The following file is an application note from st.com describing the two stages of electronic ballast for a 250 W HID (high-intensity discharge) metal halide lamp. The ballast is composed of a boost converter (power factor controller PFC) working in fixed OFF time and an inverter composed of a full bridge that drives the lamp at low frequency square wave. The components include a PFC driver, half-bridge drivers, a microcontroller, an auxiliary power supply, a voltage reference, logic parts, an amplifier, comparators, power devices as Power MOSFETs, IGBTs, and fast diodes.
Herein this file you will find detail information regarding 250 W HID lamp description, general circuit description, board description, L6385 high-voltage high and low side driver, ST7LITE39 microcontroller (application pin), auxiliary power supply, TS272 high-performance CMOS dual operational amplifiers, LM119 high-speed dual comparators, 74AC00 QUAD2-input NAND gates, lamp data, PFC section design criteria, full bridge design criteria, experimental results, firmware flowchart, references, and revision history.
Get detail information about Circuit Diagram for 250 W HID Metal Halide Electronic Ballast here – http://www.st.com/stonline/books/pdf/docs/14622.pdf – free download PDF file.