DC bias cancel circuit

Abstract

The invention discloses a DC bias elimination circuit, which can be used in a multi-stage amplifier, a multi-stage filter or a combination thereof. A variable-frequency switch, the output end of the last stage component is connected to the input end of a low-pass filter circuit, and several variable gain amplifiers are provided, and the output ends of each variable gain amplifier are respectively connected to the series connection of components at all levels. The input terminal is connected to the output terminal of the low-pass filter circuit, which can achieve the DC bias elimination effect required by multiple feedback paths without consuming large area and high power.

Description

technical field [0001] The invention relates to a DC bias elimination circuit, in particular to a DC bias elimination circuit capable of achieving the DC bias elimination effect required by multiple feedback paths without consuming large area and high power. Background technique [0002] In recent years, in the implementation of wireless communication receivers, the use of direct down-frequency architecture has become more and more common. The main reason is that it has lower cost and lower circuit complexity, and has the advantages of high signal quality and high integration. Therefore, in In the current communication industry, a general application trend is gradually formed, but the direct down-converting architecture will form a DC bias in the circuit, so eliminating the DC bias in the circuit has become a major problem. [0003] There are mainly two methods for eliminating DC bias that have been disclosed at present, and their circuit structures are as follows: figure 1...

AI Technical Summary

Problems solved by technology

These low-pass filters will cause excessive circuit area and high power loss. Therefore, in order to solve these problems, the present invention proposes a mechanism for eliminating DC bias voltage, which not only has multiple feedback paths, but also has low-cost and low-power Under the premise, it can also have the required DC bias cancellation capability

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