TPS63021: Load disconnect when VIN < VOUT

Hi   Doug,

i think there will no current flow from Vout to Vin, IC will shunt down when Vin is 0V.

Regards

Tao

Hi Tao,

Thank you for your quick response!

It turns out that my application requires a radiation hardened or radiation tolerant regulator.  Similar to my previous question, will the TPS7H4010-SEP block current flow from VOUT to VIN when VIN = 0V and VOUT > 0V?

Sincerely,

Doug Young

Hi  Doug,

you are welcome

i think the performance of TPS7H4010-SEP should be same, actually, i think most of device should not have current flow from Vout to Vin in your conditions.

Regards

Tao

Hi Tao,

Why do you think most of TI's buck regulators will not pass current from Vout to Vin when Vin = 0V?

Are the switch MOSFETs constructed in a way that prevents this reverse current flow (e.g. no body diodes or MOSFETs are setup in a back to back configuration)?

Sincerely,

Doug Young

Hi Doug,

that is right, for a PMIC, i think mostly it is a bad design if current can flow from Vout to Vin when Vin=0V. not only for TI's device, also for others.

Regards

Tao

Hi Tao,

Sure, I agree that it is not ideal if current flows from Vout to Vin when Vin=0V but this is not uncommon, especially for buck converters.  In fact TI has application notes about this condition for their own IC's.

I do not see this feature listed in the datasheet and the PSPICE model of theTPS7H4010-SEP (tps7h4010-sep_trans) indicates that reverse current will flow when Vin = 0V.  It is critical for my design to block this current.  These space grade parts come at a significant cost, so if I need to add reverse current blocking I would like to do so before I prototype my boards to save both time and money.

If you have not done so already, would you please verify with the TPS7H4010-SEP hardware team to verify that there is no current flow from Vout to Vin when Vin = 0V? 

Thank You!

Doug Young