# Voltage source with Low Quiescent and No Minimum Load

R

#### rich

Jan 1, 1970
0
I need to provide a backup voltage to a device, the current requirement is 20uA. The device is battery powered. It is my understanding that zener regulator requires enough current to put the zener into regulation which would be too much for our battery life.

I know there are voltage references out there for this but they all seem tobe in the $2 range, a bit pricey. Any elegant solutions? Thanks Rich M #### mike Jan 1, 1970 0 I need to provide a backup voltage to a device, the current requirement is 20uA. The device is battery powered. It is my understanding that zener regulator requires enough current to put the zener into regulation which would be too much for our battery life. I know there are voltage references out there for this but they all seem to be in the$2 range, a bit pricey.

Any elegant solutions?

Thanks

Rich
Since you have no requirements for nominal voltage,
accuracy, stability, size, weight...and no notion
of where the power comes from,
I'd just use an old car battery. Even a dead one
should do 20uA for a long time.

The hardest part of a solution is defining the problem.

T

#### TTman

Jan 1, 1970
0
I need to provide a backup voltage to a device, the current requirement is
20uA. The device is battery powered. It is my understanding that zener
regulator requires enough current to put the zener into regulation which
would be too much for our battery life.

I know there are voltage references out there for this but they all seem to
be in the $2 range, a bit pricey. Any elegant solutions? Thanks Rich CR2032 coin cell ? MCP1700 regulator ? has 1ua quiescent current... R #### [email protected] Jan 1, 1970 0 rich said: I need to provide a backup voltage to a device, the current requirement is 20uA. The device is battery powered. It is my understanding that zener regulator requires enough current to put the zener into regulation which would be too much for our battery life. I know there are voltage references out there for this but they all seem to be in the$2 range, a bit pricey.

Any elegant solutions?

Thanks

Rich
Depends on voltage needed.
Use a diode OR gate, where master supply voltage being slightly
higher than the backup battery which is lithium.

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its you
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