TPS53015: Measure for over voltage protection

Satoshi

Guru 19575 points

Part Number: TPS53015

Please let me confirm about way to measure OVP function for TPS53015.

I think that the method of measure OVP function is below, is it correct?

①Low side feedback resister set to short (for example, R2 resister by datasheet Figure18)

②Confirm to measure increasing Vout and occur OVP function on Vout ×120%

【Background】

・Vin: 12V, Vout: 5V, Iout: 4A

・When measure above method, OVP occurred on 8.2V, not 6V.

　I guess that effect of OVP propagation delay (10μs), is there any other reason?

　※X-axis: 200μs/div, Y-axis: 5V/div

Best regards,

Satoshi

over 5 years ago

0 JohnTucker over 5 years ago

TI__Guru**** 191445 points

Satoshi-san,

The detection does not operate that way. For OVP and UVP detection, the internal comparators use the VFB pin voltage. So shorting R2 would cause a UVP event, no matter what Vout does. The best way to check OVP operation is with a load dump step with small output capacitors.

0 Satoshi over 5 years ago in reply to JohnTucker

Guru 19575 points

John-san

Thank you for reply,
Cout changed to 1μF, 2μF, and 3μF, but OVP function was not detected.
(Vout is 5V ×120% = 6V)

Please let me know about the other careful points.
I think that it should change more lower Cout value(0.1μF, etc) is it correct?

By the way, when reduce all Cout(0F), Vout became throw 12V from Vin.

Best regards,
Satoshi

0 JohnTucker over 5 years ago in reply to Satoshi

TI__Guru**** 191445 points

Satoshi-san,

You should not need to reduce Cout that much. 22 uF should be sufficient. Then reduce load with fast slew rate, 1 A / usec, from 8 A to 0 A.

0 JohnTucker over 5 years ago in reply to JohnTucker

TI__Guru**** 191445 points

Satoshi-san,

I will close this thread for now. Please feel free to re-open it if you need further assistance.

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TPS53015: Measure for over voltage protection