LM25141: About High side ON time at Pulse skip mode

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Guru 21045 points

Part Number: LM25141

LM25141 - About High side ON time at Pulse skip mode

Hi Team,

We would like to know the High side ON pulse width at Pulse skip mode.

Therefor, could you please let us know High side turn on and off timing?

[Conditions at TINA TI]

VIN=20V

VOUT=3.8V

IOUT=100nA

[Sim Result]

Regards,

Kanemaru

over 7 years ago

0 Terry Allinder over 7 years ago

TI__Expert 3545 points

Kanemaru,

During light load (skip mode) the LM25141 outputs an HO pulse width which is forces an inductor current approximately 20% of the current limit threshold.

Terry

0 Hide over 7 years ago in reply to Terry Allinder

Guru 21045 points

Hi Terry-san,

Thank you for your response.

I understand that High side FET is turned off if the inductor current reaches an approximately 20% of the current limit (for example, it is 1A if current limit is 5A).

Is my understanding correct?

And I have one more question.

Could you please let us know the condition that High side FET is turned on?

Regards,

Kanemaru

0 Terry Allinder over 7 years ago in reply to Hide

TI__Expert 3545 points

Kanemaru,

The LM25141 enters a pulse skipping mode when

•The voltage on the FBpin >VREF

•COMP<300mV

•No HO pulses for 16 consecutive CLK cycles.

The high side FET is turned on when voltage on the FB<0.99*VREF

Terry

0 Hide over 7 years ago in reply to Terry Allinder

Guru 21045 points

Hi Terry-san,

Thank you for the detail information.

Regards,

Kanemaru

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LM25141: About High side ON time at Pulse skip mode