• State
  • Replies 2 replies
  • Subscribers 63 subscribers
  • Views 35 views
  • Users 0 members are here
Support feedback
Options
Options
Related

TPS62A04B: The switch frequency goes to much higher during 0.5A-1.2A output current

Paul Archer
Prodigy 20 points
Part Number: TPS62A04B

Tool/software:

This chip is supposed to have a fixed 2.2MHz switch frequency for medium to heavy load and lower frequency for light load as it works as PFM mode. While in our design, I found the switch frequency can go high to 4.7MHz at a medium light load saying 0.5A output current. 

Is it designed to be like that? Or anything could be wrong with my design? It's a quite simple circuit and we couldn't do much wrong with it. 

  • 0
    TI__Intellectual 1560 points

    Hi Paul,

    The device shouldn't switch with that high frequency. Can you share the scope shot, how the waveform looks like and what are the settings in your scope? What kind of load are you using, is it constant current load or a constant resistance load? Also having info about the test conditions will be nice to have like Vin, temperature etc.

    Best Regards,
    Zakir

  • 0 in reply to Muhammad Zakir Baig
    Prodigy 20 points

    Hi Zakir,

    Thanks for your response. 

    Sure, please find the scope shot at 0.8A current load. The waveform looks quite stable. The settings are no problem as the switch frequency is normal as 2.2MHz when the output current is above 1.2A. 

    The load is electronic constant current load. The input is a onboard 5V DC/DC converter from 12V input to the board. It was tested under room temperature. 

    I also attached the schematics for your information. It doesn't make any difference with Cff on or not.