TPS65311-Q1: Entering LPM0 mode and WAKE voltage

Kuramochi Tadahiko

Guru 28715 points

Part Number: TPS65311-Q1

Hi,

On my customer's system, the WAKE voltage goes low when power off by entering LPM0 mode.

So the TPS65311 can't keep LPM0 mode because WAKE voltage goes low after entering LPM0 mode.

They hope that there is some margin time from SPI command(to enter LPM0) to accepting WAKE voltage as below image.

Because they are considering that the device can keep LPM0 mode by precipitating forward WAKE LOW.

Is there such margin time?

Is their idea practical? (I think it is not...)

Please let me know if you have any question.

Best Regards,

Kuramochi

over 6 years ago

0 Krishnamurthy Hegde over 6 years ago

TI__Expert 8730 points

Hi Kuramochi-san,

We don't have any buffer time between LPM0 SPI command and WAKE detection. On WAKE signal, we have 10us blanking time and at the system level, i think it is very difficult to manage such a small timing window.

So, customer should bring the WAKE signal low before applying LPM0 SPI command, otherwise they have a risk of device detecting the WAKE signal again and it will power up.

Regards,

Murthy

0 Kuramochi Tadahiko over 6 years ago in reply to Krishnamurthy Hegde

Guru 28715 points

Murthy-san,

I concerned as well, too.
Thank you for your help!

Best Regards,
Kuramochi

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TPS65311-Q1: Entering LPM0 mode and WAKE voltage