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BQ24210: Maximum utilization of solar panel

Prudhvi Sagar
Genius 3785 points
Part Number: BQ24210

Hello,

I am trying to design an IoT device with solar power to charge a 3.7V LiPo battery. I want to utilize maximum power of the panel. I have the following doubts for the application?

1. What is the better setting leaving VDPM floating(battery tracking) or to program to a VBUS_DPM.

2. Avoid limited power charging mode by setting a voltage at TS pin (30% of VTSB).

3. Does tying EN to ground cause any issue?

Regards,

Prudhvi Sagar

  • 0
    TI__Genius 12475 points
    Prudhvi,

    VBUS_DPM is preferable to set to 80% of the open circuit voltage of the panel itself.

    EN pin can be tied low if you want to be able to always charge the battery. Could you clarify more on the TS pin usage?

    regards,
    gautham
  • 0 in reply to Gautham
    Genius 3785 points

    Hello,

    I am confused with the limited power charge mode which is controlled by the TS pin. My battery doesnt have thermistor. If I tie TS to VTSB then the device enters LPCM mode and if I give 30% V of VTSB thenTS sensing is disabled. What is the best way to get the best output of the panels.

    Regards,

    Prudhvi Sagar

  • 0 in reply to Prudhvi Sagar
    TI__Guru 67686 points

    Hello Prudhvi Sagar
    The LPCM would disable the charge timers and default charge time of 10 hours would NOT apply. If you fell that charge can complete in 10 hours or less then connect TS to 30% VTSB.

    Update -- With typical VTSB of 2.2V then 30% would be 660mV, R-TH could be 20k and RT1 would be 47k see figure 12 data sheet.  Also a move common value of 20k RT1 and 10k R-TH for 33% would meet requirements.

  • 0 in reply to Bill Johns
    TI__Guru 67686 points
    Hi Prudhvi Sagar
    Update to the above post RT1 should be 47k (lower resistor to gnd) and R-TS should be 20k (upper resistor to VTSB). This will put the voltage at TS at 30% of VTSB for 660mV.
    But the safe range for TS is 18.6% to 46% or 0.40V to 1.01V. A more common value would be 20k for RT1 and 10k for R-TS this would 33% of VTSB, also acceptable.