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TPS7B4250-Q1: VOUT short to GND behavior

Part Number: TPS7B4250-Q1

Hi team,

Could you explain the behavior of VOUT when dead short to GND?

Output short circuit protection is described in the datasheet as protected by the current limit and thermal shutdown,

1. Hit current limit (500mA maximum current)

2. die temperature rises  

3. Hit thermal protection at 175c

4. The device shutdown the output

5. The die temperature cool down to 150c

6. The device try to power up and hit current limit 

7. repeat 1. to 6.  

I would like to know even if the output is dead short to GND, the device tries to power up until the thermal shutdown hit. 

It is helpful if you can share the scope shot of this condition. 

regards,

  • Hi Tsuji-san,

    Your understanding of the behaviors when Vout shorting to Ground is correct. The device will cycle in and out from thermal shutdown which causes a voltage on output up and down from the set output level to ground repeatedly.

    Regards,
    Jason Song

  • Hi Jason,

    Thank you.

    When it resumes operation after device die temp decreased to 150c,

    does the device power up from internal soft-start?

    Or will it power up immediately?

    regards,

  • Hi Tsuji-san,

    Disabled by the thermal shutdown is different than disabling the device by enable pin. For this case, during thermal shutdown, the pass-FET of the LDO will be disabled but the internal reference voltage may still be there. Once device has been restored to lower temperature, the device will be on again but without the built-in soft-start.

    Regards,
    Jason Song