ROHM BD6592MUV-E2

LED Drivers for LCD Backlights
White Backlight LED Driver
for Medium to Large LCD Panels
(Switching Regulator Type)
BD6592MUV
No.11040ECT33
●Description
BD6592MUV is white LED driver IC with PWM step-up DC/DC converter that can boost max 42.5V and current driver that
can drive max 40mA. The wide and precision brightness can be controlled by external PWM pulse. BD6592MUV has very
accurate current drivers, and it has few current errors between each strings. So, it will be helpful to reduce brightness spots
on the LCD. Small package type is suited for saving space.
●Features
1) High efficiency PWM step-up DC/DC converter (fsw=1MHz), max efficiency 93%
2) High accuracy & good matching (±3%) current drivers 6ch
*
*
3) Drive up to 12 in series, 6 strings in parallel =72 white LEDs ( white LED Vf=3.5Vmax)
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
6) Small & thin package (VQFN024V4040) 4.0 × 4.0 × 1.0mm
●Applications
All middle size LCD equipments backlight of Notebook PC, portable DVD player, car navigation systems, etc.
●Absolute maximum ratings (Ta=25℃)
Parameter
Symbol
Ratings
Unit
Maximum applied voltage 1
VMAX1
7
V
Maximum applied voltage 2
VMAX2
25
V
Maximum applied voltage 3
VMAX3
50.5
V
Power dissipation 1
Pd1
500
mW
*1
Power dissipation 2
Pd2
780
mW
*2
Power dissipation 3
Pd3
1510
mW
*3
Operating temperature range
Topr
-30 ~ +85
℃
Storage temperature range
Tstg
-55 ~ +150
℃
*1
*2
*3
Condition
TEST, VREG, SENSP, SENSN, SW,
RSTB, PWMPOW, PWMDRV,
FAILSEL, ISETH, ISETL
LED1, LED2, LED3, LED4, LED5,
LED6, VBAT
VDET
Reduced 4.0mW/℃ With Ta>25℃ when not mounted on a heat radiation Board.
1 layer (ROHM Standard board) has been mounted. Copper foil area 0mm2, When it’s used by more than Ta=25℃, it’s reduced by 6.2mW/℃.
4 layer (JEDEC Compliant board) has been mounted.
Copper foil area 1layer 6.28mm2, Copper foil area 2~4layers 5655.04mm2, When it’s used by more than Ta=25℃, it’s reduced by 12.1mW/℃.
●Recommended operating range (Ta=-30℃ ~ +85℃)
Parameter
Power supply voltage
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Symbol
VBAT
Ratings
Min.
Typ.
Max.
2.7
12.0
22.0
1/25
Unit
Condition
V
2011.06 - Rev.C
Technical Note
BD6592MUV
●Electrical characteristic (Unless otherwise specified, VBAT=12V, RSTB=2.5V, Ta = +25℃)
Limits
Parameter
Symbol
Unit
Min.
Typ.
Max.
Condition
[FAILSEL,PWMDRV 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
Input=2.5V
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
RSTBL
0
-
0.2
V
High Input Voltage range1
RSTBH1
2.25
2.5
5.0
V
VBAT>5.0V
High Input Voltage range2
RSTBH2
2.25
2.5
VBAT
V
VBAT<5.0V
IRSTB
-
89
134
µA
RSTB=2.5V, LED1-6=3V
VREG Voltage
VREG
4.0
5.0
6.0
V
No load
Under Voltage Lock Out
UVLO
2.05
2.25
2.65
V
Quiescent Current 1
Iq1
-
0.6
3.4
µA
RSTB=0V, VBAT=12V
Quiescent Current 2
Iq2
-
4.6
10
µA
RSTB=0V, VBAT=22V
Current Consumption
Idd
-
3.4
5.1
mA
VDET=0V,ISETH=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
-
-
0.1
V
Switching frequency
fSW
0.8
1.0
1.2
MHz
Duty cycle limit
Duty
92.5
95.0
99.0
%
LED1-6=0.3V
Over voltage limit
Ovl
43.0
44.7
46.4
V
LED1-6=0.3V
LED maximum current
ILMAX
-
-
40
mA
LED current accuracy
ILACCU
-
-
±5
%
ILED=30mA
LED current matching
ILMAT
-
-
±3
%
▪Each LED current/Average (LED1- 6)
▪ILED=30mA
Iset
0.5
0.6
0.7
V
LEDOVP
10.0
11.5
13.0
V
EN terminal input current
[PWMPOW Terminal]
Low Input Voltage range
[RSTB Terminal]
Low Input Voltage range
Current Consumption
[Regulator]
[Switching Regulator]
*1
Detect voltage of VDET pin
[Current driver]
ISET voltage
LED Terminal
Over Voltage Protect
RSTB=PWMDRV=2.5V
*1 This parameter is tested with DC measurement.
