Rohm BD6066EKN White backlight led drivers for medium to large lcd panels (switching regulator type) Datasheet

LED Drivers for LCD Backlights
White Backlight LED Drivers
for Medium to Large LCD Panels
(Switching Regulator Type)
BD6066GU, BD6066EKN
No.11040EBT26
●Description
BD6066GU/BD6066EKN are white LED driver ICs with PWM step-up DC/DC converter that can boost max 40.5V and
current driver that can drive max 30mA. The wide brightness can be adjusted to control by external PWM pulse on power
control terminal. And, with extended resolution current driver, a few errors between the lines of the current driver, it is suitable
for decreasing the lacking in brightness of the display. BD6066GU, CSP package type, is suited for saving space.
BD6066EKN, HQFN package type, is suited for mounting on the flexible board.
●Features
1) High efficiency PWM step-up DC/DC converter (fsw=1MHz)
2) Extended resolution current driver 4ch
3) Driving＊12 series × 4parallel =48 white LEDs (＊white LED Vf=3.2Vmax)
4) Wide input voltage range (2.7V ~ 22V)
5) Rich safety functions
▪ Over-voltage protection (OVP)
▪ Over current limit
▪ External SBD open detect
▪ Thermal shutdown (175 ℃)
6) CSP small & thin package
VCSP85H2 2.6 × 2.6 × 0.85mm
HQFN28V 5.2 × 5.2 × 0.95mm
●Applications
Notebook PC, portable DVD player, car navigation systems
● Absolute maximum ratings (Ta=25 ℃)
Parameter
Symbol
Limits
Unit
Condition
Maximum applied voltage 1
VMAX1
7
V
TEST,ISET,VREG,SENSP,
SENSN, SW, EN1, EN2, PWM
Maximum applied voltage 2
VMAX2
15.5
V
LED1, LED2, LED3, LED4
Maximum applied voltage 3
VMAX3
30.5
V
VBAT
Maximum applied voltage 4
VMAX4
50.5
V
VDET
Power dissipation 1 (BD6066GU)
Pd1
1100 *1
mW
Power dissipation 2 (BD6066EKN)
Pd2
560 *2
mW
Power dissipation 3 (BD6066EKN)
Pd3
880 *3
mW
Power dissipation 4 (BD6066EKN)
Pd4
2650 *4
mW
Operating temperature range
Topr
-30 ~ +85
℃
Storage temperature range
Tstg
-55 ~ +150
℃
(*1) The measurement value which was mounted on the PCB by ROHM. When it’s used by more than Ta=25 ℃, it’s reduced by 8.8mW/ ℃.
(*2) Reduced 4.5mW/ ℃ With Ta>25 ℃ when not mounted on a heat radiation Board.
(*3) 70mm x 70mm x 1.6mm glass epoxy Board which has 1 layers (60mm x 60mm). When it’s used by more than Ta=25 ℃, it’s reduced by 7.0mW/ ℃.
(*4) 70mm x 70mm x 1.6mm glass epoxy Board which has 2 layers (60mm x 60mm). When it’s used by more than Ta=25 ℃, it’s reduced by 21.2mW/ ℃.
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© 2011 ROHM Co., Ltd. All rights reserved.
1/15
2011.06 - Rev.B
Technical Note
BD6066GU,BU6066EKN
●Recommended operating range (Ta=-30 ℃ ~ +85 ℃)
Parameter
Power supply voltage
Symbol
BD6066GU
BD6066EKN
VBAT
Limits
Min.
Typ.
Max.
2.7
12.0
22.0
●Electrical characteristic (Unless otherwise specified, VBAT=12V, Ta = +25 ℃)
Limits
Parameter
Symbol
Min.
Typ.
Max.
