BQ40Z50-R2: CUV delay time is not correct.

Tom Tsao

Expert 1840 points

Part Number: BQ40Z50-R2

Tool/software:

My customer is testing CUV protection with BQ40Z50-R2.

The CUV Threshold set to 2700 mV, with 1s CUV delay.

But the DFET is only turned off when the cell voltage is below the CUV threshold for 1.7s.

What are the possible reasons for this 700ms delay?

Thanks!

+1 Adrian over 1 year ago

Hello Tom,

CUV is a firmware based protection and not a hardware protection. Firmware based protections can take up to a second longer than what is programmed since these protections operate on a 1 second timing interval. To learn more, read this FAQ page: https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1111094/faq-what-are-the-differences-between-the-hardware-and-firmware-protections

Regards,

Nick Richards

0 Tom Tsao over 1 year ago in reply to Adrian

Expert 1840 points

Hi Nick,

My customers tested many times, and every time the delay was a consistent 700ms.

If the delay is caused by the firmware (F/W), would the delay be random?

Thanks!

+1 Adrian over 1 year ago in reply to Tom Tsao

Hey Tom,

I am not sure if the delay will be random or not.

Regards,

Nick Richards

Power management forum