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2/25
2011.06 - Rev.C
Technical Note
BD6592MUV
●Reference data
85℃
25℃
4.0
3.5
1.20
7
1.15
85℃
6
3.0
2.0
-30℃
1.5
25 ℃
4
3
2
1.0
0.5
1
0.0
0
0
2
4
6
-30℃
Fig.1
Current Consumption - VBAT
2.6
4
6
0
2.1
25
Ta [℃]
50
75
85%
85%
80%
80%
75%
70%
70%
65%
65%
60%
0
10 20 30 40 50 60 70 80 90 100
Duty [%]
0
Fig.5
Efficiency - PWMPOW-HI Duty
ISETH=24kΩ, PWM=200Hz
10 20 30 40 50 60 70 80 90 100
Duty [%]
Fig.6
Efficiency - PWMDRV-HI Duty
ISETH=24kΩ, PWM=200Hz
1.0
30
8 10 12 14 16 18 20 22
VBAT [V]
VBAT=12V
90%
Fig.4
UVLO - Temperature
6
95%
90%
100
4
100%
VBAT=12V
60%
0
2
Fig.3
Oscillation frequency - VBAT
75%
2.2
-25
85℃
0.90
8 10 12 14 16 18 20 22
VBAT[V]
Efficiency
Efficiency
VBAT [V]
2
95%
2
-50
0.95
Fig.2
Quiescent current - VBAT
2.5
2.3
-30℃
1.00
0.85
100%
2.4
1.05
0.80
0
8 10 12 14 16 18 20 22
VBAT [V]
25℃
1.10
5
2.5
Ist[µA]
Iin [mA]
8
Frequency [MHz]
4.5
30
0.9
25
0.8
20
15
10
0.7
0.5
10
0.3
0
0.0
0
10 20 30 40 50 60 70 80 90 100
Duty (%)
0
Fig.7
LED current - PWMDRV-HI Duty
PWM = 200Hz
0.5
1
1.5
Duty (%)
2
2.5
0
3
10 20 30 40 50 60 70 80 90 100
Duty (%)
Fig.9
LED current - PWMDRV-HI Duty
PWM = 200Hz, 1kHz,10kHz
Fig.8
LED current - PWMDRV-HI Duty
( Expansion) PWM = 200Hz
1.0
30
10kHz
5
Ta=-30,+25,+85℃
0.1
Ta=-30,+25,+85℃
0
200Hz
15
0.4
0.2
5
20
VBAT=6V, 12V, 16V
0.6
1kHz
LED Current　(mA)
VBAT=6V, 12V, 16V
LED current　(mA)
LED current　(mA)
25
30
0.9
25
15
10
16V
0.7
LED Current　(mA)
LED current　(mA)
LED current　(mA)
20
25
0.8
VBAT=6V, 12V, 16V
0.6
0.5
12V
0.4
6V
0.3
0.2
5
Ta=-30,+25,+85℃
0.0
0
0
10 20 30 40 50 60 70 80 90 100
Duty (%)
Fig.10
LED current - PWMPOW-HI Duty
PWM = 200Hz
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200Hz
15
10kHz
10
1kHz
5
Ta=-30,+25,+85℃
0.1
20
0
0
0.5
1
1.5
2
Duty (%)
2.5
3
Fig.11
LED current - PWMPOW-HI Duty
( Expansion) PWM = 200Hz
3/25
0
10 20 30 40 50 60 70 80 90 100
Duty (%)
Fig.12
LED current - PWMPOW-HI Duty
PWM = 200Hz, 1kHz,10kHz
2011.06 - Rev.C
Technical Note
BD6592MUV
3.0
3.0
2.0
2.0
PWMDRV
Max Matching = Max LED Current/Average Current
Current Matching (%)
Current Matching (%)
Max Matching = Max LED Current/Average Current
1.0
0.0
-1.0
Min Matching = Min LED Current/Average Current
-2.0
VOUT
1.0
-1.0
LED Current
10mA/div
Min Matching = Min LED Current/Average Current
-2.0
-3.0
350mV
0.0
-3.0
0%
20%
40%
60%
PWM HI Duty
80%
100%
0%
Fig.13
LED current matching - PWMDRV-HI Duty
PWM = 200Hz
2%
4%
6%
PWM HI Duty
8%
10%
Fig.14
LED current matching - PWMDRV-HI Duty
(Expansion)
PWM = 200Hz
3.0
3.0
2.0
2.0
Fig.15
VOUT response
Driver Control PWM (PWMDRV)
PWMPOW
Max Matching = Max LED Current/Average Current
Current Matching (%)
Current Matching (%)
Max Matching = Max LED Current/Average Current
1.0
0.0
-1.0
Min Matching = Min LED Current/Average Current
-2.0
1.0
VOUT
-1.0
-2.0
-3.0
180mV
0.0
LED Current
10mA/div
Min Matching = Min LED Current/Average Current
-3.0
0%
20%
40%
60%
PWM HI Duty
80%
100%
0%
Fig.16
LED current matching - PWMPOW-HI Duty
PWM = 200Hz
2%
4%
6%
PWM HI Duty
8%
10%
Fig.18
VOUT response
Power Control PWM (PWMPOW)
Fig.17
LED current matching - PWMPOW-HI Duty
(Expansion)
PWM = 200Hz
35
34
VBAT
LED Current [mA]
33
5V, 7V, 12V, 22V
32
VBAT
400μs
14ms
31
30
VOUT
VOUT
29
No peak
No peak
28
LED current
2.7V
27
LED current
26
25
-50
-25
0
25
50
temp [℃]
75
100
Fig.19
LED current - Temperature
PWMDRV=H, ISETH=30kΩ (16mA setting)
Fig.20
Line Transient (10V to 22V)
Fig.21
Line Transient (22V to 10V)
VOUT
Icc
Fig.22
VOUT@OVP (LED OPEN)
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4/25
2011.06 - Rev.C
Technical Note
BD6592MUV
●Block diagram, I/O equivalent circuit diagram
VBAT
VREG
RSTB
VIN detector
300kΩ
PW MPOW
REG
VBAT
UVLO
Internal Power suplly
500kΩ
TSD
VDET
+
-
SBD Open protect
VBAT
VREG
PIN
PIN
PIN
GND
FAILSEL
over voltage protect
300kΩ
S
SW
Q
PW Mcomp
+
Control
sence
R
1MΩ
SENSP
+
Current
Sence
100KΩ
SENSN
+
-
ERRAMP
+
LED1
LED2
GND
A
B
VBAT
VBAT
C
LED3
LED4
PIN
PIN
PIN
LED5
OSC
5.5V
LED6
GND
LED TERMINAL
Detect
GND
D
Clump
E
F
VBAT VREG
LED TERMINAL
Over Voltage Protect
TEST
100kΩ
PIN
PW MDRV
300kΩ
ISETH
ISET H
Resistor driver
+
PW MDRV=H
On
GND
-
G
ISET L
Resistor driver
ISETL
GND
GND
PW MDRV=L
On
GND
Current Driver
GND
Fig.23 Block diagram
●Pin assignment table
PIN
In/Out
Name
1
PIN
number
Fig.24 I/O equivalent circuit diagram
Function
Terminal equivalent
circuit diagram
VDET
In
Detect input for SBD open and OVP
C
2
N.C.
-
No connect pin
F
3
GND
-
GND
B
4
SW
Out
Switching Tr drive terminal
G
5
SENSP
In
+ Side Current sense terminal
G
6
TEST
In
TEST input (Pull down 100kΩ to GND)
G
7
SENSN
In
- Side Current sense terminal
A
8
GND
-
GND
B
9
ISETH
In
Resistor connection for LED current setting at PWMDRV=H
A
10
ISETL
In
Resistor connection for LED current setting at PWMDRV=L
A
11
PWMDRV
In
PWM input pin for power ON/OFF only driver
E
12
LED1
In
Current sink for LED1
C
13
LED2
In
Current sink for LED2
C
14
LED3
In
Current sink for LED3
C
15
GND
-
GND
B
16
LED4
In
Current sink for LED4
C
17
LED5
In
Current sink for LED5
C
18
LED6
In
Current sink for LED6
C
19
FAILSEL
In
Latch selectable pin of protect function
E
20
GND
-
GND
B
21
RSTB
In
Reset pin L :Reset H :Reset cancel
E
22
VREG
Out
Regulator output / Internal power-supply
D
23
PWMPOW
In
PWM input pin for power ON/OFF
E
24
VBAT
In
Battery input
C
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5/25
2011.06 - Rev.C
Technical Note
BD6592MUV
●Application example
Battery
Battery
4.7μH
10μF
10LED x 6parallel
2.2μF *
RTR020N05
4.7μH
10μF
2.2μF *
SW
10LED x 4aprallel
2.2μF *
FAILSEL
SENSP
RTR020N05
2.2μF *
SW
VDET
FAILSEL
SENSP
47mΩ
VDET
47mΩ
SENSN
Power
ON/OFF
SENSN
Power
ON/OFF
RSTB
2.2μF
LED3
VBAT
LED4
VREG
LED2
PWMDRV
200Hz
PWM
LED3
VBAT
LED1
PWMPOW
LED2
PWMDRV
200Hz
PWM
RSTB
LED1
PWMPOW
LED4
VREG
LED5
2.2μF
GND GND GND GND TEST ISETH ISETL LED6
LED5
GND GND GND GND TEST ISETH ISETL LED6
Each 40mA
12kΩ
Each 40mA
12kΩ
Fig.26 10 series x 4parallel
Fig.25 10 series x 6parallel
Hi current 40mA setting
Hi current 40mA setting
Current driver PWM application
Current driver PWM application
* Please select the capacitor which the little bias fluctuation.
