Ballast Demonstrator User Guide
-25
7629A–AVR–04/06
The boost switch ON time is maintained constant over each half cycle of the input volt-
age sinusoid. Therefore the peak current for each switching cycle is proportional to the
line voltage which is nearly constant during Ton. (Ipeak = Vin x Ton/L). Since the aver-
age value of a triangular waveform is half its peak value, the average current drawn is
also proportional to the line voltage.
Figure 6-4.
Main voltage supply cutting
PFC
DRIVING
Main Supply
Voltage
Ipeak = Vin x Ton / L
Imean = Ipeak/2
Ion
Ioff
Actual switching frequency
is higher than shown
