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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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  • Voltage_Reg.jpg
    Voltage_Reg.jpg
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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.
 

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.
 

Thanks all for your answers.
It was very useful.
 

Hi Everyone,

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

Thanks,
Satheesh
 

maybe output capacitor ≥ Input capacitor .
 

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