Battery
Battery
4.7μH
10μF
10LED x 6parallel
2.2μF *
RTR020N05
4.7μH
10μF
2.2μF *
SW
10LED x 6parallel
2.2μF *
RTR020N05
FAILSEL
SW
VDET
SENSP
2.2μF *
FAILSEL
SENSP
47mΩ
VDET
47mΩ
SENSN
Power
ON/OFF
SENSN
Power
ON/OFF
RSTB
LED1
PWMPOW
VBAT
LED3
VBAT
LED4
VREG
LED2
PWMDRV
200Hz
PWM
LED3
2.2μF
LED1
PWMPOW
LED2
PWMDRV
200Hz
PWM
RSTB
2.7V to 5.5V
LED5
2.2μF
GND GND GND GND TEST ISETH ISETL LED6
Each 30mA
LED4
VREG
LED5
GND GND GND GND TEST ISETH ISETL LED6
Each 40mA
16kΩ
12kΩ
Fig.28 Non-used Inside REG
Fig.27 10 series x 6parallel LED current 30mA setting
Power control PWM application
or operating under 5V application
* Please select the capacitor which the little bias fluctuation.
●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 2.7~5.5V, short VBAT and VREG, and put the voltage to VREG
FAILSEL, PWMDRV= Connect to GND in case of fixing at L level. Connect to VREG of IC or the power supply of more
than 1.4V in case of fixing at H level .
LED1-6= When each LED driver are not used, connect to GND of IC
GND = Each GND is connecting inside IC, but, connect to GND of all board
RSTB= RSTB is used as a power supply of internal circuit.
So, you mustn’t input RSTB voltage with pull up resistor of several kΩ. And, please care about the relation between VBAT
and RSTB enough. (ref. P9)
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6/25
2011.06 - Rev.C
Technical Note
BD6592MUV
●Description of Functions
1) PWM current mode DC/DC converter
While BD6592MUV is power ON, the lowest voltage of LED1, 2, 3, 4, 5, 6 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.
BD6592MUV has many safety functions, and their detection signals stop switching operation at once.
2) Soft start
BD6592MUV has soft start function.
The soft start function prevents large coil current.
Rush current at turning on is prevented by the soft start function.
After RSTB is changed L H, when PWMPOW is changed L H, soft start becomes effective for within 1ms and soft start
doesn't become effective even if PWMPOW is changed L H after that.
And, when the H section of PWMPOW is within 1ms, soft start becomes invalid when PWMPOW is input to H more than
three times. The invalid of the soft start can be canceled by making RSTB  L.
3) FAILSEL pin
When the error condition occurs, boost operating is stopped by the protection function, and the error condition is avoided.
On that occasion, the way to stop of boost operating by the protection function can be selected with FAILSEL pin. Details
are as shown in Fig.29, 30.
After power ON, when the protection function is operating under about 1ms have passed, the stop state of the boost
operating can be held through FAILSEL is H, the stop state can reset through RSTB is L.
And, boost operating is stopped when the protection function is operating through FAILSEL is L, but when the protection
function becomes un-detect, boost operating is started again. It never keeps holding the stop state of boost operating.
In PWM control by PWMDRV can’t use this function.
When it is off over 10ms on PWM control by PWMPOW using this function, it may be stopped the boost operating as
over current protection work at off on PWMPOW=L.
Object of protect function is as shown below.
・ Over-voltage protection
・ External SBD open detect
・ Thermal shutdown
・ LED terminal over-voltage protection
・ Over current limit
< When it is off on PWMPOW>
<FAILSEL=H>
RSTB
RSTB
PWMDRV
about 1ms
“H”
FAILSEL
un-operating range
Protection
function
un-detection
Boost
operating
PWMPOW
Output
voltage
off
detection
normal operating
un-detection
boost stop
Coil current
off
normal operating
valid
RSTB
RSTB
PWMDRV
about 1ms
“L”
Protection
function
Boost
operating
invalid
< When it is off on RSTB>
<FAILSEL=L>
FAILSEL
FAILSEL
function
PWMPOW
un-operating range
un-detectio
detection
Output
voltage
un-detection
Coil current
off
normal operating
boost stop
normal
operating
off
normal
Fig.29 FAILSEL operating description
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FAILSEL
function
invalid
Fig.30 FAILSEL=H light off control
7/25
2011.06 - Rev.C
Technical Note
BD6592MUV
4) External SBD open detect and over voltage protection
BD6592MUV has over boost protection by external SBD open and over voltage protection. It detects VDET voltage and is
stopped output Tr in abnormal condition. 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 0.1V 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.
5) Thermal shut down
BD6592MUV has thermal shut down function.
The thermal shut down works at 175C or higher, and the IC changes from activation into non-activation. Because
non-activation is different from RSTB=L, it doesn’t’ be reset inside IC. Moreover, even if thermal shut down function works,
soft start, FAILSEL, selection the number of LED lines of the current driver and starting current setting at PWMDRV=L
related RSTB are hold.
6) 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 BD6592MUV 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 BD6592MUV 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
○ Inductance 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.3.)
○ 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
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8/25
2011.06 - Rev.C
Technical Note
BD6592MUV
(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 x 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
When too large current is set, output overshoot is caused, be careful enough because it is led to break down of the IC in
case of the worst.
●Operating of the application deficiency
1) When 1 LED or 1parallel OPEN during the operating
In case of FAILSEL=L, the LED parallel which became OPEN isn't lighting, but other LED parallel is lighting. At that time,
output boosts up to the over voltage protection voltage 44.7V so that LED terminal may be 0V or it boost to the output voltage
that LED terminal voltage becomes LED terminal over voltage protection 11.5V or it becomes the output voltage restricted
by the over current limit.In case of FAILSEL=H, boost stops when LED becomes OPEN and all LED turns off the lights.
