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TMDSHVBLPFCKIT: Abnormal driving waveform

Other Parts Discussed in Thread: TIDM-1007,

Dear team:

One of my customers encountered an abnormal driver waveform when testing the suite. When the program was running normally, epwm2a would suddenly be set down by one duty, as shown in the following figure:

CH3: epwm1A

CH4: epwm2A

The software is the original code and has not been modified. The location of the test point is the original test point of the development board, PWM-1 and PWM-2. His colleagues will also encounter this problem when using the code of this development board. He tried to get rid of the peripheral load and supply power to the development board separately. In other words, in the no-load state, he would also see this problem. This abnormal state exists in different voltages and loads.

I would like to know what causes this? Is it possible that the development board has hardware problems?

  • Dear teams:

    Do we have any support in this regard?

    Will it be a hardware problem and need the customer to contact after sales?

  • We are not aware of this kind of issue with the code or with the MCU. It seems like a bad hardware. Please use the User Guide and run the software for Build 1 and Build 2 and see if it generates those waveforms provided in the User Guide. If any issue, then pls return/replace the h/w

    This is a old BLPFC design. I would recommend you check out our new designs with the latest MCUs. For example check out TIDM-1007 which is Bridgeless Totem Pole PFC ref design.


  • Hi Shamim:

    I just learned that the hardware devices that customers experimented with were made by themselves based on the TMDSHVBLPFCKIT suite.

    They have run the software for Build 1 and Build 2 but there is no abnormal waveform, only build 3 has.

    What could be the reason for this?

    Build 1:

    Build 2

    Build 3

  • They should check their current controller output and see if the duty command is zero because the PWM outputs are going low. If there is not much boost (because of high input volt) then PWM duty can be very low. Pls have then investigate this. They can also set the Bus voltage higher and see if this goes away.