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 equivalent 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