BQ20Z45-R1: Does the shutdown threshold work when the IC is in sleepmode?

Hi Nick.

Based on my test, bq20z45 will not switch from sleep mode to shutdown mode with bus lines pulled down. What could be the reason?

Thanks,

George

Hello George,

Usually the lines are not held low unless to reset the comm engine, the transition does occur when the lines are high?

Sincerely,

Wyatt Keller

Hi Wyatt,

When the battery is in storage, the bus lines are pulled low. It is expected that the battery will not be depletec once voltage falls below shutdown threshold during storage.

Yes, the transition occurs only when the bus lines are high.

Thanks,
George

Hello George,

I'm not aware if this will interfere with the gauge, with the newer gauges I've seen pulling the comm lines low can lead to unexpected behavior. Does pulling the lines low cause any other unexpected behavior?

Sincerely,

Wyatt Keller

Hi Wyatt,

The communication lines will alway be pulled down by 1M resistors on IC bus input. They are recommend on the application schematic. So, they should be fine, right?

So far, we only see issue with shutdown threshol when bus lines are pulled down.

Thanks,
George 

Hi Wyatt,

Below is the bus input circuit.

Thanks,
George

Hello George,

I think there was a problem with the image upload, you have to insert as a file.

Sincerely,

Wyatt Keller

Hi Wyatt,

I have inserted it a a file. Can you see it now?

Thanks,
George

Battery Schematic with bq20z45.pdf

Hello George,

Yes I can see it now. I don't see anything obvious that could cause an issue on the comm lines. Since this is an older gauge it may be harder to find the issue, I would suspect it's something with the timer. Can you share any data you have of this, like logs or configurations files (.gg)?

Sincerely,

Wyatt Keller

Hey Wyatt,

I sent you an email with this info internally earlier this morning

Hello Lauren,

I'll try to review it tomorrow, didn't have time today to review their settings, I have been able to find some source FW I can try to debug the issue further tomorrow.

Sincerely,

Wyatt Keller