1/25
www.rohm.com 2011.06 - Rev.C
© 2011 ROHM Co., Ltd. All rights reserved.
LED Drivers for LCD Backlights
White Backlight LED Driver
for Medium to Large LCD Panels
(Switching Regulator Type)
BD6592MUV
●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 Condition
Maximum applied voltage 1 VMAX1 7 V
TEST, VREG, SENSP, SENSN, SW,
RSTB, PWMPOW, PWMDRV,
FAILSEL, ISETH, ISETL
Maximum applied voltage 2 VMAX2 25 V LED1, LED2, LED3, LED4, LED5,
LED6, VBAT
Maximum applied voltage 3 VMAX3 50.5 V VDET
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 Reduced 4.0mW/℃ With Ta>25℃ when not mounted on a heat radiation Board.
*2 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/℃.
*3 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 Symbol
Ratings Unit Condition
Min. Typ. Max.
Power supply voltage VBAT 2.7 12.0 22.0 V
No.11040ECT33
Technical Note
2/25
BD6592MUV
www.rohm.com 2011.06 - Rev.C
© 2011 ROHM Co., Ltd. All rights reserved.
●Electrical characteristic (Unless otherwise specified, VBAT=12V, RSTB=2.5V, Ta = +25℃)
Parameter Symbol
Limits Unit Condition
Min. Typ. Max.
[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
EN terminal input current Iin - 8.3 14.0 µA Input=2.5V
[PWMPOW Terminal]
Low Input Voltage range 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 k
[RSTB Terminal]
Low Input Voltage range 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
Current Consumption IRSTB - 89 134 µA RSTB=2.5V, LED1-6=3V
[Regulator]
VREG Voltage VREG 4.0 5.0 6.0 V No load
Under Voltage Lock Out UVLO 2.05 2.25 2.65 V
[Switching Regulator]
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=24k
LED Control voltage VLED 0.4 0.5 0.6 V
Over Current Limit voltage Ocp 70 100 130 mV
*1
SBD Open Protect Sop - - 0.1 V Detect voltage of VDET pin
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
[Current driver]
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 voltage Iset 0.5 0.6 0.7 V
LED Terminal
Over Voltage Protect LEDOVP 10.0 11.5 13.0 V RSTB=PWMDRV=2.5V
*1 This parameter is tested with DC measurement.
Technical Note
3/25
BD6592MUV
www.rohm.com 2011.06 - Rev.C
© 2011 ROHM Co., Ltd. All rights reserved.
●Reference data
Fig.1
Current Consumption - VBAT
Fig.2
Quiescent current - VBAT
Fig.3
Oscillation frequency - VBAT
Fig.4
UVLO - Temperature
Fig.6
Efficiency - PWMDRV-HI Duty
ISETH=24k, PWM=200Hz
Fig.5
Efficiency - PWMPOW-HI Duty
ISETH=24k, PWM=200Hz
Fig.7
LED current - PWMDRV-HI Duty
PWM = 200Hz
Fig.8
LED current - PWMDRV-HI Duty
( Expansion) PWM = 200Hz
Fig.10
LED current - PWMPOW-HI Duty
PWM = 200Hz
Fig.11
LED current - PWMPOW-HI Duty
( Expansion) PWM = 200Hz
Fig.9
LED current - PWMDRV-HI Duty
PWM = 200Hz, 1kHz,10kHz
Fig.12
LED current - PWMPOW-HI Duty
PWM = 200Hz, 1kHz,10kHz
60%
65%
70%
75%
80%
85%
90%
95%
100%
0 10203040 5060708090100
Duty [%]
Efficiency
VBAT=12V
60%
65%
70%
75%
80%
85%
90%
95%
100%
0 10203040 5060708090100
Duty [%]
Efficiency
VBAT=12V
2
2.1
2.2
2.3
2.4
2.5
2.6
-50 -25 0 25 50 75 100
Ta [℃]
VBAT [V]
0
5
10
15
20
25
30
0 10 203040 50607080 90100
Duty (%)
LED cur rent　(mA)
Ta=-30,+25,+85℃
VBAT=6V, 12V, 16V
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
00.51 1.522.53
Duty (%)
LED cur rent　(mA)
VBAT=6V, 12V, 16V
Ta=-30,+25,+85℃
0
5
10
15
20
25
30
0 1020 3040506070 8090100
Duty (%)
LED Current　(mA)
200Hz
1kHz
10kHz
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
00.51 1.522.53
Duty (%)
LED cur rent　(mA)
6V
12V
16V
Ta=-30,+25,+85℃
0
5
10
15
20
25
30
0 10203040 5060708090100
Duty (%)
LED cur rent　(mA)
Ta=-30,+25,+85℃
VBAT=6V, 12V, 16V
0
5
10
15
20
25
30
0 102030405060708090100
Duty (%)
LED Current　(mA)
200Hz
1kHz
10kHz
0.80
0.85
0.90
0.95
1.00
1.05
1.10
1.15
1.20
0 2 4 6 8 10 12 14 16 18 20 22
VBAT [V]
Fr equency [M Hz]
-30℃
85℃
25℃
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
0 2 4 6 8 10 12 14 16 18 20 22
VBAT [V]
Iin [mA]
-30℃
25℃ 85℃
0
1
2
3
4
5
6
7
8
0 2 4 6 8 10121416182022
VBAT[V]
Ist[µA]
25 ℃
-30℃
85℃
Technical Note
4/25
BD6592MUV
www.rohm.com 2011.06 - Rev.C
© 2011 ROHM Co., Ltd. All rights reserved.
