PTH08T240W - Applying power to VO with no power applied to VI

Mark Tillmann

Other Parts Discussed in Thread: PTH08T240W

I am an in-circuit test engineer and need to perform a test on a large Power Supply board (~1500 nets, 25 regulators). I need to apply supplies directly to the VO pin of 5 regulators (PTH08T240W) with no power applied to the VI pins. At this stage of testing, there will be no other power applied to the board. Will this damage the regulators?

over 13 years ago

0 Tom Guerin over 13 years ago

TI__Mastermind 38230 points

The power module when power is applied to the output bus and input voltage is not applied, the module will have reverse current conduction through the module and it power FET diode structure . This will overstress the power FET and it short secondary to primary bus.

tom tguerin@ti.com

0 Mark Tillmann over 13 years ago in reply to Tom Guerin

Prodigy 110 points

Would it be possible to to the following without damage?

Apply Vin

Drive INH pin low

Apply voltage to VO

0 Tom Guerin over 13 years ago in reply to Mark Tillmann

TI__Mastermind 38230 points

Mark:

PTH08T240W control method for output voltage applied to this power module under the following conditions .

The vin voltage is applied, , module has inhibited pin , grounded low, the module power is tri-stated, . This is also the explanation for pre- bias function.

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PTH08T240W - Applying power to VO with no power applied to VI