Analog signal amplifier with OpAmp, Transistor or Darlington Pair?

artfuldodger · Jan 13, 2023

Hi all,

Looking for some advice please, I’m looking to modify the volage output signal of an engine sensor from 1.5-3.5v to 1.5 to 4.5v range. The sensor has a regulated 5v supply, however also provides power to 2 other amplified hall type sensors so keen any amplifier for this circuit has minimal current draw.

The sensor provides positional info for the ecu, so assume the signal will just be feeding a A-D converter.

Any advice or circuit guidance would be much appreciated.

crutschow · Jan 13, 2023

Here's the simulation of an op amp circuit that should do what you want.
It has a non-inverting gain of 1.5 to give an output swing of 3 volts for a 2 volt input swing, and adds a -0.75 volt offset so that the output is still 1.5 volts for a 1.5 volt input.

It will draw about 4 mA of power.

Any rail-to-rail op amp should work