SPRUJ53B April 2024 – September 2024 TMS320F28P550SJ , TMS320F28P559SJ-Q1
So far, none of the examples have made use of the phase register (TBPHS). It has either been set to zero or a don't care. However, by programming appropriate values into TBPHS, multiple PWM modules can address another class of power topologies that rely on phase relationship between legs (or stages) for correct operation. As described in the time-base submodule section, a PWM module can be configured to allow a SyncIn pulse to cause the TBPHS register to be loaded into the TBCTR register. To illustrate this concept, Figure 19-68 shows a sync source and sync receiver module with a phase relationship of 120° (that is, the sync receiver leads the sync source).
Figure 19-69 shows the associated timing waveforms for this configuration. Here, TBPRD = 600 for both sync source and sync receiver. For the sync receiver, TBPHS = 200 (that is, 200/600 x 360° = 120°). Whenever the sync source generates a SyncIn pulse (CTR = PRD), the value of TBPHS = 200 is loaded into the sync receiver TBCTR register so the sync receiver time-base is always leading the sync source time-base by 120°.