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UCC39002: Connection check

Roy Hsu
Intellectual 2880 points
Part Number: UCC39002
Other Parts Discussed in Thread: LM5177

Tool/software:

Hi Team,

My customer want to use 3x adapter (5A per adapter) provide 54V into their switch system, and sorry that it's my first time use UCC39002 so I have some application questions want to check.

1. If customer's system power like below, is it workable or not? Since it is high-voltage application and adapter only have V+ and GND, so I think VOUT+ and SNS+ should connect to adapter V+, but if so, I think it will lead to can not place Radj. If this workable, please let me know what connection should change compared with below Figure 7-2. 

adpater in*3> LOAD SHARE(UCC39002*3) > buck-boost keep stable 54V (LM5177*3) > BRICK TO 12V + POE 54V

  

2. If don't use UCC39002, customer should very care their layout for make sure 3x adapter can achieve current sharing by layout correct?

adapter in *3> buck-boost keep stable 54V (LM5177*3) > ORING(LM5050*3)> BRICK TO 12V + POE 54V

3. If customer's adapter already have UCC39002 inside it, and since on switch board only have V+ and GND, so if I let 3x adapter connect to switch board same V+ and GND, is it can achieve current sharing?

Best Regards,

Roy

  • 0
    TI__Expert 8680 points

    Hello Roy,

    Do you have a block diagram or mockup to better illustrate your system? It is difficult to understand based on reading just "adpater in*3> LOAD SHARE(UCC39002*3) > buck-boost keep stable 54V (LM5177*3) > BRICK TO 12V + POE 54V"

    Regards,

    Jonathan Wong

  • +1 in reply to Jonathan Wong
    TI__Expert 8680 points

    Hello Roy,

    Following up and summarizing the thread after our discussion.

    You will not be able to use the UCC39002 with a pure DC source like your adapter. You need a feedback system for the load share controller to work. In your application where the Vin and Vout are both 54V, using a buck/boost controller is ideal since you can either boost or buck the output voltage as needed based on the load share. The UCC39002 can use the LM5177 buck/boost controller's feedback system. I also recommend placing the UCC39002 after the ORing LM5050. Please see the block diagram below.

    Regards,

    Jonathan Wong