• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 63 subscribers
  • Views 1451 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.

bq51050 disable charging & use of RECT for system load

James Hillman
Expert 1436 points
Other Parts Discussed in Thread: BQ51050B

I am using the bq51050B and have seen the reference design. I just had two questions:

  1. Disable Charging

Is my understanding correct that I can choose to pull up/down TS/CTRL to disable charging? My plan is keep either the 10kOhm or thermistor, but have a FET to allow a micro-controller to disable charging if needed.

2. RECT to power system load

I noticed on the evaluation board that RECT output (typ. 5V) is used to power the charging LED. is there a spec to the current allowed to be drawn by this pin - didn't see it in the datasheet. My system load can be low .e.g a few mA. Sometimes higher 300mA. 

Many thanks,

James

  • 0
    TI__Genius 14890 points

    James,

    1. Yes, the TS/CTRL pin can be pulled high or low to disable charging.  The End Power Transfer packet will be different if a high or low is sent.  See Table 1 in the datasheet for the details.

    2. There is no spec on the RECT pin current.  RECT is not intended to power a system.  It is used for LEDs and for the FOD (Ros) resistor.  RECT voltage will vary quite a bit from power up to full load and does not make a good supply.  The system can be tied to the BAT pin, but any current used by the system does count as battery current and will impact the charging times.

    Regards,

    Dick

  • 0 in reply to Dick Stacey
    Expert 1436 points
    Thanks Dick. I thought as much but its always great to double-check. I may look for a separate charger/Qi receiver to allow my design to run from a flat battery i.e. some sort of power-path solution, which I use for USB devices. Thanks again - for your super quick reply, James.