AN3973 Datasheet, PDF (1/24 Pages) STMicroelectronics – Electronic ballast with active PFC using

AN3973
Application note
Electronic ballast with active PFC using
STD3N62K3 power MOSFET and STD845DN40 BJT device
Introduction
In the most recent developments regarding energy saving, optimization and correct
selection of design components are considered a must in order to have improved electric
efficiency. An increasing sensitivity regarding energy problems has made companies and
consumers more demanding. In this context, cooperation and support between silicon
makers and customers is paramount: an exchange of experience leads to a better and
quicker way to realize new projects. In this article, we present an electronic ballast project
designed thanks to customer input. This application note describes the demonstration board
for 2X28 W electronic lamp ballast with active PFC. The ballast is formed by a part of the
PFC section and a self-oscillating half bridge converter. The circuit has been designed for a
nominal input voltage of 230 Vrms±15% and 50-60 Hz. The key components are the power
bipolar transistor (STD845DN40), the MOSFET device (STD3N62K3), and an ST power
switching driver for the PFC section. The purpose of this application note is to show a simple
and cheap lighting application optimized in terms of power factor (PFC), THD harmonic
distortion, and electric efficiency. The DC-AC converter section presents a layout solution
that offers the customer the possibility of using a bipolar transistor, or DIP 8 or SOT-82
package.
November 2011
Doc ID 022164 Rev 1
1/24
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