A8431 Datasheet - Allegro MicroSystems

A8431 White LED Driver Constant Current Step-up Converter

Pb-Free, Surface Mount 26185.301 Preliminary Data Sheet Subject to Change Without Notice April 5, 2005 White LED Driver Constant Current Step-up Converter Functional Block Diagram FB SW A8431 VIN VREF 1.25 V 95 mV A1 RC CC A2 R S Q Driver Σ OVP Ramp Generator OVP 1.2 MHz Oscillator EN Ena.

www.DataSheet4U.com Preliminary Data Sheet Subject to Change without Notice April 5, 2005 A8431 The A8431 is a noninverting boost dc-dc converter that provides a programmable constant current output up to 32 V for driving white LEDs in series.The A8431 also offers an OVP (overvoltage protection) pin. Driving the LEDs in series ensures identical currents and uniform brightness. Up to four white LEDs can be driven at 20 mA from a single cell Li-ion or a multicell NiMH power source. Up to two par.

A8431 Features

* Output voltage up to 32 V (OVP level) 2.5 V to 10 V input Drives up to 4 LEDs at 20 mA from a 2.5 V supply Drives up to 5 LEDs at 20 mA from a 3 V supply 1.2 MHz switching frequency 300 mA switch current limit 1 µA shutdown current OVP pin eliminates the need for an external Zener diode on the outpu

A8431_AllegroMicroSystems.pdf