Unit
Condition
V
Unit
Condition
[EN Terminal]
EN threshold voltage (Low)
VthL
0
-
0.2
V
EN threshold voltage (High) 1
VthH1
1.4
-
5.0
V
VBAT > 5.0V
EN threshold voltage (High) 2
VthH2
1.4
-
VBAT
V
VBAT < 5.0V
Iin
-
8.3
14.0
µA
EN=2.5V
Iout
-2.0
-0.1
-
µA
EN=0V
PWML
0
-
0.2
V
High Input Voltage range1
PWMH1
1.4
-
5.0
V
VBAT > 5.0V
High Input Voltage range2
PWMH2
1.4
-
VBAT
V
VBAT < 5.0V
PWM pull down resistor
PWMR
300
500
700
kΩ
VREG Voltage
VREG
4.0
5.0
6.0
V
Under Voltage Lock Out
UVLO
2.05
2.35
2.65
V
Input voltage range
Vin
3.1
12.0
22.0
V
Quiescent Current 1
Iq1
-
0.6
3.4
µA
EN=0V, VBAT=12V
Quiescent Current 2
Iq2
-
4.6
10
µA
EN=0V, VBAT=22V
Current Consumption
Idd
-
3.4
5.1
mA
EN=3.6V, VDET=0V,ISET=24kΩ
LED Control voltage
VLED
0.4
0.5
0.6
V
Over Current Limit voltage
Ocp
70
100
130
mV
SBD Open Protect
Sop
-
0.2
1.4
V
Switching frequency
fSW
0.8
1.0
1.2
MHz
Duty cycle limit
Duty
92.5
95.0
99.0
%
LED1=LED2=LED3=LED4=0V
Over Voltage Limit
Ovl
40.5
42.0
43.5
V
LED1=LED2=LED3=LED4=0V
Start up time
Ts
-
0.5
1.0
ms
LED maximum current
ILMAX
-
-
30
mA
LED current accuracy
ILACCU
-
-
±5
%
ILED=20mA
LED current matching
ILMAT
-
-
±3
%
- Each LED current / Average
(LED1,2,3,4)
- ILED=20mA
Iset
0.5
0.6
0.7
V
ILOCP
35
60
90
mA
LEDOVP
12.5
13.5
14.5
V
EN terminal input current
EN terminal output current
[PWM Terminal]
Low Input Voltage range
[Regulator]
[Switching Regulator]
*1
*2
Output voltage=24V
[Current driver]
ISET voltage
LED current limiter
LED Terminal Over Voltage Protect
*1 Electrical characteristics are guaranteed from 3.1V to 22V and operating is guaranteed from 2.7V to 3.1V.
*2 This parameter is tested with dc measurement.
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2/15
2011.06 - Rev.B
Technical Note
BD6066GU,BU6066EKN
●Reference data
20
5
1.3
85℃
Frequency [MHz]
15
3
25℃
-30℃
2
Ist[µA]
Iin [mA]
25 ℃
1.2
4
85℃
10
25℃
1.1
1
-30℃
0.9
85℃
5
1
0.8
-30℃
0
0
0
5
10
15
VBAT [V]
20
0
25
5
10
15
VBAT[V]
20
0.7
25
0
5
10
15
VBAT [V]
20
25
Fig.1
Fig.2
Current Consumption - power source voltage
Fig.3
Quiescent current - power source voltage
Oscillation frequency - power source voltage
44
0.4
43
0.3
16
15
41
0.2
85℃
85℃
11
40
10
0.0
0
5
10
15
VBAT[V]
13
12
85℃
0.1
25℃
14
LED[V]
VDET[V]
VDET[V]
42
-30℃
-30, 25℃
25℃
-30℃
20
25
0
5
10
15
VBAT[V]
20
0
25
5
10
15
VBAT[V]
20
25
Fig.4
Fig.5
Fig.6
Over Voltage Limit - power source voltage
SBD Open Protect Limit - power source voltage
LED terminal Over Voltage Protect
vs power source voltage
200
5
Over current detected voltage [mV]
2.5
6
2
4
VBAT [V]
VREG[V]
1.5
3
2
0.5
1
0
0
5
10
15
VBAT[V]
20
0
-50
25
-25
0
25
Ta [o C]
50
75
2.7V, 3.1V, 6V
100
Fig.8
UVLO - Temperature
0
-50
100
21.0
21.0
20.8
20.8
20.8
20.6
20.6
20.6
20.4
20.4
20.0
19.8
19.6
20.0
19.8
-30℃
19.4
19.2
19.2
19.0
0.20
19.0
0.60
0.80
1.00
1.20
1.40
VLED[V]
Fig.10
LED current - LED terminal voltage
( Expansion)
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© 2011 ROHM Co., Ltd. All rights reserved.
