LM3409HV: Minimum supply voltage (Vin) would be over the output voltage (Vout)

Liam Wedekind

Part Number: LM3409HV
Other Parts Discussed in Thread: LM3409

Hi,

Can you confirm what the minimum supply voltage (Vin) would be over the output voltage (Vout) for the LM3409HV. I am under the impression that there needs to be a minimum voltage overhead for a buck converter but I am unsure how to calculate it for this device.

We have an LED string with a forward voltage of 34.2Vdc, what would be the expected input voltage for the driver to provide a stable output?

Thank you.

over 1 year ago

0 Dave Yaeger over 1 year ago

TI__Intellectual 2925 points

Hi Liam – our experts for this issue are currently celebrating the Chinese New Year. Please expect a delay in response. Thank you for your understanding.

0 Mason Wang over 1 year ago

TI__Genius 9630 points

hi Liam

this is actually not a specific voltage value. LM3409/09HV can be operated into dropout which occurs when the input voltage is approximately equal to output voltage. You can refer to 9.1.2 in the datasheet for more detailed information.

Power management

Power management forum

LM3409HV: Minimum supply voltage (Vin) would be over the output voltage (Vout)