This engineering report describes a low cost, non-isolated non-dimmable buck LED driver
designed to drive a 120 V LED voltage string at 170 mA output current from an input
voltage range of 190 VAC to 300 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.