Hi everyone,
I'm trying to build my bench power supply with LM317 and Atmel ATMega8 microcontroller which would control output, measure and display output voltage and current.
Everything was fine until I got to part where I had to measure current. Idea was to place shunt resistor in front (input side) of LM317 instead of on load side so that LM317 compensate for voltage drop on shunt and output voltage on load should be stable and not dependable on current.
Voltage drop on shut is measured with LM358 (set to 10x gain) but unfortunately output from LM358 is not as expected. I get 24-25mV regardless of voltage drop.
I tried connecting shunt on low-side with load in series and got some reasonable results but it's not what I'm trying to do.
I attached JPEG of my circuit running in Proteus which indicates that this should work...
Any ideas???
I'm trying to build my bench power supply with LM317 and Atmel ATMega8 microcontroller which would control output, measure and display output voltage and current.
Everything was fine until I got to part where I had to measure current. Idea was to place shunt resistor in front (input side) of LM317 instead of on load side so that LM317 compensate for voltage drop on shunt and output voltage on load should be stable and not dependable on current.
Voltage drop on shut is measured with LM358 (set to 10x gain) but unfortunately output from LM358 is not as expected. I get 24-25mV regardless of voltage drop.
I tried connecting shunt on low-side with load in series and got some reasonable results but it's not what I'm trying to do.
I attached JPEG of my circuit running in Proteus which indicates that this should work...
Any ideas???