Amplifier with reduced sensivity to offset voltages

摘要

The method for amplifying an input signal (VIN) which comprises a d.c. component and an a.c. component, includes a comparison of the input signal with a reference value to generate a correction signal (ICOR), the generation of an intermediate signal (IINT) by subtracting the correction signal from the transformed input signal (IIN), a rectification of the intermediate signal (IINT) producing a rectified intermediate signal (IRED), the evaluation of a mean value (IRECT) of the rectified intermediate signal, and a multiplication of the input signal (VIN) by the mean value (IRECT) to obtain an output signal (VOUT). The value of the correction signal is equal to the reference value for the values of the input signal higher than the reference value, and it is equal to the value of the input signal when the input signal is lower than the reference value. The reference value is selected so to eliminate the parasitic a.c. signals. A device is claimed which amplifies an input signal by implementing the method.