ROHM BD6592MUV Technical data

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

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

Maximum applied voltage 2 VMAX2 25 V

Maximum applied voltage 3 VMAX3 50.5 V VDET

Power dissipation 1 Pd1 500 mW

Power dissipation 2 Pd2 780 mW

Power dissipation 3 Pd3 1510 mW

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 0mm
*3 4 layer (JEDEC Compliant board) has been mounted.
Copper foil area 1layer 6.28mm

●Recommended operating range (Ta=-30℃ ~ +85℃)

Parameter Symbol

*

in series, 6 strings in parallel =72 white LEDs (*white LED Vf=3.5Vmax)

TEST, VREG, SENSP, SENSN, SW,
RSTB, PWMPOW, PWMDRV,
FAILSEL, ISETH, ISETL

LED1, LED2, LED3, LED4, LED5,
LED6, VBAT

*1

*2

*3

2

, When it’s used by more than Ta=25℃, it’s reduced by 6.2mW/℃.

2

, Copper foil area 2~4layers 5655.04mm2, When it’s used by more than Ta=25℃, it’s reduced by 12.1mW/℃.

Ratings

Min. Typ. Max.

Unit Condition

No.11040ECT33

Power supply voltage VBAT 2.7 12.0 22.0 V

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1/25

2011.06 - Rev.C

BD6592MUV

●Electrical characteristic (Unless otherwise specified, VBAT=12V, RSTB=2.5V, Ta = +25℃)

Parameter Symbol

[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

Min. Typ. Max.

Limits

Unit Condition

Technical Note

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

Quiescent Current 2

Current Consumption

LED Control voltage

Over Current Limit voltage

SBD Open Protect

Switching frequency

Duty cycle limit

Over voltage limit

Iq1 - 0.6 3.4 µA RSTB=0V, VBAT=12V

Iq2 - 4.6 10 µA RSTB=0V, VBAT=22V

Idd - 3.4 5.1 mA VDET=0V,ISETH=24k

VLED 0.4 0.5 0.6 V

Ocp 70 100 130 mV

Sop - - 0.1 V Detect voltage of VDET pin

fSW 0.8 1.0 1.2 MHz

Duty 92.5 95.0 99.0 % LED1-6=0.3V

Ovl 43.0 44.7 46.4 V LED1-6=0.3V

*1

[Current driver]

LED maximum current

LED current accuracy

LED current matching

ISET voltage

LED Terminal
Over Voltage Protect

*1 This parameter is tested with DC measurement.

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ILMAX - - 40 mA

ILACCU - - ±5 %

ILMAT - - ±3 %

Iset 0.5 0.6 0.7 V

LEDOVP 10.0 11.5 13.0 V

2/25

ILED=30mA

Each LED current/Average (LED1- 6)
ILED=30mA

RSTB=PWMDRV=2.5V

2011.06 - Rev.C

BD6592MUV

●Reference data

4.5

4.0

3.5

3.0

2.5

2.0

Iin [mA]

1.5

1.0

0.5

0.0
0 2 4 6 8 10 12 14 16 18 20 22

Current Consumption - VBAT

25℃

-30℃

VBAT [V]

Fig.1

2.6

2.5

2.4

2.3

VBAT [V]

2.2

2.1

2

-50 - 25 0 25 50 75 100
Ta [℃]

Fig.4

UVLO - Temperature

30

25

20

(mA)

15

10

LED c urrent

VBAT=6V, 12V, 16V

5

0

0 10 203040 50607080 90100

LED current - PWMDRV-HI Duty

30

25

(mA)

LED c urrent

VBAT=6V, 12V, 16V

20

15

10

5

0

0 102030405060708090100

Ta=-30,+25,+85℃

Duty (%)

Fig.7

PWM = 200Hz

Ta=-30,+25,+85℃

Duty (%)

Fig.10

LED current - PWMPOW-HI Duty

PWM = 200Hz

85℃

Technical Note

8

7

6

5

4

Ist[µA]

3

2

1

0

0 2 4 6 8 10121416182022

85℃

25 ℃

-30℃

VBAT[V]

Fig.2

Quiescent current - VBAT

100%

95%

90%

85%

80%

Effici ency

75%

70%

65%

60%

0 10203040 5060708090100

Duty [%]

