L), the isolation control cuts the DC path between SW and Vout,
thereby the leak current from VIN to LED is prevented.
VIN
SW
White LED
Vout
VFB
Fig.36 Isolation control
3) Short-circuit protection and over voltage protection
BD6071HFN has short-circuit protection and over voltage protection. These detect the voltage of VOUT, and at error, they
stop the output Tr. Details are as shown below.
・Short-circuit protection
In the case of short-circuit of the DC/DC output (VOUT) to GND, the coil or the IC may be destructed.
Therefore, at such an error as VOUT becoming 0.7V or below, the Under Detector shown in the figure works, and turns
off the output Tr, and prevents the coil and the IC from being destructed.
And the IC changes from its action condition into its non-action condition, and current does not flow to the coil (0mA).
・Over voltage protection
At such an error as the IC and the LED being cut off, over voltage causes the SW terminal and the VOUT terminal
exceed the absolute maximum ratings, and may destruct the IC. Therefore, when VOUT becomes 14.5V or higher, the
over voltage limit works, and turns off the output Tr, and prevents the SW terminal and the VOUT terminal from
exceeding the absolute maximum ratings.
At this moment, the IC changes from its action condition into its non action condition, and the output voltage goes down
slowly. And, when the output voltage becomes the hysteresis of the over voltage limit or below, the output voltage goes
on up to 14.5V once again.
This protection action is shown in Fig.37.
Cout
SW
Vout
OVER Detector
OVER VOLTAGE REF
driver
UNDER Detector
UNDER VOLTAGE REF
Control
Fig.37 Block diagram of short-circuit protection and over voltage
4) Thermal shut down
BD6071HFN has thermal shut down function.
The thermal shut down works at 175℃ or higher, and while holding the setting of EN control from the outside, the IC
changes from its action condition into its non action condition. And at 175℃ or below, the IC gets back to its normal action.
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© 2011 ROHM Co., Ltd. All rights reserved.
13/29
2011.01 - Rev.C
BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN
Technical Note
►BD6071HFN
●Start control and brightness control
BD6071HFN can control the start conditions by its EN terminal, and power off at 0.4V or below, and power on at 1.4V or
higher. And by changing the duty of power on and off by PWM control, the LED brightness can be adjusted.
Two techniques are available for the brightness adjustment. One is discrete time (PWM) adjustment, and the other is
continuous time adjustment.
1) PWM brightness adjustment is made by giving PWM signal to EN as shown in Fig.38.
The BD6068GU/BD6071HFN T power on/off are according to the PWM signal. By this method, LED current is controlled
from 0 to the maximum current. The average LED current increases in proportion with the duty cycle of PWM signal. While
in PWM off-cycle mode, the IC and LED both consume no currents, thus providing a high-efficiency operation. And please
don’t use duty less than 5% or more than 95% of current setting for the brightness adjustment because of the influence of
turning on and off operating is large. The recommended PWM frequency is 100Hz ~ 300Hz.
22µH
VIN
SW
VIN
VOUT
PWM
1µF
EN
TEST
GNDA
GND
VFB
24Ω
Fig.38 The brightness adjustment example of EN terminal by PWM (fPWM = 100Hz ~ 300Hz)
2-1) The continuous time the brightness adjustment is made by giving DC control voltage to VFB pin of BD6068GUT /
BD6071HFN via a series resistor as shown in Fig.39. LED luminance (current) changed by giving DC voltage to VFB
directly. DC voltage is given from filtered one of DAC signal, or PWM signal shown in Fig.41. The advantage of this
approach is that the PWM signal to be used to control the LED brightness can be set to a high frequency (1kHz or higher).
And please don’t use duty less than 5% or more than 95% of current setting for the brightness adjustment.
LED current (ILED) is approximated by the following equation.
ILED = [{(VFB-DAC) / R1} × R2 + VFB ] / RFB
22μH
3030
VIN
2525
SW
2020
VOUT
1μF
EN
ILED
TEST
GNDA
4.7kΩ
VFB
GND
22kΩ
R2
R1
ILED [mA]
VIN
1515
1010
55
24Ω
RFB
00
-5-5
0
0
DAC
0.5
1
1.5 2 2.5
1.5DAC2 [V] 2.5
(VFB=500mV)
0.5
3
1
3
4
3.5
3.5
4
Fig.40 DAC adjustment
Fig.39 The brightness adjustment example by DAC
22μH
VIN
25
SW
VOUT
EN
20
1μF
ILED
TEST
GNDA
GND
VFB
33kΩ
47kΩ
100kΩ
PWM
10kHz
0～2.85V
30Ω
ILED [mA]
VIN
15
10
5
0
47nF
0
10
20
30
40
50
60
70
80
90
100
HI Duty [%]
Fig.42 VFB PWM Control
Fig.41 The brightness adjustment example of
VFB terminal by PWM (fPWM=10kHz)
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© 2011 ROHM Co., Ltd. All rights reserved.
14/29
2011.01 - Rev.C
BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN
Technical Note
►BD6071HFN
2-2) The brightness adjustment of below is done in adjusting of R2 ON time by R1 and Duty cycle of PWM.
The minimum value of the LED current is decided by VFB / R1 at the PWM 0%, the maximum value of the LED current is
decided by VFB / R2 at the PWM 100%.