85℃
0
25
Ta [o C]
50
75
100
-30℃
25℃
20.2
20.0
19.8
19.6
19.6
19.4
0.40
20.4
25℃
20.2
ILED[mA]
ILED[mA]
25℃
-25
Over Current Limit Voltage - Temperature
21.0
85℃
5V 22V
50
Fig.9
Fig.7
VREG - power source voltage
20.2
ILED[mA]
1
150
85℃
19.4
-30℃
19.2
19.0
2
3
4
5
6
7
VLED[V]
8
9
10
Fig.11
LED current - LED terminal voltage
3/15
0
5
10
15
VBAT[V]
20
25
Fig.12
LED current - power source voltage
2011.06 - Rev.B
Technical Note
BD6066GU,BU6066EKN
25
100
ISET=27kΩ
20
-30℃
70
ISET=27kΩ
LED current [mA]
85℃
60
50
40
30
1.5
LED current [mA]
80
Efficiency[%]
2
25℃
90
15
6V, 7.4V, 10.7V, 22V
10
20
1
22V
10.7V
0.5
16V
5
16V
6V
7.4V
10
0
0
0
0
5
10
15
VBAT[V]
20
25
0
20
40
60
PWM-HI Duty [％]
Fig.13
Efficiency - source voltage
25
2
VBAT=7.4V
ISET=27kΩ
80
2
100
10
20
Fig.15
100
VBAT=7.4V
ISET=27kΩ
VBAT=7.4V
ISET=27kΩ
90
85℃
80
70
25℃
1
0.5
85℃
5
18
LED current - PWM HI Duty( Expansion)
PWM = 200Hz
Dispersion [%]
LED current [mA]
LED current [mA]
-30℃
8 10 12 14 16
PWM-HI Duty [％]
Fig.14
1.5
25℃
6
LED current - PWM HI Duty
PWM = 200Hz
20
15
4
60
50
VF Dispersion of
LED line interval is 2.6V.
40
30
VF Dispersion of LED
line interval is small.
20
-30℃
10
0
0
20
40
60
PWM-HI Duty [%]
80
100
4
0
6 8 10 12 14 16 18 20
PWM-HI Duty [%]
20
40
60
PWM-HI Duty [%]
80
100
Fig.16
Fig.17
Fig.18
LED current - PWM HI Duty( Expansion)
PWM = 200Hz
LED current matching - PWM HI Duty
PWM = 200Hz
100%
50%
90%
80%
70%
40%
VBAT=7.4V
ISET=27kΩ
40
30
Dispersion
VF Dispersion of
LED line interval is 2.6V.
VF Dispersion of
LED line interval
is small.
20
0
-10
0%
-10%
10
5
10
15
20
Duty [%]
25
30
Fig.19
LED current matching - PWM HI Duty
(Expansion) PWM = 200Hz
6V
7.4V
30%
60%
50%
40%
30%
20%
10%
0
2
LED current - PWM HI Duty
PWM = 200Hz
50
Dispersion [%]
0
6V
Dispersion
0
-10
0
7.4V
10.7V
16V
10.7V
20%
22V
10%
22V
0%
16V
-10%
0
10 20 30 40 50 60 70 80 90 100
PWM-HI Duty [%]
Fig.20
LED current matching - PWM HI Duty
VF Dispersion of LED line interval is 2.6V.
PWM = 200Hz
0
5
10
15
20
Duty [%]
25
30
Fig.21
LED current matching - PWM HI Duty (Expansion)
VF Dispersion of LED line interval is 2.6V.
PWM = 200Hz
Output
10V/div
Average current = 0.8mA
Coil current
500mA/div
Fig.22
LED Open Voltage
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4/15
2011.06 - Rev.B
Technical Note
BD6066GU,BU6066EKN
●Block diagram, I/O equivalent circuit diagram
VBAT
VREG
VBAT
VBAT
VREG
EN1
VIN detector
UVLO
Clump
EN2
PIN
REG
Internal Power suplly
Clump
PWM
SBD Open protect
VDET
+
-
PIN
PIN
GND
GND
A
B
VBAT
VBAT
C
TSD
over voltage protect
S
SW
Q
R
ERRAMP
+
PWMcomp
+
Control
sence
+
PIN
PIN
GND
+
Current
Sence
SENSN
PIN
LED1
LED2
SENSP
OSC
LED TERMINAL
Over Voltage Protect
GND
D
LED3
VBAT VREG
5.5V
5.5V
Clump
Clump
E
GND
F
VBAT VREG
LED4
PIN
ISET
Resistor driver
Current Driver
GND
GND
ISET
GND TEST
G
Fig.24 I/O equivalent circuit diagram
Fig.23 Block diagram
●Pin assignment table
PIN Name
In/Out
PIN number
BD6066GU
BD6066EKN
Function
Terminal equivalent
circuit diagram
SENSN
In
A1
1
- Side Current sense terminal
A
GND
-
A2
2
GND
B
VDET
In
C3
3
Detect input for SBD open and OVP
C
N.C.
-
-
4
No connect pin
-
N.C.
-
-
5
No connect pin
-
ISET
In
A3
6
Resistor connection for LED current setting
A
TEST
In
A4
7
TEST input (Pull down 100kΩ to GND)
G
N.C.
-
-
8
No connect pin
-
LED4
In
A5
9
Current sink for LED4
C
LED3
In
B5
10
Current sink for LED3
C
N.C.
-
-
11
No connect pin
-
LED2
In
C5
12
Current sink for LED2
C
LED1
In
D5
13
Current sink for LED1
C
N.C.
-
-
14
No connect pin
-
EN1
In
E5
15
Enable input 1
E
N.C.