2) When LED short-circuited in the plural
In case of FAILSEL=L, all LED is turned on unless LED terminal voltage is LED terminal over voltage protection of more than 11.5V.
When it was more than 11.5V only the line which short-circuited is turned on normally and LED current of other lines fall or
turn off the lights. In case of FAILSEL=H, boost stops at more than 11.5V and all LED turns off the lights.
3) When Schottky diode came off
Regardless of FAILSEL, all LED isn't turned on. Also, IC and a switching transistor aren't destroyed because boost
operating stops by the Schottky diode coming off protected function.
4) When over current detection resistor came off
Regardless of FAILSEL, all LED isn't turned on. Because the resistance of 100kΩ is between SENSP and SENSN terminal,
over current protection works instantly and LED current can't be flow.
●Control signal input timing
0V
2.7V 5V
VBAT
2
Min. 100µs
1
VBAT
5V
3
RSTB
220Ω
5V
PWMPOW
PIN
Rin
PWMDRV
GND
VREG
DC/DC VOUT
Fig.31 Control signal timing
Fig.32 Voltage with a control sign higher than VBAT
Example corresponding to application of conditions
In case you input control signs, such as RSTB, PWMPOW, and PWMDRV, in the condition that the standup of supply voltage
(VBAT) is not completed, be careful of the following point.
① Input each control signal after VBAT exceeds 2.7V.
② Please do not input each control sign until VBAT exceeds HI voltage of RSTB, PWMPOW, and PWMDRV.
③ When you input RSTB during the standup of VBAT and HI voltage is inputted into PWMPOW, please give the standup
time to stable voltage as Min.100µs 2.7V of VBAT.
There is no timing limitation at each input signal of RSTB, PWMPOW and PWMDRV.
If each control sign changes into a condition lower than VBAT in (1) and (2), it goes via the ESD custody diode by the side of
VBAT of each terminal. A power supply is supplied to VBAT and there is a possibility of malfunctioning. Moreover, when the
entrance current to the terminal exceeds 50mA, it has possibility to damage the LSI. In order to avoid this condition, as
shown in the above figure, please insert about 220ohm in a signal line, and apply current qualification. Please confirm an
internal pull down resistor in the block diagram and electrical property of P.5.
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9/25
2011.06 - Rev.C
Technical Note
BD6592MUV
BD6592MUV
Power supply
for RSTB
Limit resistor
250
RSTB　input current[ µA]
●Attendance point of the restriction resistance input to RSTB
When the restriction resistance is input to RSTB, it is necessary to
consider the input current of RSTB.
The input current of RSTB changes that depending on the
power-supply voltage and the temperature reference to Fig.33.
Because the temperature characteristic of the input current is
shown in Fig.33, please choose resistance for which the voltage
of the terminal can be guaranteed to 2.1V or more.
And, it has the margin in the decision of resistance, and please
confirm and make sure it is no problem in a real application.
+100℃
+80℃
+25℃
200
-30℃
150
100
50
RSTB
terminal
2.1
2.4
2.7
3
3.3
3.6
RSTB[V]
Fig.33 RSTB terminal voltage-RSTB inflow current
RSTB inflow current
(At the time of the current driver six lines use)
The decision example of restriction resistance
1． When use the current driver of 6 parallel
2.9V(to RSTB power-supply) - restriction resistance value × 124μA(100℃ input current) > 2.1V
restriction resistance value < (2.9-2.1)/124μA=6.45kΩ
2． 2. When use the current driver of 3 parallel
2.9V(to RSTB power-supply) - restriction resistance value × 430μA(100℃ input current) > 2.1V
restriction resistance value < (2.9-2.1)/430μA=1.86kΩ
In addition, the selection number of parallel number of the current driver is changed, the power-supply current of RSTB will
be increased. Because the maximum value of the consumption current at the RSTB=2.1V is indicated in the following Table
1, be careful enough when you calculate the restriction resistance.
Table1. The use parallel number of current driver at RSTB=2.1V , 100℃ vs. RSTB input current
Parallel numbers used for current driver
RSTB input current
6
0.12mA
5
0.23mA
4
0.33mA
3
0.43mA
2
0.53mA
1
0.63mA
0
0.74mA
●How to select the number of LED lines of the current driver
When the number of LED lines of the current driver is reduced, the un-select can be set the matter that the unnecessary
LED1 ~ 6 terminal is connected to GND. When it uses with 4 lines and so on, it can correspond to it by connecting 2
unnecessary lines to GND.RSTB is used as a power supply of this decision circuit. The select of the terminal is judged, It has
no relation to the logic of PWMPOW and PWMDRV and it isn't judged an unnecessary LED line even if it is connected to
GND when it is judged a necessary terminal once. This information can be reset by setting RSTB at 0V.
●Start control and select LED current driver
BD6592MUV can control the IC system by RSTB, and IC can power off compulsory by setting 0.2V or below. Also, It powers
on PWMPOW is at more than 1.4V and RSTB is at more than 2.25V.
When RSTB=PWMPOW=H, ISETH current is selected at PWMDRV=H and ISETL current is selected at PWMDRV=L.
The starting current in PWMDRV=L sets OFF second time rise of PWMDRV and it becomes 0mA setting after that.
After RSTB sets L once, the starting current can be flowed again by changing it to H.
RSTB
H
H
H
H
L
PWMPOW
L
H
L
H
L, H
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PWMDRV
L
L
H
H
L, H
IC
Off
On
Off
On
Off
LED current
OFF
Starting current decided with ISETL
OFF
Current decided with ISETH
OFF
10/25
2011.06 - Rev.C
Technical Note
BD6592MUV
●Start to use PWMPOW terminal for the PWM control, PWM operating
After RSTB and PWMDRV is changing L  H, input PWM to PWMPOW terminal.
There is no constraint in turn of RSTB and PWMDRV.
And, because it corresponds to PWM drive of shorter ON time than soft start time (1ms), when PWMPOW is input H more
than three times, the soft start is invalidated and it enable to correspond the high-speed drive. Until RSTB is set L,
invalidation of the soft start isn't canceled.
In case of lighting  light off  lighting, when it turns off the lights with PWM=L and It starts without soft start when it sets
PWM modulated light again.
But the peak current of the coil changes owing to discharge of output capacitor, It may flow to the over current limit value, as
follows Fig.34. Because soft start can be used when it turns off the lights with RSTB=L, The peak current of the coil can be
suppressed, as follows Fig.35 and this process of light off is recommended.
RSTB
PWMDRV
PWMPOW
Output Voltage
Current coil
Fig.34 Light off control of PWMPOW pin at PWM control on PWM=L
RSTB
PWMDRV
PWMPOW
Output Voltage
Current coil
Fig.35 Light off control of PWMPOW pin at PWM control on RSTB=L
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11/25
2011.06 - Rev.C
Technical Note
BD6592MUV
●Start to use PWMDRV terminal for the PWM control, PWM operating
After RSTB and PWMPOW is changing L  H, input PWM to PWMDRV terminal.
