Specifications

dsPIC33F/PIC24H Family Reference Manual
DS70323E-page 43-40 © 2008-2012 Microchip Technology Inc.
43.5.4.1 ADVANTAGES OF CENTER-ALIGNED MODE IN UPS APPLICATIONS
The current ripple frequency and noise frequency are double the switch frequency. A lower
magnitude of current ripple is achieved as the switch frequency of the current ripple is doubled.
Lower current ripple contributes to relaxed requirements for the DC input capacitor and output
filter inductor and capacitor. Lower current ripple contributes to lower output current harmonics.
Figure 43-8 illustrates the typical waveforms of UPS, configured for Unipolar Gate Drive in
Center-aligned mode.
Figure 43-8: Unipolar Gate Drive in Center-Aligned Mode
PWM1H
PWM1L
PWM2H
PWM2L
IL
PTPER
PDC2
PDC1