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Voltage source with Low Quiescent and No Minimum Load

Started by rich September 10, 2012
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 re=
gulator requires enough current to put the zener into regulation which woul=
d 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
On 9/10/2012 12:36 PM, rich wrote:
> 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.
"rich" <rsoennichsen@gmail.com> wrote in message 
news:b0197703-37be-4c71-93af-f67379191b27@googlegroups.com...
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... 


On 9/10/2012 4:47 PM, TTman wrote:
> "rich" <rsoennichsen@gmail.com> wrote in message > news:b0197703-37be-4c71-93af-f67379191b27@googlegroups.com... > 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... > >
At 28 cents in quantity at Mouser, the MCP1700 looks pretty hard to beat.
rich wrote:
> 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.