This engineering report describes a low component count, non-isolated, non-dimmable
LED driver in Buck topology, designed to drive a 67 V LED voltage string at 250 mA
output current from an input voltage range of 90 VAC to 132 VAC. The LED driver utilizes
the LYT1604D from the LYTSwitch-1 family of devices.
LYTSwitch-1 is a SO-8 package LED driver controller IC designed for non-isolated buck
topology applications. The LYTSwitch-1 provides high efficiency, high power factor and accurate LED current regulation. LYTSwitch-1 incorporates a high-voltage power MOSFET
and Variable Frequency / Variable On-Time, Critical Conduction Mode Control Engine for
tight current regulation, high power factor and proprietary FET utilization for high
efficiency. The controller also integrates protection features such as input and output
overvoltage protection, thermal fold-back, over temperature shutdown, output short-
circuit and overcurrent protection.