-
-
16
No connect pin
-
EN2
In
E3
17
Enable input 2
E
N.C.
-
-
18
No connect pin
-
VBAT
In
E4
19
Battery input
C
VREG
Out
E2
20
Regulator output / Internal power-supply
D
PWM
In
E1
21
PWM input
F
N.C.
-
-
22
No connect pin
-
GND
-
D1
23
GND
B
N.C.
-
-
24
No connect pin
-
VREG
Out
-
25
Regulator output / Internal power-supply
D
SW
Out
C1
26
Switching Tr drive terminal
G
SENSP
In
B1
27
+ Side Current sense terminal
G
GND
-
-
28
GND
B
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5/15
2011.06 - Rev.B
Technical Note
BD6066GU,BU6066EKN
●Application example
Battery
Battery
4.7μH
4.7μH
10LED
RB160M-60
10LED
RB160M-60
10μF (25V)
10μF (25V)
2.2μF (50V)
2.2μF (50V)
C3
C3
RTR020N05
C1
SW
RTR020N05
VDET
B1 SENSP
C1
SW
VDET
B1 SENSP
68mΩ
68mΩ
A1 SENSN
A1 SENSN
Power
ON/OFF
LED1 D5
E5 EN1
200Hz
PWM
E3 EN2
LED2 C5
E1 PWM
LED3 B5
200Hz
PWM
LED4 A5
E4 VBAT
GND
A2
E3 EN2
LED2 C5
E1 PWM
LED3 B5
LED4 A5
E4 VBAT
each 20mA
E2 VREG
1μF(10V)
LED1 D5
E5 EN1
Power
ON/OFF
E2 VREG
1μF(10V)
GND TEST ISET
D1
A4
GND
GND TEST ISET
A2
A3
D1
A4
A3
24kΩ
24kΩ
Fig.25 LED current 20mA setting example
(10 series × 4parallel)
Fig.26 LED current 20mA setting example
(10 series × 3parallel)
Battery
Battery
4.7μH
4.7μH
10LED
RB160M-60
12LED
RB160M-60
10μF (25V)
10μF (25V)
2.2μF (100V)
2.2μF (50V)
C3
RTR020N05
C1
SW
C1
SW
VDET
B1 SENSP
39mΩ
68mΩ
A1 SENSN
A1 SENSN
LED1 D5
E5 EN1
E3 EN2
LED2 C5
200Hz
PWM
E1 PWM
LED3 B5
3.1 to 5.5V
E4 VBAT
LED4 A5
Power
ON/OFF
200Hz
PWM
GND
A2
LED1 D5
E5 EN1
E3 EN2
LED2 C5
E1 PWM
LED3 B5
LED4 A5
E4 VBAT
each 20mA
Each 20mA
E2 VREG
E2 VREG
1μF(10V)
270kΩ
C3
VDET
B1 SENSP
Power
ON/OFF
each 20mA
1μF(10V)
GND TEST ISET
D1
A4
GND
A2
A3
GND TEST ISET
D1
A4
A3
24kΩ
24kΩ
Fig.27 Separated power supply of IC and coil setting example
Fig.28 Over voltage 48.1V(typ) by external resistor,
LED current 20mA setting example
(12 series (VF3.6Vmax) × 4parallel)
●Terminal processing
TEST pin = Connect to GND
N.C.
= Nothing specified in particular. Open is recommended.
VREG
= When IC is driving from the outside of 3.1~5.5V, short VBAT and VREG, and put the voltage to VREG
EN1, 2
= Connect to GND in case of fixing at L level
LED1, 2 = When each LED driver are not used at EN setting, connect to VREG terminal or the power supply of more
than 1V.
GND
= Each GND is connecting inside IC. Connect to GND of all PCB
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6/15
2011.06 - Rev.B
Technical Note
BD6066GU,BU6066EKN
●Description of Functions
1) PWM current mode DC/DC converter
While BD6066GU/EKN is power ON, the lowest voltage of LED1, 2, 3, 4 is detected, PWM duty is decided to be 0.5V and
output voltage is kept invariably. 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 to prevent sub harmonic oscillation. This output controls external Nch Tr
via the RS latch. In the period where external Nch Tr gate is ON, energy is accumulated in the external inductor, and in the
period where external Nch Tr gate is OFF, energy is transferred to the output capacitor via external SBD. BD6066GU/EKN
has many safety functions, and their detection signals stop switching operation at once.
2) Soft start and off status
BD6066GU/EKN has soft start function and off status function.
The soft start function and the off status function prevent large coil current.
Rush current at turning on is prevented by the soft start function, and invalid current at turning off is prevented by the off
status function.
