LM5157-Q1: SW1,SW2 pin function

wenjun yang

Intellectual 360 points

Part Number: LM5157-Q1

Hi,TI experts

I see to LM5157 datasheet,SW1 SW2 have internal connection,I don't understand theirs function,as below image.

As I know ,Generally, Swithch node only connection Highside MOS and inductor.Could you help to me?

thank you

over 2 years ago

0 wenjun yang over 2 years ago

Intellectual 360 points

Sorry ,errata to part number is LM5175-Q1

0 Brigitte over 2 years ago in reply to wenjun yang

TI__Guru 70065 points

Hello wenjun,

For the high-side FETs, the switch node is the reference voltage for the driver signal. The gate or an NMOS needs to be higher than the source and the source of the high-side FET is the switch node.

Best regards,
Brigitte

0 wenjun yang over 2 years ago in reply to Brigitte

Intellectual 360 points

Hello,Brigitte

Thanks for your kindly support

I am not understand clealy,could you help to explain more details.and I check LM61495 block diagram,it have no similar design,as below

thank you again

0 Brigitte over 2 years ago in reply to wenjun yang

TI__Guru 70065 points

Hello wenjun,

LM5175 is a controller, so needs external MOSFETs. LM61495 is a converter with the FETs integrated. Please check the application section in the datasheet for the full schematic with external FETs.

Best regards,
Brigitte

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LM5157-Q1: SW1,SW2 pin function