• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 260 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

BQ76942: BQ76942 CMOS on off issue

Star Xu
Genius 9645 points
Part Number: BQ76942

Hi 

The customer design with BQ76942, When they verify the overcurrent protection of the product, the charging MOS will burp once when it is release.

The test step as below:

1, Setting the register as attached file.

2, Open the CMOS and DMOS.

3,  Charging the battery to OCC protection.

4, Discharging the battery with 0.5A to release the OCC protection.

5, Use an oscilloscope to monitor the CMOS drive waveform is shown as below.

 

Disable Sleep_ EN, repeat 2~5 steps, and the test waveform is shown as below:

Attached the .gg file.

4380.gg.csv

Please help analyze.

Thanks

Star

  • 0
    TI__Expert 3425 points

    Hi Star, 

    After a closer look this does appear to be behaving reasonably. The 'burp' you are seeing may be caused by the body diode protection triggering you can read more on this in section 5.2.3.1 FET Configuration. When coming out of SLEEP mode where the FET turn on timing takes up to 1s in this mode and up to 250ms in Normal mode. 

    Disabling SLEEP_EN may have cleared the issue being seen as it has the shorter turn on time.  

    To better understand the timing please refer to Table 6-9 in the TRM for NORMAL and SLEEP modes times for FET turn on. 

    Best, 

    -Luis T