There is no constraint in turn of RSTB and PWMPOW.
When resistance is set as ISET, after RSTB and PWMPOW is changing L  H as follows Fig.36, when it is not input PWM to
PWMDRV pin but input L, boost of DC/DC is unstable state because current driver doesn’t pass current.
The starting current is pulled from each LED terminal and pressure up operating is stabilized to escape from this state.
Also, the starting current can be set up by the resistance value connected to the ISETL terminal.
After starting, as the starting current in PWM brightness control become useless, the starting current is set up 0mA at the
second rise time of PWMDRV automatically as follows Fig.37.
In case of lighting  light off  lighting, when it turns off the lights with PWM=L and It starts without soft start because of soft
start period was end when it sets PWM modulated light again.
But the peak current of the coil changes owing to discharge of output capacitor, It may flow to the over current limit value, as
follows Fig.37. Because soft start can be used when it turns off the lights with RSTB=L, The peak current of the coil can be
suppressed, as follows Fig.38 and this process of light off is recommended.
RSTB
PWMPOW
PWMDRV
L
H
L
H
OFF
ON
OFF
L
H
L
Output voltage
LED pin
ON
Current driver of
starting current
Fig.36 Off timing of starting current at PWMDRV=L
RSTB
PWMPOW
PWMDRV
Output Voltage
Current coil
Fig.37 Light off control of PWMDRV pin at PWM control on PWM=L
RSTB
PWMPOW
PWMDRV
Output Voltage
Current coil
Fig.38 Light off control of PWMDRV pin at PWM control on RSTB=L
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12/25
2011.06 - Rev.C
Technical Note
BD6592MUV
●Brightness control
There are two dimming method is available, first method is analog dimming that apply analog voltage to ISET terminal, and
second method is PWM control via digital dimming of PWMPOW or PWMDRV. Because each method has the different merit,
please choose a suitable method for the application of use.
Two techniques can be used as digital dimming by the PWM control One is PWM control of current driver, the other is PWM
control of power control.
As these two characteristics are shown in the below, selects to PWM control process comply with application.
•Efficiency emphasis in the low brightness which has an influence with the battery life
•LED current dispersion emphasis in the PWM brightness control
 2) Power control PWM control
 1) Current driver PWM control
(Reference)
PWM regulation process
Current driver
Power control
Efficiency of LED current 0.5mA
(PWM Duty=2.5%)
70%
93%
PWM frequency 200Hz
Limit dispersion capability of low duty
0.2%
0.5%
1) Current driver PWM control is controlled by providing PWM signal to PWMDRV, as it is shown Fig.25.
The current set up with ISETH is chosen as the Hi section of PWMDRV and the current is off as the Lo section. Therefore,
the average LED current is increasing in proportion to duty cycle of PWMDRV signal. This method that it lets internal
circuit and DC/DC to work, because it becomes to switch the driver, the current tolerance is a few when the PWM
brightness is adjusted, it makes it possible to brightness control until 20µs (MIN0.4% at 200Hz). And, don't use for the
brightness control, because effect of ON/OFF changeover is big under 20µs ON time and under 20µs OFF time. There is
no effect of ON/OFF changeover at 0% and 100%, so there is no problem on use. Typical PWM frequency is
100Hz~10kHz. When resistance is set as ISET, RSTB sets H  L, so the starting current may be effective, after RSTB
sets L  H, it becomes PWM of the starting current and PWM of ISETH setting current to PWM two times.
PW MDRV
ON
OFF
LED current
ON
OFF
Coil current
ON
OFF
ON
IC’s active current
Fig.39
2) Power control PWM control is controlled by providing PWM signal to PWMPOW, as it is shown Fig.27. The current setting
set up with PWMDRV logic is chosen as the Hi section and the current is off as the Lo section. Therefore, the average LED
current is increasing in proportion to duty cycle of PWMPOW signal. This method is, because IC can be power-off at
off-time, the consumption current can be suppress, and the high efficiency can be available, so it makes it possible to
brightness control until 50µs (MIN1% at 200Hz). And, don't use for the brightness control, because effect of power
ON/OFF time changeover is big under 50µs ON time and under 50µs OFF time.
There is no effect of ON/OFF changeover at 0% and 100%, so there is no problem on use. Typical PWM frequency is
100Hz~1kHz. Also, PWM can't control RSTB and PWMPOW at the same time.
After RSTB sets H, control PWM only PWMPOW.
PWMPOW
ON
OFF
LED current
ON
OFF
Coil current
ON
OFF
IC’s active current
ON
OFF
Fig.40
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13/25
2011.06 - Rev.C
Technical Note
BD6592MUV
●LED current setting range
LED current can set up Normal and Starting setting current.
LED current can set up Normal current by resistance value (RISETH) connecting to ISETH voltage and LED current can set
Starting current by resistance value (RISETL) connecting to ISETL voltage.
Setting of each LED current is given as shown below.
Normal current = 20mA(24kΩ/RISETH)
Starting constant current = 0.6/RISET L
Also, Normal current setting range is 10mA~25mA, Starting current setting range is OFF setting or 1µA~100µA.
LED current can set OFF setting by open setting ISETL pin.
LED current becomes a leak current MAX 1µA at OFF setting.
ISETH Normal current setting example
RISETH
LED current
12kΩ (E12)
16 kΩ (E16)
24kΩ (E24)
25.5 kΩ (E96)
27 kΩ (E12)
30kΩ (E24)
40mA
30mA
20mA
18.8mA
17.8mA
16.0mA
ISETL Starting current setting example
RISETL
LED current
6.2kΩ (E24)
97µA
10kΩ (E6)
60µA
47kΩ (E6)
13µA
100 kΩ (E6)
6µA
560 kΩ (E12)
1.1µA
Connect to VREG pin
0mA
●The separations of the IC Power supply and coil Power supply
This IC can work in separating the power source in both IC power supply and coil power supply. With this application, it can
obtain that decrease of IC power consumption, and the applied voltage exceeds IC rating 22V.
That application is shown in below Fig 41. The higher voltage source is applied to the power source of coil that is connected
from an adapter etc. Next, the IC power supply is connected with a different coil power supply. Under the conditions for
inputting from 2.7V to 5.5V into IC VBAT, please follow the recommend design in Fig 38. It connects VBAT terminal and
VREG terminal together at IC outside.
When the coil power supply is applied, it is no any problem even though IC power supply is the state of 0V. Although IC
power supply is set to 0V, pull-down resistance is arranged for the power off which cuts off the leak route from coil power
supply in IC inside, the leak route is cut off. And, there is no power on-off sequence of coil power supply and IC power supply.