3) External SBD open detect and over voltage protection
BD6066GU/EKN has over boost protection by external SBD open and over voltage protection. This function will stop the
switching. Details are as shown below.
▪ External SBD open detect
In the case of external SBD is not connected to IC, the coil or external Tr may be destructed. Therefore, at such an error as
VOUT becoming 0.2V 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 activation into non-activation, and current does not flow to the coil (0mA).
▪ Over voltage protection
At such an error of output open as the output DC/DC and the LED is not connected to IC, the DC/DC will boost too much
and the VDET terminal exceed the absolute maximum ratings, and may destruct the IC. Therefore, when VDET becomes
sensing voltage or higher, the over voltage limit works, and turns off the output Tr, and the pressure up made stop. At this
moment, the IC changes from activation into non-activation, 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 pressure up to sensing voltage
once again and unless the application error is recovered, this operation is repeated.
This protection action is shown in Fig.29.
Cout
VDET
SW
OVER Detector
OVER VOLTAGE REF
SBD Open Detector
SBD Open VOLTAGE REF
Control
Fig.29 Block diagram of external SBD open detect and over voltage
4) Thermal shut down
BD6066GU/EKN has thermal shut down function.
The thermal shut down works at 175C or higher, and while holding the setting of EN control from the outside, the IC
changes from activation into non-activation. And at 175C or below, the IC gets back to its normal action.
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7/15
2011.06 - Rev.B
Technical Note
BD6066GU,BU6066EKN
5) Over Current Limit
Over current flows the current detection resistor that is connected to switching transistor source and between GND,
SENSP pin voltage turns more than detection voltage, over current protection is operating and it is prevented from flowing
more than detection current by reducing ON duty of switching Tr without stopping boost.
As over current detector of BD6066GU/EKN is detected peak current, current more than over current setting value does
not flow.
And, over current value can decide freely by changing over current detection voltage.
<Derivation sequence of detection resistor>
Detection resistor =Over current detection voltage / Over current setting value
TYP value of over current detection voltage is 100mV, MIN = 70mV and MAX = 130mV and after the current value which
was necessary for the normal operation was decided, detection resistor is derived by using MIN value of over current
detection value.
For example, detection resistor when necessary current value was set at 1A is given as shown below.
Detection resistor =70mV / 1A = 70mΩ
MAX current dispersion of this detection resistor value is
MAX current = 130mV / 70mΩ = 1.86A
<The estimate of the current value which need for the normal operation >
As over current detector of BD6066GU/EKN is detected the peak current, it have to estimate peak current to flow to the
coil by operating condition.
In case of, Supply voltage of coil = VIN
Reactance value of coil = L
Switching frequency = fsw
MIN=0.8MHz, Typ=1MHz, MAX=1.2MHz
Output voltage = VOUT
Total LED current = IOUT
Average current of coil = Iave
Peak current of coil = Ipeak
Efficiency = eff
(Please set up having margin, it refers to data on p.4.)
ON time of switching transistor = Ton
Ipeak = (VIN / L) × (1 / fsw) × (1-(VIN / VOUT))
Iave=(VOUT × IOUT / VIN) / eff
1/2
Ton=(Iave × (1-VIN/VOUT) × (1/fsw) × (L/VIN) × 2)
Each current is calculated.
As peak current varies according to whether there is the direct current superposed, the next is decided.
(1-VIN/VOUT) × (1/fsw) < Ton→ peak current = Ipeak /2 + Iave
(1-VIN/VOUT) × (1/fsw) > Ton→ peak current = Ipeak
(Example 1)
In case of, VIN=6.5V, L=4.7µH, fsw=1MHz, VOUT=39V, IOUT=80mA, Efficiency=85%
Ipeak = (6.5V / 4.7µH) × (1 / 1MHz) × (1-(6.5V / 39V)) =1.08A
Iave = (39V × 80mA / 6.0V) / 85% = 0.61A
1/2
Ton = (0.61A × (1-6.0V / 39V) × (1 / 1MHz) × ( 4.7µH /6.0V) × 2) = 0.90µs
(1-VIN/VOUT) × (1/fsw)=0.85µs < Ton
Peak current = 1.08A/2+0.61A = 1.15A
(Example 2)
In case of, VIN=12.0V, L=4.7µH, fsw=1MHz, VOUT=39V, IOUT=80mA, Efficiency=85%
Ipeak = (12.0V / 4.7µH) × (1 / 1MHz) × (1-(12V / 39V)) =1.77A
Iave = (39V × 80mA / 12.0V) / 85% = 0.31A
1/2
Ton = (0.31A × (1-12 V / 39V) × (1 / 1MHz) × ( 4.7µH /12 V) × 2) = 0.41µs
(1-VIN/VOUT) × (1/fsw)=0.69µs > Ton
Peak current = 12V/4.7µH × 0.41µs = 1.05A
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8/15
2011.06 - Rev.B
Technical Note
BD6066GU,BU6066EKN
●Start control and select constant current driver
BD6066GU/EKN can control the start conditions by EN1, 2 terminal and PWM terminal, and sets 0.2V or below EN1, 2
terminal or sets 0.2 or below PWM terminal and IC can power off by being 0V LED terminal selected EN1, 2. PWM, EN
power on at more than 1.4V, constant current can select ON/OFF by the combination of EN as shown below table. When
there is unused constant current driver, connect unused LED terminal to VREG terminal or connect to fixed voltage of more
than 1V. And, EN1, 2 are changed with PWM=H and it is prohibited to change a constant current driver.