VOUT
Ic
c
-3.0
-2.0
-1.0
0.0
1.0
2.0
3.0
0% 20% 40% 60% 80% 100%
PWM HI Duty
Cur rent Matching (%)
Min Matching = Min LED Current/Average Current
Max Matching = Max LED Current/Average Current
-3.0
-2.0
-1.0
0.0
1.0
2.0
3.0
0% 2% 4% 6% 8% 10%
PWM HI Duty
Cur rent Matching (%)
Max Matching = Max LED Current/Average Current
Min Matching = Min LED Current/Average Current
VBAT
VOUT
LED curren
t
400s
No peak
14ms
VBAT
VOUT
LED current
No peak
-3.0
-2.0
-1.0
0.0
1.0
2.0
3.0
0% 2% 4% 6% 8% 10%
PWM HI Duty
Cur rent Matching ( %)
Max Matching = Max LED Current/Average Current
Min Matching = Min LED Current/Average Current
25
26
27
28
29
30
31
32
33
34
35
-50 -25 0 25 50 75 100
temp [℃]
LED Current [m A]
2.7V
5V, 7V, 12V, 22V
-3.0
-2.0
-1.0
0.0
1.0
2.0
3.0
0% 20% 40% 60% 80% 100%
PWM HI Duty
Cur rent Matching ( %)
Min Matching = Min LED Current/Average Current
Max Matching = Max LED Current/Average Current
PWMPOW
VOUT 180mV
10mA/div
LED Current
LED Current
350mV
10mA/div
PWMDR
V
VOUT
Fig.21
Line Transient (22V to 10V)
Fig.18
VOUT response
Power Control PWM (PWMPOW)
Fig.22
VOUT@OVP (LED OPEN)
Fig.13
LED current matching - PWMDRV-HI Duty
PWM = 200Hz
Fig.14
LED current matching - PWMDRV-HI Duty
(Expansion) PWM = 200Hz
Fig.16
LED current matching - PWMPOW-HI Duty
PWM = 200Hz
Fig.17
LED current matching - PWMPOW-HI Duty
(Expansion) PWM = 200Hz
Fig.15
VOUT response
Driver Control PWM (PWMDRV)
Fig.19
LED current - Temperature
PWMDRV=H, ISETH=30k (16mA setting)
Fig.20
Line Transient (10V to 22V)
Technical Note
5/25
BD6592MUV
www.rohm.com 2011.06 - Rev.C
© 2011 ROHM Co., Ltd. All rights reserved.
●Block diagram, I/O equivalent circuit diagram
Fig.23 Block diagram Fig.24 I/O equivalent circuit diagram
●Pin assignment table
PIN
Name In/Out PIN
number Function Terminal equivalent
circuit diagram
1 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 100k 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
GND
VBAT VREG
PIN
A
VBAT
PIN
B
GND
PIN
C
GND
VBAT
PIN
D
GND
VBAT
PIN
E
5.5V
Clump
PIN
F
GND
VBAT
PIN
G
VREG
Current
Sence
S
Q R
-
+
-
+
over voltage protect
SBD Open protect
VIN detector
REG
Internal Power suplly
VDET
SW
UVLO
RSTB
300k
Current Driver
+
-
-
-
LED1
LED2
LED3
ERRAMP
+
+
-
OSC
Control
sence
100k
PWMcomp
TEST
PWMPOW
SENSP
SENSN
LED4
-
1M
100K
LED TERMINAL
Over Voltage Protect
500k
VBAT VREG
FAILSEL
PWMDRV
-
-
LED5
LED6
+
-
PWMDRV=H
On
ISET L
Resistor driver
PWMDRV=L
On
ISETH
ISETL
ISET H
Resistor driver
300k
TSD
300k
GND
GND
GND
GND
LED TERMINAL
Detect
Technical Note
6/25
BD6592MUV
www.rohm.com 2011.06 - Rev.C
© 2011 ROHM Co., Ltd. All rights reserved.