VBAT=12V

Fig.5

Efficiency - PWMPOW-HI Duty

ISETH=24k, PWM=200Hz

1.0

0.9

0.8

0.7
VBAT=6V, 12V, 16V

(mA)

0.6

0.5

0.4

LED c urrent

0.3

0.2

0.1

0.0

00.51 1.522.53

Ta=-30,+25,+85℃

Duty (%)

Fig.8

LED current - PWMDRV-HI Duty

( Expansion) PWM = 200Hz

1.0

0.9

0.8

0.7

(mA)

0.6

0.5

0.4

LED c urrent

0.3

0.2

0.1

0.0

00.51 1.522.53

16V

12V

6V

Ta=-30,+25,+85℃

Duty (%)

Fig.11

LED current - PWMPOW-HI Duty

( Expansion) PWM = 200Hz

1.20

1.15

1.10

1.05

1.00

0.95

Fr equency [M Hz]

0.90

0.85

0.80
0 2 4 6 8 10 12 14 16 18 20 22

25℃

-30℃

85℃

VBAT [V]

Fig.3

Oscillation frequency - VBAT

100%

95%

90%

85%

80%

Effici ency

75%

70%

65%

60%

0 10203040 5060708090100

Duty [%]

VBAT=12V

Fig.6

Efficiency - PWMDRV-HI Duty

ISETH=24k, PWM=200Hz

30

25

20

(mA)

15

10

LED C urr ent

5

0

200Hz

0 1020 30405060708090100

1kHz

10kHz

Duty (%)

Fig.9

LED current - PWMDRV-HI Duty

PWM = 200Hz, 1kHz,10kHz

30

25

20

(mA)

15

10

LED C urr ent

5

0

200Hz

10kHz

1kHz

0 102030405060708090100

Duty (%)

Fig.12

LED current - PWMPOW-HI Duty

PWM = 200Hz, 1kHz,10kHz

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3/25

2011.06 - Rev.C

c

t

V

BD6592MUV

3.0

2.0

Max Matching = Max LED Current/Average Current

1.0

0.0

-1.0

Cur rent M atching ( %)

Min Matching = Min LED Current/Average Current

-2.0

-3.0
0% 20% 40% 60% 80% 100%

PWM HI Duty

Fig.13

LED current matching - PWMDRV-HI Duty

PWM = 200Hz

3.0

2.0

Max Matching = Max LED Current/Average Current

1.0

0.0

-1.0

Cur rent M atching ( %)

Min Matching = Min LED Current/Average Current

-2.0

-3.0
0% 20% 40% 60% 80% 100%

PWM HI Duty

Fig.16

LED current matching - PWMPOW-HI Duty

PWM = 200Hz

35

34

33

32

31

30

29

LED C urr ent [m A]

28

27

26

25

-50 -25 0 25 50 75 100

5V, 7V, 12V, 22V

2.7V

temp [

]

℃

Fig.19

LED current - Temperature

PWMDRV=H, ISETH=30k (16mA setting)

VOUT

Ic

Fig.22

VOUT@OVP (LED OPEN)

3.0

2.0

Max Matchin g = Max LED Current/Ave rage Current

1.0

0.0

-1.0

Cur rent M atching ( %)

Min Matching = Min LED Current/Average Current

-2.0

-3.0
0% 2% 4% 6% 8% 10%

PWM HI Duty

Fig.14

LED current matching - PWMDRV-HI Duty

(Expansion) PWM = 200Hz

3.0

Max Matching = Max LED Current/Average Current

2.0

1.0

0.0

-1.0

Cur rent M atching ( %)

Min Matching = Min LED Current/Average Current

-2.0

-3.0
0% 2% 4% 6% 8% 10%

PWM HI Duty

Fig.17

LED current matching - PWMPOW-HI Duty

(Expansion) PWM = 200Hz

VBAT

VOUT

LED curren

400s

No peak

Fig.20

Line Transient (10V to 22V)

PWMDR

VOUT

LED Current

10mA/div

PWMPOW

VOUT

LED Current

10mA/div

VBAT

VOUT

LED current

Technical Note

350mV

Fig.15

VOUT response

Driver Control PWM (PWMDRV)

180mV

Fig.18

VOUT response

Power Control PWM (PWMPOW)

14ms

No peak

Fig.21

Line Transient (22V to 10V)

