Device for correcting input offset voltage

Abstract

The present invention is an input offset voltage adjusting device used in operational amplifier. The invention is characterized in comprising a switch element, a buffer element, an offset voltage adjusting element and a micro control element. The technical proposal of the present invention is that the micro control element controls the switch element through the buffer element, and the different operation modes are switched by the switch element. The input offset voltage of the operational amplifier is adjusted by the offset voltage adjusting element when the input offset voltage adjusting device is under the offset voltage adjusting mode to input more accurate signal. Besides, the present invention can adjust the offset voltage at any time according to the work environment in order to maintain the best performance of the operational amplifier.

Description

technical field [0001] The invention relates to a device for correcting input offset voltage, in particular to a correction device for adjusting input offset voltage of operational amplifier. Background technique [0002] The input offset voltage is the DC voltage that must be applied to the input in order for the quiescent DC output voltage to be equal to zero or some default value. If the op amp's input stage was perfectly symmetrical and the transistors were perfectly matched, the input offset voltage would be equal to zero. But due to variations in the manufacturing process, on-chip geometries and doping can never be perfect, so all op amps require a small voltage across the inverting and non-inverting inputs to compensate for them. mismatch between. [0003] Therefore, when applying the characteristics of a comparator or an operational amplifier, the input offset voltage is one of the important parameters to be considered. The size of the input offset voltage will af...

AI Technical Summary

Problems solved by technology

However, using the test adjustment method to correct the input offset voltage, the corrected result can only guarantee the performance under the environment of the calibration, because the input offset voltage will drift with different operating voltage, operating temperature and input voltage

Therefore, if the input offset voltage is corrected by testing and adjusting, once the working environment is different, the characteristics of the operational amplifier will deteriorate, resulting in larger errors

However, if the chopper method is used, the circuit will require additional clock circuits and filters, so the circuit cost will be higher, the operating bandwidth cannot be improved, and the circuit response speed is slow, so it cannot be suitable for high-speed comparators or amplifiers. Application and other disadvantages

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