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.

BQ40Z50-R2: BQ40Z50 Automatic Switch Between Charge and Discharge

Part Number: BQ40Z50-R2
Other Parts Discussed in Thread: BQ40Z50,

Hello,

I have designed a custom battery management board based around the BQ40Z50 EVM schematic. I am now in the process of trying to set up the chip for my application. I plan to connect a basic LiPo charger (in Charge mode without balance since the BQ chip handles this on its own) to the PACK+ and PACK- inputs during the charging process, and connect the load during discharging. My question is how does the BQ40Z50 know when to be in charge mode or discharge mode? Can it do this automatically? My application needs to be fully automated as the 4S battery I am using is inside a pressure-sealed contained to be used in an AUV. The only connection out of the battery pod is the power connection, so I want to just be able to connect the power connection to the AUV to discharge, and connect it to the charger to charge it, but I am unsure how to have the BQ40Z50 do this automatically. Thank you in advance!

  • Hello Parker,

    The BQ40z50-R2 will switch between Charge, RELAX, and Discharge automatically based on the current measured through the sense resistor. If positive current, then the device is considered to be charging and so on. Please see the below chart for gauge mode of operations. 



     Note: For autonomous FW controlled, please ensure FET_EN is set. The FW will control the protection FETs automatically if FET_EN is set. It will also clear the protections when it meets the recovery conditions. All of this information is listed in the TRM.

    Regards,
    Jose Couso