Introduction to Digital Power Conversion
XMC4000/1000 Family
PWM Generation
Application Guide 33 V1.0, 2015-01
4.10.2 Edge Aligned Mode
Dual PWM channels with fixed phase-shift can be provided by two CCU4 slices in edge-aligned
compare mode, representing each PWM channel by the associated output of each status bit.
There should be a Global Start and Synchronization sequence, before the system is prepared for run-
time.
Figure 22 PWM – Fixed Phase-Shift in Edge Aligned Mode for Interleave
Start-up sequence
During the start-up phase the duty-cycle of CC40 is set to 0 by pre-setting a high compare level,
exceeding the period register value pre-set, which implies no PWM generation during the start-up. A
similar situation prevents the CC41 from generating a PWM stream too early.
Fixed Phase-Shift with Different Duty-Cycles
There is no negative effect, but there can be a benefit, to using fixed phase-shift in edge aligned
mode with different duty-cycles, especially in split converters using a mutual controller. The split in
time will mean that the EMC qualities will be better.
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