SM8131B

NIPPON PRECISION CIRCUITS INC.—1

White LED Driver IC

OVERVIEW

The SM8131B is a charge pump DC/DC converter that switches between

×1 and ×1.5 automatically. The

SM8131B switches between

×1 and ×1.5 according to detected LED drive current, so that the battery life can

be prolonged to the fullest extent. Since the connected LED are all detected for the switching, the SM8131B

can respond to the variation of LED forward voltage. 6-channel of LED drive current control circuit is built-in,

the SM8131B can control 1 to 6 lights of white LED, which are connected in parallel. The LED drive current

per channel is set up by external resistor. Besides, by setting up SEL1/SEL2 pins, 6-channel of LED drive cur-

rent control circuit can be divided to 2-groups, and input signal controlling of EN1/EN2 pins allow ON/OFF

and dimming per group.

FEATURES

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Battery life extension by automatic charge pump

switch between

×1 and ×1.5 according to the

detection of the LED drive current

I

Controlling 1 to 6 lights of white LED connected

in parallel

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Set up LED drive current value by external resistor

(5k

Ω:5mA/ch, 15kΩ:15mA/ch, 20kΩ:20mA/ch)

I

Dividing 6-channel to 2-groups by setting up

SEL1/SEL2 pins (L/L

= 6:0ch, L/H = 5:1ch,

H/L

= 4:2ch, H/H = 3:3ch)

I

2-wire input controlling (1-wire input controlling

when SEL1/SEL2 pins are set to “LOW”)

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ON/OFF and brightness control by input signal

controlling of EN1/EN2 pins

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Supply voltage range

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Maximum output voltage: 4.2V (typ)

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Maximum output current: 120mA (typ)

I

Quiescent current

• Not-switching (

×1 mode): 0.7mA (typ)

• Switching (

×1.5 mode): 2.0mA (typ)

I

Standby current (Power save mode): 0.01

µA (typ)

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Operating frequency (

×1.5 mode): 750kHz (typ)

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LED drive current accuracy (RSET

= 20kΩ)

:20mA

± 3%

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Input signal frequency for dimming (Duty

= 50%)

:150kHz (max)

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Package:20-pin QFN

APPLICATIONS

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Cellular phone

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PDA

I

Portable games

I

Handy terminal

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Digital still camera

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Digital video camera

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LCD back light

I

White LED driving

PINOUT

(Top view)

PACKAGE DIMENSIONS

(Unit: mm)

ORDERING INFORMATION

Device

Package

SM8131B00B

20-pin QFN

12 345

15 14 13 12 11

10

9

8

7

6

16

17

18

19

20

VREG

C2P

C2M

PGND

C1M

EN1

DIN6

DIN5

DIN4

GND

4.20 ± 0.20

4.00 ± 0.10

1

0.50

0.60 ± 0.10

0.22 ± 0.05

0.05

0.05 M