Hello, is anybody able to help me with this current mirror issue?
I have a board for manufacturing test that was just updated to measure current.
This was simulated using ltspice and looked good.
The finished circuit does not behave even remotely close to the simulation. I realized the transistors are going to vary but I was hoping it would be in the ball park.
The simulation is attached. Basically R1 is the load and on the other side of the mirror Vout goes (through a buffer) into a micro ADC.
We wanted to measure 0-250ma through the load and I was expecting Vout to be 0-3.3 volts corresponding to this current.
In the actual circuit there is way more current on the measuring side of the circuit that expected by the simulation.
Is this just totally wrong and not ever going to work?
Thanks
Chris
I have a board for manufacturing test that was just updated to measure current.
This was simulated using ltspice and looked good.
The finished circuit does not behave even remotely close to the simulation. I realized the transistors are going to vary but I was hoping it would be in the ball park.
The simulation is attached. Basically R1 is the load and on the other side of the mirror Vout goes (through a buffer) into a micro ADC.
We wanted to measure 0-250ma through the load and I was expecting Vout to be 0-3.3 volts corresponding to this current.
In the actual circuit there is way more current on the measuring side of the circuit that expected by the simulation.
Is this just totally wrong and not ever going to work?
Thanks
Chris