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TPS1HC100-Q1: Overcurrent Capability Test Request

Oliver Tang
Genius 12290 points
Part Number: TPS1HC100-Q1
Other Parts Discussed in Thread: TPS1H100-Q1, , TPS1HB08-Q1

Hi Team,

    1) In customer's application, when TPS1HC100-Q1 or TPS1H100-Q1 is used to drive relays, the pulse current waveform through HSS could look like 5.5A/300ms, 9A/200ms. My question is, if the maximum current limit is set to 6.9A, will TPS1HC100-Q1 suffering from thermal shutdown with 5.5A/300ms? By the way, what is the response time for current limit circuit if 9A/200ms pulse current is applied? Will the load current be clamped to ICL as expected too early?

    2) Can we conduct an experiment to validate customer's request?

    Any help or response will be appreciated.

BR,

Oliver Tang

  • 0
    TI__Mastermind 32650 points

    Hi Oliver,

    1. From our internal testing, it is not possible to limit current at 5.5A for 300ms or 9A for 200ms with these devices. When the current limit is triggered, the device moves into a resistive mode of operation and significant power is then dropped across the FET. At higher currents, this power is high enough to cause the device to thermally shut down quite fast.

    2. You can use the PSPICE model to fill up a capacitor load and test if the device hits thermal shutdown or not. But I do not think this test is worth because we have data to confirm that the device cannot withstand such high current limits for extended periods of time.

    I would recommend looking at lower R_on devices like TPS1HB08-Q1 that can withstand higher DC currents. Do note that this device has a current limit that shuts down immediately and does not hold current. Another option may be TPS1HA08C-Q1 which has the ability to clamp current at a fixed value of 20A.

    Thanks,

    Shreyas

  • 0 in reply to Shreyas Dmello
    TI__Genius 12290 points

    Hi Shreyas,

    1) Is it possible to provide the transient thermal impedance of TPS1HC100 for our customer to calculate whether junction temperature would exceed maximum rating with given load condition?

    2) Can you share the experimental data of internal testing so that I can convince our customer into using TPS1H100/TPS1HB08-Q1?

    BR,

    Oliver Tang

  • 0 in reply to Oliver Tang
    TI__Mastermind 32650 points

    Hi Oliver,

    Transient thermal impedance is a function of time. As such the PSPICE models are the best way to test your use case.

    As mentioned previously, it is not possible to limit current at 5.5A for 300ms or 9A for 200ms with these devices. There will exist significant power loss across the FET as intended to protect the downstream load. This will turn off the FET in a few hundred us to the ms range. Hundreds of ms is not possible for current limiting at these values.

    We are willing to provide the customer with an EVM for their testing.

    Thanks,

    Shreyas