I'm analyzing a potential fault condition where a 4.2 V stiff supply gets applied to the OUT pin of TPS731. The regulation FB network will be set for around 3.7 V. IN is at 5V (USB).
Is this safe for the part?
Will there be appreciable leakage current from OUT to IN?
HI,
As long as you do not violate the absolute maximum ratings of the OUT pin and VIN is definitely 5V, This is OK.
Note, if the 5V is removed with 4.2V forced on VOUT, that 4.2V will leak to VIN and keep the device enabled.
Using a device like the TPS3839 might be a good option to drive the EN pin of the TPS731 to prevent leakage from, VOUT to VIN in the event the 5V is removed. I have not tested this configuration, so would recommend ordering free samples if you would like to try it.
I hope this helps.
