SGM3140B

500mA Buck/Boost

Charge Pump LED Driver

GENERAL DESCRIPTION

The SGM3140B is a current-regulated charge pump

ideal for powering high brightness LEDs for camera

flash applications. The charge pump can be set to

regulate two current levels for Flash and Torch modes.

The

SGM3140B

automatically

switches

modes

between step-up and step-down ensuring that LED

current does not depend on the forward voltage. It

switches at 2.2MHz, allowing the use of tiny

components. The supply voltage ranges from 2.7V to

5.5V and is ideally suited for all applications powered

by a single Li-ion battery cell or three to four NiCd,

NiMH, or Alkaline battery cells.

The SGM3140B also features a very low shutdown

current, an automatic soft-start mode to limit inrush

current, as well as over-current, over-voltage and

over-temperature thermal shutdown control.

A low current-sense reference voltage (47mV) allows

the use of small 0603 current sensing resistors.

The SGM3140B is available in Green TDFN-3×3-10L

package and is specified over an ambient temperature

range of -40

℃ to +85℃.

APPLICATIONS

White LED Torch, Flash for Cell

Phones, DSCs and Camcorders

White LED Backlighting

Generic Lighting, Flash and Strobe Applications

General Purpose High Current Boost

FEATURES

● Output Current Up to 500mA

● Up to 90% Efficiency in Torch Mode

● Adjustable Flash Mode Current

● Automatic Buck/Boost Mode Switchover

● Input Voltage Range: 2.7V to 5.5V

● Minimum External Components: No Inductors

● High Frequency Operation: 2.2MHz

● Low 47mV Reference for Low Loss Sensing

● Automatic Soft-Start Limits Inrush Current

● Low Input and Output Ripple and Low EMI

● Output Over-Voltage Protection

● Over-Current and Over-Temperature Protection

● Available in Green TDFN-3×3-10L Package

TYPICAL APPLICATION

VIN

C1

C2

FLASH

EN

VOUT

PGND

SGND

FB

RSET

1

2

3

4

5

10

9

8

7

6

1μF

4.7μF

2.7V to 5.5V

SGM3140B

ENABLE

86.6kΩ

0.33Ω

1μF

TORCH/FLASH

WLED

REV. A

SG Micro Corp

www.sg-micro.com