ILED is given as shown below.
ILED=VFB / R1 + VFB / R2 × HI Duty
Standard PWM frequency is 100Hz~1kHz. And please don’t use duty less than 5% or more than 95% of current setting for
the brightness adjustment.
25
22μH
VIN
20
SW
VIN
ILED [mA]
VOUT
1μF
EN
15
10
TEST
GNDA
5
VFB
GND
R2
47Ω
R1
47Ω
0
0
10 20 30 40
PWM
1kHz
50 60 70 80 90 100
HI Duty [%]
Fig.44 VFB PWM Control
Fig.43 The brightness adjustment example of VFB terminal by PWM
(fPWM=100Hz ~ 1kHz)
●Setting range of LED current
LED current is determined by the voltage of VFB
and the resistor connected to VFB terminal.
ILED is given as shown below.
ILED=VFB/RFB
The current in the standard application is as shown below.
VFB=0.5V, RFB=24Ω
ILED=20.8mA
22μH
VIN
1μF
SW
VIN
VOUT
PWM
EN
1μF
ILED
TEST
GNDA
GND
VFB
RFB
24Ω
Fig.45 Recommended circuit diagram
The shaded portion in the figure below is the setting range of LED current to become the standard. In case of using 2LED,
LED current might increase due to over boosting when VOUT is less than 5.5V. Therefore some ICs may not be used at
desired currents. Consequently, for the proper setting of LED current, thoroughly check it for the suitability under use
conditions including applicable power supply voltage and temperature.
VIN=5.5V
70
70
60
60
50
50
40
30
2LED
20
VIN=3.1V ~ 4.2V
80
ILED [mA]
ILED [mA]
80
40
30
2LED
3LED
20
3LED
10
10
0
5.5
0
7
8
9
10
11
12
13
14
7
8.5
10
11.5
13
14
VOUT [V]
VOUT [V]
Fig.46 LED Setting range of LED current
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© 2011 ROHM Co., Ltd. All rights reserved.
15/29
2011.01 - Rev.C
BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN
Technical Note
►BD6071HFN
●Selection of external parts
Recommended external parts are as shown below.
When to use other parts than these, select the following equivalent parts.
・Coil
Value
Tolerance
Manufacturer
Product number
Size (mm)
W
L
H
DCR(Ω)
22μH
±10%
MURATA
LQH32CN220K53
2.5
3.2
1.55
0.71
22μH
±20%
TDK
VLF3012AT220MR33
2.6
2.8
1.2
0.66
22μH
±20%
Coil Craft
DO1608
4.45
6.6
2.92
0.37
22μH
±20%
TDK
VLF3010AT220MR33
2.6
2.8
1.0
1.30
Please refer to the reference data of p.11 for the change in the efficiency when the coil is changed.
・Capacitor
Value
Manufacturer
Product number
Size (mm)
L
W
H
Temperature
range
<CIN>
1µF
MURATA
GRM188B11A105K
1.6
0.8
0.8
-25deg~+85deg
MURATA
GRM188B31E105K
1.6
0.8
0.8
-25deg~+85deg
<COUT>
1µF
・Resistor
Value
Tolerance
24Ω
±1%
Manufacturer
Product number
Size (mm)
L
W
H
0.6
0.3
0.23
<RFB>
ROHM
MCR006YZPF24R0
The coil is the part that is most influential to efficiency. Select the coil whose direct current resistor (DCR) and current inductance characteristic is excellent. The BD6068GUT/BD6071HFN is designed for the inductance value of 22µH. Do not
use other inductance value. Select a capacitor of ceramic type with excellent frequency and temperature characteristics.
Further, select Capacitor to be used for CIN/COUT with small direct current resistance, and pay sufficient attention to the
PCB layout shown in the next page.
●PCB Layout
To battery power source
CIN
GNDA
EN
TEST
VFB
RFB
VIN
VOUT
COUT
L1
SW
GND
To battery GND
Fig.47 PCB Layout Image
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© 2011 ROHM Co., Ltd. All rights reserved.
In order to make the most of the performance of this IC, its PCB layout is
very important. Characteristics such as efficiency and ripple and the likes
change greatly with layout, which please note carefully.
Connect the input bypath capacitor CIN nearest to between VIN and
GNDA pin, as shown in the upper diagram. Thereby, the input voltage
ripple of the IC can be reduced. And, connect the output capacitor COUT
nearest to between VOUT and GND pin. Thereby, the output voltage ripple
of the IC can be reduced. Connect the current setting RFB nearest to VFB
pin. Connect the GND connection side of RFB directly to GND pin.
Connect the GNDA pin directly to GND pin. When those pins are not
connected directly near the chip, influence is given to the performance of
BD6068/BD6071HFN and may limit the current drive performance. As for
the wire to the inductor, make its resistance component small so as to
reduce electric power consumption and increase the entire efficiency. And
keep the pins that are subject to the influence like VFB pin away from the
wire to SW. The PCB layout in consideration of these is shown in the
Fig.49.
