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US 2026/0051865 A1Published application
High precision jfet amplifier
AssigneeWeed Instrument Company, Inc.
InventorHoria Bendea
Life of this patent
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Abstract
An all-JFET operational amplifier provides improved accuracy and lower thermal drift than conventional JFET amplifiers. In some examples, the JFET operation amplifier includes an input stage including input transistors supplied with equal drain currents by matched current sources. In some examples, the input circuit is stabilized by local current feedback.
Claims19
A junction field effect transistor (JFET) amplifier, comprising:
- a differential input stage including first and second JFETs supplied with equal drain currents by matched first and second current sources, respectively, wherein the first JFET and the first current source are coupled at a control node;
- and
- a gain stage controlled by the control node.
A junction field effect transistor (JFET) amplifier, comprising:
- a differential input stage including matched first and second JFETs supplied with equal drain currents by matched first and second JFET current sources, respectively, wherein a drain of the first JFET and the first current source are coupled at a control node;
- a gain stage including a third JFET controlled by the control node;
- and
- a fourth JFET coupled between a drain and a source of the second JFET to provide local feedback current, wherein the third and fourth JFETs are matched, such that drain-to-source voltages of the first and second JFETs are equalized.
1 more element
A method of operating a junction field effect transistor (JFET) amplifier, comprising:
- providing first and second JFETs of a differential input stage equal drain currents by matched first and second current sources, wherein the first JFET and the first current source are coupled at a control node;
- receiving, at the first and second JFETs, a differential input signal;
- and
- amplifying, by a gain stage, a voltage at the control node.
1 more element
Dependencies are inferred from the claim text.