LMR23630: Condition of DCM, LS switch is turned off

GARAM AN

Intellectual 1990 points

Part Number: LMR23630

Hello,

I could find that the condition of LS switch is turned off is when inductor current drops to -40mA (I_L_zc) on the datasheet.

Could you explain the where the point of I_L_zc is on the graph? first arrow(The line)? or second arrow(Valley)?

Thank you

over 5 years ago

0 Andy Chen over 5 years ago

TI__Mastermind 34105 points

Hi Garam,

The inductor current drops to IL_ZC (-40mA typical) means the inductor current must decrease to zero and then change direction to flows into SW pin, LS switch will turn-off when it reach 40mA.

On you above figure, the red or blue line of inductor current valley is still above zero. so both not illuminate the -40mA.

B R
Andy

0 GARAM AN over 5 years ago in reply to Andy Chen

TI__Intellectual 1990 points

This means that all of PFM is working as a DCM, is this correct?

0 Andy Chen over 5 years ago in reply to GARAM AN

TI__Mastermind 34105 points

Yes, PFM is definitely working in DCM mode.

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LMR23630: Condition of DCM, LS switch is turned off