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4/25

2011.06 - Rev.C

BD6592MUV

Technical Note

●Block diagram, I/O equivalent circuit diagram

VBAT

RSTB

PWMPOW

300k

500k

TSD

REG

VREG

VIN detector

Internal Power suplly

SBD Open protect

FAIL SEL

SW

SENSP

SENSN

TEST

PWMD RV

ISETH

ISETL

300k

100k

300k

S

Q R

Current

Sence

GND

ISET H

Resistor driver

ISET L

Resistor driver

GND

1M

100K

Control

sence

GND

over voltage protect

PWMcom p

-

+

+

Over Voltage Protect

GND

ERRAMP

OSC

LED TERMINAL

Detect

LED TERMINAL

PWMDR V=H

On

PWMDRV=L

On

Fig.23 Block diagram Fig.24 I/O equivalent circuit diagram

●Pin assignment table

PIN

Name

In/Out

PIN

number

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

UVLO

+

-

+

-

-

-

-

-

-

­+

+

-

Current Driver

VDET

LED1

LED2

LED3

LED4

LED5

LED6

VBAT VREG

PIN

GND

VBAT

PIN

GND

VBAT

PIN

GND

A

D

VREG

G

Function

PIN

PIN

VBAT

B

VBAT

5.5V

Clump

GND

E

Terminal equivalent

circuit diagram

PIN

GND

C

PIN

F

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5/25

2011.06 - Rev.C

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BD6592MUV

Technical Note

●Application example

RTR020N05

10F

47m

Power

ON/OFF

200Hz
PWM

Battery

2.2F

4.7H

2.2F *

2.2F *

SW

SENSP

SENSN

RSTB

PWMPOW

PWMDRV

VREG

GND

VBAT

GND

GND

GND

FAILSEL

ISETL

ISETH

TEST

12k

Fig.25 10 series x 6parallel

Hi current 40mA setting

Current driver PWM application

VDET

LED1

LED2

LED3

LED4

LED5

LED6

Each 40mA

10LED x 6parallel

10F

RTR020N05

47m

Power

ON/OFF

200Hz

PWM

Battery

2.2F

4.7H

2.2F *

SENSP

SENSN

RSTB

PWMPOW

GND

SW

PWMDRV

VBAT

VREG

2.2F *

GND

TEST

GNDGND

Fig.26 10 series x 4parallel

Hi current 40mA setting

Current driver PWM application

* Please select the capacitor which the little bias fluctuation.

FAIL SEL

ISETH

12k

ISETL

10LED x 4aprallel

VDET

LED1

LED2

LED3

LED4

LED5

LED6

Each 40mA

VDET

LED1

LED2

LED3

LED4

LED5

LED6

Each 30mA

10LED x 6parallel

Batter

10F

RTR020N05

47m

Power

ON/OFF

200Hz

PWM

2.7V to 5.5V

4.7H

2.2F *

2.2F

2.2F *

SENSP

SENSN

PWMPOW

GND

SW

RSTB

PWMDRV

VBAT

VREG

GND

GNDGND

TEST

FAIL SEL

ISETH

12k

ISETL

Fig.28 Non-used Inside REG

or operating under 5V application

VDET

LED1

LED2

LED3

LED4

LED5

LED6

10LED x 6parallel

Each 40mA

10F

RTR020N05

47m

Power

ON/OFF

200Hz

PWM

Fig.27 10

Battery

4.7H

2.2F *

2.2F *

SW

SENSP

SENSN

RSTB

PWMPOW

PWMDRV

VBAT

VREG

2.2F

GND

GND

GND

series x 6parallel LED current 30mA setting

GND

FAIL SEL

ISETH

ISETL

TEST

16k

Power control PWM 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)

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6/25

2011.06 - Rev.C

t

t

p

g

BD6592MUV

Technical Note

●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

<FAILSEL=H>

RSTB

“H”

FAIL SEL

Protection

function

Boost

operating

<FAILSEL =L>

RSTB

Protection

“L”

function

Boost

operating

about 1ms

un-operating range

un-detection un-detection

normal operating off boost stop

about 1ms

un-operating range FAILSEL

un-detectio

normal operating off

detection

detection

boost stop

un-detection

normal

o

eratin

off

off normal operating

normal

< When it is off on PWMPOW>

RSTB

PWMDRV

PWMPOW

Outpu

voltage

Coil current

FAI LS EL

function

< When it is off on RSTB>

RSTB

PWMDRV

PWMPOW

Outpu

voltage

Coil current

FAI LS EL

function

invalid valid

invalid

Fig.29 FAILSEL operating description Fig.30 FAILSEL=H light off control

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7/25

2011.06 - Rev.C

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 = 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
○

