PMLKBUCKEVM: Vsw wavefrom issue

Mason Liu

Part Number: PMLKBUCKEVM
Other Parts Discussed in Thread: TPS54160

Hi,

Currently i'm doing the experiment 1 test 1, Vin 24V, Vout 3.3V, Iout change from 0.1A to 1.5A.

i find when the Iout is lower than 0.7A, the Vsw will show some weird waveform. shown below.

Iout=0.1A

Iout=0.5A

In the Iout=0.1A image, i think maybe TPS54160 is in ECO-mode. But what cause the ringing in the red circle?

In the Iout=0.5A image, what cause the Vsw is high in the red circle?

Thanks.

Best regards

Mason Liu

0 Frank De Stasi over 4 years ago

With this device, the light load mode will show some pulse skipping and double pulsing.

The ringing is normal in DCM mode. It is caused by the parasitic capacitance and the main

inductance of the power stage.

0 Mason Liu over 4 years ago in reply to Frank De Stasi

Hi Frank,

Thank you for your reply.

I still have a question, how do i test the Ts ?

For example, Iout=0.1A. Can i say the Ts is shown below? which is 13.44us.

Or the Ts is still the same as the normal mode, which is 4.46us?

What about the Iout=0.5A image?

Thanks.

Best regards

Mason Liu

Power management forum