TPS54J061EVM: switching behavior between 6kHz and 2MHz

Fred Cheng

Part Number: TPS54J061EVM

Hi team,

I noticed some behavior shown in the below, the test condition is transient 0.01A to 0.5A in 2MHz.

But instead of scatter pulse which behave normally in the 600kHz picture, it appears a group of dense switching pulse in the light load DCM mode in the 2MHz condition.

why does this happen ? does it somehow trigger back to CCM and operate in 2MHz?

2MHZ Zoom-in

600KHz

Regards,

Fred

over 3 years ago

0 Yitzhak Bolurian over 3 years ago

TI__Mastermind 18370 points

Hi Fred,

What is the Vin and Vout during the test you have conducted?

Is the device configured in "Skip mode" or in "Forced CCM"?

If in "Skip mode", try the same without lowering the load current below 60mA.

This should help avoiding the grouped pulses.

Regards,

Yitzhak Bolurian

0 Fred Cheng over 3 years ago in reply to Yitzhak Bolurian

TI__Expert 5900 points

Hi,

Vin is 12V and vout is 1.8V.

and it's operated in skip mode.

may I know why? since if it enter skip mode , it shouldn't behave like that no matter how much Iload (60mA or 10mA whatever).

Regards,

Fred

0 Yitzhak Bolurian over 3 years ago in reply to Fred Cheng

TI__Mastermind 18370 points

Hi Fred,

This is a noise related issue.

Regards,

Yitzhak Bolurian

Power management

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TPS54J061EVM: switching behavior between 6kHz and 2MHz