TPS54202EVM-716: TPS54202

Skylar Li

Part Number: TPS54202EVM-716
Other Parts Discussed in Thread: TPS54202

I tested TPS54202EVM today and I don't understand why when TPS54202 entered DCM mode, under different output current, the pinnacles are different.

over 1 year ago

0 Zixu Wang over 1 year ago

TI__Expert 8100 points

Hi Skylar,

I will make further analysis and give you response by tomorrow!

BRs

Zixu

0 Zixu Wang over 1 year ago

TI__Expert 8100 points

Hi Skylar,

During ringing period, Low Side MOSFET and its body diode both shutdown, meaning that load energy is supplied all by output capacitors. If load current is big, Vo falls in fast speed, meaning that the time needed for Vfb falls to Vref is short. So the ringing time could be short, causing ringing variations shown on waveforms.

It would be better to understand it if you compare load current of both conditions.

BRs

Zixu

0 Skylar Li over 1 year ago in reply to Zixu Wang

TI__Intellectual 760 points

The blue waveform represents Vsw and could you please tell me the relationship among Vsw, Vo and load current.

+1 Zixu Wang over 1 year ago in reply to Skylar Li

TI__Expert 8100 points

Hi Skylar,

In order to supply higher load current without dropping Vout too much, internal control circuit will send pulse to conduct High Side MOSFET in advance, reducing time of Toff and time of ringing. So in Vsw, it is obvious to observe that less ringing appears when load current increases.

BRs

Zixu

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TPS54202EVM-716: TPS54202