●Application example
Fig.25 10 series x 6parallel
Hi current 40mA setting
Current driver PWM application
Fig.26 10 series x 4parallel
Hi current 40mA setting
Current driver PWM application
* Please select the capacitor which the little bias fluctuation.
Fig.27 10 series x 6parallel LED current 30mA setting
Power control PWM application
Fig.28 Non-used Inside REG
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 k. And, please care about the relation between VBAT
and RSTB enough. (ref. P9)
10F
Batter
y
VDET
SW
LED1
LED2
LED3
4.7H 10LED x 6parallel
SENSP
SENSN
LED4
Each 40mA
47m
RTR020N05
2.2F *
RSTB
PWMPOW
PWMDRV
Power
ON/OFF
200Hz
PWM
VBA
T
LED5
LED6
FAILSEL
GND
12k
TEST
GND
ISETH
VREG
2.2F
ISETL
GND
GND
2.2F *
10F
Battery
VDET
SW
LED1
LED2
LED3
4.7H 10LED x 4aprallel
SENSP
SENSN
LED4
Each 40mA
47m
RTR020N05
2.2F *
RSTB
PWMPOW
PWMDRV
Power
ON/OFF
200Hz
PWM
VBAT
LED5
LED6
FAILSEL
GND
12k
TEST
GND ISETH
VREG
2.2F
ISETL
GNDGND
2.2F *
10F
Batter
y
VDET
SW
LED1
LED2
LED3
4.7H 10LED x 6parallel
SENSP
SENSN
LED4
Each 30mA
47m
RTR020N05
2.2F *
RSTB
PWMPOW
PWMDRV
Power
ON/OFF
200Hz
PWM
VBAT
LED5
LED6
FAILSEL
GND
16k
TEST
GND
ISETH
VREG
2.2F
ISETL
GND
GND
2.2F *
10F
Batter
y
VDET
SW
LED1
LED2
LED3
4.7H 10LED x 6parallel
SENSP
SENSN
LED4
Each 40mA
47m
RTR020N05
2.2F *
RSTB
PWMPOW
PWMDRV
Power
ON/OFF
200Hz
PWM
VBAT
LED5
LED6
FAILSEL
VREG
2.2F
2.7V to 5.5V
GND
12k
TEST
GND ISETH
ISETL
GNDGND
2.2F *
Technical Note
7/25
BD6592MUV
www.rohm.com 2011.06 - Rev.C
© 2011 ROHM Co., Ltd. All rights reserved.
●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.
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
Fig.29 FAILSEL operating description Fig.30 FAILSEL=H light off control
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.
RSTB
PWMDRV
Coil current
FAILSEL
function invalid valid
< When it is off on PWMPOW>
Outpu
t
voltage
PWMPOW
RSTB
PWMDRV
PWMPOW
invalid
Outpu
t
voltage
Coil current
FAILSEL
function
< When it is off on RSTB>
about 1ms
un-operating range
FAILSEL
RSTB
Protection
function
detection
Boost
operating
normal operating off boost stop
“H”
off normal operating
un-detection un-detection
<FAILSEL=H>
about 1ms
un-operating range FAILSEL
RSTB
Protection
function
normal operating off
un-detection
detection
normal
o
eratin
boost stop off normal
“L”
un-detectio
<FAILSEL=L>
Boost
operating
Technical Note
8/25
BD6592MUV
www.rohm.com 2011.06 - Rev.C
© 2011 ROHM Co., Ltd. All rights reserved.
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 175C 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 = 70m
MAX current dispersion of this detection resistor value is
MAX current = 130mV / 70m = 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
Ton=(Iave × (1-VIN/VOUT) × (1/fsw) × (L/VIN) × 2)1/2
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
Technical Note
9/25
BD6592MUV
www.rohm.com 2011.06 - Rev.C
© 2011 ROHM Co., Ltd. All rights reserved.
(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
Ton = (0.61A × (1-6.0V / 39V) × (1 / 1MHz) × ( 4.7µH /6.0V) × 2)1/2 = 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
Ton = (0.31A × (1-12 V / 39V) × (1 / 1MHz) × ( 4.7µH /12 V) × 2)1/2 = 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 100k is between SENSP and SENSN terminal,
over current protection works instantly and LED current can't be flow.
●Control signal input timing
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.
