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BQ24210: Solar Powered Battery Operated system

Prabakaran Ganesan
Prodigy 20 points
Part Number: BQ24210


Tool/software:

Hi ,

     I need help to review my attached schematic. Its BQ24210 based Power management circuit which would process the solar PV panel primarily to charge the 3.7V li-ion Battery and also its power the Load. For emergency backup, added USB power adapter input as well incase of no battery and no solar panel but still aimed to power the load.

The buck converter output USWP +3.3V will be connected to Microcontroller. So Microcontroller will be powered always

The switched power output SWP +3.3V will be connected to 4G module to power it on need basis, decided by the microcontroller

Kindly review all the passive components and its ranges and give the feed back. 

SolarCharger2020_Modified.pdf

Looking forward to hear from you all...

Thanks,

Prabakaran 

  • 0
    TI__Mastermind 41905 points

    Hi Prabakaran,

    My schematic review is as follows:

    1. I see charge current of 100 mA.

    2. VDPM acting in battery tracking mode.

    3. /EN tied to /PG pin for auto-enabling charging operations and disabling of Load mode.

    4. Please make sure the TS circuit is correct for your application.

    Regards,

    Mike Emanuel

  • 0 in reply to Michael Emanuel35
    Prodigy 20 points

    Hi  ,

        Thanks for your kind response. Follow-up on your review comment

    1. I see charge current of 100 mA. - Yes, the input solar panel is 6V 100ma capacity, so designed the circuit with 100ma charge current . Does it make sense?

    2. VDPM acting in battery tracking mode - Yes, I thought that works for 3.7v li-ion battery. Please let me know if any changes required.

    3. /EN tied to /PG pin for auto-enabling charging operations and disabling of Load mode - Yes, I understood. But I assumed that still my load is getting power from the BQ24210 Bat pin continuously. But I was wondering since the load is directly connected to battery(via buck converter) how the BQ24210 would cut off the load to ensure that battery should not drain completely and also charging and discharging should happen parallel since the load is always connected and solar panel also always connected.

    4. Please make sure the TS circuit is correct for your application - I have chosen NTC which is 10K @ 25•c so I have used another 10K in that voltage divider circuit. My battery is standard 18650 3.7V 2000mah battery. If that case how can I ensure the voltage divider would works. Any input?

    Looking forward for you input, 

    Thanks,

    Prabakaran 

  • 0 in reply to Prabakaran Ganesan
    TI__Mastermind 41905 points

    Hello Prabakaran ,

    1. Please understand that the charger will try to crash the solar panel. A 6V solar panel refers to Open Circuit Voltage, the loaded voltage may be less. Please make sure it is higher than the battery voltage for charge to happen.

    2. From the datasheet, "When VDPM is floating, the VIN DPM loop operates in battery tracking mode, and the VIN DPM threshold is BAT+100 mV (BAT>3.6 V) or 3.7 V (BAT≤3.6 V) in this case."

    3. If the load is connected directly to the battery it will limit charge current when charging the battery and drain the battery when no input is present. Load mode is intended to be used when the solar cell is removed and an accessory is attached to the input. 

    4. Please checkout Section 8.4.5.9 for equations and diagrams describing correct operation.

    Regards,

    Mike Emanuel