TPS27SA08-Q1: Will the current flowback from VOUT to VBB if no electrical power or signal is provided to VBB and EN.

Xiang Maverick

Part Number: TPS27SA08-Q1

The usage is as follows

The main part has a backup. The main part and its backup each has a high side swith. The main part and its backup have a common Load connected to both high side swithes.

When the signal MAIN_EN is active, the isolated DCDC of the main part output power and that of the backup is disabled. If the controller in the main part power domain turn on the swith, the load is powered. Will the current flowback from the load to VOUT and finally to the VBB of the swith of the backup?

over 1 year ago

0 Yichi Zhang. over 1 year ago

TI__Genius 16390 points

Hi Maverick,

In case when load is powered by the main switch, and VCC2 is 0, the current will backflow from load to VCC2 through the body diode of the high-side switch. Some mitigation can be having a blocking diode at VCC1 and VCC2 before the high-side switch, or use our efuse before the high-side switch to minimize the power loss caused by the diode.

Please let me know if there are additional questions.

Regards,

Yichi

0 Xiang Maverick over 1 year ago in reply to Yichi Zhang.

Intellectual 750 points

If I have a efuse which is not powered at the in port, but at the output. Will It flowback to in?

0 Yichi Zhang. over 1 year ago in reply to Xiang Maverick

TI__Genius 16390 points

Hi Maverick,

If you have a efuse between the output pin and the load, then it should prevent the back flow.

Regards,

Yichi

0 Xiang Maverick over 1 year ago in reply to Yichi Zhang.

Intellectual 750 points

If I use efuse instead of TPS27SA08-Q1, would the backup design in the above figure be OK?

+1 Yichi Zhang. over 1 year ago in reply to Xiang Maverick

TI__Genius 16390 points

Hi Maverick,

There are separate Apps engineer for eFuses. I suggest you follow up with a different thread with a eFuse part number and someone from the eFuse team would be able to evaluate if eFuse can meet all the needs.

Please let me know if anything else is needed from the high-side switch side and I can follow up.

Thanks!

Regards,

Yichi

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TPS27SA08-Q1: Will the current flowback from VOUT to VBB if no electrical power or signal is provided to VBB and EN.