• State TI Thinks Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 280 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.

TPS61251: The PFM of TPS61251

Charlie Xiao
Expert 7545 points
Part Number: TPS61251

Hi,

When will TPS61251 switch from PWM to PFM? What is the current threshold for the switching? Thanks.

Regards,

Charlie

  • 0
    TI__Genius 12505 points

    Hi Charlie,

    The switching current threshold should be around 300mA, it'd better to test in bench for double check.

    Regards,

    Nathan 

  • 0 in reply to Nathan Ding
    TI__Expert 7545 points

    Hi Nathan,

    Thanks for your support.

    TPS61251 doesn't seem to have a FPWM mode. The customer's needs are as follows:

    The input of Boost is 3.2V, and the output is 3.7V, followed by an LDO to convert to 3.3V.Preferably with input current limiting and soft start. Because the hot-swapping current cannot exceed 600mA. The actual output current used is only about 100mA, so I hope to have FPWM mode. Thanks.

    Regards,

    Charlie

  • 0 in reply to Charlie Xiao
    TI__Genius 12505 points

    Hi Charlie,

    Why does customer want FPWM mode? Because large ripple in PFM or is there some other reasons?

    About the current limit 600mA, does customer want this function only in soft start or does customer want this in any conditions?

    Regards,

    Nathan

  • 0 in reply to Nathan Ding
    TI__Expert 7545 points

    Hi Nathan,

    Because it is to power the MCU, customers want FPWM to provide smaller ripple. But BOOST is followed by LDO, so I don't think FPWM is needed.

    The customer wants the current not to exceed 600mA under any conditions. Thanks.

    TPS61251 should be able to meet customer requirements. thanks.

    Regards,

    Charlie