• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 62 subscribers
  • Views 117 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

BQ76940: BQ76940 FET Driver Pins - CHG and DSG

Yunus Emre Çetinkaya
Prodigy 20 points
Part Number: BQ76940
Other Parts Discussed in Thread: BQ76200, TIDA-010030, TIDA-00792, BQ76930, TIDA-00449

In the battery management system I made with the BQ76940 integration; I made a design to control the mosfets by driving the optocoupler. This design can be represented as in the image.

The design is a BMS circuit for 10 series li-on batteries.

How much current can be drawn from the FET driver pins (CHG and DSG) of the BQ76940 integration?

Is it possible to drive the PC817 optocoupler via these pins?

I would like to know if you have a better structure suggestion than what you see in the image.

  • 0
    TI__Mastermind 23081 points

    Hello Yunus,

    Are you trying to use a high side driver? We have reference designs which uses the BQ76200 high side driver. Please click HERE for a list of reference designs. TIDA-00792 and TIDA-010030 will be the ones to look for if high side driver is desired.

    High-side N-channel FETs need a charge-pump type driver or other supply to provide a voltage above the FET sources. The BQ76200 high-side N-channel FET driver can be used with the BQ769x0 to control high-side FETs.

    Yunus Emre Çetinkaya said:
    How much current can be drawn from the FET driver pins (CHG and DSG) of the BQ76940 integration?


    Typically multiple FETs in parallel are used to drive more current. TIDA-010030 demonstrates the BQ76940 and BQ76200 high-side FET driver with parallel FETs. TIDA-00449 uses the BQ76930 with parallel FETs. 

    Yunus Emre Çetinkaya said:
    Is it possible to drive the PC817 optocoupler via these pins?

    I have not seen it, but I would say is possible. Is there a specific reason you are using optocoupler?

    For your reference, the Top 10 Design Considerations app note covers in details many interesting design ideas for the device.

    Regards,
    Jose Couso