Specifications

© 2008-2012 Microchip Technology Inc. DS70323E-page 43-63
Section 43. High-Speed PWM
High-Speed PWM
43
Figure 43-28: Effect of Phase Shift on PWM Triggers
When phase shifting the PWM signal, the PWM timer value is updated to reflect the new phase
value. There is a possibility of missing trigger events when changing the phase from a smaller
value to a larger value. The user-assigned application must ensure that this does not affect any
control loop execution.
PTPER = 100
Master
Time Base
(PMTMR)
Requested
PHASEx
PMTMR rollover on PTPER match
Next Phase Next Phase
(EIPU = 0)
(EIPU = 0)
PTMRx = 50
PTMRx = 75
PTMRx = 50
PTMRx = 75
PTPER = 100
50
50
75 25
75 25
PHASEx
PWM Timer
PTMRx
Trigger event is missed
when PHASEx is increased
60
60
TRIGx = 60
PTMRx = 25
Load PHASEx on PTMRx rollover
Load PHASEx on PTMRx rollover
60
TRIGx = 60 TRIGx = 60
Load PTMRx with PHASEx
on PMTMR rollover
Load PTMRx with PHASEx
on PMTMR rollover
Load PTMRx with PHASEx
on PMTMR rollover