LM73605-Q1: When the input voltage goes to lower than the output voltage, will LM73605-Q1 have any problem?

Mamoru_Uozu

Part Number: LM73605-Q1

When the input voltage goes to lower than the output voltage, will LM73605-Q1 have any problem?

This condition means that the input voltage will ramps down or the power supply will be off for some reason before the output capacitor discharges.

Thanks,

0 Samuel Jaffe over 4 years ago

Mamoru,

If VIN ramps down slowly, VOUT will track VIN with a small drop. This is the dropout condition.

If VIN ramps down quickly and COUT is still charged, current will flow through the body diode of the high-side FET to VIN. This will discharge COUT.

-Sam

0 K.Kitamura over 4 years ago in reply to Samuel Jaffe

To Sam

Our concern is the current flowing body diode would break IC or not when VIN ramps down quickly.
Vout voltage is set 3.3V.

Keita

0 Samuel Jaffe over 4 years ago in reply to K.Kitamura

Keita,

Unless you have a supercapacitor or battery on the output, I don't expect a typical output capacitance to have enough energy to damage the diode.

-Sam

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