○ 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)
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

Average current of coil = Iave

Peak current of coil = Ipeak

○

1/2

Technical Note

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8/25

2011.06 - Rev.C

3

BD6592MUV

Technical Note

(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

VBAT

RSTB

5V 2.7V

2

1

PWM POW

PWMDRV

VR EG

DC/DC VOUT

Fig.31 Control signal timing Fig.32 Voltage with a control sign higher than VBAT

5V Min. 100 µs

220

5V

0V

VBAT

PIN

Rin

GND

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

BD6592MUV

Technical Note

●Attendance point of the restriction resistance input to RSTB

When the restriction resistance is input to RSTB, it is necessary to

250

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.

A]

200

µ

Because the temperature characteristic of the input current is
shown in Fig.33, please choose resistance for which the voltage

input current[

RSTB

150

100

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.

BD6592MUV

Power supply

for RSTB

Limit resistor

terminal

RSTB inflow current

The decision example of restriction resistance

RSTB

50

2.1 2.4 2.7 3 3.3 3.6

RSTB[ V]

Fig.33 RSTB terminal voltage-RSTB inflow current

(At the time of the current driver six lines use)

1． When use the current driver of 6 parallel

2.9V(to RSTB power-supply) - restriction resistance value × 124A(100℃ input current) > 2.1V
restriction resistance value < (2.9-2.1)/124A=6.45k

2． 2. When use the current driver of 3 parallel

2.9V(to RSTB power-supply) - restriction resistance value × 430A(100℃ input current) > 2.1V
restriction resistance value < (2.9-2.1)/430A=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

+100℃
+80℃

+25℃

-30℃

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10/25

2011.06 - Rev.C

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.

Technical Note

Output

Fig.34 Light off control of PWMPOW pin at PWM control on PWM=L

PWMPOW

Output Voltage

Current coil

Fig.35 Light off control of PWMPOW pin at PWM control on RSTB=L

RSTB

PWMDRV

PWMPOW

Voltage

Current

RSTB

PWMDRV

coil

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11/25

2011.06 - Rev.C

f

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.

Output voltage

Current driver o

starting current

RSTB

PWMPOW

PWMDRV

LED pin

L H L H L H L

ON OFF ON OFF

Fig.36 Off timing of starting current at PWMDRV=L

Output Voltage

Fig.37 Light off control of PWMDRV pin at PWM control on PWM=L

Output Voltage

Fig.38 Light off control of PWMDRV pin at PWM control on RSTB=L

RSTB

PWMPOW

PWMDRV

Current

RSTB

PWMPOW

PWMDRV

Current

coil

coil

Technical Note

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12/25

2011.06 - Rev.C

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  2) Power control PWM control

•LED current dispersion emphasis in the PWM brightness control  1) Current driver PWM control

(Reference)

PWM regulation process

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.

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.

PW MDRV

LED current

Coil current

IC’s active current

Efficiency of LED current 0.5mA

(PWM Duty=2.5%)

ON OFF

ON OFF

ON OFF

ON

Fig.39

PWM frequency 200Hz

Limit dispersion capability of low duty

Technical Note

PWMPOW

LED current

Coil current

IC’s active current

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ON OFF

ON

ON

ON OFF

Fig.40

OFF

OFF

13/25

2011.06 - Rev.C

BD6592MUV

Technical Note

●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

16 k (E16) 30mA

24k (E24) 20mA

25.5 k (E96) 18.8mA

27 k (E12) 17.8mA

30k (E24) 16.0mA

6.2k (E24) 97µA

10k (E6) 60µA

47k (E6) 13µA

100 k (E6) 6µA

560 k (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

10F

RTR020N05

47m

IC Power supply

2.7V to 5.5V

Power

ON/OFF

200Hz

PWM

1F

4.7H

2.2F

SENSP

SENSN

PWMPOW

GND

SW

RSTB

PWMDRV

VBAT

VREG

2.2F

GND

FAIL SEL

ISETH

TEST

GNDGND

12k

ISETL

VDET

LED1

LED2

LED3

LED4

LED5

LED6

10LED x 6列

40mA

各

Fig.42 Application at the time of power supply isolation

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14/25

2011.06 - Rev.C

W

y

BD6592MUV

Technical Note

●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.

to Power Suppl

CIN

L

PWM Reset

C

BAT

C

REG

C

SBD

OUT

Tr

to Cathode

of LED

R

to GND

SENSE

VDET

N.C.

