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TPS92641: High side MOSFET failed

Part Number: TPS92641
Other Parts Discussed in Thread: CSD18502KCS, CSD18502Q5B

Hi,

We use the TPS92641 for LED driver chip, the vin is 24V and the LED Vf is 4.6V, LED current is 30A.

In current design the MOSFETs of both high side and low side are two CSD18502 parallel.

After we run this TPS92641 LED driver BD around 800 hours, the both high side MOSFET are failed and the resistance between drain and source is shorted.

The schematic is as below, the original MOSFETs are CSD17501, we use the CSD18502 to instead of CSD17501 because of Vds rating.

Please help us to figure out this problem.

Regards.

Zeno

  • Hi Zeno,

    • What is the output voltage? 4.6V?
    • Could you show me the complete schematic for TPS92641? The left part is missing in the above pic.
    • What do you mean by "BD"? 
      fter we run this TPS92641 LED driver BD around 800 hours
    • What is the complete part number for CSD18502? CSD18502KCS or CSD18502Q5B?
    • Does the same failure occur to CSD17501?
    • How do you run the TPS92641 in the first 800 hours? Under what condition?
    • Is this an occasional failure that happens to a single board? Or is it a general failure? 

    Best Regards,

    Steven

  • Hi Steven,

    Thank you for your attention.

    1. The output voltage is 4.6V.

    2. I can't show the complete schematic in this e2e, but I can email to you.

    3. The BD mean "board".

    4. We use CSD18502Q5B.

    5. Yes, the same failure occurred to CSD17501 first, we measured the Vds voltage of CSD17501 and the value was close to 30V, then we replaced CSD17501 with CSD18502. 

    6. We assembled the LED driver board to our device and ran at room temperature. The LED turn ON and OFF every 5 seconds.

    7. This is the first time occur to CSD18502, but the CSD17501 failed several times.

    Regards,

    Zeno

  • Hi Zeno,

    I have sent you a friendship request on the E2E forum with my e-mail address attached. You can send me the schematic through the e-mail.

    BR,

    Steven