Switching circuit at high frequency with low insertion loss
AssigneeSony Corporation
InventorsKazumasa Kohama, Kazuto Kitakubo
Life of this patent
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Abstract
In a switching circuit, low insertion loss and enough isolation can be ensured at a desired frequency at the same time. An inductor is externally connected in parallel with the path between the drain and source of each of field-effect transistors built in a switching integrated circuit, and the inductor and the OFF capacitance of the field-effect transistor are made to generate parallel resonance. At this time, by suitably adjusting the inductance, low insertion loss and enough isolation are ensured at a desired frequency at the same time.
Claims18
A switching circuit comprising:
- a field-effect transistor having a signal path between a drain terminal and a source terminal,
- a first impedance element connected to a gate terminal of said field-effect transistor, and
- first and second input/output terminals connected to said drain terminal and said source terminal of said field-effect transistor respectively,
- a second impedance element which is connected between said drain terminal and a bias voltage source,
- a third impedance element which is connected between said source terminal and said bias voltage source, and
- an inductor connected directly to said drain and source terminals of said field effect transistor;
- wherein said switching circuit further comprises another field-effect transistor connected in series between said first input/output terminal and a third input/output terminal.
A switching circuit comprising:
- first, second, third and fourth input/output terminals,
- a first field-effect transistor having drain and source terminals connected to said first and second input/output terminals respectively,
- a second field-effect transistor having drain and source terminals connected to said second and third input/output terminals respectively,
- a third field-effect transistor having drain and source terminals connected to said third and fourth input/output terminals respectively,
- a fourth field-effect transistor having drain and source terminals connected to said fourth and first input/output terminals respectively, and
- first, second, third and fourth impedance elements connected to gate terminals of said first, second, third and fourth field-effect transistors respectively;
- and
- first, second, third and fourth inductors connecting said first and second input/output terminals to each other, said second and third input/output terminals to each other, said third and fourth input/output terminals to each other, and said fourth and first input/output terminals to each other respectively.
A switching circuit comprising:
- a field-effect transistor having a signal path between a drain terminal and a source terminal,
- a first impedance element connected to a gate terminal of said field-effect transistor, and
- first and second input/output terminals connected to said drain terminal and said source terminal of said field effect transistor respectively,
- a second impedance element which is connected between said drain terminal and a bias voltage source,
- a third impedance element which is connected between said source terminal and said bias voltage source,
- an inductor connected between said first and second input/output terminals,
- a second field-effect transistor connected between said first input/output terminal and a third input/output terminal.
Dependencies are inferred from the claim text.