GND
VBAT
PIN
Rin
0V
5V
220
RSTB
DC/DC VOUT
3
VREG
PWMDRV
PWMPOW
5V Min. 100µs
2
5V 2.7V
1
VBAT
Technical Note
10/25
BD6592MUV
www.rohm.com 2011.06 - Rev.C
© 2011 ROHM Co., Ltd. All rights reserved.
●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.
The decision example of restriction resistance
1． When use the current driver of 6 parallel
2.9V(to RSTB power-supply) - restriction resistance value × 124A(100℃ input current) > 2.1V
restriction resistance value < (2.9-2.1)/124A=6.45k
2． 2. When use the current driver of 3 parallel
2.9V(to RSTB power-supply) - restriction resistance value × 430A(100℃ input current) > 2.1V
restriction resistance value < (2.9-2.1)/430A=1.86k
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 PWMPOW PWMDRV IC LED current
H L L Off OFF
H H L On Starting current decided with ISETL
H L H Off OFF
H H H On Current decided with ISETH
L L, H L, H Off OFF
Limit resistor RSTB
terminal
BD6592MUV
RSTB inflow current
Power supply
for RSTB
50
100
150
200
250
2.1 2.4 2.7 3 3.3 3.6
RSTB[V ]
RSTB　input current[ µA]
-30℃
+25℃
+80℃
+100℃
Fig.33 RSTB terminal voltage-RSTB inflow current
(At the time of the current driver six lines use)
Technical Note
11/25
BD6592MUV
www.rohm.com 2011.06 - Rev.C
© 2011 ROHM Co., Ltd. All rights reserved.
●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
Technical Note
12/25
BD6592MUV
www.rohm.com 2011.06 - Rev.C
© 2011 ROHM Co., Ltd. All rights reserved.
RSTB
PWMPOW
PWMDRV
Output Voltage
Current coil
●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.
Fig.36 Off timing of starting current at PWMDRV=L
Fig.37 Light off control of PWMDRV pin at PWM control on PWM=L
Fig.38 Light off control of PWMDRV pin at PWM control on RSTB=L
RSTB
PWMPOW
PWMDRV
Output Voltage
Current coil
L H L H L H L
ON OFF ON OFF
RSTB
PWMPOW
PWMDRV
Output voltage
LED pin
Current driver o
f
starting current
Technical Note
13/25
BD6592MUV
www.rohm.com 2011.06 - Rev.C
© 2011 ROHM Co., Ltd. All rights reserved.
PW MDRV
LED current
Coil current
IC’s active current
ON OFF
ON OFF
ON OFF
ON
●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 2) Power control PWM control
•LED current dispersion emphasis in the PWM brightness control 1) Current driver PWM control
(Reference)
PWM regulation process Efficiency of LED current 0.5mA
(PWM Duty=2.5%)
PWM frequency 200Hz
Limit dispersion capability of low duty
Current driver 70% 0.2%
Power control 93% 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.
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
LED current
Coil current
IC’s active current
ON OFF
ON
OFF
ON
OFF
ON OFF
Fig.40
Technical Note
14/25
BD6592MUV
www.rohm.com 2011.06 - Rev.C
© 2011 ROHM Co., Ltd. All rights reserved.
●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(24k/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 ISETL Starting current setting example
RISETH LED current RISETL LED current
12k (E12) 40mA 6.2k (E24) 97µA
16 k (E16) 30mA 10k (E6) 60µA
24k (E24) 20mA 47k (E6) 13µA
25.5 k (E96) 18.8mA 100 k (E6) 6µA
27 k (E12) 17.8mA 560 k (E12) 1.1µA
30k (E24) 16.0mA 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.
Fig.42 Application at the time of power supply isolation
10F
Battery
VDET
SW
LED1
LED2
LED3
4.7H 10LED x 6 列
SENSP
SENSN
LED4
各40mA
47m
RTR020N05
2.2F
RSTB
PWMDRV
PWMPOW
Power
ON/OFF
200Hz
PWM
VBAT
LED5
LED6
FAILSEL
VREG
1F
2.7V to 5.5V
GND
12k
TEST
GND
ISETH ISETL
GNDGND
2.2F
IC Power supply
Coil Power supply
7V to 28V
Technical Note
15/25
BD6592MUV
www.rohm.com 2011.06 - Rev.C
© 2011 ROHM Co., Ltd. All rights reserved.
LED6
LED5
LED4
LED3
LED2
GND
TEST
GND
VDET
N.C.
SW
SENSP
VBAT
PWMPO
W
VREG
RSTB
GND
FAILSEL
SENSN
GND
ISETH
ISETL
PWMDRV
LED1
PWM Reset
CBAT
L
CIN
to Power Suppl
y
Tr
SBD
RSENSE
COUT
to Cathode
of LED
CREG
RISET
to Anode
of each LED
to GND
●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 = output capacitor 2.2µF/50V 1pcs
6.8µH = output capacitor 2.2µF/50V 2pcs
10µH = output capacitor 2.2µF/50V 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.
