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TPS3430-Q1: Use TPS3430 to latching circuit

YenHung Lin
Prodigy 40 points
Part Number: TPS3430-Q1
Other Parts Discussed in Thread: TPS3430, TPS3840,

Hi Teams

I designed a watchdog latch for protection in accordance with the document "SNVA837".

But, now I need to shorten the protection delay time.

I need to complete protection in one second as required.

I plan to use ~2Hz for WDI, How can I modify the TPS3430 R / C value better?

Tnanks

  • 0
    TI__Expert 3835 points
    Hi YenHung,

    Can you clarify what you mean by protection delay time? Would this be considered the upper boundary of the watchdog timer tWDU? The capacitor will cause additional delay, but the tWDU of the TPS3840 will be primarily the cause of the delay time.

    Regards,
    Ethan
  • 0 in reply to Ethan T
    Prodigy 40 points

    Hi Ethan

    When a failure occurs, I need to complete the circuit protection mechanism in one second.

    I think this is the upper limit of tWDU(max)

    But because of the system boot delay, I also need a tWDL (min)

    So I need to adjust the circuit design. Let the valid window range be between 0.5~1 seconds.

  • 0 in reply to YenHung Lin
    TI__Expert 3835 points

    Hi YenHung,

    You can change the timing of the upper limit by attaching a capacitor on the CWD pin. The section below from the TPS3430-Q1 datasheet shows the formula on how to calculate it. The lower boundary are fixed based on the value of SET1 and SET0 pin. The ratio allows the lower boundary to be 1/8, 1/2, or 3/4 of the upper boundary.

    Regards,

    Ethan