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Original question:

DRV8353RS-EVM: Low-side gate drive undervoltage; Low charge pump voltage -- Broken IC?

DRV8353: Charge pump gets broken randomly

Joonho Seo1
Prodigy 50 points
Part Number: DRV8353
Other Parts Discussed in Thread: CSD19532Q5B,

I'm using DRV8353S to make a customized motor driver, and the charge pump gets broken randomly. 

The gate current is at its minimum, and the signal looks good. (no ringing)

I'm using CSD19532Q5B for the FETs.

What part should I look into?

Thanks in advance

  • 0
    TI__Intellectual 840 points

    Hi Joonho,

    I had a few quick questions for you:

    • When the charge pump breaks, does this require replacement of the DRV8353, or is it an intermittent issue?
    • Have you seen this issue on multiple devices?
    • In what situation does the failure occur? Are you driving a motor?
    • Do you have any scope captures that show gate driver input/outputs during the test that the charge pump is failing during?

    If you have a block diagram of your system or a schematic we could look at, that would be helpful as well.

    Best regards,

    Omar

  • 0 in reply to Omar Naamani
    Prodigy 50 points

    Hello,

    Thanks for your questions. 

    Here are my replies:

    • When the charge pump breaks, does this require replacement of the DRV8353, or is it an intermittent issue? - The gate driver gets permanent damage.
    • Have you seen this issue on multiple devices? - yes
    • In what situation does the failure occur? Are you driving a motor? - The situation occurs very randomly when I drive a bldc motor. It wasn't any harsh situation such as sudden stopping.  We increase the speed gradually as well. One of the situations that I remember is the motor gets started and a few seconds later, the charge pump got damaged. 
    • Do you have any scope captures that show gate driver input/outputs during the test that the charge pump is failing during? Unfortunately, no. The gate driver survived all the bench-top testings. It only happens in field tests. 

    Answering your questions, it came to me that it might not be the circuit itself that's damaging the gate driver.

    I kinda suspect all the wires that sit on the circuit board may cause the problem (HDMI, DP, Power, USB cables were randomly located on the circuit board when we did the field test).

    Do you think that might cause any charge pump problem?

    Sorry that I ask very broad and vague questions.

    Thanks in advance.

  • 0 in reply to Joonho Seo1
    TI__Intellectual 840 points

    Hi Joonho,

    I cannot say with certainty that the wiring might cause an issue without seeing it, but it may be worth looking into if possible. What I can say is that the most common way to damage the device in this way is by overvoltage. If the motor is forcing energy back into the supply it is possible to exceed abs. max ratings. You did mention that the system does not overdrive the FETs and ramps speed gradually though, so it most likely isn't due to this.

    My recommendation would be to take a look at the cabling for any potential of shorting high-side gate to source, or shorting signals to ground. Also, If the flying capacitor on the charge pump is shorted to ground, it will create an over temperature condition and surely damage the part. I hope this helps in your debug process.

    Best regards,

    Omar

  • 0 in reply to Omar Naamani
    TI__Intellectual 840 points

    Hi again Joonho,

    I just wanted to check in and see if there were any developments. Were you able to determine root cause?

    Best regards,

    Omar

  • 0 in reply to Omar Naamani
    Prodigy 50 points

    Hi Omar, 

    I'm afraid this issue hasn't been solved yet. All the damaging situations were not likely to be related to Back EMF (and we tried to break normal ones by giving it back EMF). 

    All the cables were organized and the board was protected with an acrylic cover, but it still broke. 

    I'm doubting that dust might be causing ESD or some bad influence to the board. The environment that we are testing in has very bad air conditioning and dust flowing. Do you think that might be the cause?

    Thanks in advance 

  • 0 in reply to Joonho Seo1
    TI__Intellectual 840 points

    Hi Joonho,

    There are a lot of potential causes for an issue but I am not sure that the dust would be a contributing factor. Could you outline the actual motor application and describe how you tried to model this system when testing for back EMF in the lab? I am wondering if it was an edge case in the field that may not be easy to recreate with bench-top equipment.

    Best regards,

    Omar