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.
Technical Note
16/25
BD6592MUV
www.rohm.com 2011.06 - Rev.C
© 2011 ROHM Co., Ltd. All rights reserved.
●Recommended PCB layout pattern
Fig.43 Frontal surface <Top view>
Fig.44 Rear surface <Top view>
COUT
CIN
CBAT
LTr
CREG
RISET
BD6592MUV
RSENSE
Technical Note
17/25
BD6592MUV
www.rohm.com 2011.06 - Rev.C
© 2011 ROHM Co., Ltd. All rights reserved.
●Selection of external parts
Recommended external parts are as shown below. When to use other parts than these, select the following equivalent parts.
・Coil
Value Manufacturer Product number Size DC current
(mA)
DCR
()
Vertical Horizontal Height (MAX)
4.7H TOKO A915AY-4R7M 5.2 5.2 3.0 1870 0.045
4.7H TOKO B1015AS-4R7M 8.4 8.3 4.0 3300 0.038
4.7H TOKO A1101AS-4R7M 4.1 4.1 1.2 1400 0.115
4.7H TDK LTF5022T-4R7N2R0 5.0 5.2 2.2 2000 0.073
4.7H TDK VLP6810T-4R7M1R6 6.3 6.8 1.0 1600 0.167
10H TDK VLP6810T-100M1R1 6.3 6.8 1.0 1100 0.350
・Capacitor
Value Pressure Manufacturer Product number Size TC Cap
Tolerance
Vertical Horizontal Height
[ Supply voltage capacitor ]
10F 25V MURATA GRM31CB31E106K 3.2 1.6 1.6±0.2 B +/-10%
10F 10V MURATA GRM219BB31A106K 2.0 1.25 0.85±0.15 B +/-10%
4.7F 25V MURATA GRM319B31E475K 3.2 1.6 0.85±0.1 B +/-10%
4.7F 25V MURATA GRM21BB31E475K 2.0 1.25 1.25±0.1 B +/-10%
[ Smoothing capacitor for built-in regulator ]
1F 10V MURATA GRM188B10J105K 1.6 0.8 0.8±0.1 B +/-10%
2.2F 10V MURATA GRM219B11A225K 2.0 1.25 0.85±0.1 B +/-10%
[ Output capacitor ]
1F 50V MURATA GRM31MB31H105K 3.2 1.6 1.15±0.1 B +/-10%
1F 50V MURATA GRM21BB31H105K 2.0 1.25 1.25±0.1 B +/-10%
1F 100V MURATA GRM31CR72A105K 3.2 1.6 1.6±0.2 X7R +/-10%
2.2F 50V MURATA GRM31CB31H225K 3.2 1.6 1.6±0.2 B +/-10%
0.33F 50V MURATA GRM219B31H334K 2.0 1.25 0.85±0.1 B +/-10%
・Resistor
Value Tolerance Manufacturer Product number Size
Vertical Horizontal Height
[ Resistor for LED current decision <ISETH pin> ]
16k ±0.5% ROHM MCR006YZPD163 0.6 0.3 0.23±0.03
[ Resistor for over current decision <SENSP pin> ]
47m ±1% ROHM MCR10EZHFSR047 2.0 1.25 0.55±0.1
・SBD
Pressure Manufacturer Product number Size
Vertical Horizontal Height
60V ROHM RB160M-60 3.5 1.6 0.8±0.1
・MOS FET Nch
Pressure Manufacturer Product number Size Current
ability
Driving
voltage
Vertical Horizontal Height
45V ROHM RTR020N05 2.8 2.9 1.0 2A 2.5V
60V ROHM RSS065N06 6.0 5.0 1.75 6.5A 4.0V
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. 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.
Technical Note
18/25
BD6592MUV
www.rohm.com 2011.06 - Rev.C
© 2011 ROHM Co., Ltd. All rights reserved.
●Application example
・LED current setting controlled ISETH resistor.
24k : 20mA
16k : 30mA
12k : 40mA
・Brightness control
Please input PWM pulse from PWMPOW or PWMDRV terminal.
Please refer electrical characteristic p.3 and function (p.12).