Coil Power supply
7V to 28V
Battery
4.7μH
10μF
10LED x 6 列
2.2μF
RTR020N05
2.2μF
SW
FAILSEL
SENSP
VDET
47mΩ
SENSN
Power
ON/OFF
RSTB
LED1
PWMDRV
LED2
PWMPOW
200Hz
PWM
LED3
VBAT
IC Power supply 2.7V to 5.5V
LED4
VREG
1μF
LED5
GND GND GND GND TEST ISETH ISETL LED6
各 40mA
12kΩ
Fig.42 Application at the time of power supply isolation
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14/25
2011.06 - Rev.C
Technical Note
BD6592MUV
●The coil selection
The DC/DC is designed by more than 4.7µH. When L value sets to a lower value, it is possibility that the specific
sub-harmonic oscillation of current mode DC / DC will be happened.
Please do not let L value to 3.3µH or below.
And, L value increases, the phase margin of DC / DC becomes to zero. Please enlarge the output capacitor value when you
increase L value.
Example)
4.7µH
6.8µH
10µH
=
=
=
output capacitor
output capacitor
output capacitor
2.2µF/50V
2.2µF/50V
2.2µF/50V
1pcs
2pcs
3pcs
This value is just examples, please made sure the final judgment is under an enough evaluation.
●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.
to Power Supply
PWM
Reset
CIN
CBAT
to Cathode
of LED
SBD
Tr
FAILSEL
GND
RSTB
VREG
PWMPOW
CREG
VBAT
L
VDET
LED6
N.C.
LED5
GND
LED4
SW
GND
SENSP
LED3
to Anode
of each LED
LED2
LED1
PWMDRV
ISETL
to GND
ISETH
TEST
GND
RSENSE
SENSN
COUT
RISET
Fig.42 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. 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 RSENSE pin to GND pin. And RSENSE GND line must be wired directly to GND pin of output capacitor. It has the
possibility that restricts the current drive performance by the influence of the noise when other GND is connected to this
GND.
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, RISET of GND side must be wired directly to GND pin.
When those pins are not connected directly near the chip, influence is given to the performance of BD6592MUV, 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 layout pattern in consideration of these is shown in next page.
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15/25
2011.06 - Rev.C
Technical Note
BD6592MUV
●Recommended PCB layout pattern
BD6592MUV
CREG
RISET
CBAT
L
CIN
Tr
RSENSE
COUT
Fig.43 Frontal surface <Top view>
Fig.44 Rear surface <Top view>
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16/25
2011.06 - Rev.C
Technical Note
BD6592MUV
●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
DC current
DCR
Value
Manufacturer
Product number
(mA)
(Ω)
Vertical
Horizontal Height (MAX)
4.7μH
TOKO
A915AY-4R7M
5.2
5.2
3.0
1870
0.045
4.7μH
TOKO
B1015AS-4R7M
8.4
4.7μH
4.7μH
TOKO
A1101AS-4R7M
4.1
4.1
1.2
1400
0.115
TDK
LTF5022T-4R7N2R0
5.0
5.2
2.2
2000
0.073
4.7μH
TDK
VLP6810T-4R7M1R6
6.3
6.8
1.0
1600
0.167
10μH
・Capacitor
TDK
VLP6810T-100M1R1
6.3
6.8
1.0
1100
0.350
Vertical
Size
Horizontal
Height
TC
Cap
Tolerance
Value
Pressure
Manufacturer
Product number
8.3
4.0
3300
0.038
[ Supply voltage capacitor ]
10μF
25V
MURATA
GRM31CB31E106K
3.2
1.6
1.6±0.2
B
+/-10%
10μF
10V
MURATA
GRM219BB31A106K
2.0
1.25
0.85±0.15
B
+/-10%
4.7μF
25V
MURATA
GRM319B31E475K
3.2
1.6
0.85±0.1
B
+/-10%
4.7μF
25V
MURATA
GRM21BB31E475K
2.0
1.25
1.25±0.1
B
+/-10%
[ Smoothing capacitor for built-in regulator ]
1μF
10V
MURATA
GRM188B10J105K
1.6
0.8
0.8±0.1
B
+/-10%
2.2μF
10V
MURATA
GRM219B11A225K
2.0
1.25
0.85±0.1
B
+/-10%
50V
MURATA
GRM31MB31H105K
3.2
1.6
1.15±0.1
B
+/-10%
1μF
50V
MURATA
GRM21BB31H105K
2.0
1.25
1.25±0.1
B
+/-10%
1μF
100V
MURATA
GRM31CR72A105K
3.2
1.6
1.6±0.2
X7R
+/-10%
2.2μF
50V
MURATA
GRM31CB31H225K
3.2
1.6
1.6±0.2
B
+/-10%
0.33μF
・Resistor
50V
MURATA
GRM219B31H334K
2.0
1.25
0.85±0.1
B
+/-10%
Vertical
Size
Horizontal
Height
0.6
0.3
0.23±0.03
2.0
1.25
0.55±0.1
Vertical
3.5
Size
Horizontal
1.6
Height
0.8±0.1
Size
Horizontal
2.9
Height
1.0
Current
ability
Driving
voltage
2A
2.5V
5.0
1.75
6.5A
4.0V
[ Output capacitor ]
1μF
Value
Tolerance Manufacturer
[ Resistor for LED current decision
16kΩ
±0.5%
ROHM
[ Resistor for over current decision
47mΩ
・SBD
±1%
Pressure
ROHM
Product number
<ISETH pin> ]
MCR006YZPD163
<SENSP pin> ]
MCR10EZHFSR047
Manufacturer
Product number
ROHM
RB160M-60
Pressure
Manufacturer
Product number
45V
ROHM
RTR020N05
Vertical
2.8
60V
ROHM
RSS065N06
6.0
60V
・MOS FET Nch
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. BD6592MUV is designed for the inductance value of 4.7µH.
Don’t use the inductance value less than 2.2µH. 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 P.16.
●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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17/25
2011.06 - Rev.C
Technical Note
BD6592MUV
●Application example
・LED current setting controlled ISETH resistor.
24kΩ : 20mA
16kΩ : 30mA
12kΩ : 40mA
・Brightness control
Please input PWM pulse from PWMPOW or PWMDRV terminal.
Please refer electrical characteristic p.3 and function (p.12).
