Radio-frequency switches having gate bias and frequency-tuned body bias
First Claim
Patent Images
1. A radio-frequency (RF) switch comprising:
- a plurality of field-effect transistors (FETs) disposed between a first node and a second node, each of the plurality of FETs having a respective source, drain, gate and body, the plurality of FETs including a first FET connected in series with a second FET;
a coupling circuit that connects the body of each of the plurality of FETs to the gate of each of the plurality of FETs, the coupling circuit including a first circuit coupled in series to a resistance, the first circuit including a capacitance and a diode, the coupling circuit configured to behave as an approximately closed circuit at low frequencies below a selected value and an approximately open circuit at an operating frequency, the approximately closed circuit allowing removal of surface charge from the body;
a bias circuit that connects the gate of each of the plurality of FETs to a gate bias voltage, the bias circuit configured to bias the gate of each of the plurality of FETs; and
a compensation circuit including a non-linear capacitor connected at a first end to both the source of the first FET and the drain of the second FET, and further connected at a second end to a ground reference, the compensation circuit configured to generate one or more harmonics to substantially cancel a non-linearity effect generated by at least one of the plurality of FETs.
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Abstract
Radio-frequency (RF) switch circuits are disclosed providing improved switching performance. An RF switch system includes a plurality of field-effect transistors (FETs) connected in series between first and second nodes, each FET having a gate and a body. A compensation network including a gate-coupling circuit couples the gates of each pair of neighboring FETs. The compensation network may further including a body-coupling circuit that couples the bodies of each pair of neighboring FETs.
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Citations
18 Claims
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1. A radio-frequency (RF) switch comprising:
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a plurality of field-effect transistors (FETs) disposed between a first node and a second node, each of the plurality of FETs having a respective source, drain, gate and body, the plurality of FETs including a first FET connected in series with a second FET; a coupling circuit that connects the body of each of the plurality of FETs to the gate of each of the plurality of FETs, the coupling circuit including a first circuit coupled in series to a resistance, the first circuit including a capacitance and a diode, the coupling circuit configured to behave as an approximately closed circuit at low frequencies below a selected value and an approximately open circuit at an operating frequency, the approximately closed circuit allowing removal of surface charge from the body; a bias circuit that connects the gate of each of the plurality of FETs to a gate bias voltage, the bias circuit configured to bias the gate of each of the plurality of FETs; and a compensation circuit including a non-linear capacitor connected at a first end to both the source of the first FET and the drain of the second FET, and further connected at a second end to a ground reference, the compensation circuit configured to generate one or more harmonics to substantially cancel a non-linearity effect generated by at least one of the plurality of FETs. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for operating a radio-frequency (RF) switch, the method comprising:
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controlling a plurality of field-effect transistors (FETs) disposed between first and second nodes so that each of the plurality of FETs is in an ON state or an OFF state; selectively removing surface charge from a respective body of each of the plurality of FETs at low frequencies below a selected value, the selective removal facilitated by a coupling circuit that behaves as an approximately closed circuit at the low frequencies, the coupling circuit including a first circuit coupled in series to a resistance, the first circuit including a capacitance and a diode; biasing the gate of each of the plurality of FETs when the plurality of FETs is in an OFF state; and compensating a non-linear effect of the plurality of FETs by applying another non-linear signal to a source or a drain of the plurality of FETs and by generating one or more harmonics to substantially cancel the non-linear effect of the plurality of FETs, the compensating facilitated by a compensation circuit, and the compensation circuit include a non-linear capacitor. - View Dependent Claims (12, 13)
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14. A radio-frequency (RF) switch module comprising:
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a packaging substrate configured to receive a plurality of components; a semiconductor die mounted on the packaging substrate, the die including a plurality of field-effect transistors (FETs); a coupling circuit that connects a respective body of each of the plurality of FETs to a respective gate of each of the plurality of FETs, the coupling circuit including a first circuit coupled in series to a resistance, the first circuit including a capacitance and a diode, the coupling circuit configured to behave as an approximately closed circuit at low frequencies below a selected value and as an approximately open circuit at an operating frequency, the approximately closed circuit allowing removal of surface charge from the respective body; a bias circuit that connects a gate of each of the plurality of FETs to the reference node, the bias circuit configured to bias the gate; and a compensation circuit including a non-linear capacitor connected at a first end to both the source of the first FET and the drain of the second FET, and further connected at a second end to a ground reference, the compensation circuit configured to generate one or more harmonics to substantially cancel a non-linearity effect generated by at least one of the plurality of FETs. - View Dependent Claims (15, 16, 17, 18)
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Specification