SC624AEVB(2007) Просмотр технического описания (PDF) - Semtech Corporation

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производитель

SC624AEVB
(Rev.:2007)

LED Light Management Unit Charge Pump, 4 LEDs, Dual LDOs, and I2C Interface

Semtech Corporation 

POWER MANAGEMENT

Features

„ Input supply voltage range — 3.0V to 5.5V

„ Charge pump modes — 1x, 1.5x and 2x

„ Four programmable current sinks with 32 steps from

0.5mA to 25mA

„ Two user-configurable 100mA low-noise LDO

regulators

„ Charge pump frequency — 250kHz

„ I2C compatible interface — up to 400kHz

„ Backlight current accuracy ±1.5% typical

„ Backlight current matching ±0.5% typical

„ Programmable fade-in/fade-out for main backlight

„ Automatic sleep mode (LEDs off ) — I = 100μA

Q

„ Low shutdown current — 0.1μA (typical)

„ Ultra-thin package — 3mm x 3mm x 0.6mm

„ Fully WEEE and RoHS compliant

Applications

„ Cellular phone backlighting

„ PDA backlighting

„ Camera I/O and core power

SC624A

LED Light Management Unit

Charge Pump, 4 LEDs, Dual LDOs,

and I2C Interface

Description

The SC624A is a high efficiency charge pump LED driver

using Semtech’s proprietary mAhXLifeTM technology.

Performance is optimized for use in single-cell Li-ion

battery applications.

The charge pump provides backlight current in

conjunction with four matched current sinks. The load

and supply conditions determine whether the charge

pump operates in 1x, 1.5x, or 2x mode. An optional fading

feature that gradually adjusts the backlight current is

provided to simplify control software. The SC624A also

provides two low-dropout, low-noise linear regulators for

powering a camera module or other peripheral circuits.

The SC624A uses an I2C compatible serial interface. The

interface controls all functions of the device, including

backlight current and two LDO voltage outputs.

In sleep mode, the device reduces quiescent current to

100μA while continuing to monitor the serial interface.

The two LDOs can be enabled when the device is in sleep

mode. Total current reduces to 0.1μA in shutdown.

Typical Application Circuit

VBAT

CIN

1μF

I2C Data

I2C Clock

Enable Control

CBYP

22nF

June 27, 2007

VIN

VOUT

SDA SC624A

SCL

EN

BYP

BL 1

BL 2

BL 3

BL 4

COUT

2.2μF

MAIN BACKLIGHT

AGND

PGND

LDO 1

LDO 2

VLDO1 = 2.5V to 3.3V

VLDO2 = 1.5V to 1.8V

C1+ C1- C2+ C2-

C1

C2

1μF

1μF

CLDO1

1μF

CLDO2

1μF

© 2007 Semtech Corporation

US Patents: 6,504,422; 6,794,926

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