TPS65094: TPS65094 PCH_PEROK Sequence is greater than 125ms

Lawrence He

Genius 3280 points

Part Number: TPS65094

Dear,

we use TPS65094, but we measurment PCH_PEROK sequence is greater then 125ms.

i saw the datasheet page 42. sequence was 100ms

measurment sequence:

GUI can change timing? or need PMIC heardware to setting?

schematic:

[removed]

If any suggestion, Please advise me.

Thanks,

Best regards,

Lawrence.

over 6 years ago

0 Nick Jakse49 over 6 years ago

TI__Expert 4155 points

Lawrence,

How does the BUCK6/VTT voltage look in comparison to the PCH_PWROK signal?

My thought is maybe this BUCK is coming up slow, and so the PCH_PWROK signal is waiting for this.

If not, the PCH_PWROK signal is also monitoring BUCK1, BUCK4, and BUCK5 so you might want to check these as well.

0 Andrew Tien over 6 years ago in reply to Nick Jakse49

Prodigy 30 points

Hi Nick:

The Buck6 (VDDQ) voltage is 1.35V ，PCH_PWROK is 2.75V.

Buck1 BUCK4 BUCK5 and BUCK6 appear earlier than PCH_PWROK signal.

B.R Andrew

0 Nick Jakse49 over 6 years ago in reply to Andrew Tien

TI__Expert 4155 points

Andrew,

I talked it over with one of our designers and he said this could be due to variation in the internal clock of the device. Anything less than 100ms might be too quick for the processor, so the PMIC will always make the delay a little longer to avoid running into issues with devices that have a slightly faster internal clock due to process variation. In devices with a slightly slower clock a delay of 125ms is not outside of the expected range.

0 Andrew Tien over 6 years ago in reply to Nick Jakse49

Prodigy 30 points

Hi Nick:

However, in the INTEL SPEC, written that Buck is greater than 5ms.
Over 100ms is too long.

0 Nick Jakse49 over 6 years ago in reply to Andrew Tien

TI__Expert 4155 points

Andrew,

The Intel spec I see is that the delay must be greater than 5ms. I don't see any maximum spec for the delay.

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TPS65094: TPS65094 PCH_PEROK Sequence is greater than 125ms