Enable
Constant current driver
EN1
EN2
PWM
LED1
LED2
LED3
LED4
H
L
H
L
H
L
H
L
H
H
L
L
H
H
L
L
H
H
H
H
L
L
L
L
OFF
OFF
ON
OFF
ON
ON
ON
ON
ON
ON
ON
ON
OFF
(As for these setups, power-off IC.)
●Off sequence
Off sequence controls power off timing of each block, LED terminal may not exceed the pressure.
After EN or PWM terminal set H→L, it continues electric current by the current value decided with ISET terminal until all the
LED terminals selected with EN are less than 40mV and output voltage reduces. On that occasion, the DC/ DC power-off is
given and it doesn't have a charge to the output capacitor. After that, LED driver is turned off, built-in REG is turned off, and
power-off is completed. If the VF tolerance of the LED is large, it doesn't need to examine VF not to exceed pressure of the
LED terminal by this sequence.
EN
DCDC_EN
DRV_EN
REG_EN
Terminal voltage is detected, and turned off.
LED Terminal Voltage is high.
LED Terminal Voltage is low.
Power
Control
REG_EN
REG
LED
10 lights
5V
EN1, 2,PW M
DCDC_EN
DCDC
LED
9 lights
SW
…
…
…
…
LED4
LED3
DRV_EN
DRV
LED2
Terminal voltage is low
LED1
Terminal voltage is high
Fig.30 Block diagram of off sequence
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© 2011 ROHM Co., Ltd. All rights reserved.
9/15
2011.06 - Rev.B
Technical Note
BD6066GU,BU6066EKN
●Setting of LED current and current range
LED current can set up resistance value (RISET) connecting to ISET,
LED current setting range is 4mA~30mA.
ISET setting example
RISET
24.0 kΩ (E24)
25.5 kΩ (E96)
27.0 kΩ (E12)
28.0 kΩ (E96)
30.0 kΩ (E24)
33.0 kΩ (E6)
Setting of LED current is given as shown below.
LED current = 20mA × ( 24kΩ / RISET)
The current in the standard application is as shown below.
RISET=24kΩ, LED current=20mA
LED current
20.0mA
18.8mA
17.8mA
17.1mA
16.0mA
14.5mA
●Brightness control
PWM brightness adjustment is made by inputting PWM pulse to PWM pin.
The electric current select setting with ISET in the Hi section, and the Lo section turns off the electric current. Lo.
The average current increases in proportion with the duty cycle of PWM signal. By this method, IC can power off at the OFF
time, the IC and LED both consume no currents, thus providing a high-efficiency operation.
The recommended PWM frequency is 100Hz ~ 300Hz.
<ON time limit>
On time is necessary more than 750μs (at the time of 200Hz, 15%) to require the start up-time of 750μs.
< OFF time limit >
OFF time is approximated by the following parameter.
External output capacitor
: Cvout
LED current setting
: ILED
(worst = +5%)
LED sequence number
: NPLED
LED series number
: NSLED
VF tolerance of LED terminal
: ∆VF
Reaction time of internal circuit
: 10μs
(worst = 15μs)
Necessary time for OFF (typ) = Cvout × ((∆VF × NSLED) + 0.5V)/(ILED × NPLED)+10μs
(example)
Necessary time for OFF (typ) = 2μF × ((0.2V × 10 lights) + 0.5V)/(20mA × 4)+10μs = 72.5μs
<PWM=200Hz, duty1.5% equivalent>
Please use worst value of each parameter when you calculate the worst time.
(example)
Necessary time for OFF (worst) = (2μF × 1.3) × ((0.26V × 10 lights) + 0.7V)/((20mA × 1.05) × 4)+15μs =117μs
<PWM=200Hz, duty2.3% equivalent >
And please don’t use ON time under 750μs or under OFF time calculated in the above of current setting for the brightness
control, because power-on/off has very influential.
