ZXLD383ET5TA Diodes Incorporated

A Product Line of Diodes Incorporated ZXLD383 SINGLE OR MULTI CELL LED DRIVER SOLUTION Summary The ZXLD383 is a single or multi cell LED driver designed for applications requiring step-up voltage conversion from a very low input voltage. The IC generates constant current pulses that are ideal for driving single or multiple LEDs over a wide range of operating voltages. It includes an on/off enable input that can be driven directly from a photocell array or an open collector/drain logic output. The enable input features an ultra-low voltage drop diode to ground, eliminating the need for a photocell array isolation diode in Garden Light applications. The ZXLD383 uses a PFM control technique to drive an internal switching transistor which exhibits a low saturation resistance. This ensures high efficiency, even for input voltages as low as 1.0V. The IC can start up under full load and operates down to an input voltage of below 0.9V. The ZXLD383 is offered in the space saving TSOT23-5 package or in die form, offering an excellent cost vs. performance solution for single cell LED driving applications. Features Pin Assignments 85% Efficiency TSOT23-3 User adjustable output current 1 5 ENA VCC Single cell operation Low saturation voltage TSOT23-3 package 2 GND Available also in die form Simple application circuit 3 4 NC VOUT (Top View) Application Garden lights Door/pathway illumination LED flashlight and torches LED backlights White LED driver Gated boost supply generator Typical Application Circuit 1 of 10 May 2010 ZXLD383 Diodes Incorporated www.diodes.com Document number: DS32189 Rev. 3 - 2 A Product Line of Diodes Incorporated ZXLD383 Block Diagram VCC L1 ZXLD383 Diode Array VOUT ENA Pulse Control LED NIMH 1.2V Dch Con Coff Rsense GND Fig 1. ZXLD383 Block Diagram Pin Description Pin No. Name Description 1 ENA Enable / Photodiode array battery charge input 2 GND Ground 3 NC Not connected (internally open circuit) 4 Switch output external inductor/LED V OUT 5 V Supply voltage, generally Alkaline, NiMH or NiCd single cell CC 2 of 10 May 2010 ZXLD383 Diodes Incorporated www.diodes.com Document number: DS32189 Rev. 3 - 2