TPS2363 Turns off with12V line glitch

Stephen Kim

Other Parts Discussed in Thread: TPS2363

Here is a custmer's issue.

We are using the TI part TPS2363 extensively. In one application we have two of them controlling four PCIe slots on a riser card. We are finding that when we use the TI load test board and activate a short circuit with it that adjacent slots will also be turned off. If those adjacent slots have cards with sufficient supply capacitance, this tendency goes away. When we look at the voltage sag (~10.2V for 12V) on the board induced by the short circuit, it is still way above the under voltage (UVLO) limit indicated in the datasheet (9V for 12V). When we added additional capacitance to the SH12x pin, this made the problem worse.

Any suggestions to improve the perfomance?

over 15 years ago

0 Bob Kando over 15 years ago

TI__Genius 9415 points

The TI load board shorts the output by turning on a FET driven at logic speed. This may be a sharper edge than a practical short. Try a wire short and see if you getthe same results.

You can soften the edge by putting a .1uF cap on U3 pin 4 of the load board.

0 Stephen Kim over 15 years ago in reply to Bob Kando

TI__Prodigy 620 points

Hi Bob,

The question is "Does TI know what is tripping the adjacent slot controllers under a sudden short circuit condition and what we need to do to remedy this?"

Do you have any ideas?

Stephen

0 Bob Kando over 15 years ago in reply to Stephen Kim

TI__Genius 9415 points

It could be layout or power supply. Can you send me a schematic and layout?

If you have I2C, it may be helpful to read the adjacent chips status registers after the event..

Power management

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TPS2363 Turns off with12V line glitch