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UCC5870-Q1: UCC5870-Q1

KEXIN DI
Prodigy 110 points
Part Number: UCC5870-Q1

Dears,

I am trying to make a new board based on the design of the evaluation board. I only added a Zener diode to regulate the output voltage from the ZA9710 transformer and changed the gate resistors to 10 ohms. However, when I try to use GUI to connect my board, it shows the hardware is connected, but I cannot move to the configuration 2 state, and all registers become zero. I try to load registers, but it still becomes zero. I checked the VCC1, VCC2, and VEE2, they are normal.
Could anyone give me a clue to do the further check?

Many thanks
Kexin

  • 0
    TI__Expert 5801 points

    Hi Kexin,

    Thanks for reaching out!

    Typically this happens when the secondary supply (VCC2) is not in the expected limits.

    Could you share waveforms of VCC2 during power up? 

    Additionally, could you try using a bench power supply for VCC2 instead of the on board isolated supply? If you are able to connect this way it narrows down the issue to the supply.

    Regards,

    Daniel

  • 0 in reply to Daniel Norwood
    Prodigy 110 points

    Hi Daniel,

    Many thanks for your kind feedback. 

    I monitored the VCC2 and VEE2 during power-up. They are almost constant around 15.2V and -5.1V. I will upload the waveform later. I also tried to connect the VCC2 and VEE2 to to power supply directly and then power up. The current consumptions are 0.01A (15V) and 0.02A(-5V). However, it still can not move to the configuration 2 state. The GUI indicated that the high-side driver is in Reset State and BIST is running. I wait for a long time but it seems stuck. The low-side driver is stuck in configuration 1. I am looking forward to your kind reply.

    Many thanks

    Kexin

  • 0 in reply to KEXIN DI
    TI__Expert 5801 points

    Hi Kexin,

    Would you be able to share the schematic of your board?

    This behaviour is not the expected behaviour of the driver. 

    Things to check are:

    1. ABA swap. Does the board work if you replace the IC with a new driver?

    2. Could you share a picture of the test setup? 

    3. What is the voltage of the VREG2 pin?

    4. what is the voltage of the VBST pin?

    5. What is the voltage of the VREG1 pin?

    Regards,

    Daniel