GENERAL DEscriptION

The SGM3138 is a current-regulated white LED driver with integrated low dropout current sources and a high efficiency charge pump. The charge pump has automatically selectable 1×/1.5× fractional operation modes. The SGM3138 is well suited for white LED applications powered by a Li-Ion battery due to small e open-loop resistance in 1× mode.

The supply voltage operates from 2.7V to 5.5V. The SGM3138 supports up to 6 LEDs for total maximum 120mA current. The LED reference current is set through an internal resistor. The SGM3138 contains a 4-bit digital-to-analog converter for 16-step LED current control. The LED current can be set between 1.25mA and 20mA by a serial pulse input signal into the EN/SET pin.

The SGM3138 provides less than 1μA shutdown current and soft-start function. Built-in soft-start circuitry avoids excessive inrush current during startup and mode transition.

The SGM3138 is available in a Green TQFN-3×3-16L package. It operates over an ambient temperature range of -40℃ to +85℃.

FEATURES

• Input Voltage Range: 2.7V to 5.5V

• Support to 6 LEDs at 20mA Each

• 16-Step Brightness Control Through One-Wire Interface

• 1× and 1.5× Charge Pump for High Conversion Efficiency

• Switching Frequency: 1MHz

• ±5% Regulated LED Current Matching

• Built-in Soft-Start for Reducing Inrush Current

• Low Input Ripple and Low EMI

• Protection Features

  Over-Current Protection

  Under-Voltage Lockout

  Thermal Shutdown

• Operating Temperature Range: -40℃ to +85℃

• Available in a Green TQFN-3×3-16L Package

APPLICATIONS

White LED Backlighting

Mobile Phones, MP3s

Digital Still Cameras

LCD Displays