16/29
2011.01 - Rev.C
BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN
Technical Note
►BD6071HFN
112mVpp
VOUT
(VBAT=3.6V, Ta=25℃, VOUT=14V, 20mA Load)
Fig.48 Output noise
●Recommended PCB layout
Front surface (Top view)
Bottom surface (Top view)
Fig.49 PCB Layout
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© 2011 ROHM Co., Ltd. All rights reserved.
17/29
2011.01 - Rev.C
BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN
Technical Note
►BD6069GUT, BD6072HFN
●Absolute maximum ratings (Ta=25℃)
Parameter
Symbol
Ratings
Unit
Power supply voltage 1
VMAX1
7 *1
V
Vin,EN,VFB,TEST
Power supply voltage 2
VMAX2
20 *1
V
SW,Vout
BD6069GUT
Power dissipation
Pd
BD6072HFN
800 *
2
mW
630 *3
mW
Operating temperature range
Topr
-30 ~ +85
℃
Storage temperature range
Tstg
-55 ~ +150
℃
Conditions
50mm×58mm×1.75mm
At glass epoxy board mounting.
70mm×70mm×1.6mm
At glass epoxy board mounting.
*1 These values are based on GND and GNDA pins.
*2 When it’s used by more than Ta=25℃, it’s reduced by 6.4mW/℃.
*3 When it’s used by more than Ta=25℃, it’s reduced by 5.04mW/℃.
●Recommended operating range (Ta=-30℃ ~ +85℃)
Parameter
Operating
supply voltage
Symbol
BD6069GUT
BD6072HFN
Vin
Ratings
Min.
Typ.
Max.
2.7
3.6
5.5
●Electrical characteristics (Unless otherwise specified Ta = +25℃, Vin=3.6V)
Limits
Parameter
Symbol
Min.
Typ.
Max.
Unit
Conditions
V
Unit
Conditions
<EN terminal>
EN threshold voltage (Low)
VthL
-
-
0.4
V
EN threshold voltage (High)
VthH
1.4
-
-
V
Iin
-
18.3
30.0
μA
EN=5.5V
Iout
-2.0
-0.1
-
μA
EN=0
Input voltage range
Vin
3.1
-
5.5
V
Quiescent Current
Iq
-
0.1
2.0
μA
EN=0V
Current Consumption
Idd
-
1.1
1.5
mA
EN=2.6V,VFB=1.0V,VIN=3.6V
Feedback voltage
Vfb
0.47
0.50
0.53
V
Inductor current limit
Icoil
270
350
430
mA
SW saturation voltage
Vsat
-
0.14
0.28
V
Isw=200mA, Vout=13V
SW on resistance P
Ronp
-
2.1
3.2
Ω
Ipch=200mA,Vout=13V
Switching frequency
fSW
0.8
1.0
1.2
MHz
Duty cycle limit
Duty
82.7
85.0
-
%
Output voltage range
Vo
-
-
18.0
V
Over voltage limit
Ovl
18.0
18.5
19.0
V
Start up time
Ts
-
0.5
1.0
ms
EN terminal input current
EN terminal output current
<Switching regulator>
Vin=3.6V *1
VFB=0V
VFB=0V
*1 This parameter is tested with dc measurement.
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18/29
2011.01 - Rev.C
BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN
Technical Note
►BD6069GUT, BD6072HFN
●Electrical characteristic curves (Reference data)
5.0
1.0
1.4
0.9
1.3
Switching freqency [MHz]
0.8
4.0
0.7
IIN [µA]
IIN [mA]
3.0
Ta=85℃
2.0
Ta=25℃
0.6
0.5
0.4
0.3
1.0
Ta=-30, 25, 85℃
0.2
3
3.5
4
Vin [V]
4.5
5
0.0
2.5
5.5
90
Ta=25℃
1
0.9
Ta=85℃
0.8
3
3.5
4
VIN [V]
4.5
5
0.6
2.5
5.5
Fig.51 Quiescent current vs
power source voltage
Fig.50 Current Consumption vs
Power source voltage
Ta=-30℃
1.1
0.7
0.1
Ta=-30℃
0.0
2.5
1.2
3
3.5
4
4.5
VIN [V]
5
5.5
Fig.52 Oscillation frequency vs.
power source voltage
90
90
CoilCraft : DO1608C-223
CoilCraft : DO1608C-223
MURATA:LQH32CN220K53
75
TDK:VLCF4020T-220MR56
70
85
85
80
80
75
TDK:VLCF4020T-220MR56
70
MURATA:LQH32CN220K53
TDK:VLF3012AT-220MR33
65
TDK:VLF3012AT-220MR33
65
60
20
25
30
ILED [mA]
35
40
15
20
90
430
85
410
IIN [mA]
75
70
VIN=5.5V
15
20
VIN=4.2V
25
30
35
35
40
10
VIN=3.1V
370
350
330
VIN=3.6V
270
-30
-10
25
30
ILED [mA]
35
40
Fig.55 Efficiency vs. LED
current in each coil
< 3LED > (VOUT=10.5V, VIN=3.6V, Ta=25℃)
1500
Ta=25℃
1000
500
10
30
50
Temparature [℃]
ILED [mA]
70
85
Fig.57 Inductor current limits vs.
Temperature
Fig.56 Efficiency vs.
