ZXLD381FHTA Diodes Incorporated

A Product Line of Diodes Incorporated ZXLD381 SINGLE OR MULTI CELL LED DRIVER SOLUTION Summary The ZXLD381 is a single cell LED driver designed for applications where step-up voltage conversion from a very low input voltage is required. These applications mainly operate from 1.5V or 1.2V cells. The IC generates constant current pulses that are ideal for driving single or multiple LEDs over a wide range of operating voltages. The ZXLD381 uses a PFM control technique to drive an internal switching transistor which a low saturation resistance. This ensures high efficiency, even for input voltages as low as 1V. The IC can start up under full load and operates down to an input voltage of only 0.9V. The ZXLD381 is offered in the space saving SOT23 package or in die form, offering an excellent cost vs performance solution for single cell LED driving applications. Features Pin Assignments 85% Efficiency SOT23-3 User adjustable output current Single cell operation (0.9V minimum) Low saturation voltage switching transistor SOT23-3 package Available also in Die form Simple Application circuit (Top View) Application LED flashlights and torches LED backlights White LED driver Typical Application Circuit V IN L1 V CC LED V OUT GND ZXLD381 1 of 9 May 2010 ZXLD381 Diodes Incorporated www.diodes.com Document number: DS32188 Rev. 3 - 2 A Product Line of Diodes Incorporated ZXLD381 Block Diagram VCC L1 ZXLD381 VOUT Pulse Control LED 1.5V Con Cof f Rsense GND Fig 1. ZXLD381 Block Diagram Pin Description Pin No. Name Description 1 GND Ground 2 Switch output external inductor/LED V OUT 3 Supply voltage, generally Alkaline, NiMH or NiCd single cell V CC 2 of 9 May 2010 ZXLD381 Diodes Incorporated www.diodes.com Document number: DS32188 Rev. 3 - 2