Voltage is dropping down !!!

[shaikss]

Hi Folks,

I have designed a rectifier and regulator for RFID Tag. Both are working fine when they are simulated independently.
When I gave 500mV as input to 4-stage rectifier, I got 1V output for open load ckt condition.

Now, I have connected rectifier to regulator. Rectifier output is 500mV. What may be the reason? Because of the load, current decreases. That is fair. But why voltage is decreasing? Any clue. When regulator has run independently, it consumes 836nW of power. I am in desperate need of help. Pls help me.

[rkupka]

how about posting a schematic first ?

[vk6zgo]

The fact that the output voltage is halved implies that the input impedance of the regulator is equal to the output impedance of the rectifier.
Do you have any figures for these impedances?

My first reaction was that your input voltage was too small to turn a diode on,but when I Googled for 4 stage rectifier I found the following which may be helpful.:

ftp://202.196.33.229/NSTL-english/2010/20100105/zx94333767_02.pdf

It lost me on the second page!