• State Resolved
  • Locked Locked
  • Replies 7 replies
  • Subscribers 63 subscribers
  • Views 311 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

LM25122-Q1: schematic review

Sherry Liang
Genius 10255 points
Part Number: LM25122-Q1
Other Parts Discussed in Thread: LM5122

Dear team,

Could you please help review the schematic? In addition, do we have the efficiency curve? The customer wants to compute the input current, but we can't compute it without efficiency?

LM25122.pdf

Thanks & Best Regards,

Sherry

  • 0
    TI__Intellectual 2775 points

    Hi Sherry,

    Could you share me the input voltage and output current ?

  • 0 in reply to dehuan Qi
    TI__Genius 10255 points

    Hi Dehuan,

    Vin=6-18V, typical value is 13.2V, Vout=12V, Iout=5A. The customer wants to evaluate our load current capacity when VIN=6V, so I need to know the efficiency.

    Thanks & Best Regards,

    Sherry

  • +1 in reply to Sherry Liang
    TI__Intellectual 2775 points

    Hi Sherry,

    LM25122 is a controller, so the efficiency is base on the  external components. And I didn’t see the relationship between Vin=6V output current capability and efficiency. Of course, if the customer only needs a reference data, it can be calculated using Webench.

    I did not see any problems with the schematic, but adding MOS to the feedback loop need to be check the turn on and off time sequence to prevent the feedback loop from disconnecting.

  • 0 in reply to dehuan Qi
    TI__Genius 10255 points

    Hi Dehuan,

    Thanks for your reply! But I didn't find the webench for our LM25122-Q1. 

    Thanks & Best Regards,

    Sherry

  • 0 in reply to Sherry Liang
    TI__Intellectual 2775 points

    Hi Sherry,

    You can ref LM5122 webench.

  • 0 in reply to dehuan Qi
    TI__Genius 10255 points

    Hi Dehuan,

    1. Could you please help clarify "And I didn’t see the relationship between Vin=6V output current capability and efficiency. "? In my understanding, the smaller VIN, the larger input current. If the input current exceeds the current limit value, our device will enter into fault condition. VIN*Iin*efficiency=VOUT*Iout, If I get the efficiency, then I can know whether the input current is smaller than the current limit. 

    2. Our device has bypass function. Do we have the threshold voltage and delay time? For example, Vout=12V, once VIN exceeds 12V, our device will enter bypass mode, right? If the VIN has some fluctuating, for example, 11.9V -->12.1V-->11.9V, how does our device work, boost mode-->bypass mode-->boost mode? Or only VIN-VOUT> threshold value for fixed delay time, our device just switch the mode?

    Thanks & Best Regards,

    Sherry

  • +1 in reply to Sherry Liang
    TI__Intellectual 2775 points

    Hi Sherry，

    For item 1 you are correct.

    For the Item 2 it is define by PWM. the feedback adjust the PWM to 100% it enter bypass mode.