LED current in each coil
20
Ta=85℃
VIN=5.5V
290
40
15
Ta=-30℃
310
60
10
VIN=3.1V
2000
390
80
VIN=3.1V
25
30
ILED [mA]
< 4LED > (VOUT=14V, VIN=3.6V, Ta=25℃)
< 3LED > (VOUT=10.5V, VIN=3.6V, Ta=25℃)
65
VIN=3.6V
Fig.54 Efficiency vs.
LED current in each coil
Fig.53 Efficiency vs.
LED current in each coil
VIN=3.6V
VIN=4.5V
70
60
10
Output Power [mW]
15
VIN=5.5V
75
65
60
10
Efficiency [%]
Efficiency [%]
80
Efficiency [%]
Efficiency [%]
85
0
2.5
3
3.5
VIN [V]
4
4.5
Fig.58 Output power vs.
Power source voltage
< 4LED > (VOUT=14V, VIN=3.6V, Ta=25℃)
0.53
VOUT
1V/div
0.52
EN
2V/div
IIN
200mA/div
Ta=85℃
0.51
VFB [V]
⊿V=1.57V
Ta=25℃
0.5
ILED
20mA/div
10ms
Ta=-30℃
0.49
VOUT
5V/div
IIN
200mA/div
0.48
Ave IIN =1.5mA
0.47
2.5
3
3.5
4
4.5
VIN [V]
5
( 4ms/div )
( 4ms/div )
5.5
Fig.59 Feedback voltage vs.
Power source voltage
Fig.60 LED Open output voltage
Fig.61 LED luminance adjustment
( VIN = 3.6V, Ta = 25℃, 3LED, 20mA Load )
(ILED=20mA)
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19/29
2011.01 - Rev.C
BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN
Technical Note
►BD6069GUT, BD6072HFN
●Block diagram, recommended circuit example, pin location diagram
L
22µH
CIN
1µF
VIN
SW
VOUT
over voltage
protect
Q2
TSD
Q1
short protect
PWMcomp
Q
S
Q
R
+
-
Current
Sence
white LED
ERRAMP
+
+
Control
COUT
1µF
+
-
VFB
+
RFB
24Ω
OSC
300kΩ
GND
GNDA
EN
TEST
Fig.62 Block diagram and recommended circuit diagram
<BD6069GUT>
C1
C2
8
7
6
5
1
2
3
4
C3
B3
B1
A1
<BD6072HFN>
A2
A3
Fig.63 Pin location diagram VCSP60N1 (Bottom view)
Fig.64 Pin location diagram HSON8 (Top view)
●Pin assignment table
PIN Name
In/Out
GNDA
EN
Ball number
Function
BD6069GUT
BD6072HFN
-
A1
1
Analog GND
In
A2
2
Enable control (pull down is integrated on resistance)
TEST
In
A3
3
TEST input (pull down is integrated on resistance)
VIN
In
B1
8
Power supply input
VFB
In
B3
4
Feedback input voltage
VOUT
Out
C1
7
Output
SW
In
C2
6
Switching terminal
GND
-
C3
5
Power GND
●Operation
BD6069GUT is a fixed frequency PWM current mode DC/DC converter, and adopts synchronous rectification architecture.
As for the inputs of the PWM comparator as the feature of the PWM current mode, one is overlapped with error components
from the error amplifier, and the other is overlapped with a current sense signal that controls the inductor current into Slope
waveform for sub harmonic oscillation prevention. This output controls Q1 and Q2 via the RS latch.
Timing of Q1 and Q2 is precisely adjusted so that they will not turn ON at the same time, thus putting them into
non-overlapped relation. In the period where Q1 is ON, energy is accumulated in the external inductor, and in the period
where Q1 is OFF, energy is transferred to the capacitor of VOUT via Q2. Further, BD6069GUT/BD6072HFN has many safety
functions, and their detection signals stop switching operation at once.
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© 2011 ROHM Co., Ltd. All rights reserved.
20/29
2011.01 - Rev.C
BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN
Technical Note
►BD6069GUT, BD6072HFN
●Description of Functions
1) Soft starts and off status
BD6069GUT/BD6072HFN has soft start function and off status function.
The soft start function and the off status function prevent large current from flowing to the IC via coil.
Occurrence of rush current at turning on is prevented by the soft start function, and occurrence of invalid current at turning
off is prevented by the off status function.
2) Isolation control
BD6069GU/BD6072HFN T has isolation control to prevent LED wrong lighting at power off.
The cause of the LED wrong lighting is leak current from VIN to the white LED.
Therefore, when BD6069GUT/BD6072HFN gets in power off (EN = L), the isolation control cuts the DC path between SW
and Vout, thereby the leak current from VIN to LED is prevented.
VIN
White LED
Vout
SW
VFB
Fig.65 Isolation control
3) Short-circuit protection and over voltage protection
BD6069GUT/BD6072HFN has short-circuit protection and over voltage protection. These detect the voltage of VOUT, and
at error, they stop the output Tr. Details are as shown below.
・Short-circuit protection
In the case of short-circuit of the DC/DC output (VOUT) to GND, the coil or the IC may be destructed.
Therefore, at such an error as VOUT becoming 0.7V or below, the Under Detector shown in the figure works, and turns
off the output Tr, and prevents the coil and the IC from being destructed.
And the IC changes from its action condition into its non action condition, and current does not flow to the coil (0mA).