GND

SW

SENSP

TEST

VBAT

SENSN

PWMPO

GND

VREG

ISETH

RSTB

ISETL

GND

PWMDRV

FAI LSE L

LED6

LED5

LED4

GND

LED3

LED2

LED1

to Anode

of each LED

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 R
the low resistance. Wiring to the SENSP pin isn't Tr side, but connect it from R
low when wiring from Tr side. Connect R
wiring from R

pin to GND pin. And R

SENSE

of GND side isolated to SENS pin. Don’t wire between R

SENSE

GND line must be wired directly to GND pin of output capacitor. It has the

SENSE

side. Over current value may become

SENSE

and SNESN pin

SENSE

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.

SENSE

by

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15/25

2011.06 - Rev.C

BD6592MUV

●Recommended PCB layout pattern

C

REG

C

BAT

L

Tr

CIN

C

OUT

Fig.43 Frontal surface <Top view>

Fig.44 Rear surface <Top view>

BD6592MUV

RISET

R

SENSE

Technical Note

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16/25

2011.06 - Rev.C

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

Value Manufacturer Product number

4.7H TOKO A915AY-4R7M 5.2 5.2 3.0 1870 0.045

4.7H TOKO B1015AS-4R7M 8.4 8.3 4.0 3300 0.038

4.7H TOKO A1101AS-4R7M 4.1 4.1 1.2 1400 0.115

4.7H TDK LTF5022T-4R7N2R0 5.0 5.2 2.2 2000 0.073

4.7H TDK VLP6810T-4R7M1R6 6.3 6.8 1.0 1600 0.167

10H TDK VLP6810T-100M1R1 6.3 6.8 1.0 1100 0.350

・Capacitor

Val ue Pressure Manufacturer Product number

[ Supply voltage capacitor ]

10F 25V MURATA GRM31CB31E106K 3.2 1.6 1.6±0.2 B +/-10%

10F 10V MURATA GRM219BB31A106K 2.0 1.25 0.85±0.15 B +/-10%

4.7F 25V MURATA GRM319B31E475K 3.2 1.6 0.85±0.1 B +/-10%

4.7F 25V MURATA GRM21BB31E475K 2.0 1.25 1.25±0.1 B +/-10%

[ Smoothing capacitor for built-in regulator ]

1F 10V MURATA GRM188B10J105K 1.6 0.8 0.8±0.1 B +/-10%

2.2F 10V MURATA GRM219B11A225K 2.0 1.25 0.85±0.1 B +/-10%

[ Output capacitor ]

1F 50V MURATA GRM31MB31H105K 3.2 1.6 1.15±0.1 B +/-10%

1F 50V MURATA GRM21BB31H105K 2.0 1.25 1.25±0.1 B +/-10%

1F 100V MURATA GRM31CR72A105K 3.2 1.6 1.6±0.2 X7R +/-10%

2.2F 50V MURATA GRM31CB31H225K 3.2 1.6 1.6±0.2 B +/-10%

0.33F 50V MURATA GRM219B31H334K 2.0 1.25 0.85±0.1 B +/-10%

・Resistor

Val ue Tolerance Manufacturer Product number

[ 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

60V ROHM RB160M-60 3.5 1.6 0.8±0.1

・MOS FET Nch

Pressure Manufacturer Product number

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

Vertical Horizontal Height (MAX)

Vertical Horizontal Height

Vertical Horizontal Height

Vertical Horizontal Height

Vertical

Size

Size

Size

Size

Size

Horizontal Height

Technical Note

DC current

(mA)

TC

Current

ability

DCR

()

