Hi team,
We encountered a PWM lost problem in our customer. And here is the details:
1: Background:
As the figure shows, they four PWM output EPWM1A/B(Channel 1/2) EPWM3A/B(Channel 3/4).
They need to switch the dead-band between 1/2 and 3/4. Between each switching, they trip all the EPWMs as the blanking in the following figure.
2. Problem:
In the first PWM period after the trip, only half PWM is observed on channel 1. For the following periods, it runs normally. And this only happens when EPwm1Regs.HRPCTL.bit.HRPE = 1. As I know, there is some imperfections on F28035 HRPWM, could you help to identify is this a imperfection?
3. Details:
For pwm trip, they achieved this by configuring AQCTL. For dead-band, they also achieved by AQCTL, eg.:
EPwm1Regs.CMPA = CMP1 - CMPdelta,
EPwm3Regs.CMPA = CMP1
To make it clear, I have to emphasis this only happens when EPwm1Regs.HRPCTL.bit.HRPE = 1.
Could you please give some suggestions?