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TPS63020 overshoot at startup

K.Hamamoto
Guru 12155 points
Other Parts Discussed in Thread: TPS63020EVM-487, TPS63000

Hi

Our customer evaluates the TPS63020EVM. They found a overshoot at startup like the following waveform.

The problem is that the overshoot was larger than below. (The setting voltage is 3.3V. The peak voltage of overshoot is 3.6V)

The condition ; EVM is TPS63020EVM-487. However the Cout is reduced to 22uFx2 from (22uFx3+2.2uF).

                        Vout=3.3V.

 

Why does this happen? And how can we reduce that overshoot?

Regards,

Koji Hamamoto

  • 0
    TI__Expert 7110 points
    This phenomena is expected behavior of the device's regulation loop. It changes state once it reaches the target voltage and therefore generates a dynamic control loop behavior.
    Decreasing the capacitance will generate more overshoot.
    Did you enable the device in Power Safe Mode or in FPWM?
  • 0 in reply to Florian Feckl
    Guru 12155 points
    Thank you for your support.

    As you mentioned, can we reduced that overshoot to connect the large capacitor?
    Can we calculate that capacitor value?

    On the other hand, can we reduce the overshoot if we use the TPS63000?
    Because TPS63000 has lower current limit. (The condition is Vin=2.5~5.5V, Vout=3.3V, Io=600mA)

    Our customer use this device for new opportunity. We need to reduce that overshoot below 100mV(it it target spec).

    Regards,
    Koji Hamamoto