Filter and operating method thereof

Abstract

A filter and an operating method thereof are provided. The filter includes a logic circuit, a power circuit and a filter circuit. The logic circuit provides a switching control signal. The power circuit is coupled to the logic circuit. The filter circuit is coupled to the power circuit and the logic circuit. The filter circuit includes an amplifier, a first capacitor and a first transistor. An output end of the amplifier is coupled to the logic circuit, and provides an output signal. The first capacitor is coupled between an input end and output end of the amplifier. The first transistor is connected in parallel with the first capacitor. A control end of the first transistor is coupled to the power circuit. The logic circuit provides a switching control signal to the power circuit according to the output signal. The power circuit supplies a control voltage to the first transistor according to the switching control signal. Therefore, the filter of the present invention and its method of operation can provide an accurate filtered signal output function.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application claims the priority benefit of China application serial no. 201811557626.7, filed on Dec. 19, 2018. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.BACKGROUND OF THE INVENTION1. Field of the Invention[0002]The present invention generally relates to a circuit, in particular, to a filter and an operating method thereof.2. Description of Related Art[0003]In a circuit architecture of an existing filter, a transistor may usually be applied to the circuit architecture of the filter as a pseudo-resistor due to a specific operation characteristic thereof. However, since a threshold voltage Vth of a transistor may change with a temperature or a manufacturing procedure to correspondingly change a current flowing through the transistor, equivalent resistance value of the transistor is likely to change with the temperature to generate a great offse...

AI Technical Summary

Benefits of technology

The present invention provides a filter and operating method that can accurately produce a stable and accurate filter signal output function even when subjected to changes in manufacturing process and temperature. The filter circuit includes a transistor serving as a pseudo-resistor, which can be controlled to compensate for temperature variations and ensure the filter circuit runs stably. Additionally, in case of saturated output, the transistor can be quickly switched on to effectively reset the filter, providing an efficient means to recover from filter saturation. Overall, the filter and operating method of the present invention offer a reliable and accurate solution for filtering purposes.

Problems solved by technology

In view of this, how to reduce an equivalent resistance value change brought by a manufacturing procedure and a temperature to a pseudo-resistor to improve output accuracy is a problem to be solved in the industry.

Images