CN-116930586-B - Calibration method and calibration device

Abstract

A calibration method and a calibration device are provided, wherein the method is suitable for an operational amplifier. The operational amplifier has a first input stage, a second input stage, a first output stage, and a second output stage, the first input stage is coupled to the second output stage, and the second input stage is coupled to the first output stage. The calibration method comprises the steps of closing the second input stage, measuring a first offset voltage of the first input stage when the second input stage is closed and the first output stage and the second output stage are connected in series in a first mode, connecting the first output stage and the second output stage in series in a second mode different from the first mode, and measuring a second offset voltage of the first input stage when the second input stage is closed and the first output stage and the second output stage are connected in series in the second mode.

Inventors

• CHEN BAISHENG

Assignees

• 新唐科技股份有限公司

Dates

Publication Date

20260505

Application Date

20220704

Priority Date

20220407

Claims (10)

1. 1. A calibration method for an operational amplifier, wherein the operational amplifier has a first input stage, a second input stage, a first output stage, and a second output stage, the first input stage is coupled to the second output stage, and the second input stage is coupled to the first output stage, wherein the calibration method comprises: closing the second input stage; When the second input stage is turned off and the first output stage and the second output stage are connected in series in a first manner, measuring a first offset voltage of the first input stage, wherein the first offset voltage is a sum of the offset voltage of the first input stage, a first equivalent value and a second equivalent value, wherein the first equivalent value is an equivalent value of the offset voltage of the first output stage in the first input stage, and the second equivalent value is an equivalent value of the offset voltage of the second output stage in the first input stage; the first output stage and the second output stage are connected in series in a second mode, wherein the first mode and the second mode are different; When the second input stage is turned off and the first output stage and the second output stage are connected in series in the second mode, a second offset voltage of the first input stage is measured; Closing the first input stage; When the first input stage is turned off and the first output stage and the second output stage are connected in series in the first manner, measuring a third offset voltage of the second input stage, wherein the third offset voltage is a sum of the offset voltage of the second input stage, the first equivalent value and the second equivalent value, wherein the first equivalent value is an equivalent value of the offset voltage of the first output stage and the second input stage, and the second equivalent value is an equivalent value of the offset voltage of the second output stage and the second input stage; concatenating the first output stage and the second output stage in the second mode, and When the first input stage is turned off and the first output stage and the second output stage are connected in series in the second mode, a fourth offset voltage of the second input stage is measured.
2. 2. The method of claim 1, wherein the first output stage comprises a first sub-output stage and a second sub-output stage, the second output stage comprises a third sub-output stage and a fourth sub-output stage, wherein the first sub-output stage and the third sub-output stage are serially connected to each other when the first output stage and the second output stage are serially connected in the first manner, and the second sub-output stage and the fourth sub-output stage are serially connected to each other when the first output stage and the second output stage are serially connected in the second manner, and wherein the first sub-output stage and the fourth sub-output stage are serially connected to each other when the first output stage and the second output stage are serially connected in the second manner.
3. 3. The method of calibrating according to claim 1, further comprising: and calculating a voltage calibration value of the operational amplifier according to the first offset voltage, the second offset voltage, the third offset voltage and the fourth offset voltage.
4. 4. The method of claim 3, wherein the second offset voltage is an offset voltage of the first input stage minus the first equivalent value plus the second equivalent value, and wherein the method further comprises: And performing mathematical operation on the first offset voltage and the second offset voltage to obtain a first value, wherein the first value is the sum of the offset voltage of the first input stage and the second equivalent value.
5. 5. The method of claim 4, wherein the fourth offset voltage is an offset voltage of the second input stage plus the first equivalent minus the second equivalent, and wherein the method further comprises: Performing a mathematical operation on the third offset voltage and the fourth offset voltage to obtain a second value, wherein the second value is the sum of the offset voltage of the second input stage and the first equivalent value, and And calculating the voltage calibration value of the operational amplifier according to the first value and the second value, wherein the voltage calibration value is the sum of the first value and the second value.
6. 6. A calibration device for calibrating an operational amplifier, wherein the operational amplifier has a first input stage, a second input stage, a first output stage, and a second output stage, the first input stage is coupled to the second output stage, and the second input stage is coupled to the first output stage, the calibration device comprising: closing the second input stage; When the second input stage is turned off and the first output stage and the second output stage are connected in series in a first manner, measuring a first offset voltage of the first input stage, wherein the first offset voltage is a sum of the offset voltage of the first input stage, a first equivalent value and a second equivalent value, wherein the first equivalent value is an equivalent value of the offset voltage of the first output stage in the first input stage, and the second equivalent value is an equivalent value of the offset voltage of the second output stage in the first input stage; the first output stage and the second output stage are connected in series in a second mode, wherein the first mode and the second mode are different; When the second input stage is turned off and the first output stage and the second output stage are connected in series in the second mode, a second offset voltage of the first input stage is measured; Closing the first input stage; When the first input stage is turned off and the first output stage and the second output stage are connected in series in the first manner, measuring a third offset voltage of the second input stage, wherein the third offset voltage is a sum of the offset voltage of the second input stage, the first equivalent value and the second equivalent value, wherein the first equivalent value is an equivalent value of the offset voltage of the first output stage and the second input stage, and the second equivalent value is an equivalent value of the offset voltage of the second output stage and the second input stage; concatenating the first output stage and the second output stage in the second mode, and When the first input stage is turned off and the first output stage and the second output stage are connected in series in the second mode, a fourth offset voltage of the second input stage is measured.
7. 7. The calibration device of claim 6, wherein the first output stage comprises a first sub-output stage and a second sub-output stage, the second output stage comprises a third sub-output stage and a fourth sub-output stage, wherein the first sub-output stage and the third sub-output stage are serially connected to each other when the first output stage and the second output stage are serially connected in the first manner, the second sub-output stage and the fourth sub-output stage are serially connected to each other when the first output stage and the second output stage are serially connected in the second manner, and the first sub-output stage and the fourth sub-output stage are serially connected to each other when the first output stage and the second output stage are serially connected in the second manner.
8. 8. The calibration device of claim 6, wherein said calibration device further comprises: and calculating a voltage calibration value of the operational amplifier according to the first offset voltage, the second offset voltage, the third offset voltage and the fourth offset voltage.
9. 9. The calibration device of claim 8, wherein the second offset voltage is an offset voltage of the first input stage minus the first equivalent value plus the second equivalent value, and wherein the calibration method further comprises: And performing mathematical operation on the first offset voltage and the second offset voltage to obtain a first value, wherein the first value is the sum of the offset voltage of the first input stage and the second equivalent value.
10. 10. The calibration device of claim 9, wherein the fourth offset voltage is an offset voltage of the second input stage plus the first equivalent minus the second equivalent, wherein the calibration method further comprises: Performing a mathematical operation on the third offset voltage and the fourth offset voltage to obtain a second value, wherein the second value is the sum of the offset voltage of the second input stage and the first equivalent value, and And calculating the voltage calibration value of the operational amplifier according to the first value and the second value, wherein the voltage calibration value is the sum of the first value and the second value.

