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TPS57140-Q1: Need to help to check if Vout working ok of TPS57140-Q1

LeoChen
Intellectual 500 points
Part Number: TPS57140-Q1

I screenshot TPS57140-Q1 Pin10 PH Vout waveform, help to check if Vout working ok of TPS57140-Q1? If not, kindly give some suggestions.

  • 0
    TI__Genius 11040 points
    Hello,

    What are your input voltage, output voltage, and load conditions? This looks similar to expected for the PH pin. Is your output voltage as you expect?

    Best Regards,
    Katelyn Wiggenhorn
  • 0
    Intellectual 500 points
    Dear Katelyn,
    12v input/3.3v@500mA output, because it is designed for automotive application, i need to check PH pin output like this is working ok? I'm afraid that EMI issues will be produced. I think if it is assumed to be a square wave will be reasonable.
  • 0 in reply to LeoChen
    TI__Guru**** 191445 points

    Leo.

    TPS57140-Q1 is a non-synchronous converter.  The waveform you show is normal for anon-synchronous converter operating in discontinuous conduction mode (DCM).

  • 0 in reply to JohnTucker
    Intellectual 500 points
    Dear John,
    Thanks for feedback.
    And in additions, what conditions TPS57140-Q1 will work under Light Loads mode?
  • 0 in reply to LeoChen
    TI__Guru**** 191445 points
    Leo,

    There are three distinct operating modes, CCM, DCM and eco-mode.

    CCM is Continuous Conduction Mode. The TPS57140-Q1 operates in CCM any time the load current is greater than one half the peak to peak inductor current (ILp-p).

    DCM is Discontinuous Conduction mode. The TPS57140-Q1 enters DCM when the load current falls below ILp-p / 2. DCM is the operating condition shown in your waveform.

    When the load current drops further, TPS57140-Q1 can enter a pulse skipping eco-mode operation. Eco-mode can increase the efficiency above DCM operation by skipping pulses. It is not possible to exactly determine the load condition boundary for eco-mode. See this app note for details:
    www.ti.com/.../slva388