SM8135AB 参数 Datasheet PDF下载

SM8135A

White LED Driver IC

OVERVIEW

The SM8135A is a charge pump type white LED driver. It can drive 1 to 4 backlight white LED connected in

parallel, making it ideal for portable devices with small LCD. The charge pump switches between

×

1 bypass

mode,

×

1.5 and

×

2 boost mode in response to LED drive current requirements. The boost switching occurs in

response to the drive current of all the connected LED and thus supports variations in LED forward-bias volt-

age drop (VF). Besides, the detection of switching is repeated in approx. 1sec-cycle by mode reset action, the

SM8135A can respond to temporary variation of supply voltage. These ingenuities on switching detection can

prolong the battery life to the fullest extent. Each LED drive current is controlled by a 4-channel LED drive

current control circuit. The LED drive current per channel is setup by external resistor. Moreover, the PWM

signal control of EN pin can realize nonstep brightness control (10% to 100%). The IC ON/OFF is controlled

by EN pin.

FEATURES

I

PINOUT

(Top view)

GND

NC

DIN3

DIN4

DIN2

DIN1

VOUT

C2P

C2M

PGND

C1P

C1M

ISET

EN

GND

VIN

I

I

I

I

I

I

I

I

I

I

A

3.0 ± 0.08

0.3 ± 0.1

0.5

I

1.8

C 0.3

0.22 ± 0.05

I

0.1 ± 0.05

I

3 = 1.5 ± 0.05

I

Battery life extension by automatic charge pump

switch between

×

1,

×

1.5 and

×

2 according to the

detection of the LED drive current

Controlling 1 to 4 lights of white LED connected

in parallel

Set up LED drive current value by external resistor

(120k

Ω

: 20mA/ch)

1-wire input controlling

ON/OFF and brightness control by PWM signal

controlling of EN pin (10 to 100%)

Soft start circuit built-in

Thermal shut down circuit built-in

Input voltage range

No-load current (I

OUT

= 0mA): 2.7 to 4.6V

Load current (I

OUT

= 80mA): 3.0 to 4.6V

Maximum output voltage: 4.9V (typ)

Maximum output current: 80mA (typ)

Quiescent current

Not-switching (×1 mode): 0.3mA (typ)

Switching (×1.5 mode): 1.5mA (typ)

Switching (×2 mode): 1.5mA (typ)

Standby current: 0.01

µ

A (typ)

Operating frequency: 1MHz (typ)

LED drive current accuracy between channel

(REST = 120k

Ω

): ± 5% (max)

Package: 16-pin QFN

PACKAGE DIMENSIONS

(Unit: mm)

TOP VIEW

3.0 ± 0.08

B

BOTTOM VIEW

1.8

0.02 S A B

S

0.2 S

φ

0.05 M

S A B

APPLICATIONS

I

I

I

I

I

I

I

I

0.2 ± 0.05

Cellular phone

PDA

Portable games

Handy terminal

Digital still camera

Digital video camera

LCD panel back light

White LED driving

0.05 S

0.5

ORDERING INFORMATION

Device

SM8135AB

Package

16-pin QFN

0.7 ± 0.05

SEIKO NPC CORPORATION —1