Description

Calibration method and calibration device Technical Field The present invention relates to a calibration method and a calibration device, and more particularly, to a calibration method and a calibration device for measuring offset voltage of an operational amplifier. Background In an operational amplifier using a Metal-Oxide-semiconductor (MOSFET) device, according to its ideal operation, when the gate voltages of the input transistor pairs are equal, the drain currents of the input transistor pairs are equal and stable. However, the operational amplifier often has a slight offset voltage (offset voltage) due to the influence of the process variation of the metal oxide semiconductor. In addition, the gain of the operational amplifier is very high, and any slight offset voltage is amplified by the gain of the operational amplifier, so that the output result is converted to have obvious influence. Therefore, it is necessary to measure the offset voltage of the operational amplifier, thereby suppressing the offset voltage of the operational amplifier. Disclosure of Invention The invention provides a calibration method of an operational amplifier, which is used for accurately measuring the offset voltage of the operational amplifier, so that a user can finely adjust the offset voltage of the operational amplifier according to the use situation of the operational amplifier. In addition, the calibration method provided by the invention can also respectively obtain the respective offset voltages of the input stage and the output stage. In view of the above, the present invention provides a calibration method for an operational amplifier, wherein the operational amplifier has a first input stage, a second input stage, a first output stage and a second output stage, the first input stage is coupled to the second output stage, and the second input stage is coupled to the first output stage. The calibration method includes closing the second input stage, measuring a first offset voltage of the first input stage when the second input stage is closed and the first output stage and the second output stage are connected in series in a first manner, wherein the first offset voltage is a sum of the offset voltage of the first input stage, a first equivalent value and a second equivalent value, wherein the first equivalent value is an equivalent value of the first input stage, the second equivalent value is an equivalent value of the first input stage, the offset voltage of the second output stage is connected in series in a first manner, wherein the first output stage and the second output stage are different in the first manner, measuring a second offset voltage of the first input stage when the second input stage is closed and the first output stage and the second output stage are connected in series in the second manner, wherein the first equivalent value is a sum of the first input stage, the second equivalent value is a value of the first input stage, the first output stage and the second output stage is connected in series in the first manner, the first equivalent value is a sum of the first output stage and the second equivalent value is a sum of the first output stage and the first equivalent value is a sum of the first output stage and the second equivalent value is connected in series, the second equivalent value is an equivalent value of the offset voltage of the second output stage and the second input stage, the first output stage and the second output stage are connected in series in the second mode, and a fourth offset voltage of the second input stage is measured when the first input stage is turned off and the first output stage and the second output stage are connected in series in the second mode. According to an embodiment of the present invention, the first output stage includes a first sub-output stage and a second sub-output stage, the second output stage includes a third sub-output stage and a fourth sub-output stage, wherein when the first output stage and the second output stage are connected in series in the first manner, the first sub-output stage and the third sub-output stage are connected in series, the second sub-output stage and the fourth sub-output stage are connected in series, and when the first output stage and the second output stage are connected in series in the second manner, the first sub-output stage and the fourth sub-output stage are connected in series, and the second sub-output stage and the third sub-output stage are connected in series. According to an embodiment of the present invention, the calibration method further includes calculating a voltage calibration value of the operational amplifier according to the first offset voltage, the second offset voltage, the third offset voltage, and the fourth offset voltage. According to an embodiment of the present invention, the second offset voltage is an offset voltage of the first input stage minus the first equivalent value plu