TPS65381 Wake Up

R11

Other Parts Discussed in Thread: TPS65381-Q1, RM48L950

Is there any method on the TPS65381-Q1 for controlling whether or not the PMIC can be woken up by the CANWU pin (e.g. register setting, etc.)? From what I’ve seen in the datasheet, it looks like it is always going to wake up from either source. We have CAN transceivers on our design and intend to have the option of waking the system via CAN wake-up, but would like the option of whether or not it is enforced. Can this be done in the TPS65381-Q1 or must there be some external mechanism for controlling it? If external, any ideas on how to implement?

over 12 years ago

0 Jeffery Pfarr over 12 years ago

TI__Genius 14317 points

I think that an AND gate driving the CANWU pin with CANWU and WU_Enable at the inputs, would do what you want.

0 R11 over 12 years ago in reply to Jeffery Pfarr

Expert 1485 points

The MCU (RM48L950) would be unpowered when the PMIC is in standby…so I’m not sure where we would be getting a signal such as this. Where is WU_Enable coming from?

Thanks!

0 Jeffery Pfarr over 12 years ago in reply to R11

TI__Genius 14317 points

Another power supply in your system? I guess we need a more complete picture of your system and the conditional requirements for a WU event.

0 Haixiao Weng over 12 years ago

TI__Genius 13810 points

A 14-pin CAN transceiver with INH signal (to be connected to CANWU) works for your case. The CAN transceiver will share the same voltage input (VBAT) as the TPS65381.

Regards,

Haixiao

0 R11 over 12 years ago in reply to Haixiao Weng

Expert 1485 points

Haixiao, the configuration you suggested is what is being used now. The INH of each of the three transceivers is diode-OR’d to the CANWU pin of the PMIC. My problem is that I don’t know how to select (in software) which of the transceivers, if any, are allowed to wake up the PMIC. Ideas?

0 Haixiao Weng over 12 years ago in reply to R11

TI__Genius 13810 points

I don't know how to identify two different CANWU signals.

Regards,

Haixiao

0 R11 over 12 years ago in reply to Haixiao Weng

Expert 1485 points

Thanks for checking. If you do discover a way in the future please let me know.

0 Henry Nguyen over 12 years ago in reply to R11

TI__Expert 4225 points

Rustin,

just for curiosity, assume INH has 3.3v output, can you connect this pin from each transceiver to the MCU GIO pins instead of to the TPS65381?

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TPS65381 Wake Up