15inch panel
10F
Batter
y
VDET
SW
LED1
LED2
LED3
4.7H 10LED x 6parallel
SENSP
SENSN
LED4
Each 40mA
47m
RTR020N05
2.2F *
RSTB
PWMPOW
PWMDRV
Power
ON/OFF
100Hz~10kHz
PWM
VBAT
LED5
LED6
FAILSEL
GND
12k
TEST
GND
ISETH
VREG
2.2F
ISETL
GND
GND
Can be set up to each15~40mA
2.2F
Fig.45 10 series×6 parallel, LED current 40mA setting
Current driver PWM application
13~14inch panel
8LED x 6parallel
Each 40mA
Can be set up to each15~40mA
10F
Batter
y
VDET
SW
LED1
LED2
LED3
4.7H
SENSP
SENSN
LED4
51m
RTR020N05
2.2F *
RSTB
PWMPOW
PWMDRV
Power
ON/OFF
100Hz~1kHz
PWM
VBAT
LED5
LED6
FAILSEL
GND
12k
TEST
GND
ISETH
VREG
2.2F ISETL
GND
GND
2.2F
8LED x 6parallel
Each 40mA
Can be set up to each15~40mA
10F
Batter
y
VDET
SW
LED1
LED2
LED3
4.7H
SENSP
SENSN
LED4
51m
RTR020N05
2.2F *
RSTB
PWMPOW
PWMDRV
Power
ON/OFF
100Hz~10kHz
PWM
VBAT
LED5
LED6
FAILSEL
GND
12k
TEST
GND ISETH
VREG
2.2F
ISETL
GNDGND
2.2F
Fig.46 8 series× 6 parallel, LED current 40mA setting
Power control PWM application
Fig.47 8 series×6 parallel, LED current 40mA setting
Current driver PWM application
Technical Note
19/25
BD6592MUV
www.rohm.com 2011.06 - Rev.C
© 2011 ROHM Co., Ltd. All rights reserved.
●Application example
・LED current setting controlled ISETH resistor.
24k : 20mA
16k : 30mA
12k : 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
7LED x 6parallel
Each 30mA
Can be set up to each15~40mA
10F
Batter
y
VDET
SW
LED1
LED2
LED3
4.7H
SENSP
SENSN
LED4
56m
RTR020N05
2.2F *
RSTB
PWMPOW
PWMDRV
Power
ON/OFF
100Hz~10kHz
PWM
VBAT
LED5
LED6
FAILSEL
GND
16k
TEST
GND
ISETH
VREG
2.2F
ISETL
GND
GND
2.2F
10LED x 4parallel
Each 40mA
Can be set up to each15~40mA
10F
Batter
y
VDET
SW
LED1
LED2
LED3
4.7H
SENSP
SENSN
LED4
56m
RTR020N05
2.2F *
RSTB
PWMPOW
PWMDRV
Power
ON/OFF
100Hz~10kHz
PWM
VBAT
LED5
LED6
FAILSEL
GND
12k
TEST
GND ISETH
VREG
2.2F
ISETL
GNDGND
2.2F
Fig.48 7 series×6 parallel, LED current 30mA setting
Current driver PWM application
Fig.49 10 series×4 parallel, LED current 40mA setting
Current driver PWM application
7inch panel
8LED x 3parallel
Each 40mA
Can be set up to each15~40mA
10F
Batter
y
VDET
SW
LED1
LED2
LED3
4.7H
SENSP
SENSN
LED4
68m
RTR020N05
2.2F *
RSTB
PWMPOW
PWMDRV
Power
ON/OFF
100Hz~10kHz
PWM
VBAT
LED5
LED6
FAILSEL
GND
12k
TEST
GND
ISETH
VREG
2.2F
ISETL
GND
GND
2.2F
6LED x 4parallel
Each 40mA
Can be set up to each15~40mA
10F
Batter
y
VDET
SW
LED1
LED2
LED3
4.7H
SENSP
SENSN
LED4
68m
RTR020N05
2.2F *
RSTB
PWMPOW
PWMDRV
Power
ON/OFF
100Hz~10kHz
PWM
VBAT
LED5
LED6
FAILSEL
GND
12k
TEST
GND ISETH
VREG
2.2F
ISETL
GNDGND
2.2F
Fig.50 8 series×3 parallel, LED current 40mA setting
Current driver PWM application
Fig.51 6 series×4 parallel, LED current 40mA setting
Current driver PWM application
Technical Note
20/25
BD6592MUV
www.rohm.com 2011.06 - Rev.C
© 2011 ROHM Co., Ltd. All rights reserved.
●Application example
・LED current setting controlled ISETH resistor.
24k : 20mA
16k : 30mA
12k : 40mA
・Brightness control
Please input PWM pulse from PWMPOW or PWMDRV terminal.
Please refer electrical characteristic p.3 and function (p.13).
