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US 7,098,737 B2Granted
Variable inductor, oscillator including the variable inductor and radio terminal comprising this oscillator, and amplifier including the variable inductor and radio terminal comprising this amplifier
AssigneeKabushiki Kaisha Toshiba
InventorsRyuichi Fujimoto, Tetsuro Itakura
Life of this patent
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Abstract
An amplifier comprises an amplifier circuit which comprises a first inductor as an impedance element for degeneration, and a control circuit which has a second inductor electro-magnetically connected to the first inductor, and changes a control current flowing through the second inductor to change an inductance value of the first inductor, thereby changing amplification characteristics of the amplifier circuit.
Claims10
A variable inductor comprising:
- a signal input terminal which receives an input signal;
- a distributor including first and second active elements, configured to vary a distribution ratio of first and second currents flowing through the first and second active elements respectively;
- output terminals which output the first and second currents, respectively;
- a first inductor through which the first current flows;
- a second inductor through which the second current flows, the first and second inductors mutually coupled with each other,
- wherein an inductance of the variable inductor is determined by an inductance of the first inductor, an inductance of the second inductor, a mutual inductance between the first and second inductors, and the distribution ratio.
3 more elements
Dependencies are inferred from the claim text.