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UC2843A: UC2843A

Part Number: UC2843A
Other Parts Discussed in Thread: UCC28740, UC2843


I need to design DC DC converter using UC2843A having input voltage 40 - 60VDC and variable output 10A current limit. This will be used to charge the Li ion battery having BMS in place with switching in -ve line. BMS can charge the battery with 50A current if the current is >50A, DC DC converter will take over and charge the battery with constant 10A. Battery +ve is directly connected with charger and in the -ve line MOSFETS are placed as switch. Please suggest how to achieve the DC DC converter design.



  • Hi,

    To switch back and forth between BMS and UC2843A, you would need establish a switching condition. For example, you design a circuit to sense the charging current and at certain level to switch to UC2843A. You have to define this condition as we are not sure what you want to switch from BMS or vice versa. 

    For constant current operation, you can use a current sense to be your feedback signal for the feedback loop. 

    It looks more appropriate you re-create the thread oriented it to BMS support as you need make your mind how to make the switch between BMS and UC2843A and if you only need UC2843A to operate with 10A constant current. After you settle down these with details, you can come back UC2843A with your detailed specifications for UC2843A design.  

  • Also, if you want to make CVCC design using UC2843A, it would be better you can consider UCC28740 as it has CVCC embedded feature.

  • Hi Hng

    Thanks for the reply.

    The conditions of switching to UC2843A and between BMS we will take care and as per the application we know when to switch on MOSFETS of BMS and when to switch on UC2843A. The question is that since Battery +ve is directly connected with Charger +ve and switches are placed in the Battery -ve to Charger -ve line so how to design the DC DC converter using UC2843?

  • Hi,

    You need to parallel your UC2843A converter with BMS. So open the two MOSFETs for BMS when stop BMS. Then DC-DC MOSFETs start to work.