LM5001 boost & bypass behavior

Nicolas Bruneau

Other Parts Discussed in Thread: LM5001, LM5118

Hi,
I'm looking to use LM5001 for a specific application where I need to regenerate the voltage of a source.
The conditions on the system are as following:

Here I would like to make sure that LM5001 will not close its FET for Vin > Vout, allowing current to flow directly from the input to the output.

The second concern is for the case where the device will start switching when the input voltage starts to drops below the 55V limit. Here I don't know what to expect as a response...

If you have suggestion of device, or topology which would make more sense to use in that particular case, please let me know.

Thanks in advance for your support.
-nico

over 9 years ago

0 JohnTucker over 9 years ago

TI__Guru**** 191445 points

Always best to include the part number in the title of you post. That way the correct person will see it.

0 David Baba over 9 years ago

TI__Mastermind 40120 points

When Vin>Vout, the converter will stop switching completely. When Vin is lowered slowly below Vout, there maybe some bursting of switching pulses depending on the ripple voltage at the input as it relates to the output. You could opt to use a SEPIC or even the LM5118 that will be switching at ~50% duty cycle when Vin = Vout.

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LM5001 boost & bypass behavior