Transconductance operational amplifier circuit and filter circuit

Abstract

The invention discloses a transconductance operational amplifier circuit and a filter circuit, the transconductance operational amplifier circuit comprises an input stage, an upper bias circuit, a lower bias circuit, a source electrode degradation structure and an improved Wilson current mirror structure, and a low-pass filter circuit comprises five identical transconductance operational amplifiers and five identical capacitors. The low-pass filter circuit structure based on the transconductance operational amplifier structure provided by the invention has the characteristics of low power consumption, low noise and low harmonic distortion, and has a very wide application prospect. Due to the fact that the OTA structure with the small transconductance value is used for achieving the function of the resistor, the capacitance value of the filter circuit under the cut-off frequency of 250 Hz is compatible with the CMOS technology. The OTA structure provided by the invention combines the technologies of current segmentation, current cancellation and source degradation, reduces the transconductance of OTA, and improves the linearity of OTA. The OTA provided by the invention works in a weak inversion working area, so that the power consumption of the circuit is reduced.

Description

technical field [0001] The invention belongs to the field of circuit design, and relates to a transconductance operational amplifier circuit and a filter circuit. Background technique [0002] As the demand for portable biological signal detection devices becomes more prominent, the demand for SoC circuit structures with low power consumption is increasing day by day. At the same time, the analog front-end filter circuit used for biological signal detection plays an important role in filtering out-of-band signals and noise of the front-end amplifier circuit. [0003] Traditional passive RC low-pass filter circuits require large resistor and capacitor values ​​and are not compatible with CMOS processes. Therefore, a low-pass filter circuit with a low cut-off frequency can be realized with a small capacitance value by using an OTA with a small transconductance instead of a resistor. At the same time, compared with the circuit structure working in the saturation region, the t...

AI Technical Summary

Problems solved by technology

[0003] Traditional passive RC low-pass filter circuits require large resistor and capacitor values ​​and are not compatible with CMOS processes

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