LMR16006: Switching with light load

na na78

Guru 16770 points

Part Number: LMR16006

I want to confirm LMR16006 operation under following condition.

Vin:12.5V

Vout:12V

Iout:50mA

I obtained following waveform using LMR16006XEVM.

1. CH1:SW, CH2:VOUT

12Vout seems to be regulated.

Is the switching wave correct?

The following is obtained when VIN is decreased by 12.3V.

Vin is 12.3V but the output 12V is regulated.

Could it be possible to regard that the SW waveform in upper figure is correct ?

BestRegards

over 5 years ago

0 David Baba over 5 years ago

TI__Mastermind 18890 points

Hello,

The waveform looks correct to me. You are violating the Toff min time, or the DMax stated in the datasheet.

As a result of this violation the switch node will node be periodic in nature.

See link below, which discusses limitations of buck device.

www.ti.com/.../slyt293.pdf

Hope this helps?

David.

0 na na78 over 5 years ago in reply to David Baba

Guru 16770 points

Hi David

Thank you for your reply.

I understood this waveform was obtained from normal operation.

Is this waveform caused of Wimp FET operation?

BestRegards

0 David Baba over 5 years ago in reply to na na78

TI__Mastermind 18890 points

Correct, the Wimp FET is employed to ensure Cbbot is charged to Supply high side Gate drive circuitry.

Hope this helps?

David.

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LMR16006: Switching with light load