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Charging/Discharging Time in Voltage Regulator

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satheeshvelu

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Hi Everyone,

I'm evaluating an LDO.
Vin=5V
Vout=3.3V

According to my evaluation, Vin discharge timing faster than Vout, will there be any effect due to this?

Please refer to the attached.

Thanks,
Satheesh
 

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erikl

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If your output transistor is a MOSFET, its parasitic anti-parallel diode will take care of a max. inverse in-out voltage difference of about 1V . In case of a BJT, a small inverse in-out voltage difference (a few volts) won't matter.
 

umesh49

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If your output transistor is a MOSFET, its parasitic anti-parallel diode will take care of a max. inverse in-out voltage difference of about 1V . In case of a BJT, a small inverse in-out voltage difference (a few volts) won't matter.
I read somewhere that if input will become less than output, a reverse current may flow in opposite direction which may lead to damage the LDO.
For this particular applicatino a small reverse current may flow for short time and LDO could sustain for that, but still I am not sure.
 

satheeshvelu

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Thanks all for your answers.
It was very useful.
 

satheeshvelu

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Hi Everyone,

Is there any way to calculate the reverse current and howto determine that it's safe?

Thanks,
Satheesh
 

wjvictor

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maybe output capacitor ≥ Input capacitor .
 

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