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BQ27Z746-DEVICE-FW: bq27z746 Hardware and software consulting

Part Number: BQ27Z746-DEVICE-FW

Tool/software:

1、Schematic evaluation:

A、The circuit needs to have a "0V" no-charge function, how much resistance does R12 need in the circuit? Is the current circuit suitable?

B、The precision resistance supported in the circuit is 1~20 milliohm, the current used circuit is 2 milliohm precision resistance, the actual circuit working charge is 200mA, placed within 1mA, I would like to ask: the following parameters of the coulometer how to set more in line with the actual requirements?

C、The above circuit needs to be UL certified, add a two-protected circuit (U2), and there is a double protection circuit with the coulometer.
Please help evaluate whether there are any defects or hidden dangers in this circuit

D、The coulometer in the process of burning an occasional power failure, resulting in the board can not activate or enter the ROM mode, what is the method to restore normal (the board has communication and can be activated)?

  • Hello, 

    In your schematic, ENAB should not be left floating. Additionally, R12 can be the same value as R1. For the current threshold values, please refer to the Achieving the Successful Learning Cycle document for what to set these values to based on your system. For the secondary protection, I have seen this done before and do not see any obvious issues with using a low-side secondary protection. 

    Regards, 

    Robert. 

  • 1、Does R12 and R1 have the same value to satisfy that the circuit is "0" V forbidden?   2、How to connect ENAB feet?3、The charging current of the project is 200mA, and the discharge current is 1mA. Are the following parameters set correctly?

  • 1、The coulometer in the process of burning an occasional power failure, resulting in the board can not activate or enter the ROM mode, what is the method to restore normal (the board has communication and can be activated)?