LMR14030: overcurrent trigger condition and thermal

Betty Guo

Part Number: LMR14030

Hi team,

customer test LMR14030 over current protection. customer applicaiton are that:

input 24V ; output 5V

test condition is connect 5V to ground, power up 24V, they found that the tempature of LMR14030 will be very high, can reach up to about 100C. also, the tempature of inductior and diode will up to 168C.

could you give suggestions about why the LMR14030 tempature very high, does this the normal? what's the over current protection conditions?

thank you.

over 4 years ago

0 Marshall_Beck over 4 years ago

TI__Mastermind 29670 points

The device has cycle by cycle current limit. I wouldn't think the device would see this much temp rise with proper design.

What is the inductor part number?

Thank you.

0 Betty Guo over 4 years ago in reply to Marshall_Beck

TI__Expert 7300 points

Hi Marshall,

the P/N of D1 is SRM54ALF, I don;t know the inductor partnumber, attached the schematic 8233.LMR14030 SCH.pdf

0 Betty Guo over 4 years ago in reply to Marshall_Beck

TI__Expert 7300 points

Hi Marshall,

the P/N of D1 is SRM54ALF, I don;t know the inductor partnumber, attached the schematic 4530.LMR14030 SCH.pdf

0 Betty Guo over 4 years ago in reply to Betty Guo

TI__Expert 7300 points

Hi Marshall,

One more question, my understanding is when the over current trigger, the LMR14030 will constant output with the limit current, and can't shunt down, right?

when the over current, LMR14030 flow 5.5A current always until trigger over thermal protection, right?

thank you

0 Marshall_Beck over 4 years ago in reply to Betty Guo

TI__Mastermind 29670 points

Reason I ask inductor part number is the inductor might become saturated. If it becomes saturated, it will become very low impedance and result in high peak currents flowing through the device, possibly.

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LMR14030: overcurrent trigger condition and thermal