TPS53211: skip mode

Jim Tsai

Expert 4470 points

Part Number: TPS53211

Hi,

I would like to know how the device operation in skip mode or CCM.

Depends on inductor current or output voltage?

over 3 years ago

0 Gerold Dhanabalan - Online Design Tools over 3 years ago

TI__Genius 14455 points

The TPS53211 uses Rdson sensing of the low side FET to detect the zero current and turns of the low side FET to improve the light load efficiency.

To skip pulses, when the Vout becomes larger because of light load, the FB voltage becomes larger which controls the output of the internal error amplifier and is used to skip pulses.

Please let us know if you have further questions.

Regards,

Gerold

0 Jim Tsai over 3 years ago in reply to Gerold Dhanabalan - Online Design Tools

TI__Expert 4470 points

Hi Dhanabalan,

Please check the waveform and schematic.

As I know dead time is auto adaptive controlled by HS and LS Vgs voltage.

The Vgs waveform looks like shoot through, do you have any comment of the waveform and schematic?

CH1: Hi side VGS

CH2: Low side VGS

CH3: 3.3V vout

0 Peter James Miller over 3 years ago in reply to Jim Tsai

TI__Guru 52745 points

Jim Tsai

No, this does not look like shoot-through. It looks like "sub-threshold cross-over" You can see in the Channel 2 waveform that the switching node voltage begins to dip, indicating the turn-off of the low-side FET before the high-side driver beings to rise and well before the high-side gate drive reaches the MOSEFT threshold voltage.

Was the UGATE waveform taken from the UGATE pin or one of the two top-side FET gate drives?

+1 Young Zhao over 3 years ago

TI__Genius 9300 points

Hi Jim,

I will close this first, please let us know if you have any further concern .

BRs,

Young

0 Jim Tsai over 3 years ago in reply to Young Zhao

TI__Expert 4470 points

Hi Young,

I have reached to BU and discussed the issue via mail, thanks for your support and we can close the thread.

Because of the Thanksgiving holiday in the U.S., TI E2E™ design support forum responses may be delayed from November 25 through December 2. Thank you for your patience.

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TPS53211: skip mode