15inch panel
Battery
4.7μH
10μF
10LED x 6parallel
2.2μF *
RTR020N05
2.2μF
SW
FAILSEL
VDET
SENSP
47mΩ
SENSN
Power
ON/OFF
RSTB
LED1
PWMPOW
LED2
PWMDRV
100Hz~10kHz
PWM
LED3
VBAT
LED4
VREG
2.2μF
LED5
GND GND GND GND TEST ISETH ISETL LED6
Each 40mA
12kΩ
Can be set up to each15~40mA
Fig.45 10 series×6 parallel, LED current 40mA setting
Current driver PWM application
13~14inch panel
Battery
Battery
4.7μH
10μF
8LED x 6parallel
2.2μF *
RTR020N05
SW
4.7μH
10μF
2.2μF
8LED x 6parallel
2.2μF *
FAILSEL
SENSP
RTR020N05
SW
VDET
2.2μF
FAILSEL
SENSP
51mΩ
VDET
51mΩ
SENSN
Power
ON/OFF
SENSN
Power
ON/OFF
RSTB
LED1
PWMPOW
100Hz~1kHz
PWM
LED2
PWMDRV
2.2μF
LED3
2.2μF
GND GND GND GND TEST ISETH ISETL LED6
Each 40mA
LED5
GND GND GND GND TEST ISETH ISETL LED6
12kΩ
Can be set up to each15~40mA
Each 40mA
Can be set up to each15~40mA
Fig.46 8 series× 6 parallel, LED current 40mA setting
Power control PWM application
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© 2011 ROHM Co., Ltd. All rights reserved.
LED4
VREG
LED5
12kΩ
LED2
VBAT
LED4
VREG
LED1
PWMDRV
100Hz~10kHz
PWM
LED3
VBAT
RSTB
PWMPOW
Fig.47 8 series×6 parallel, LED current 40mA setting
Current driver PWM application
18/25
2011.06 - Rev.C
Technical Note
BD6592MUV
●Application example
・LED current setting controlled ISETH resistor.
24kΩ : 20mA
16kΩ : 30mA
12kΩ : 40mA
・Brightness control
Please input PWM pulse from PWMPOW or PWMDRV terminal.
Please refer electrical characteristic p.3 and function (p.13).
10~12inch panel
Battery
Battery
4.7μH
10μF
7LED x 6parallel
2.2μF *
RTR020N05
4.7μH
10μF
2.2μF
SW
10LED x 4parallel
2.2μF *
FAILSEL
SENSP
RTR020N05
2.2μF
SW
VDET
FAILSEL
SENSP
56mΩ
VDET
56mΩ
SENSN
Power
ON/OFF
SENSN
Power
ON/OFF
RSTB
PWMPOW
2.2μF
LED3
VBAT
LED4
VREG
LED2
PWMDRV
100Hz~10kHz
PWM
LED3
VBAT
LED1
PWMPOW
LED2
PWMDRV
100Hz~10kHz
PWM
RSTB
LED1
LED4
VREG
LED5
2.2μF
GND GND GND GND TEST ISETH ISETL LED6
LED5
GND GND GND GND TEST ISETH ISETL LED6
Each 30mA
16kΩ
Fig.48 7 series×6 parallel, LED current 30mA setting
Current driver PWM application
Each 40mA
12kΩ
Can be set up to each15~40mA
Can be set up to each15~40mA
Fig.49 10 series×4 parallel, LED current 40mA setting
Current driver PWM application
7inch panel
Battery
Battery
4.7μH
10μF
8LED x 3parallel
2.2μF *
RTR020N05
SW
4.7μH
10μF
2.2μF
6LED x 4parallel
2.2μF *
FAILSEL
SENSP
RTR020N05
SW
VDET
2.2μF
FAILSEL
SENSP
68mΩ
VDET
68mΩ
SENSN
Power
ON/OFF
SENSN
Power
ON/OFF
RSTB
LED1
PWMPOW
LED2
PWMDRV
100Hz~10kHz
PWM
2.2μF
LED3
2.2μF
GND GND GND GND TEST ISETH ISETL LED6
Each 40mA
Fig.50 8 series×3 parallel, LED current 40mA setting
Current driver PWM application
LED5
GND GND GND GND TEST ISETH ISETL LED6
12kΩ
Can be set up to each15~40mA
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© 2011 ROHM Co., Ltd. All rights reserved.
LED4
VREG
LED5
12kΩ
LED2
VBAT
LED4
VREG
LED1
PWMDRV
100Hz~10kHz
PWM
LED3
VBAT
RSTB
PWMPOW
Each 40mA
Can be set up to each15~40mA
Fig.51 6 series×4 parallel, LED current 40mA setting
Current driver PWM application
19/25
2011.06 - Rev.C
Technical Note
BD6592MUV
●Application example
・LED current setting controlled ISETH resistor.
24kΩ : 20mA
16kΩ : 30mA
12kΩ : 40mA
・Brightness control
Please input PWM pulse from PWMPOW or PWMDRV terminal.
Please refer electrical characteristic p.3 and function (p.13).
7inch panel
Battery
Battery
4.7μH
10μF
4LED x 6parallel
2.2μF *
RTR020N05
4.7μH
10μF
2.2μF
SW
8LED x 3parallel
2.2μF *
FAILSEL
SENSP
RTR020N05
2.2μF
SW
VDET
FAILSEL
SENSP
68mΩ
VDET
68mΩ
SENSN
Power
ON/OFF
SENSN
Power
ON/OFF
RSTB
LED1
PWMPOW
100Hz~1kHz
PWM
LED2
PWMDRV
RSTB
LED1
PWMPOW
100Hz~1kHz
PWM
LED2
PWMDRV
LED3
VBAT
VREG
2.2μF
LED3
VBAT
LED4
LED4
VREG
LED5
2.2μF
GND GND GND GND TEST ISETH ISETL LED6
LED5
GND GND GND GND TEST ISETH ISETL LED6
Each 40mA
12kΩ
Fig.52 4 series×6 parallel, LED current 40mA setting
Power control PWM application
Each 80mA
12kΩ
Can be set up to each15~40mA
Can be set up to each30~80mA
Fig.53 8 series×3 parallel, LED current 80mA setting
Power control PWM application
5inch panel
Battery
Battery
4.7μH
10μF
8LED x 2parallel
2.2μF *
RTR020N05
SW
4.7μH
10μF
2.2μF
8LED x 2parallel
2.2μF *
FAILSEL
SENSP
RTR020N05
SW
VDET
2.2μF
FAILSEL
SENSP
82mΩ
VDET
82mΩ
SENSN
Power
ON/OFF
SENSN
Power
ON/OFF
RSTB
LED1
PWMPOW
LED2
PWMDRV
100Hz~10kHz
PWM
RSTB
LED1
PWMPOW
100Hz~1kHz
PWM
LED2
PWMDRV
LED3
VBAT
VREG
2.2μF
LED3
VBAT
LED4
2.2μF
GND GND GND GND TEST ISETH ISETL LED6
12kΩ
Each 40mA
Fig.54 8 series×2 parallel, LED current 40mA setting
Current driver PWM application
LED5
GND GND GND GND TEST ISETH ISETL LED6
12kΩ
Can be set up to each15~40mA
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© 2011 ROHM Co., Ltd. All rights reserved.
