This application note describes, step-by-step, all the principles and calculations used for a modified buck converter intended for high brightness LED applications. The converter is designed as a constant current source to achieve the best lighting performance from the LEDs.
This document details the design principles and calculations for a modified buck converter intended for high brightness LED applications. The topology is designed as a constant current source where the power switch connects to ground, simplifying control compared to standard buck topologies. It operates in fixed off-time (FOT) network mode within continuous conduction mode (CCM).
| Current sense threshold | 1.08 V (typ) |
|---|---|
| ZCD threshold | 0.7 V |
| ZCD clamp voltage | 5.7 V |
The converter operates in fixed off-time (FOT) network mode within continuous conduction mode (CCM).
The basic principle of the design uses the L6562A controller.