LM27952

LM27952 www.ti.com SNVS364B – MAY 2005 – REVISED MAY 2013 LM27952 White LED Adaptive 1.5X/1X Switched Capacitor Current Driver Check for Samples: LM27952 FEATURES 1 2 Drives up to 4 LEDs with up to 30mA each Regulated current sources with 0.2%(typ.) matching 3/2x, 1x Gain transition based on LED VF Peak Efficiency Over 85% Input Voltage Range: 3.0V to 5.5V PWM Brightness Control Very Small Solution Size - NO INDUCTOR Fixed 750kHz Switching Frequency <1µA Shutdown Current 14-pin WSON Package: 4.0mm X 3.0mm X 0.8mm APPLICATIONS White LED Display Backlights White LED Keypad Backlights General Purpose LED Lighting DESCRIPTION The LM27952 is a switched capacitor white-LED driver capable of driving up to 4 LEDs with 30mA through each LED. Its 4 tightly regulated current sinks ensure excellent LED current and brightness matching. LED drive current is programmed by an external sense resistor. The LM27952 operates over an input voltage range from 3.0V to 5.5V and requires only four low-cost ceramic capacitors. The LM27952 provides excellent efficiency without the use of an inductor by operating the charge pump in a gain of 3/2, or in a gain of 1. Maximum efficiency is achieved over the input voltage range by actively selecting the proper gain based on the LED forward voltage requirements. Typical Application Circuit VIN = 3.0V - 5.5V CIN 3.3 µF C1 1 µF VIN C1+ VOUT 3.3 µF C1- D4 C2+ LM27952 D3 C2 1 µF D2 C2- D1 ISET PWM D4 COUT D3 D2 D1 ID...