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US 2017/0346454 A1Published application
Transconductance amplifier having low distortion
AssigneeFluke Corporation
InventorDavid J. Menacher
Life of this patent
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Abstract
A low distortion transconductance amplifier provides current to a grounded load using a virtual ground input stage, a pair of current mirrors, and a bias current source. The virtual ground input stage may include transistors arranged as a Darlington pair. The low distortion transconductance amplifier can function as a voltage-controlled AC current source that is operable at high frequencies.
Claims19
A circuit, comprising:
- a voltage source;
- a reference resistor coupled to the voltage source;
- an input stage including
- an operational amplifier coupled to the reference resistor;
- a transistor coupled to be driven by the operational amplifier;
- and
- a bias current source coupled to the transistor and the operational amplifier;
- an output stage including a grounded load resistor;
- and
- a pair of current mirrors, each current mirror coupling the input stage to the output stage.
7 more elements
A method of operating a circuit comprising:
- creating an input current source by coupling an input voltage source to a reference resistor;
- coupling the current source to a virtual ground;
- coupling a bias resistor to the virtual ground;
- coupling the virtual ground to a current mirror that provides a bias current via the bias resistor;
- supplying the bias current to a load resistor;
- and
- controlling the bias current by modulating the input current source.
4 more elements
A circuit, comprising:
- a current source;
- a transconductance amplifier coupled to the current source, the transconductance amplifier having a virtual ground input stage;
- and
- an output stage coupled to the transconductance amplifier, the output stage having a grounded load.
1 more element
Dependencies are inferred from the claim text.