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LM5064: LM5064 current limit shunt resistor selection

Zoe Yang
Intellectual 2210 points
Part Number: LM5064

Dear team,

My customer plan to use LM5064 on -48V telecom power system as ORing. But they have concerns about technical issues:

  • They require voltage monitor accuracy 0.5% and current accuracy 1%. LM5064 current accuracy is only 1%. Do we have higher accuracy?
  • LM5064 current limitation is 500A, How to conclude if this feature is sufficient when customer rated current was 63A/125A?
  • How to set up shunt resistor value and VCL threshold if protection current limit is 500A? Would it be too much power dissipation on shunt resistor?
  • Do we have any other roadmap update of the next generation of LM5064?
  • They target competitor device XDP710 XDP700 

Looking forward to your reply!

 

  • 0
    TI__Mastermind 30915 points

    Hi Zoe,

    Thanks for reaching out. Please see the responses below.

    • They require voltage monitor accuracy 0.5% and current accuracy 1%. LM5064 current accuracy is only 1%. Do we have higher accuracy? Avishek: No, LM5064 is the only device in our portfolio for -48 V applications, which comes with PMBus. 
    • LM5064 current limitation is 500A, How to conclude if this feature is sufficient when customer rated current was 63A/125A? Avishek: Sorry, I am not able to understand your query. Please explain in detail. 
    • How to set up shunt resistor value and VCL threshold if protection current limit is 500A? Would it be too much power dissipation on shunt resistor? Avishek: Does the customer need 500 A of current limit? If yes, why? 500 A design at 48 V is not feasible.  
    • Do we have any other roadmap update of the next generation of LM5064? Avishek: No
  • 0 in reply to Avishek Pal
    TI__Intellectual 2210 points

    Hi Pal,

    1.Sorry to mention, as for LM5064 current limitations to 500A is referring to the draft spec from Ti.com. I just wondering how come this value up to 500A? Is that means customer can use this device when normal working current is 125A?

    2.As in the datasheet mentioned, CL is set to 26mV by connecting to VDD or 50mV when connected to VEE. How to configure this parameter of shunt resistor if customer normal working current is 63A or 125A?

  • 0 in reply to Zoe Yang
    TI__Mastermind 30915 points

    Response to your query 1: Please fill out the design calculator and share it with us for review.

                                               https://www.ti.com/lit/zip/slvc556

    Response to your query 2: CL pin can be connected to VDD or VEE to select the required current limit threshold as implemented in the EVM.

    You can also use 0Ω resistors to implement this.