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US 2009/0153233 A1Published application
Bias circuit
AssigneeFujitsu Limited
InventorTomoyuki ARAI
Life of this patent
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Abstract
A gm compensation current source controls current that runs through a current source transistor, source-grounded transistors that determine a gain so that mutual conductance gm of the source-grounded transistors is compensated and the gain is compensated. A 1/r current source runs current inversely proportional to variation of load resistors of an amplifier so that gate bias points of gate-grounded transistors that are connected to the source-grounded transistors remain constant, and deterioration of linearity at a drain terminal of a gate-grounded transistor is suppressed.
Claims7
A bias circuit comprising:
- a current source transistor;
- a source-grounded transistor connected to the current source transistor;
- a gate-grounded transistor connected to the source-grounded transistor;
- a load resistor connected to the gate-grounded transistor;
- a first current source that runs electric current to the current source transistor and the source-grounded transistor, the electric current compensating mutual conductance of the source-grounded transistor;
- and
- a second current source that runs electric current based on the load resistor to control a gate bias of the gate-grounded transistor.
4 more elements
Dependencies are inferred from the claim text.