Universal digitally controlled offset adjustment circuit for op amps

As shown in the figure, this is a general digital control offset adjustment circuit. The offset change is digitally controlled. The integrated chip DAC-08C is used as a 6-bit D/A converter. Pins ② and ④ are output terminals, and two l00kΩ resistors are connected externally. These two resistors are equivalent to load resistors, on which an output voltage Vo1 is generated. The output voltage Vo1 is converted into an offset adjustment current of A2 through two 4.7MΩ large resistors. The two 4.7MΩ resistors are determined according to the range of offset adjustment required. This circuit is very useful for large circuit systems, because in fact any offset voltage can be stored in the memory and added to the amplifier when needed.