Cap

Tolerance

Driving

voltage

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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2011.06 - Rev.C

y

BD6592MUV

●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

10LED x 6parallel

VDET

LED1

LED2

LED3

LED4

LED5

LED6

Can be set up to each15~40mA

Each 40mA

10F

RTR020N05

47m

Power

ON/OFF

100Hz~10kHz

PWM

Battery

2.2F

4.7H

2.2F *

SENSP

SENSN

PWMPOW

PWMDRV

GND

SW

RSTB

VBAT

VREG

GND

GND

2.2F

GND

TEST

FAI LSEL

ISETH

12k

ISETL

Fig.45 10 series×6 parallel, LED current 40mA setting

Current driver PWM application

Technical Note

13~14inch panel

8LED x 6parallel

VDET

LED1

LED2

LED3

LED4

LED5

LED6

Can be set up to each15~40mA

Each 40mA

10F

RTR020N05

51m

Power

ON/OFF

100Hz~1kHz

PWM

Battery

2.2F

4.7H

2.2F *

SW

SENSP

SENSN

RSTB

PWMPOW

PWMDRV

VBAT

VREG

GND

GND

GND

2.2F

GND

TEST

FAIL SEL

ISETH

12k

ISETL

Fig.46 8 series× 6 parallel, LED current 40mA setting

Power control PWM application

Batter

4.7H

10F

RTR020N05

51m

ON/OFF

100Hz~10kHz

PWM

Power

2.2F

2.2F *

SENSP

SENSN

GND

SW

RSTB

PWMPOW

PWMDRV

VBAT

VREG

GND

2.2F

GNDGND

TEST

FAIL SEL

ISETH

12k

ISETL

VDET

LED1

LED2

LED3

LED4

LED5

LED6

Can be set up to each15~40mA

Fig.47 8 series×6 parallel, LED current 40mA setting

Current driver PWM application

8LED x 6parallel

Each 40mA

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© 2011 ROHM Co., Ltd. All rights reserved.

18/25

2011.06 - Rev.C

y

y

BD6592MUV

●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

VDET

LED1

LED2

LED3

LED4

LED5

LED6

Can be set up to each15~40mA

Each 30mA

10F

RTR020N05

56m

Power

ON/OFF

100Hz~10kHz

PWM

Battery

2.2F

4.7H

2.2F *

SW

SENSP

SENSN

RSTB

PWMPOW

PWMDRV

VBAT

VREG

GND

GND

GND

2.2F

GND

TEST

FAIL SEL

ISETH

16k

ISETL

Fig.48 7 series×6 parallel, LED current 30mA setting

Current driver PWM application

Technical Note

Batter

4.7H

10F

RTR020N05

56m

ON/OFF

100Hz~10kHz

PWM

Power

2.2F

2.2F *

SENSP

SENSN

GND

SW

RSTB

PWMPOW

PWMDRV

VBAT

VREG

GND

2.2F

GNDGND

TEST

FAIL SEL

ISETH

12k

ISETL

Fig.49 10 series×4 parallel, LED current 40mA setting

Current driver PWM application

VDET

LED1

LED2

LED3

LED4

LED5

LED6

Can be set up to each15~40mA

10LED x 4parallel

Each 40mA

7inch panel

VDET

LED1

LED2

LED3

LED4

LED5

LED6

Can be set up to each15~40mA

Each 40mA

10F

RTR020N05

68m

Power

ON/OFF

100Hz~10kHz

PWM

Battery

2.2F

4.7H

2.2F *

SW

SENSP

SENSN

RSTB

PWMPOW

PWMDRV

VBAT

VREG

GND

GND

GND

2.2F

GND

TEST

FAIL SEL

ISETH

12k

ISETL

Fig.50 8 series×3 parallel, LED current 40mA setting

Current driver PWM application

8LED x 3parallel

Batter

4.7H

10F

RTR020N05

68m

ON/OFF

100Hz~10kHz

PWM

Power

2.2F

2.2F *

SENSP

SENSN

PWMPOW

GND

SW

RSTB

PWMDRV

VBAT

VREG

GND

2.2F

GNDGND

TEST

FAIL SEL

ISETH

12k

ISETL

VDET

LED1

LED2

LED3

LED4

LED5

LED6

Can be set up to each15~40mA

Fig.51 6 series×4 parallel, LED current 40mA setting

Current driver PWM application

6LED x 4parallel

Each 40mA

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© 2011 ROHM Co., Ltd. All rights reserved.

