Electronic ballast and method for arc straightening

摘要

A method and apparatus for controlling a lamp ballast having a DC-DC converter with first and second MOSFETs acting as switches alternately connecting a DC power source to a power transformer, with an output of the power transformer being connected to a DC-AC inverter driving the lamp. The first and second MOSFETs in the DC-DC converter are alternately opened and closed at a frequency that is swept repeatedly between predetermined minimum and maximum frequencies. A microcontroller-based feedback element determines instantaneous power consumption by the lamp and controls the MOSFETs through a pulse width modulator to continuously adjust a duty cycle of signals driving gates of the MOSFETs to maintain a desired level of power consumption.