●Noise of ceramic capacitor by PWM brightness control
In order to use a ceramic capacitor as the output capacitor, noise of capacitor occurs by the kind of the circuit board and
mounted method, the mounting place.
As for the noise cause, the resonant of ceramic capacitor and the board give cause by output voltage fluctuation.
Measures of this trouble are shown.
(1) Ceramic capacitor is changed to tantalum capacitor.
By changing to tantalum capacitor, noise is stopped because of changing ceramic capacitor itself bringing about the noise.
But, as the output ripple increases by ESR that is characteristic of the tantalum, it needs to select tantalum with low ESR.
Also, it recommends connecting parallel capacitor for the noise measure of 0.1µF
Recommended capacitor is shown next page.
(2) Ceramic capacitor is floated from the top of the circuit board.
Reducing the contact surface of the ceramic capacitor and the circuit board can reduce the noise.
Capacitor that can float a capacitor from the circuit board are as shown below. This capacitor is connected the metal cap both
electrodes of the capacitor, so It can have the effect which be floated because the metal cap is connected to the circuit board.
Recommended capacitor is shown next page.
The metal cap
CKG45NX7R2A225N (TDK)
The circuit board
Fig.31 The metal cap capacitor
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© 2011 ROHM Co., Ltd. All rights reserved.
10/15
2011.06 - Rev.B
Technical Note
BD6066GU,BU6066EKN
●Selection of external parts
Recommended external parts are as shown below.
When to use other parts than these, select the following equivalent parts.
Coil
Size
Vertical
Horizontal
Height
DC current
(mA)
DCR
(Ω)
Use power
voltage range
B1015AS-4R7N
8.4
8.3
4.0
3300
0.038
2.7 ~ 22V
4.7μH TAIYO YUDEN
NR4012T4R7M
4.0
4.0
1.2
960
0.14
2.7 ~ 22V
4.7μH TAIYO YUDEN
NR4018T4R7M
4.0
4.0
1.8
1200
0.11
2.7 ~ 22V
6.8μH TAIYO YUDEN
NR4012T6R8M
4.0
4.0
1.2
840
0.18
7.0 ~ 22V
Value
Manufacturer
Product number
4.7μH
TOKO
Capacitor
Value
Pressure
Manufacturer
Product number
Size
Temperature range
Vertical
Horizontal
Height
3.2
1.6
1.6
-25deg ~ +85deg
[ Power supply capacitor ]
10μF
25V
MURATA
GRM31CB31E106KA75
[ Smoothing capacitor for built-in regulator ]
1μF
10V
MURATA
GRM188B10J105KA01
1.6
0.8
0.8
-25deg ~ +85deg
[ Output capacitor ]
1μF
50V
MURATA
GRM31MB31H105KA87
3.2
1.6
1.15
-25deg ~ +85deg
2.2μF
50V
MURATA
GRM31CB31H225KA87
3.2
1.6
1.6
-25deg ~ +85deg
[ Output capacitor ] Noise measure 1 of ceramic capacitor (tantalum capacitor +0.1µF)
0.1μF
50V
MURATA
GRM188B31H104KA92
1.6
0.8
0.8
-25deg ~ +85deg
1.0μF
50V
KYOCERA
TAJW105M050
6.0
3.2
1.5
-55deg ~ +125deg
2.2μF
50V
KYOCERA
TAJC225M050
6.0
3.2
2.6
-55deg ~ +125deg
5.5
-55deg ~ +125deg
[ Output capacitor ] Noise measure 2 of ceramic capacitor (capacitor with the metal cap)
2.2μF
100V
TDK
CKG45NX7R2A225N
Tolerance
Manufacturer
Product number
5.5
4.0
Resistor
Value
[ Resistor for LED current decision
24kΩ
±0.5%
ROHM
[ Resistor for over current decision
47mΩ
±1%
Size
Vertical
Horizontal
Height
0.6
0.3
0.23
2.0
1.25
0.55
<ISET pin> ]
MCR006YZPD243
<SENSP pin> ]
ROHM
MCR10EZHFLR047
Pressure
Manufacturer
Product number
60V
ROHM
RB160M-60
Pressure
Manufacturer
Product number
45V
ROHM
RTR020N05
Vertical
3.5
Horizontal
1.6
Height
0.8
SBD
Size
Vertical
Horizontal
Height
3.5
1.6
0.8
MOS FET Nch
Size
Current
ability
Driving
voltage
2A
2.5V
60V
ROHM
2SK2503
9.5
6.5
2.3
5A
4.0V
60V
FAIR CHILD
NDT3055L
6.5
7.0
1.8
4A
2.0V
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. BD6066GU/EKN are designed for the inductance value of 4.7µH or 6.8µH. Do not use
other inductance value. Select a capacitor of ceramic type with excellent frequency and temperature characteristics.
