• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 62 subscribers
  • Views 61 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

Original question:

LM5122: Current detection position

LM5122: CSP, CSN recommended operation voltages and measure position

Iulian Popa
Prodigy 10 points
Part Number: LM5122
Other Parts Discussed in Thread: LM5121, LM5171

Hello,

I came across a similar question on the thread regarding the LM5122 current detection position (Previous answer from TI Forums). As was already answered, using CSP, CSN pins on the low side of the HB is possible but not recommended due to negative spikes during switching.

We are looking for a Synchronous Boost Controller like this LM5122 or the LM5121/-Q1 but we are managing a slightly higher input voltage. In the Datasheet it says that the recommended Vin, CSP, CSN voltages are 65V and the AMR are 75V. Our system is powered up by a Li-ion pack batteries in a 16s2p configuration, so the worst case could be when this pack is fully charged (16 cells x 4.25V = 68V) and the converter is "off" without load.

Would this situation cause any damage or excessive stress on the IC? Should we explore alternative components, or would the LM5122 be suitable for our application?

P.S. This battery voltage will drop immediately as the converter starts regulating the output voltage under load. Therefore, this worst-case scenario only occurs during brief periods when the converter is off or just starting up and the battery is fully charged.

  • 0
    TI__Genius 15485 points

    Hello Iulian,

    Thanks for reaching out to us via e2e.

    The LM5171 can handle 75V in and 80V out.
    If you are using an asynchronous controller with low side surrent sense resistor, you can supply the controller with a lower voltage than the power stage.

    For a commercial product I strongly recommend staying within the recommended operation conditions.
    The part may not immediately break when you go above that, but we can neither guarantee for proper operation, nor specify which problems you should expect.
    You would run into liability issues if you are violating the recommended operating conditions.

    By the way, trying to place the CSP / SCN amplifier on the low side cannot work, as the amplifier itself is powered by the CSP pin.

    Best regards
    Harry