DER-597 - 40W 2-Stage, Buck-Boost, Isolated Flyback Dimmable LED Ballast Power Supply

This engineering report describes a constant voltage (CV) and constant current (CC) output 40 W LED ballast with 3-way dimming capability. In constant voltage applications, the LED ballast is designed to provide an output voltage of 42 V with an output current load of 0 mA to 960 mA, while in constant current mode operation, it can provide 960 mA at 42 V (three channels available). dimming) constant current – ​​30 V LED voltage string. The design is optimized to operate over an input voltage range of 90 VAC to 305 VAC. The LED ballast adopts a two-stage design, with the first stage using a buck-boost PFC and the secondary stage using an isolated flyback DC-DC. The buck-boost PFC uses the LNK419EG from the LinkSwitch-PH family of devices, while the second-stage flyback uses a LYTSwitch-6 controller. LinkSwitch-PH is a highly integrated controller that eliminates passive circuitry for power factor correction. The LinkSwitch-PH IC contains a 725 V power MOSFET, a continuous-mode PWM controller, a high-voltage switching current source for self-biasing, frequency dithering, protection circuitry including cycle-by-cycle current limiting and hysteretic thermal shutdown. The LYTSwitch-6 IC combines primary, secondary and feedback circuits in a surface mount, offline flyback switch IC. LYTSwitch-6 IC contains primary FET, primary side controller and secondary side synchronous rectification controller. The new ICs also include FluxLink™, an innovative technology that safely bridges the isolation barrier and eliminates the need for an optocoupler. The DER-597 provides a high power factor, wide input and output voltage range, 3-way dimming and low component count solution for 40 W LED ballasts. The main design goals are low component count, high power factor, high efficiency and low component count. This document contains power supply specifications, schematics, bill of materials, transformer documentation, printed circuit layout and performance data.