7inch panel
4LED x 6parallel
Each 40mA
Can be set up to each15~40mA
10F
Batter
y
VDET
SW
LED1
LED2
LED3
4.7H
SENSP
SENSN
LED4
68m
RTR020N05
2.2F *
RSTB
PWMPOW
PWMDRV
Power
ON/OFF
100Hz~1kHz
PWM
VBAT
LED5
LED6
FAILSEL
GND
12k
TEST
GND
ISETH
VREG
2.2F ISETL
GND
GND
2.2F
8LED x 3parallel
Each 80mA
Can be set up to each30~80mA
10F
Batter
y
VDET
SW
LED1
LED2
LED3
4.7H
SENSP
SENSN
LED4
68m
RTR020N05
2.2F *
RSTB
PWMPOW
PWMDRV
Power
ON/OFF
100Hz~1kHz
PWM
VBAT
LED5
LED6
FAILSEL
GND
12k
TEST
GND ISETH
VREG
2.2F
ISETL
GNDGND
2.2F
Fig.52 4 series×6 parallel, LED current 40mA setting
Power control PWM application
Fig.53 8 series×3 parallel, LED current 80mA setting
Power control PWM application
5inch panel
8LED x 2parallel
Each 40mA
Can be set up to each15~40mA
10F
Batter
y
VDET
SW
LED1
LED2
LED3
4.7H
SENSP
SENSN
LED4
82m
RTR020N05
2.2F *
RSTB
PWMPOW
PWMDRV
Power
ON/OFF
100Hz~10kHz
PWM
VBAT
LED5
LED6
FAILSEL
GND
12k
TEST
GND
ISETH
VREG
2.2F
ISETL
GND
GND
2.2F
8LED x 2parallel
Each 80mA
Can be set up to each30~80mA
10F
Batter
y
VDET
SW
LED1
LED2
LED3
4.7H
SENSP
SENSN
LED4
82m
RTR020N05
2.2F *
RSTB
PWMPOW
PWMDRV
Power
ON/OFF
100Hz~1kHz
PWM
VBAT
LED5
LED6
FAILSEL
GND
12k
TEST
GND ISETH
VREG
2.2F
ISETL
GNDGND
2.2F
Fig.54 8 series×2 parallel, LED current 40mA setting
Current driver PWM application
Fig.55 8 series×2 parallel, LED current 80mA setting
Power control PWM application
Technical Note
21/25
BD6592MUV
www.rohm.com 2011.06 - Rev.C
© 2011 ROHM Co., Ltd. All rights reserved.
●Application example
・LED current setting controlled ISETH resistor.
24k : 20mA
16k : 30mA
12k : 40mA
・Brightness control
Please input PWM pulse from PWMPOW or PWMDRV terminal.
Please refer electrical characteristic p.3 and function (p.13).
5inch panel
4LED x 4parallel
Each 40mA
Can be set up to each30~80mA
10F
Batter
y
VDET
SW
LED1
LED2
LED3
4.7H
SENSP
SENSN
LED4
82m
RTR020N05
2.2F *
RSTB
PWMPOW
PWMDRV
Power
ON/OFF
100Hz~10kHz
PWM
VBAT
LED5
LED6
FAILSEL
GND
12k
TEST
GND
ISETH
VREG
2.2F
ISETL
GND
GND
2.2F
8LED x 2parallel
Each 120mA
Can be set up to each45~120mA
10F
Batter
y
VDET
SW
LED1
LED2
LED3
4.7H
SENSP
SENSN
LED4
82m
RTR020N05
2.2F *
RSTB
PWMPOW
PWMDRV
Power
ON/OFF
100Hz~10kHz
PWM
VBAT
LED5
LED6
FAILSEL
GND
12k
TEST
GND ISETH
VREG
2.2F
ISETL
GNDGND
2.2F
Fig.56 4 series×4 parallel, LED current 40mA setting
Current driver PWM application
Fig.57 8 series×2 parallel, LED current 120mA setting
Current driver PWM application
3LED x 5parallel
Each 40mA
Can be set up to each15~40mA
10F
Batter
y
VDET
SW
LED1
LED2
LED3
4.7H
SENSP
SENSN
LED4
82m
RTR020N05
2.2F *
RSTB
PWMPOW
PWMDRV
Power
ON/OFF
100Hz~1kHz
PWM
VBAT
LED5
LED6
FAILSEL
GND
12k
TEST
GND
ISETH
VREG
2.2F
ISETL
GND
GND
2.2F
Fig.58 3 series×5 parallel, LED current 40mA setting
Power control PWM application
Technical Note
22/25
BD6592MUV
www.rohm.com 2011.06 - Rev.C
© 2011 ROHM Co., Ltd. All rights reserved.
●Application example
・LED current setting controlled ISETH resistor.