・Over voltage protection
At such an error as the IC and the LED being cut off, over voltage causes the SW terminal and the VOUT terminal
exceed the absolute maximum ratings, and may destruct the IC. Therefore, when VOUT becomes 18.5V or higher, the
over voltage limit works, and turns off the output Tr, and prevents the SW terminal and the VOUT terminal from
exceeding the absolute maximum ratings.
At this moment, the IC changes from its action condition into its non action condition, and the output voltage goes down
slowly. And, when the output voltage becomes the hysteresis of the over voltage limit or below, the output voltage goes
on up to 18.5V once again.
This protection action is shown in Fig.66.
Cout
SW
Vout
OVER Detector
OVER VOLTAGE REF
driver
UNDER Detector
UNDER VOLTAGE REF
Control
Fig.66 Block diagram of short-circuit protection and over voltage
4) Thermal shut down
BD6069GUT/BD6072HFN has thermal shut down function.
The thermal shut down works at 175℃ or higher, and while holding the setting of EN control from the outside, the IC
changes from its action condition into its non action condition. And at 175℃ or below, the IC gets back to its normal action.
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21/29
2011.01 - Rev.C
BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN
Technical Note
►BD6069GUT, BD6072HFN
●Start control and brightness control
BD6069GUT/BD6072HFN can control the start conditions by its EN terminal, and power off at 0.4V or below, and power on
at 1.4V or higher. And by changing the duty of power on and off by PWM control, the LED brightness can be adjusted.
Two techniques are available for the brightness adjustment. One is discrete time (PWM) adjustment, and the other is
continuous time adjustment.
1) PWM brightness adjustment is made by giving PWM signal to EN as shown in Fig.67.
The BD6069GUT/BD6072HFN power on/off is according to the PWM signal. By this method, LED current is controlled
from 0 to the maximum current. The average LED current increases in proportion with the duty cycle of PWM signal. While
in PWM off-cycle mode, the IC and LED both consume no currents, thus providing a high-efficiency operation. And please
don’t use duty less than 5% or more than 95% of current setting for the brightness adjustment because of the influence of
turning on and off operating is large. The recommended PWM frequency is 100Hz ~ 300Hz.
22µH
VIN
SW
VIN
VOUT
PWM
1µF
EN
TEST
GNDA
GND
VFB
24Ω
Fig.67 The brightness adjustment example of EN terminal by PWM (fPWM = 100Hz ~ 300Hz)
2-1) The continuous time the brightness adjustment is made by giving DC control voltage to VFB pin of BD6069GUT /
BD6072HFN via a series resistor as shown in Fig.68. LED luminance (current) changed by giving DC voltage to VFB
directly. DC voltage is given from filtered one of DAC signal, or PWM signal shown in Fig.70. The advantage of this
approach is that the PWM signal to be used to control the LED brightness can be set to a high frequency (1kHz or higher).
And please don’t use duty less than 5% or more than 95% of current setting for the brightness adjustment.
LED current (ILED) is approximated by the following equation.
ILED = [{(VFB-DAC) / R1} × R2 + VFB ] / RFB
3030
22µH
VIN
2525
2020
VOUT
1µF
EN
ILED
TEST
GNDA
GND
22kΩ
R2
R1
1515
1010
55
4.7kΩ
VFB
ILED [mA]
SW
VIN
24Ω
RFB
00
-5-5
0
0
0.5
1
0.5
1
1.5
1.5
2
2
2.5
2.5
3
3
3.5
3.5
4
4
DAC [V]
(VFB=500mV)
DAC
Fig.69 DAC adjustment
Fig.68 The brightness adjustment example by DAC
22µH
25
VIN
SW
VOUT
EN
20
1µF
ILED
TEST
GNDA
GND
VFB
33kΩ
47kΩ
100kΩ
PWM
10kHz
0～2.85V
30Ω
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15
10
5
0
47nF
0
10
20
30
40
50
60
70
80
90 100
HI Du ty [%]
Fig.70 The brightness adjustment example
of VFB terminal by PWM (fPWM=10kHz)
© 2011 ROHM Co., Ltd. All rights reserved.
ILED [mA]
VIN
Fig.71 VFB PWM Control
22/29
2011.01 - Rev.C
BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN
Technical Note
►BD6069GUT, BD6072HFN
2-2) The brightness adjustment of below is done in adjusting of R2 ON time by R1 and Duty cycle of PWM.
The minimum value of the LED current is decided by VFB / R1 at the PWM 0%, the maximum value of the LED current is
decided by VFB / R2 at the PWM 100%.
ILED is given as shown below.
ILED=VFB / R1 + VFB / R2 × HI Duty
Standard PWM frequency is 100Hz~1kHz. And please don’t use duty less than 5% or more than 95% of current setting for
the brightness adjustment.
22µH
25
VIN
SW
VIN
20
VOUT
ILED [mA]
1µF
EN
TEST
GNDA
GND
15
10
VFB
R2
47Ω
5
R1
47Ω
0
PWM
1kHz
0
10 20
30 40
50 60
70 80
90 100
HI Duty [%]
Fig.73 VFB PWM Control
Fig.72 he brightness adjustment example of
VFB terminal by PWM (fPWM=100Hz~1kHz)
●Setting range of LED current
LED current is determined by the voltage of VFB
and the resistor connected to VFB terminal.
