Low pass filter

Abstract

Disclosed is a low pass filter. According to the filter, parameters, such as the cut-off frequency, the direct-current gain and the Q factor, of the filter can be quite flexibly selected. Due to the fact that a proper resistance value is selected for a single integrated circuit by the low pass filter, compared with configurations of low pass filters of other standards, the low pass filter has the quite low capacitance, the quite low capacitivity and an active circuit.

Description

technical field [0001] The present invention generally relates to continuous time analog integrated circuit filters. More specifically, the present invention provides a fully tunable second order low pass filter with minimal active circuitry. Background technique [0002] Analog filters are essential to the operation of most electronic circuits and are often used to separate signals from noise. In general, an analog filter is an electrical network that alters the amplitude and / or phase characteristics and attenuates signals at other frequencies relative to signals in one or more frequency bands that pass freely. [0003] Filters are divided into five basic types according to frequency band: all-pass, band-pass, notch, low-pass, and high-pass. An all-pass filter has no effect on the amplitude of the signal at different frequencies, its function is to simply change the phase of the signal without affecting the signal amplitude. The other four types of filters freely pa...

AI Technical Summary

Problems solved by technology

This will lead to difficult tunability of filter components because of the flexibility of cutoff frequency, DC gain and Q factor

Second, in order to achieve a definite Q factor of Q>1, the capacitance ratio can be quite large, making it difficult to match capacitors to a good accuracy

Finally, the total capacitance required by the MFB circuit is quite high, which leads to higher manufacturing costs and a wider range of die area

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