LM4132 VIN<VOUT condition

Hirotsugu Kobayashi

Mastermind 8485 points

Other Parts Discussed in Thread: LM4132

Hi,

When VOUT is bigger than VIN, do a reverse current flow in LM4132?

Is a diode for protection necessary?

over 8 years ago

0 Hirotsugu Kobayashi over 8 years ago

Mastermind 8485 points

Please answer my question.

0 Christopher Dean over 8 years ago

TI__Intellectual 1745 points

Hi Hirotsugu,

What do you think is going to cause VIN< VOUT? In normal operation, if VIN drops below VOUT, the part will not operate and VOUT will deregulate or shut off. I would expect the reference to be driving an input to another IC, so the only way VOUT could stay high while VIN drops is very large output capacitance with a very high impedance load. You can use an output capacitor but this part will work without one.

What are you trying to do with the part that you think this condition will occur?

0 Hirotsugu Kobayashi over 8 years ago in reply to Christopher Dean

Mastermind 8485 points

Thank you for your answer.
In case of LDO, a external diode is sometimes used to protect reverse voltage if the VIN is shorted GND.
Does LM4132 need a similar protection circuit if the VIN is shorted GND?

0 Christopher Dean over 8 years ago in reply to Hirotsugu Kobayashi

TI__Intellectual 1745 points

Hi,
I can't find information that would show there is reverse current protection built into the LM4132. I would suggest adding the protection circuit.

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LM4132 VIN<VOUT condition