Hi,
First of all, Happy New Year to everybody!! Hope you are doing good.
Now my problem:
I want to power a microphone with a button cell. The button cell is a silver oxide one with an initial voltage of 1.55V (new).
The microphone works down to 0.9V, it's maximum rating is 1.45V though. The microphone consumes not more than 25uA. I want to limit the voltage on the microphone to 1.4V max without adding more than a few uA (< 10). I know it can be done with a comparator and voltage reference and P-FET but current will be higher than just a few uA due to the voltage reference AND the component count is quite high.
Just putting a schottky in series will not allow me to completely discharge the battery, unfortunately discharge curves for that battery available on the internet vary widely also, some are straight at about 1.3V, some decrease almost linearily...
Any ideas? Low component count, low additional current, 1.35 to 1.4V maximum output voltage. Ideally I would remove 0.15V when the battery is new and once it arrives at 1.4V it just goes straight through to the load (microphone)
Thanks
Link to datasheet: http://store.invensense.com/datasheets/invensense/ICS-40310_ProductSpec_V1 0.pdf
First of all, Happy New Year to everybody!! Hope you are doing good.
Now my problem:
I want to power a microphone with a button cell. The button cell is a silver oxide one with an initial voltage of 1.55V (new).
The microphone works down to 0.9V, it's maximum rating is 1.45V though. The microphone consumes not more than 25uA. I want to limit the voltage on the microphone to 1.4V max without adding more than a few uA (< 10). I know it can be done with a comparator and voltage reference and P-FET but current will be higher than just a few uA due to the voltage reference AND the component count is quite high.
Just putting a schottky in series will not allow me to completely discharge the battery, unfortunately discharge curves for that battery available on the internet vary widely also, some are straight at about 1.3V, some decrease almost linearily...
Any ideas? Low component count, low additional current, 1.35 to 1.4V maximum output voltage. Ideally I would remove 0.15V when the battery is new and once it arrives at 1.4V it just goes straight through to the load (microphone)
Thanks
Link to datasheet: http://store.invensense.com/datasheets/invensense/ICS-40310_ProductSpec_V1 0.pdf