LED4
VREG
LED5
Each 80mA
Can be set up to each30~80mA
Fig.55 8 series×2 parallel, LED current 80mA setting
Power control PWM application
20/25
2011.06 - Rev.C
Technical Note
BD6592MUV
●Application example
・LED current setting controlled ISETH resistor.
24kΩ : 20mA
16kΩ : 30mA
12kΩ : 40mA
・Brightness control
Please input PWM pulse from PWMPOW or PWMDRV terminal.
Please refer electrical characteristic p.3 and function (p.13).
5inch panel
Battery
Battery
4.7μH
10μF
4LED x 4parallel
2.2μF *
RTR020N05
4.7μH
10μF
2.2μF
SW
8LED x 2parallel
2.2μF *
FAILSEL
SENSP
RTR020N05
SW
VDET
2.2μF
FAILSEL
SENSP
82mΩ
VDET
82mΩ
SENSN
Power
ON/OFF
SENSN
Power
ON/OFF
RSTB
LED1
PWMPOW
2.2μF
LED3
VBAT
LED4
VREG
LED4
VREG
LED5
2.2μF
GND GND GND GND TEST ISETH ISETL LED6
Each 40mA
12kΩ
LED2
PWMDRV
100Hz~10kHz
PWM
LED3
VBAT
LED1
PWMPOW
LED2
PWMDRV
100Hz~10kHz
PWM
RSTB
GND GND GND GND TEST ISETH ISETL LED6
12kΩ
Can be set up to each30~80mA
Fig.56 4 series×4 parallel, LED current 40mA setting
Current driver PWM application
LED5
Each 120mA
Can be set up to each45~120mA
Fig.57 8 series×2 parallel, LED current 120mA setting
Current driver PWM application
Battery
4.7μH
10μF
3LED x 5parallel
2.2μF *
RTR020N05
SW
2.2μF
FAILSEL
SENSP
VDET
82mΩ
SENSN
Power
ON/OFF
RSTB
LED1
PWMPOW
100Hz~1kHz
PWM
LED2
PWMDRV
LED3
VBAT
LED4
VREG
2.2μF
LED5
GND GND GND GND TEST ISETH ISETL LED6
12kΩ
Each 40mA
Can be set up to each15~40mA
Fig.58 3 series×5 parallel, LED current 40mA setting
Power control PWM application
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© 2011 ROHM Co., Ltd. All rights reserved.
21/25
2011.06 - Rev.C
Technical Note
BD6592MUV
●Application example
・LED current setting controlled ISETH resistor.
24kΩ : 20mA
16kΩ : 30mA
12kΩ : 40mA
・Brightness control
Please input PWM pulse from PWMPOW or PWMDRV terminal.
Please refer electrical characteristic p.3 and function (p.13).
Over 22V application
For Big LED Current
Coil Power supply
6~30V
Battery
Battery
4.7μH
10μF
2.2μF *
2.2μF *
SW
FAILSEL
SENSP
51mΩ
SW
FAILSEL
SENSP
VDET
SENSN
Power
ON/OFF
RSTB
RSTB
LED3
LED3
VBAT
2.7~22V
1μF
VBAT
LED4
VREG
2.2μF
LED2
PWMDRV
100Hz~10kHz
PWM
LED2
PWMDRV
LED1
PWMPOW
LED1
PWMPOW
200Hz
PWM
VDET
82mΩ
SENSN
Power
ON/OFF
2.2μF
2.2μF
RTR020N05
RTR020N05
IC Power supply
8LED x 1parallel
8LED x 6parallel
4.7μH
10μF
LED4
VREG
2.2μF
LED5
GND GND GND GND TEST ISETH ISETL LED6
GND GND GND GND TEST ISETH ISETL LED6
12kΩ
Each 40mA
12kΩ
LED5
240mA
Can be set up to each90~240mA
Can be set up to each15~40mA
Fig.59
Fig.60
The separation of less than an IC power supply 5V and the coil power supply
Coil Power supply
6~30V
Battery
10LED x 6parallel
4.7μH
10μF
2.2μF *
RTR020N05
SW
2.2μF
FAILSEL
SENSP
VDET
51mΩ
SENSN
Power
ON/OFF
RSTB
LED1
PWMPOW
200Hz
PWM
LED3
VBAT
2.7~5.5V
IC Power supply
LED2
PWMDRV
1μF
2.2μF
LED4
VREG
LED5
GND GND GND GND TEST ISETH ISETL LED6
12kΩ
Each 40mA
Can be set up to each15~40mA
Fig.61
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© 2011 ROHM Co., Ltd. All rights reserved.
22/25
2011.06 - Rev.C
Technical Note
BD6592MUV
●Application example of Analog dimming
Control LED current to charged D/A voltage.
Show application example and typ control.
Please decide final value after you evaluated application, characteristic.
Battery
4.7μH
10μF
8LED x 6Parallel
2.2μF *
RTR020N05
SW
D/A
0.05V
0.2V
0.4V
0.5V
0.6V
0.7V
2.2μF
FAILSEL
SENSP
VDET
51mΩ
SENSN
Power
ON/OFF
RSTB
LED1
PWMPOW
LED2
PWMDRV
LED current
19.4mA
14.4mA
7.7mA
4.4mA
1.0mA
0mA
LED3
VBAT
LED4
VREG
2.2μF
LED current =
LED5
GND GND GND GND TEST ISETH ISETL LED6
Each 20mA
24kΩ
470kΩ
typ LED current =
D/A
ISET voltage ISET voltage -D/A
+
×800
470kΩ
24kΩ
0.6V
470kΩ
+
0.6V-D/A
24kΩ
×800
Fig.62 Analog style optical application
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© 2011 ROHM Co., Ltd. All rights reserved.
23/25
2011.06 - Rev.C
Technical Note
BD6592MUV
●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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24/25
2011.06 - Rev.C
Technical Note
BD6592MUV
●Ordering part number
B
D
6
Part No.
5
9
2
M
Part No.
6592
U
V
Package
MUV: VQFN024V4040
-
E
2
Packaging and forming specification
E2: Embossed tape and reel
VQFN024V4040
<Tape and Reel information>
4.0±0.1
4.0±0.1
1.0MAX
2.4±0.1
0.4±0.1
7
12
19
18
0.5
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
)
6
24
0.75
E2
2.4±0.1
1
2500pcs
(0.22)
+0.03
0.02 -0.02
S
C0.2
Embossed carrier tape
Quantity
Direction
of feed
1PIN MARK
0.08 S
Tape
13
+0.05
0.25 -0.04
1pin
(Unit : mm)
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© 2011 ROHM Co., Ltd. All rights reserved.
Reel
25/25
Direction of feed
∗ Order quantity needs to be multiple of the minimum quantity.
2011.06 - 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