TPS61178: Can't shutdown TPS61178 output.

Mark Gelfgat

Prodigy 70 points

Part Number: TPS61178

Have an issue to power off TPS61178 output - it always goes down to VIN, but never discharged to 0V.

Vin = 12V, Vout = 18.9V:

over 5 years ago

0 Jasper Li over 5 years ago

TI__Mastermind 46905 points

Hi Mark,

a PFET is required to isolate the VIN and VOUT if you want zero voltage at output when EN is low, refer to the datasheet of the TPS61178 or the EVM user guide for the schematic.

0 Mark Gelfgat over 5 years ago in reply to Jasper Li

Prodigy 70 points

Hi Jasper

The issue is not only VIN leaks to VOUT in OFF mode, but it has also has full current supply capability, so I basically can drive motor with VIN. In this case I don't understand why this DC-DC has ON/OFF - it basically always ON. If something wrong with my design or its limitation of this DC-DC?

BR,

Mark.

0 Jasper Li over 5 years ago in reply to Mark Gelfgat

TI__Mastermind 46905 points

Hi Mark,

for the conventional boost converter, the VOUT is approxiamtely VIN-0.7at EN=L and the VOUT is setting value at EN=H. the setting value is 18.8V in your case.

if you want zero voltage at EN=L, it requirment a PFET to disconnect the VIN and VOUT for TPS61178

0 Jasper Li over 5 years ago in reply to Jasper Li

TI__Mastermind 46905 points

I closed the post as I assume you had solve the issue. if not, just reply below

Power management

Power management forum

TPS61178: Can't shutdown TPS61178 output.