ILED is given as shown below.
ILED=VFB/RFB
The current in the standard application is as shown below.
VFB=0.5V, RFB=24Ω
ILED=20.8mA
22µH
VIN
1µF
SW
VIN
VOUT
PWM
EN
1µF
ILED
TEST
GNDA
GND
VFB
RFB
24Ω
Fig.74 Recommended circuit diagram
The shaded portion in the figure below is the setting range of LED current to become the standard. Depending on coils and
white LEDs to be used, however, some ICs may not be used at desired currents. Consequently, for the proper setting of LED
current, thoroughly check it for the suitability under use conditions including applicable power supply voltage and
temperature.
80
70
ILED[mA]
60
50
40
30
20
10
0
7
8
9 10 11 12 13 14 15 16 17 18
VOUT[V]
Fig.75 Setting range of LED current
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© 2011 ROHM Co., Ltd. All rights reserved.
23/29
2011.01 - Rev.C
BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN
Technical Note
►BD6069GUT, BD6072HFN
●Selection of external parts
Recommended external parts are as shown below.
When to use other parts than these, select the following equivalent parts.
・Coil
Manufacturer
Size (mm)
Value
Tolerance
Product number
22μH
±10%
MURATA
22μH
±20%
TDK
VLF3012AT220MR33
2.6
2.8
1.2
0.66
22μH
±20%
Coil Craft
DO1608
4.45
6.6
2.92
0.37
22μH
±20%
TDK
VLF3010AT220MR33
2.6
2.8
1.0
1.30
LQH32CN220K53
DCR (Ω)
W
L
H
2.5
3.2
1.55
0.71
Please refer to the reference data of p.20 for the change in the efficiency when the coil is changed.
・Capacitor
Value
Manufacturer
Size (mm)
Product number
L
W
H
Temperature range
<CIN>
1µF
MURATA
GRM188B11A105K
1.6
0.8
0.8
-25deg~+85deg
MURATA
GRM188B31E105K
1.6
0.8
0.8
-25deg~+85deg
<COUT>
1µF
・Resistor
Value
Tolerance
Manufacturer
Size (mm)
Product number
L
W
H
0.6
0.3
0.23
<RFB>
24Ω
±1%
ROHM
MCR006YZPF24R0
The coil is the part that is most influential to efficiency. Select the coil whose direct current resistor (DCR) and current inductance characteristic is excellent. The BD6069GUTT/BD6072HFN is designed for the inductance value of 22µH. Do not
use other inductance value. Select a capacitor of ceramic type with excellent frequency and temperature characteristics.
Further, select Capacitor to be used for CIN/COUT with small direct current resistance, and pay sufficient attention to the
PCB layout shown in the next page.
●PCB Layout
In order to make the most of the performance of this IC, its PCB layout is very important. Characteristics such as efficiency
and ripple and the likes change greatly with PCB layout, which please note carefully.
To battery
power source
CIN
CIN
GNDA
EN
TEST
GNDA
VIN
RFB
VIN
VOUT
EN
VFB
TEST
GND
SW
COUT
To battery GND
L1
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VFB
RFB
Fig.76 BD6069GUT PCB Layout Image
© 2011 ROHM Co., Ltd. All rights reserved.
To battery
power source
VOUT
COUT
L1
SW
GND
To battery GND
Fig.77 BD6072HFN PCB Layout Image
24/29
2011.01 - Rev.C
BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN
Technical Note
►BD6069GUT, BD6072HFN
Connect the input bypath capacitor CIN nearest to between VIN and GNDA pin, as shown in the upper diagram. Thereby, the
input voltage ripple of the IC can be reduced. And, connect the output capacitor COUT nearest to between VOUT and GND
pin. Thereby, the output voltage ripple of the IC can be reduced. Connect the current setting RFB nearest to VFB pin.
Connect the GND connection side of RFB directly to GND pin. Connect the GNDA pin directly to GND pin. When those pins
are not connected directly near the chip, influence is given to the performance of BD6069GUT /BD6072HFN, and may limit
the current drive performance. As for the wire to the inductor, make its resistance component small so as to reduce electric
power consumption and increase the entire efficiency. And keep the pins that are subject to the influence like VFB pin away
from the wire to SW.
The PCB layout in consideration of these is shown in the Fig.79 to 82.
112mVpp
VOUT
(VBAT=3.6V, Ta=25℃, VOUT=14V, 20mA Load)
Fig.78 Output noise
●Recommended PCB layout
GNDA
FB
EN
GND
L ED
Ci n
RFB
１ ２V
１ ２V
１ １G
LED
Cout
SW
SW
L1
VOUT
LED
VB AT
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VOUT
GND
Fig.79 BD6069GUT
Front surface (Top view)
© 2011 ROHM Co., Ltd. All rights reserved.
１ １G
VOUT
25/29
Fig.80 BD6069GUT
Bottom surface (Top view)
VOUT
2011.01 - Rev.C
BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN
Technical Note
►BD6069GUT, BD6072HFN
●Recommended PCB layout
Fig.81 BD6072HFN
Front surface (Top view)
Fig.82 BD6072HFN
Bottom surface (Top view)
●Attention point of PCB layout
In PCB design, the wiring of power supply line should be low Impedance, and put the bypass capacitor if necessary.