19/25

2011.06 - Rev.C

y

y

BD6592MUV

●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

VDET

LED1

LED2

LED3

LED4

LED5

LED6

Can be set up to each15~40mA

Each 40mA

10F

RTR020N05

68m

Power

ON/OFF

100Hz~1kHz

PWM

Battery

2.2F

4.7H

2.2F *

SW

SENSP

SENSN

RSTB

PWMPOW

PWMDRV

VBAT

VREG

GND

GND

GND

2.2F

GND

TEST

FAIL SEL

ISETH

12k

ISETL

Fig.52 4 series×6 parallel, LED current 40mA setting

Power control PWM application

5inch panel

8LED x 2parallel

VDET

LED1

LED2

LED3

LED4

LED5

LED6

Can be set up to each15~40mA

Each 40mA

10F

RTR020N05

82m

Power

ON/OFF

100Hz~10kHz

PWM

Battery

2.2F

4.7H

2.2F *

SW

SENSP

SENSN

RSTB

PWMPOW

PWMDRV

VBAT

VREG

GND

GND

GND

2.2F

GND

TEST

FAIL SEL

ISETH

12k

ISETL

Fig.54 8 series×2 parallel, LED current 40mA setting

Current driver PWM application

Technical Note

Batter

4.7H

10F

RTR020N05

68m

ON/OFF

100Hz~1kHz

PWM

Power

2.2F

2.2F *

SENSP

SENSN

GND

SW

RSTB

PWMPOW

PWMDRV

VBAT

VREG

GND

2.2F

GNDGND

TEST

FAIL SEL

ISETH

12k

ISETL

Fig.53 8 series×3 parallel, LED current 80mA setting

Power control PWM application

Batter

4.7H

10F

RTR020N05

82m

ON/OFF

100Hz~1kHz

PWM

Power

2.2F

2.2F *

SENSP

SENSN

GND

SW

RSTB

PWMPOW

PWMDRV

VBAT

VREG

GND

2.2F

GNDGND

TEST

FAIL SEL

ISETH

12k

ISETL

Fig.55 8 series×2 parallel, LED current 80mA setting

Power control PWM application

VDET

LED1

LED2

LED3

LED4

LED5

LED6

Can be set up to each30~80mA

VDET

LED1

LED2

LED3

LED4

LED5

LED6

Can be set up to each30~80mA

8LED x 3parallel

Each 80mA

8LED x 2parallel

Each 80mA

www.rohm.com

© 2011 ROHM Co., Ltd. All rights reserved.

20/25

2011.06 - Rev.C

y

BD6592MUV

●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

VDET

LED1

LED2

LED3

LED4

LED5

LED6

Can be set up to each30~80mA

Each 40mA

10F

RTR020N05

82m

Power

ON/OFF

100Hz~10kHz

PWM

Battery

2.2F

4.7H

2.2F *

SW

SENSP

SENSN

RSTB

PWMPOW

PWMDRV

VBAT

VREG

GND

GND

GND

2.2F

GND

TEST

FAIL SEL

ISETH

12k

ISETL

Fig.56 4 series×4 parallel, LED current 40mA setting

Current driver PWM application

3LED x 5parallel

VDET

LED1

LED2

LED3

LED4

LED5

LED6

Can be set up to each15~40mA

Each 40mA

10F

RTR020N05

82m

Power

ON/OFF

100Hz~1kHz

PWM

Battery

2.2F

4.7H

2.2F *

SW

SENSP

SENSN

RSTB

PWMPOW

PWMDRV

VBAT

VREG

GND

GND

GND

2.2F

GND

TEST

FAIL SEL

ISETH

12k

ISETL

Fig.58 3 series×5 parallel, LED current 40mA setting

Power control PWM application

Technical Note

Batter

4.7H

10F

RTR020N05

82m

ON/OFF

100Hz~10kHz

PWM

Power

2.2F

2.2F *

SENSP

SENSN

GND

SW

RSTB

PWMPOW

PWMDRV

VBAT

VREG

GND

2.2F

GNDGND

TEST

FAIL SEL

ISETH

12k

ISETL

Fig.57 8 series×2 parallel, LED current 120mA setting

Current driver PWM application

VDET

LED1

LED2

LED3

LED4

LED5

LED6

Can be set up to each45~120mA

8LED x 2parallel

Each 120mA

www.rohm.com

© 2011 ROHM Co., Ltd. All rights reserved.

