LM3409: Iout couldn't be adjusted based on the surrounding components.

Pang

Part Number: LM3409

Hi,

Current facing an issue for LM3409 which based on the specs below and unable to achieve the Iout because the Iout follows the Iin values.When the nput 24Vdc, the output current follow the input current setting on DC power supply. Using Onsemi PFET FQD7P20 in the circuit.

If mean when the input current 2A fromDC power supply, the LED output current also 2A.

Vin: 10 ~ 60VDC > 24Vdc typ.

Vout: 6.6V @ 2.1A

As for schematic and layout is confidential, please provide email in order for me to share the file.

When input 24Vdc, the output current follow the input current setting on DC power supply.

If mean when I set input current 2A on DC power supply, the LED output current also 2A.

over 5 years ago

0 Irwin Nederbragt over 5 years ago

TI__Mastermind 28655 points

Hello,

Can you check if the Drain and Source are swapped on the MOSFET connections?

I will send an email to you as well.

Also, if you're turning up the voltage slowly on the power supply the current setting of the power supply needs to be higher than the peak current trip of the LM3409 otherwise the power supply will just current limit and the LM3409 will never reach peak trip threshold.

Best Regards,

0 Irwin Nederbragt over 5 years ago in reply to Irwin Nederbragt

TI__Mastermind 28655 points

Hello,

I'm going to close this thread since we are communicating via email.

Best Regards,

Power management

Power management forum

LM3409: Iout couldn't be adjusted based on the surrounding components.