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TPS61089: About switching time of PWM/PFM

Tsukui Yusuke
Guru 21930 points
Part Number: TPS61089
Other Parts Discussed in Thread: TPS61088

Hi,

Could you tell me about　PFM/PWM switching time?
Customer is struggling with voltage drops when switching from PWM to PFM.
(In EVM evaluation, when Iout = 300 mA / 20 msec, voltage drops.)
For that reason,
Customers want to know the delay time when pfm and PWM switch.

I am introducing TPS 610891 to customers.
However, customers want the PFM mode function for efficiency.

Could you give me your advice?

Best Regards,
Yusuke/Japan Disty

  • 0
    TI__Mastermind 40080 points

    PFM/PWM switching time is just seceral cycle, about 20us.

    To be more clear, are you mean  the customer makes the TPS61088 work in the PFM mode, but when  output current increase from 0A to 300mA, the output voltage drops?

  • 0 in reply to Helen chen
    Guru 21930 points

    Helen-san,

    Thank you for you response.
    Customers are evaluating TPS61089EVM.
    Customer useing condition is :
    ・Iout=1A→Iout=0.3A→Iout=1A
    ・Fsw=500kHz(EVM default condition)

    Could you give me your advice?

    Best Regards,
    Yusuke/Japan Disty

  • 0 in reply to Tsukui Yusuke
    TI__Mastermind 40080 points

    I think the drop should be happended at the 0.3A to 1A load step. It is a normal phenomenon when there's a load step.  What is the maximum allowbale volatge drop in their design? 


    Could you please share the detailed application information for us? Like in what kind of equipment? Which company? my email address is helen-chen@ti.com