Especially the wiring impedance must be lower around the DC/DC converter.
●About heat loss
In heat design, operate the DC/DC converter in the following condition.
(The following temperature is a guarantee temperature, so consider the margin.)
1. Periphery temperature Ta must be less than 85℃.
2. The loss of IC must be less than dissipation Pd.
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26/29
2011.01 - Rev.C
BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN
Technical Note
●Notes for use
1) Absolute Maximum Ratings
An excess in the absolute maximum ratings, such as supply voltage, temperature range of operating conditions, etc., can
break down devices, thus making impossible to identify breaking mode such as a short circuit or an open circuit. If any
special mode exceeding the absolute maximum ratings is assumed, consideration should be given to take physical safety
measures including the use of fuses, etc.
2) Operating conditions
These conditions represent a range within which characteristics can be provided approximately as expected. The
electrical characteristics are guaranteed under the conditions of each parameter.
3) Reverse connection of power supply connector
The reverse connection of power supply connector can break down ICs. Take protective measures against the breakdown
due to the reverse connection, such as mounting an external diode between the power supply and the IC’s power supply
terminal.
4) Power supply line
Design PCB pattern to provide low impedance for the wiring between the power supply and the GND lines. In this regard,
for the digital block power supply and the analog block power supply, even though these power supplies has the same
level of potential, separate the power supply pattern for the digital block from that for the analog block, thus suppressing
the diffraction of digital noises to the analog block power supply resulting from impedance common to the wiring patterns.
For the GND line, give consideration to design the patterns in a similar manner. Furthermore, for all power supply
terminals to ICs, mount a capacitor between the power supply and the GND terminal. At the same time, in order to use an
electrolytic capacitor, thoroughly check to be sure the characteristics of the capacitor to be used present no problem
including the occurrence of capacity dropout at a low temperature, thus determining the constant.
5) GND voltage
Make setting of the potential of the GND terminal so that it will be maintained at the minimum in any operating state. Furthermore,
check to be sure no terminals are at a potential lower than the GND voltage including an actual electric transient.
6) Short circuit between terminals and erroneous mounting
In order to mount ICs on a set PCB, pay thorough attention to the direction and offset of the ICs. Erroneous mounting can
break down the ICs. Furthermore, if a short circuit occurs due to foreign matters entering between terminals or between
the terminal and the power supply or the GND terminal, the ICs can break down.
7) Operation in strong electromagnetic field
Be noted that using ICs in the strong electromagnetic field can malfunction them.
8) Inspection with set PCB
On the inspection with the set PCB, if a capacitor is connected to a low-impedance IC terminal, the IC can suffer stress.
Therefore, be sure to discharge from the set PCB by each process. Furthermore, in order to mount or dismount the set
PCB to/from the jig for the inspection process, be sure to turn OFF the power supply and then mount the set PCB to the jig.
After the completion of the inspection, be sure to turn OFF the power supply and then dismount it from the jig. In addition,
for protection against static electricity, establish a ground for the assembly process and pay thorough attention to the
transportation and the storage of the set PCB.
9) Input terminals
In terms of the construction of IC, parasitic elements are inevitably formed in relation to potential. The operation of the
parasitic element can cause interference with circuit operation, thus resulting in a malfunction and then breakdown of the
input terminal. Therefore, pay thorough attention not to handle the input terminals, such as to apply to the input terminals a
voltage lower than the GND respectively, so that any parasitic element will operate. Furthermore, do not apply a voltage to
the input terminals when no power supply voltage is applied to the IC. In addition, even if the power supply voltage is
applied, apply to the input terminals a voltage lower than the power supply voltage or within the guaranteed value of
electrical characteristics.
10) Ground wiring pattern
If small-signal GND and large-current GND are provided, It will be recommended to separate the large-current GND
pattern from the small-signal GND pattern and establish a single ground at the reference point of the set PCB so that
resistance to the wiring pattern and voltage fluctuations due to a large current will cause no fluctuations in voltages of the
small-signal GND. Pay attention not to cause fluctuations in the GND wiring pattern of external parts as well.
11) External capacitor
In order to use a ceramic capacitor as the external capacitor, determine the constant with consideration given to a
degradation in the nominal capacitance due to DC bias and changes in the capacitance due to temperature, etc.
12) Thermal shutdown circuit (TSD)
When junction temperatures become 175℃ (typ) or higher, the thermal shutdown circuit operates and turns a switch OFF.
The thermal shutdown circuit, which is aimed at isolating the LSI from thermal runaway as much as possible, is not aimed
at the protection or guarantee of the LSI. Therefore, do not continuously use the LSI with this circuit operating or use the
LSI assuming its operation.
13) Thermal design
Perform thermal design in which there are adequate margins by taking into account the permissible dissipation (Pd) in
actual states of use.
14) Selection of coil
Select the low DCR inductors to decrease power loss for DC/DC converter.
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27/29
2011.01 - Rev.C
BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN
Technical Note
●Ordering part number
B
D
6
Part No.
0
6
7
G
Part No.
