data/text/DLP1/899586

BQ25703A: protect circuit

Part Number: BQ25703A Hicompany engineer, I am in a puzzle about the schematic in PMP40294 Reference Design Board. It's protect circuit has NetLable named GG_CHG and GG_DSG, they don't have a corresponding lable in the schematic. Could you please explain a little about the working principle of the circuit in the picture below? especially why choose the CELL1 as the Q12's Grid, and how GG_CHG or GG_DSG refluce the charge and discharge process. Thanks a lot!

It looks like part of the schematic is missing. Let me check with the circuit designer.

Hi, The designer of this project was no longer in TI. Let me look for other guy to figure it out. Will reply you once I got it. Regards, Richard

Thank you for taking the time out of your busy schedule to help me answer my doubts . Thanks again!

Hi, Friend, If we see the schematic, this block is connected to battery pack. Usually, this block will contain gas gauge IC, back-to-back FET, and battery. Original design is planning to add the circuit of gas gauge IC, back-to-back FET. With some reason the designer removed this part(U7 is not soldered on the board). However, it doesn't affect us to evaluate the whole system. The below reserved schematic will help you understand how these block work. Hope this will help. If you are interested in the gas gauge part, please check the BQ3060.

Thank you very much. I have learned a lot from this schematic.company engineers are awesome！