21/25

2011.06 - Rev.C



z

y

BD6592MUV

●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

Power supply

Power

ON/OFF

200H

PWM

6~30V
Battery

1F

2.2F

4.7H

2.2F *

SENSP

SENSN

PWMPOW

GND

SW

RSTB

PWMDRV

VBAT

VREG

GND

2.2F

GND

GND

Batter

8LED x 6parallel

10F

RTR020N05

82m

ON/OFF

100Hz~10kHz

PWM

Power

2.2F

VDET

FAILSEL

LED1

LED2

LED3

LED4

LED5

ISETH

ISETL

TEST

12k

LED6

Each 40mA

Coil

10F

RTR020N05

51m

2.7~22V

IC Power supply

Can be set up to each15~40mA

Fig.59

The separation of less than an IC power supply 5V and the coil power supply

Power supply

RTR020N05

2.7~5.5V

IC Power supply

Coil

10F

51m

200Hz

PWM

6~30V
Battery

Power

ON/OFF

1F

2.2F

4.7H

2.2F *

SW

SENSP

SENSN

RSTB

PWMPOW

PWMDRV

VREG

GND

VBAT

GND

2.2F

GND

GND

10LED x 6parallel

FAI LSEL

VDET

LED1

LED2

LED3

LED4

LED5

ISETL

ISETH

TEST

12k

LED6

Each 40mA

Can be set up to each15~40mA

Fig.61

4.7H

2.2F *

SENSP

SENSN

GND

SW

RSTB

PWMPOW

PWMDRV

VBAT

VREG

GND

2.2F

GNDGND

TEST

Fig.60

FAIL SEL

ISETH

12k

Technical Note

8LED x 1parallel

VDET

LED1

LED2

LED3

LED4

LED5

ISETL

LED6

Can be set up to each90~240mA

240mA

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© 2011 ROHM Co., Ltd. All rights reserved.

22/25

2011.06 - Rev.C

A

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.

VDET

LED1

LED2

LED3

LED4

LED5

LED6

D/A

24k

8LED x 6Parallel

LED current =

Each 20mA

typ LED current =

10F

RTR020N05

51m

Power

ON/OFF

Battery

2.2F

4.7H

2.2F *

SW

SENSP

SENSN

RSTB

PWMPOW

PWMDRV

VBAT

VREG

GND

GND

GND

2.2F

GND

TEST

FAIL SEL

ISETH

470k

ISETL

Fig.62 Analog style optical application

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

ISET voltage

470k

0.6V

470k

Technical Note

ISET voltage -D/

+

24k

0.6V-D/A

+

24k

×800

×800

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© 2011 ROHM Co., Ltd. All rights reserved.

23/25

2011.06 - Rev.C

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 cap
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.

acitor as the external capacitor, determine the constant with consideration given to a

Technical Note

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© 2011 ROHM Co., Ltd. All rights reserved.

24/25

2011.06 - Rev.C

BD6592MUV

●Ordering part number

Technical Note

B D

Part No. Part No.

VQFN024V4040

4.0±0.1

1.0MAX

0.08 S

C0.2

24

19

0.4±0.1

0.75

6 5 9 2

6592

4.0±0.1

1PIN MARK

2.4±0.1

16

0.5

S

0.02

-

+0.03

(0.22)

0.02

7

2.4±0.1

12

1318

+0.05

0.25

-

0.04

(Unit : mm)

MU V

Package

MUV: VQFN024V4040

<Tape and Reel information>

Embossed carrier tapeTape

Quantity

Direction
of feed

2500pcs
E2

The direction is the 1pin of product is at the upper left when you hold

()

reel on the left hand and you pull out the tape on the right hand

Reel

1pin

-

E 2

Packaging and forming specification
E2: Embossed tape and reel

Direction of feed

Order quantity needs to be multiple of the minimum quantity.

∗

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© 2011 ROHM Co., Ltd. All rights reserved.

25/25

2011.06 - Rev.C

Notes

No copying or reproduction of this document, in par t 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, ofce-automation equipment, commu­nication devices, electronic appliances and amusement devices).

The Products specied in this document are not designed to be radiation tolerant.

While ROHM always makes effor ts 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
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 specied 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.

Notice

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Thank you for your accessing to ROHM product informations.
More detail product informations and catalogs are available, please contact us.

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A