Further, select Capacitor to be used with small direct current resistance, and pay sufficient attention to the PCB layout shown
in the next page.
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© 2011 ROHM Co., Ltd. All rights reserved.
11/15
2011.06 - Rev.B
Technical Note
BD6066GU,BU6066EKN
●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 layout patterns, which please note carefully.
Reset
PWM
CBAT
RSENSE
NC
EN2
NC
VREG
NC
SW
LED3
SENSP
GND
LED4
SENSN
ISET
SBD
LED2
NC
Tr
NC
NC
CREG
LED1
VDET
to Cathode
of LED
L
EN1
NC
GND
GND
COUT
VBAT
PWM
NC
CIN
VREG
to Power supply
to GND
to Anode
of each LED
NC
TEST
RISET
Fig.32 PCB Layout
Connect the input bypath capacitor CIN(10µF) nearest to coil L, as shown in the upper diagram.
Wire the power supply line by the low resistance from CIN to VBAT pin.
And, when it can't be wired by the low resistance, connect the input capacitor CBAT(1µF) nearest to between VBAT and
GND pin, as shown in the upper diagram. Thereby, the input voltage ripple of the IC can be reduced.
Connect smoothing capacitor CREG of the regulator nearest to between VREG and GND pin, as shown in the upper diagram.
Connect schottky barrier diode SBD of the regulator nearest to between coil L and switching transistor Tr.
And connect output capacitor COUT nearest to between CIN and GND pin. Thereby, the output voltage ripple of the IC can
be reduced.
Connect switching transistor Tr nearest to SW pin. Wire coil L and switching transistor Tr, current sensing resistor RSENSE by
the low resistance. Wiring to the SENSP pin isn't Tr side, but connect it from RSENSE side.
Over current value may become low when wiring from Tr side.
Connect RSENSE of GND side isolated to SENS pin. Don’t wire between RSENSE and SNESN pin wiring from SNESN pin to
GND pin. After via SENSN pin, connect GND pin, as shown in the upper diagram.
Connect LED current setting resistor RISET nearest to ISET pin. There is possibility to oscillate when capacity is added to
ISET terminal, so pay attention that capacity isn't added. And, connect RISET of GND side directly to GND pin.
When those pins are not connected directly near the chip, influence is given to the performance of BD6066GU/EKN, 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.
The PCB layout in consideration of these is shown in the next page.
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© 2011 ROHM Co., Ltd. All rights reserved.
12/15
2011.06 - Rev.B
Technical Note
BD6066GU,BU6066EKN
●Recommended PCB layout
Cin
L
Cout
SBD
CBAT
Tr
Creg
Rsense
RISET
Fig.33 BD6066EKN Component side（Top view）
Fig.34 BD6066EKN Back side（Top view）
●Attention point of PCB layout
In PCB layout 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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13/15
2011.06 - Rev.B
Technical Note
BD6066GU,BU6066EKN
●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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14/15
2011.06 - Rev.B
Technical Note
BD6066GU,BU6066EKN
●Ordering part number
B
D
6
Part No.
0
6
6
G
Part No.
6066
U
-
Package
GU : VCSP85H2
EKN : HQFN28V
E
2
Packaging and forming specification
E2: Embossed tape and reel
VCSP85H2 (BD6066GU)
<Tape and Reel information>
2.60±0.1
1.0MAX
0.25± 0.1
2.60± 0.1
1PIN MARK
Tape
Embossed carrier tape
Quantity
3000pcs
Direction
of feed
0.08 S
17- φ 0.3±0.05
0.05 A B
B
1
2 3 4 5
1pin
P=0.5×4
0.3±0.1
)
P=0.5 × 4
A
E
D
C
B
A
(φ0.15)INDEX POST
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
0.3± 0.1
S
E2
Reel
(Unit : mm)
Direction of feed
∗ Order quantity needs to be multiple of the minimum quantity.
HQFN28V
15
14
22
7
0.05
M
Embossed carrier tape (with dry pack)
Quantity
2500pcs
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
)
0.05
)
.5
(0
3(0
0.5
(3.1)
.2
2)
5)
.3
(0
(3.1)
0.22±0.05
0.22±0.05
0.95MAX
1
Tape
Direction
of feed
8
28
+0.03
0.02 -0.02
5.0±0.1
5.2±0.1
21
+0.1
0.6 -0.3
<Tape and Reel information>
5.2±0.1
5.0±0.1
(1.1)
Notice :
Do not use the dotted line area
for soldering
(Unit : mm)
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© 2011 ROHM Co., Ltd. All rights reserved.
1pin
Reel
15/15
Direction of feed
∗ Order quantity needs to be multiple of the minimum quantity.
2011.06 - Rev.B
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