an-1131| Application Note

Application Note AN-1131
Universal Input (90 VAC 265 VAC) LED Driver Using IRS2541

Table of Contents
Page 1. Introduction ..................................................................................1 2. Circuit Description ......................................................................................2 3. Component Selection .................................................................................4 4. Electrical Characteristics ............................................................................5 5. Dimming ......................................................................................8 6. Efficiency, Power Losses and Temperature Considerations ...................8 7. Other Design Considerations ..........................................................11 8. Design Procedure Summary ............................................................14

1. Introduction
Explosive growth in emerging applications will drive demand for Light Emitting Diodes (LEDs). LEDs have proven a viable alternative to less efficient light sources. LED benefits include extremely long life, small size, design flexibility, architectural effects, significant maintenance cost savings, energy savings, and safe, low-voltage operation. With their cost decreasing and efficiency increasing over the long term, the industry is eagerly embracing LEDs. This application note describes a universal input (90-265 VAC) LED driver using International Rectifier's IRS2541 LED driver IC. The IRS2541 is a high-voltage, high-frequency, buck control IC for constant LED current regulation. It incorporates a continuous-mode, time-delayed hysteretic buck regulator to directly control the average load current, using an accurate on-chip band-gap voltage reference. LEDs require drivers that have specific features such as constant current control over temperature, input voltage and manufacturing variations as well as dimm
ing capability and appropriate fault protection. The IRS2541 is specifically designed to address these requirements.

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AN-1131