TPS4811-Q1: MOSFET Broken out during test with load supplied by loader

Hi Youngsoo,

Welcome to E2E!

What is the output capacitance ? I see 100nF in the schematic. Is there any additional capacitance ? If yes, please add precharge FET to charge the Cout and then enable the main power FETs

Best Regards

Rakesh

Is there any way to solve this without adding a pre-charge FET?

Please suggest a solution.

Hi Youngsoo,

It depends on Cout value. 

What is the output capacitance ?

Do they have any requirement on startup time ?

Best Regards

Rakesh

No start-up time required Currently, there is no output capacitor in our product, but a DC-DC converter is expected to exist in the connected device. I'm guessing around 1000uF.

Hi Youngsoo,

For systems with output capacitance, RC on the main FETs is an option without additional pre-charge FET. However, starting up with load with RC on the main FETs will stress and damage the FETs.

To avoid that we have to enable the load once the system output is up. This can be done by enabling EN of DC-DC converter.

I would suggest to use actual DC-DC converter as load on TPS4811-Q1 and test

Best Regards

Rakesh 

Hi Youngsoo,

Let us know if any help is needed.

When a DC-DC converter is connected to the output terminal, the external enable signal is applied, but sometimes the output is blocked.

At this time, the gate signal of the MOSFET switch fluctuates.

The protection function seems to work, do I need a precharging circuit to solve this?

Or is it possible to improve through Turn on or Turn OFF time in a different way?

Hi Youngsoo,

You can use RC on the GATE of the main FETs to control the turn-on time. Please use design calculator https://www.ti.com/lit/zip/slurb09 to find the C1 value.

Best Regards

Rakesh