Patent ID: 8344635
Filing Date: 2013-01-01
Classification: H05B

Abstract:
1. A method of driving regulation for bipolar transistors in an electronic ballast, the method comprising: sensing voltage at midpoint of half bridge of the transistors; producing a reference time interval according to a sync signal from a timer; producing an actual time interval in each of a plurality of switching cycles by comparing rising edge of the voltage at midpoint of the half bridge of the transistors with rising edge of a driving signal for the transistors in upper bridge arm; comparing the actual time interval with the reference time interval to determine a pulse width of the driving signal; regulating, in which the pulse width of the driving signal in one of said plurality of switching cycles is prolonged relative to the pulse width of the driving signal in a previous one of said plurality of said switching cycles if the actual time interval is larger than the reference time interval, while the pulse width of the driving signal in said one of said plurality of switching cycles is shortened relative to the pulse width of the driving signal in a previous one of said plurality of switching cycles if the actual time interval is smaller than the reference time interval.