Transconductor circuit
AssigneeSTMicroelectronics Design and Application GmbH
InventorSebastian Zeller
Life of this patent
Estimating the term…
Abstract
A transconductor circuit, particularly according to the multi-tanh principle, having a first input node and a second input node, a first differential amplifier coupled to the first and second input nodes, and having a first offset voltage, and a second differential amplifier coupled to the first and second input nodes, and having a second offset voltage different from the first offset voltage. A first resistance circuit is coupled between the first differential amplifier and at least one current source, and a second resistance circuit is coupled between the second differential amplifier and the at least one current source. Varying of the current sources enables control of the transconductance without degrading linearity.
Claims21
A circuit, comprising:
- a current source;
- a first differential amplifier coupled to first and second input nodes and structured to have a first offset voltage;
- a second differential amplifier coupled to the first and second input nodes and structured to have a second offset voltage different from the first offset voltage;
- and
- a first resistance circuit coupled between the first differential amplifier and at least one current source, and a second resistance circuit coupled between the second differential amplifier and the at least one current source, the first and second resistance circuits each comprising a first transconductance element and a second transconductance element, and wherein the at least one current source is structured to be controllable to control the transconductance of the first and second transconductances without degrading linearity of the circuit.
A system, comprising:
- a first input node structured to receive a first input signal and a second input node structured to receive a second input signal;
- a first differential amplifier coupled to the first and second input nodes and structured to have a first offset voltage;
- and
- a second differential amplifier coupled to the first and second input nodes and structured to have a second offset voltage different from the first offset voltage;
- respective output paths of the first and second differential amplifiers that are connected in parallel;
- a first resistance circuit coupled between the first differential amplifier and a current source, and a second resistance circuit coupled between the second differential amplifier and the current source;
- and
- each of the first and second resistance circuits having at least one diode element coupled between the respective differential amplifier and the at least one current source in a forward direction, and having a transistor with a controlled path coupled in parallel with the diode element, wherein the diode element comprises a first transconductance and the transistor is structured to provide a second transconductance that is negative with respect to the first transconductance.
A tuner for processing broadcast signals, the tuner comprising:
- a transconductor circuit having a current source, first and second differential amplifiers coupled in parallel to first and second input nodes and first and second output nodes and to respective first and second resistance circuits each including a first transconductance element and a second transconductance element, the first and second resistance circuits coupled to a current source structured to be controllable to control a transconductance of the first and second transconductances.
Dependencies are inferred from the claim text.