Trying to increase the voltage out of a photodiode.

[gittenlucky]

I have an impulse of ~200mV, ~50nA for about 0.15 seconds. To interface with my circuit, I need it to be 1V+. The problem is, I don't want to use an opamp, or something else that needs to be constantly powered. An ideal solution would be a relay or a FET that has a gate threshold in the millivolt range. However, I can't find anything similar to this. I have power available, but I do not want it to be used until the impulse occurs. Are there any other options for me at this low voltage level?

 

[berkeman]

I have an impulse of ~200mV, ~50nA for about 0.15 seconds. To interface with my circuit, I need it to be 1V+. The problem is, I don't want to use an opamp, or something else that needs to be constantly powered. An ideal solution would be a relay or a FET that has a gate threshold in the millivolt range. However, I can't find anything similar to this. I have power available, but I do not want it to be used until the impulse occurs. Are there any other options for me at this low voltage level?

The output from a photodiode is a photocurrent. Are you getting that 200mV by putting the 50nA through a 4 MegOhm resistor?

How often do the pulses occur? Do you need to know the pulse width, or is it okay if you just get a trigger signal for each pulse?

There are also some very low power opamps that may do what you want...

 

[berkeman]

Looks like Maxim has some with supply currents in the 20uA range...

http://www.maximintegrated.com/products/amp_comp/low_power/

.

 

[Studiot]

Depends upon your application.
One option might be a charge pump.

 

[yungman]

Get a micro power op-amp!

 

[berkeman]

Get a micro power op-amp!

Great minds think alike

 

[yungman]

Great minds think alike

Thanks, I take it as a big compliment.