BQ40Z80: BQ40z80 wake up from shut down mode

Hollis Liu

Part Number: BQ40Z80

Hi team,

If we want to wake up the shutdown pack by applying a voltage pulse(>Vshutdown+) on the PACK+, do we have any limitation for the voltage pulse duration time？Can a 1ms voltage pulse work? Thx.

over 6 years ago

0 Kang Kang over 6 years ago

TI__Mastermind 24870 points

Hello Hollis,

I have assigned this to an apps engineer, they will respond shortly.

Thanks!

0 Damian Lewis over 6 years ago

TI__Mastermind 34775 points

Hi Hollis,

I would recommend testing on an EVM. This feature was intended for a more static signal. You can use a signal as a button press. The pulse high duration would be more on the order of seconds, not milliseconds. I would recommend a pulse duration > 2s, so FW can detect the wake up state and change mode.

0 Hollis Liu over 6 years ago in reply to Damian Lewis

TI__Intellectual 2595 points

Hi Damian,

Thanks for your feedback.

In my understanding, the wake up circuit is like a comparator, right? Does it need 2s to trigger a comparator? And i remember 100ms voltage pulse is enough to wake up BQ27742 from shutdown mode. Can you help to double confirm? Thx.

0 Damian Lewis over 6 years ago in reply to Hollis Liu

TI__Mastermind 34775 points

Hello Hollis,

Yes it's a comparator to trigger the wake up, but there's also deglitch filters to prevent unintended wake up. The feature was intended to detect a charger connection.

To answer your question please see wake timer (twake) on pg. 10 of the datasheet

http://www.ti.com/lit/ds/symlink/bq40z80.pdf

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BQ40Z80: BQ40z80 wake up from shut down mode