Method for single-end offset compensation of an operational amplifier

A method for single-end compensation of an operational amplifier, comprising:

• designing an operational amplifier having a single-end offset style, preparing a common-mode circuit, a switch circuit, a comparator, a digital circuit and a compensation circuit;
• wherein a set of double-end input signals of the operational amplifier is initially inputted to the common circuit and the switch circuit, and then the common mode circuit will generate an average signal that will be transmitted to the operational amplifier via the switch circuit;
• outputs of the operational amplifier will generate a single-end offset voltage which is inputted to the comparator, so that the comparator will generate an initial output to trigger the digital circuit;
• the digital circuit will generate a group of digital signals to make the compensation circuit generate a compensation current;
• the compensation current is provided to the operational amplifier to compensate the single-end offset voltage of the operational amplifier;
• when the single-end offset voltage of the operational amplifier is converted, the output of the comparator will change state and will be detected by the digital circuit, so that the digital circuit will fix the group of digital signals and instruct the switch circuit to block the average signal of the common mode circuit, allowing the set of double-end input signals to be inputted to the operational amplifier directly.