Operational transconductance amplifier, operational transconductance amplifier-capacitor filter and high order reconfigurable analog filter

An operational transconductance amplifier-capacitor (OTA-C) filter comprising a plurality of electrically connected operational transconductance amplifiers and a plurality of capacitors, wherein each of the operational transconductance amplifiers comprises:

• a fully-differential amplifying circuit, configured for receiving a differential input voltage and for providing a differential output voltage, the fully-differential amplifying circuit comprising a plurality of diffusor-differential-pair circuits;
• a bias driving circuit, electrically connected with the fully-differential amplifying circuit, the bias driving circuit being configured for providing at least one first bias current to drive the fully-differential amplifying circuit and adjust the transconductance of the operational transconductance amplifier;
• and
• a common mode feedback circuit, electrically connected with the fully-differential amplifying circuit, the common mode feedback circuit being configured for stabilizing the differential output voltage.

A high order filter comprises:

• plurality of cascadable operational transconductance amplifier-capacitor filters, each of the operational transconductance amplifier-capacitor filters comprising a plurality of electrically connected operational transconductance amplifiers and a plurality of capacitors, wherein each of the operational transconductance amplifiers comprises;
• a fully-differential amplifying circuit, configured for receiving a differential input voltage and for providing a differential output voltage, the fully-differential amplifying circuit comprising a plurality of diffusor-differential-pair circuits;
• a bias driving circuit, electrically connected with the fully-differential amplifying circuit, the bias driving circuit being configured for providing at least one first bias current to drive the fully-differential amplifying circuit and adjust the transconductance of the operational transconductance amplifier;
• and
• a common mode feedback circuit, electrically connected with the fully-differential amplifying circuit, the common mode feedback circuit being configured for stabilizing the differential output voltage;
• and
• a control module, configured for controlling the operational transconductance amplifier-capacitor filters to be selectively cascaded according to an external signal.