• State
  • Locked Locked
  • Replies 6 replies
  • Subscribers 29 subscribers
  • Views 194 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

MCT8329A: Regarding an undervoltage failure on the GVDD pin

Tomofumi Okamoto
Prodigy 150 points
Part Number: MCT8329A

In a prototype motor controller using the MCT8329A, the GVDD pin failed in short-circuit mode. The output voltage is supposed to be about 13V, but no voltage is output. Also, the ceramic capacitor connected to GVDD is about 20uF, but this did not fail.

Could you please tell me what could cause the GVDD pin to fail in short-circuit mode? Also, please let me know if there is any way to prevent this.

  • 0
    TI__Genius 13920 points

    Hello Tomofumi,

    Does this GVDD issue occur with every device or only some MCT8329A devices? Also, did this GVDD issue occur after an attempt to drive the motor or did this issue occur the first time that you powered on the device?

    Can you measure the AVDD voltage and make sure it is outputting 3.3V? If GVDD and AVDD are both below their expected voltage, can you provide the SLEEP/WAKE pin a 3.3V voltage to try and bring the MCT8329A out of sleep mode in case it is in sleep mode?

    Regards,

    Joshua

  • 0 in reply to Joshua Horlander Cruz
    Prodigy 150 points

    Hi Joshua,

    >>Does this GVDD issue occur with every device or only some MCT8329A devices? Also, did this GVDD issue occur after an attempt to drive the motor or did this issue occur the first time that you powered on the device?

    This GVDD problem has only occurred in one or two units yet. The GVDD problem has occurred since the power supply started up, i.e., there is always no output, and if I try to rotate the motor, I get an OCP error and of course the motor will not rotate. If the motor is not connected, a VDS error occurs. At first I suspected it was around the gate drive, but I thought it was the power supply for the gate drive.

  • 0 in reply to Tomofumi Okamoto
    Prodigy 150 points

    And I measured the voltage of AVDD. 3.3V is continuously output here. only GVDD is not output.

  • 0 in reply to Tomofumi Okamoto
    TI__Genius 13920 points

    Hi Tomofumi,

    Tomofumi Okamoto said:
    This GVDD problem has only occurred in one or two units yet.

    I assume that you have some units that work as expected then? If you do have a board that is not experiencing this GVDD issue can you preform an ABA test to see if the issue follows the device or if the issue follows the board?

    Regards,

    Joshua

  • 0 in reply to Joshua Horlander Cruz
    Prodigy 150 points

    We believe we have already performed that AB test. The schematic is as per the recommended circuit. The artwork is also as ideal.

  • 0 in reply to Tomofumi Okamoto
    TI__Genius 13920 points

    Hi Tomofumi,

    Tomofumi Okamoto said:
    We believe we have already performed that AB test.

    What were the results of the ABA test? Did replacing the MCT8329A on the board that was having the GVDD issue with a MCT8329A from a board not having the GVDD issue fix the issue, or did the known good device have the issue as well?

    Regards,

    Joshua