24k : 20mA
16k : 30mA
12k : 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
8LED x 6parallel
Each 40mA
Can be set up to each15~40mA
10F
Batter
y
VDET
SW
LED1
LED2
LED3
4.7H
SENSP
SENSN
LED4
51m
RTR020N05
2.2F *
RSTB
PWMPOW
PWMDRV
Power
ON/OFF
200H
z
PWM
VBA
T
LED5
LED6
FAILSEL
GND
12k
TEST
GND
ISETH
VREG
2.2F
ISETL
GND
GND
2.7~22V
1F
Coil Power supply
6~30V
IC Power supply
2.2F
Can be set up to each90~240mA
10F
Batter
y
VDET
SW
LED1
LED2
LED3
4.7H
SENSP
SENSN
LED4
240mA
82m
RTR020N05
2.2F *
RSTB
PWMPOW
PWMDRV
Power
ON/OFF
100Hz~10kHz
PWM
VBAT
LED5
LED6
FAILSEL
GND
12k
TEST
GND ISETH
VREG
2.2F
ISETL
GNDGND
2.2F
8LED x 1parallel
Fig.59
Fig.60
The separation of less than an IC power supply 5V and the coil power supply
10LED x 6parallel
Each 40mA
Can be set up to each15~40mA
Coil Power supply
6~30V
IC Power supply
10F
Batter
y
VDET
SW
LED1
LED2
LED3
4.7H
SENSP
SENSN
LED4
51m
RTR020N05
2.2F *
RSTB
PWMPOW
PWMDRV
Power
ON/OFF
200Hz
PWM
VBAT
LED5
LED6
FAILSEL
GND
12k
TEST
GND
ISETH
VREG
2.2F
ISETL
GND
GND
2.7~5.5V
1F
2.2F
Fig.61
Technical Note
23/25
BD6592MUV
www.rohm.com 2011.06 - Rev.C
© 2011 ROHM Co., Ltd. All rights reserved.
●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.
10F
Batter
y
VDET
SW
LED1
LED2
LED3
4.7H 8LED x 6Parallel
SENSP
SENSN
LED4
Each 20mA
51m
RTR020N05
2.2F *
RSTB
PWMPOW
PWMDRV
Power
ON/OFF
VBAT
LED5
LED6
FAILSEL
GND
470k
TEST
GND
ISETH
VREG
2.2F
ISETL
GND
GND
24k
D/A
2.2F
D/A LED current
0.05V 19.4mA
0.2V 14.4mA
0.4V 7.7mA
0.5V 4.4mA
0.6V 1.0mA
0.7V 0mA
LED current = ISET voltage
470k + ISET voltage -D/
A
24k ×800
typ LED current = 0.6V
470k + 0.6V-D/A
24k ×800
Fig.62 Analog style optical application
Technical Note
24/25
BD6592MUV
www.rohm.com 2011.06 - Rev.C
© 2011 ROHM Co., Ltd. All rights reserved.
●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.
Technical Note
25/25
BD6592MUV
www.rohm.com 2011.06 - Rev.C
© 2011 ROHM Co., Ltd. All rights reserved.
●Ordering part number
B D 6 5 9 2 MU V - E 2
Part No. Part No.
6592
Package
MUV: VQFN024V4040
Packaging and forming specification
E2: Embossed tape and reel
(Unit : mm)
VQFN024V4040
0.08 S
S
16
7
12
19
24
1318
0.4±0.1
0.02+0.03
-
0.02
1PIN MARK
2.4±0.1
C0.2
0.5
4.0±0.1
0.75
2.4±0.1
4.0±0.1
1.0MAX
(0.22)
0.25+0.05
-
0.04
∗
Order quantity needs to be multiple of the minimum quantity.
<Tape and Reel information>
Embossed carrier tapeTape
Quantity
Direction
of feed
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
2500pcs
E2
()
Direction of feed
Reel 1pin
R1120
A
www.rohm.com
© 2011 ROHM Co., Ltd. All rights reserved.
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Thank you for your accessing to ROHM product informations.
More detail product informations and catalogs are available, please contact us.
Notes
No copying or reproduction of this document, in part or in whole, is permitted without the
consent of ROHM Co.,Ltd.
The content specied herein is subject to change for improvement without notice.
The content specied 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 specications,
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 specied 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 specied 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 specied in this document are intended to be used with general-use electronic
equipment or devices (such as audio visual equipment, ofce-automation equipment, commu-
nication devices, electronic appliances and amusement devices).
The Products specied 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, re or any other damage caused in the event of the
failure of any Product, such as derating, redundancy, re 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
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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.
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obtain a license or permit under the Law.