DER-442 - 30 W Isolated Flyback, 1–10V Analog Dimmable LED Driver

This document is an engineering report describing a wide output voltage range and 1 V to 10 V dimmable optically isolated flyback LED driver (power supply) using the LYT4315E from the LYTSwitch-4 family of devices. The design provides a constant output current of 500mA over a 30V to 60V output range and an input range of 90VAC to 132VAC. The main design goals are high efficiency, 1 V to 10 V dimming and constant current regulation over the entire output range. The LYTSwitch-4 driver IC incorporates PFC functionality to meet both power factor and harmonic requirements. The topology used is an isolated flyback topology operating in continuous conduction mode. Constant current and dimming adjustments are achieved through a secondary feedback control circuit utilizing a quad operational amplifier. An internal controller adjusts the power MOSFET duty cycle to maintain a sinusoidal input current, providing high power factor and low harmonic currents. The LYT4315E also provides multiple protection features, including automatic restart in open control loop and output short-circuit conditions, line overvoltage protection, and over-temperature protection. Line overvoltage provides longer line fault and surge tolerance, output overvoltage protects the power supply when the load is disconnected, and accurate hysteretic thermal shutdown ensures safe average PCB temperatures under all conditions. This document contains power supply specifications, schematics, bill of materials, transformer documentation, printed circuit layout, design spreadsheet, and performance data.