U
-
E
Package
GU : VCSP85H1
2
Packaging and forming specification
E2: Embossed tape and reel
VCSP85H1 (BD6067GU)
<Tape and Reel information>
1.68±0.1
Tape
Embossed carrier tape
Quantity
3000pcs
E2
Direction
of feed
1.0MAX
0.25±0.1
1.68±0.1
1PIN MARK
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
)
0.34±0.1
S
0.08 S
8-φ0.3±0.05
0.05 A B
P=0.5×2
A
(φ0.15)INDEX POST C
B
B
A
1
0.34±0.1
2
3
Reel
(Unit : mm)
B
D
6
Part No.
Direction of feed
1pin
P=0.5×2
0
6
9
G
Part No.
∗ Order quantity needs to be multiple of the minimum quantity.
U
T
Package
GUT : VCSP60N1
-
E
2
Packaging and forming specification
E2: Embossed tape and reel
VCSP60N1 (BD6069GUT)
<Tape and Reel information>
1.68±0.05
1.68±0.05
0.21±0.05
0.6±0.08
1PIN MARK
(φ0.15)INDEX POST
A
C
B
B
A
1
0.34±0.05
2
3000pcs
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
)
P=0.5×2 0.34±0.05
0.08 S
Embossed carrier tape
Quantity
Direction
of feed
S
8-φ0.3±0.05
0.05 A B
Tape
3
1pin
P=0.5×2
(Unit : mm)
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© 2011 ROHM Co., Ltd. All rights reserved.
Reel
28/29
Direction of feed
∗ Order quantity needs to be multiple of the minimum quantity.
2011.01 - Rev.C
BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN
B
D
6
Part No.
0
7
1
H
Part No.
6071 6072
F
Technical Note
N
Package
HFN : HSON8
-
T
R
Packaging and forming specification
TR: Embossed tape and reel
HSON8
<Tape and Reel information>
0.475
6
5
2
3
4
1PIN MARK
(0.2)
1
+0.03 0.6MAX
0.02 –0.02
5
6
7
8
(1.8)
(0.45)
3.0 ± 0.2
2.8 ± 0.1
8 7
(0.05)
(2.2)
4
3
2
(0.3)
(0.15)
(0.2)
2.9±0.1
(MAX 3.1 include. BURR)
1
Tape
Embossed carrier tape
Quantity
3000pcs
Direction
of feed
TR
The direction is the 1pin of product is at the upper right when you hold
( reel on the left hand and you pull out the tape on the right hand
+0.1
0.13 –0.05
)
1pin
S
0.65
0.1 S
0.32±0.1
0.08
M
Direction of feed
Reel
(Unit : mm)
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© 2011 ROHM Co., Ltd. All rights reserved.
29/29
∗ Order quantity needs to be multiple of the minimum quantity.
2011.01 - Rev.C
Notice
Notes
No copying or reproduction of this document, in part or in whole, is permitted without the
consent of ROHM Co.,Ltd.
The content specified herein is subject to change for improvement without notice.
The content specified herein is for the purpose of introducing ROHM's products (hereinafter
"Products"). If you wish to use any such Product, please be sure to refer to the specifications,
which can be obtained from ROHM upon request.
Examples of application circuits, circuit constants and any other information contained herein
illustrate the standard usage and operations of the Products. The peripheral conditions must
be taken into account when designing circuits for mass production.
Great care was taken in ensuring the accuracy of the information specified in this document.
However, should you incur any damage arising from any inaccuracy or misprint of such
information, ROHM shall bear no responsibility for such damage.
The technical information specified herein is intended only to show the typical functions of and
examples of application circuits for the Products. ROHM does not grant you, explicitly or
implicitly, any license to use or exercise intellectual property or other rights held by ROHM and
other parties. ROHM shall bear no responsibility whatsoever for any dispute arising from the
use of such technical information.
The Products specified in this document are intended to be used with general-use electronic
equipment or devices (such as audio visual equipment, office-automation equipment, communication devices, electronic appliances and amusement devices).
The Products specified in this document are not designed to be radiation tolerant.
While ROHM always makes efforts to enhance the quality and reliability of its Products, a
Product may fail or malfunction for a variety of reasons.
Please be sure to implement in your equipment using the Products safety measures to guard
against the possibility of physical injury, fire or any other damage caused in the event of the
failure of any Product, such as derating, redundancy, fire control and fail-safe designs. ROHM
shall bear no responsibility whatsoever for your use of any Product outside of the prescribed
scope or not in accordance with the instruction manual.
The Products are not designed or manufactured to be used with any equipment, device or
system which requires an extremely high level of reliability the failure or malfunction of which
may result in a direct threat to human life or create a risk of human injury (such as a medical
instrument, transportation equipment, aerospace machinery, nuclear-reactor controller, fuelcontroller or other safety device). ROHM shall bear no responsibility in any way for use of any
of the Products for the above special purposes. If a Product is intended to be used for any
such special purpose, please contact a ROHM sales representative before purchasing.
If you intend to export or ship overseas any Product or technology specified herein that may
be controlled under the Foreign Exchange and the Foreign Trade Law, you will be required to
obtain a license or permit under the Law.
Thank you for your accessing to ROHM product informations.
More detail product informations and catalogs are available, please contact us.
ROHM Customer Support System
http://www.rohm.com/contact/
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R1120A