• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 63 subscribers
  • Views 386 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.

bq28550 Programming of Protection threshold

K. Sasaki14
Guru 10200 points

My customer said that bq28550-R1 is developed and support the following function as programmable.

-Over Charge

-Over Discharge

-Over Current in charge / discharge

-Over Temp

-Short Circuit

 

So, I have some questions.

---------------------------------------------------------------

[Question1]

Is there a bq28550-R1?

If it is true, what are the difference points between bq28550 and bq28550-R1?

 

[Question2]

I think that it is possible to change the protection threshold by rewriting DF parameter.

But it looks like the threshold parameters in DF are for firmware detection.

The operation is different when the thresholf is detected.  When over charge and over current in charge, bq28550 doesn't control CHG FET.

Does bq28550 have two kinds of detection, by hardware and firmware?

Can the customer change the defined value (detection voltage and delay time) in datasheet P.5?

Even if the COV threshold in DF is set to more than 4.28V, does the bq28550 detect COV at 4.28V?

 

[Question3]

In Technical Reference P.59, why the LT COV Recvery threshold is bigger than the LT COV Threshold?

---------------------------------------------------------------

  • 0
    TI__Prodigy 210 points

    Q1 Answer

    [Question1]

    Is there a bq28550-R1?

    Yes

    If it is true, what are the difference points between bq28550 and bq28550-R1?

    bq28550-R1 has been configured through firmware change and pin 12 to be a GPIO, so we can use this with external circuit as recommend to control CHG FET.

    Aletrnatively if you do NOT want to use this pin for CHG FET control it can be configured as an ALERT output to interface to MCU

     

    [Question2]

    I think that it is possible to change the protection threshold by rewriting DF parameter.

    But it looks like the threshold parameters in DF are for firmware detection.  - YES

    The operation is different when the thresholf is detected.  When over charge and over current in charge, bq28550 doesn't control CHG FET..

    In this case only hardware set limits control CHG FET

    Does bq28550 have two kinds of detection, by hardware and firmware?-  YES

    Can the customer change the defined value (detection voltage and delay time) in datasheet P.5?. Customer can change detection voltage but the value has to be lower than the hardware limit for OVP and higher than CUV limit. This again is DF parameters in firmware

    Even if the COV threshold in DF is set to more than 4.28V, does the bq28550 detect COV at 4.28V?. The COV is a harware limit and so it will detect this. In the bq28550 there is NO firmware for COV settings

     

    [Question3]

    In Technical Reference P.59, why the LT COV Recvery threshold is bigger than the LT COV Threshold?

    It should be the other way, 4200 for recovery and say 4300 for threshold