SGM3138

SGM3138 6-Channel Charge Pump White LED Driver with Low Dropout Current Source GENERAL DESCRIPTION The SGM3138 is a high performance white LED driver. It integrates current sources and automatic mode selection charge pump. The part maintains the high efficiency by utilizing a 1×/1.5× fractional charge pump and low dropout current sources. The small equivalent 1× mode open loop resistance and ultra-low dropout voltage of current source extend the operating time of 1× mode and optimize the efficiency of Li-ion battery in white LED applications. The SGM3138 supports up to 6 white LEDs and regulates a constant current which the initial value can be set by an internal resistor. The part implements a 4-bit DAC for brightness control. Users can easily configure the LED current from 1.25mA to 20mA by a serial pulse. The dimming of white LEDs current can be achieved by applying a pulse signal to the EN/SET pin. There are totally 16 steps of current could be set by users. The operating voltage range is 2.7V to 5.5V. Internal soft-start circuitry effectively reduces the in-rush current while both start-up and mode transition. FEATURES  Input Voltage Range: 2.7V to 5.5V  Drives Up to 6 LEDs at 20mA Each  One Single Wire Interface  16-Step Brightness Control  High Efficiency by Fractional Conversion with 1× and 1.5× Modes  Switching Frequency: 1MHz  Regulated Output Current with ±5% Matching  Internal Soft-Start Limits Inrush Current  Low Input Ripple and Low EMI  Over-Current...