LM3414HV: Thermal Foldback Question

Ken Kelly

Part Number: LM3414HV

Hello to all, Trying to figure out how to use the "foldback" feature on this part. Does anyone have component values for the reference circuit or have something that works? I'm trying to reduce the current automatically if the aluminum clad PCB gets too hot. I have tried a bunch of different things but cannot get it to work correctly. Thanks!

over 4 years ago

0 Sean Zhou over 4 years ago

TI__Mastermind 22745 points

Hi Kelly,

Here is the LM3414EVM user guide, here is a detailed example from page 5.

Sean

0 Ken Kelly over 4 years ago in reply to Sean Zhou

Prodigy 20 points

Thank you Sean for pointing me in the right direction. Had to play with the values a bit to get it to work. 2.2K, 24.9K, MMBT3904, and 10K PTC Thermistor is what worked for me. 11.8K (as per data sheet) was too small and would not let the initial startup current get to 1 amp. It would start up at around 650mA and go down from there as the PCB heated up. 24.9K was the magic number for me. Just posting all of this in case anyone else want to use this feature. Thanks Again Sean!!

0 Sean Zhou over 4 years ago in reply to Ken Kelly

TI__Mastermind 22745 points

Hi Kelly,

That would be helpful, thank you for the information.

Sean

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LM3414HV: Thermal Foldback Question