bq20z90: PLSOFF flag

Kevin H.

Part Number: BQ20Z90

Hello,

In the bqEval software under the Charge Status flags, what causes the PLSOFF to get set? We are testing a 4S3P LFP pack (22.2Ah) and charging at 8A. When the packs is almost full and the charge current drops to around 2A, the PLSOFF flag turns on and the CHG FET turns off. Several seconds later, the PLSOFF flag is off and charging resumes. Then the charge on/charge off cycle repeats. I would like to stop the PLSOFF flag from turning on. Is there a way to do this?

Thanks,

Kevin

over 7 years ago

0 Bryan Kahler over 7 years ago

TI__Mastermind 25955 points

Hi Kevin,

Thank you for the question - I will update this post on Monday.

Sincerely,
Bryan Kahler

0 Bryan Kahler over 7 years ago in reply to Bryan Kahler

TI__Mastermind 25955 points

Hi Kevin,

The PLSOFF flag may set when pulse charging has turned the charge FET off.

The PLSOFF flag may be set If any cell voltage during charging is equal to or above _Max OFF Voltage_ or _Turn OFF Voltage_ for _Max On Pulse Time_.

To stay out of the charge on/charge off cycle, please ensure that both:
1. the maximum voltage of any cells remain less than Max OFF Voltage
2. the maximum voltage of any cells remain less than Turn OFF Voltage for the duration of Max On Pulse Time.

If either of these two conditions are met, the device will enter Fast Charge Pulse Charging as described in section 2.4.8 and illustrated in Figure 2-13 of the TRM ( http://www.ti.com/lit/sluu264 ).

Sincerely,
Bryan Kahler

0 Kevin H. over 7 years ago in reply to Bryan Kahler

Intellectual 560 points

Thank you Bryan......that worked........Regards, Kevin

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bq20z90: PLSOFF flag