Integrated tunable resonance circuit
An integrated tunable resonance circuit is provided for providing a high-frequency output signal with a frequency dependent on a control signal, comprising a parallel resonance circuit with a first inductive element and an output for providing the high-frequency output signal, a switching unit with a controlled path, and a control terminal for switching between states, whereby the switching unit is designed to exhibit a predominantly capacitive behavior in a first state and a predominantly resistive behavior in a second state, whereby the resonance circuit is designed to drive the control terminal of the switching unit as a function of the control signal. The resonance circuit has a second inductive element which can be mutually coupled to the first inductive element, whereby the controlled path is connected parallel to the second inductive element. The invention relates furthermore to a voltage-controlled oscillator and to an integrated circuit.
1. An integrated tunable resonance circuit for providing a high-frequency output signal with a frequency that is dependent on a control signal, the circuit comprising:
a parallel resonance circuit with a first inductive element and an output for providing the high-frequency output signal;
a second inductive element, which is coupled mutually to the first inductive element; and
a switching unit connected in parallel to the second inductive element and having multiple parallel branches, the branches including a first branch formed of a switch having a control terminal for switching between states and a second branch formed of a capacitive unit, wherein the switching unit exhibits a capacitive behavior in a first state with the switch open and a resistive behavior in a second state with the switch closed, the resonance circuit driving the control terminal of the switch as a function of the control signal.
2. The resonance circuit according to claim 1 , wherein the capacitive behavior of the switching unit is based partially on a capacitance of the switch in the first state.
3. The resonance circuit according to claim 2 , wherein the capacitive behavior of the switching unit is further based on a capacitance of the capacitive unit.
4. The resonance circuit according to claim 1 , wherein the resistive behavior of the switching unit is based on an ohmic resistance of the switch in the second state.
5. The resonance circuit according to claim 1 , wherein the switch is a field-effect transistor whose drain-source channel forms a controlled current path when the switch is closed and whose gate terminal is connected to the control terminal.
6. The resonance circuit according to claim 1 , wherein the switch is a microelectromechanical switching element.
7. The resonance circuit according to claim 1 , wherein the parallel resonance circuit has a second capacitive unit connected in parallel to the first inductive element.
8. The resonance circuit according to claim 7 , wherein the second capacitive unit has a settable capacitance value and the resonance circuit is designed to set the settable capacitance value of the second capacitive unit as a function of at least one additional control signal.
9. The resonance circuit according to claim 7 , wherein the second capacitive unit has at least one metal-insulator-metal capacitor, a varactor, a switched MIM capacitor, or a switched capacitor bank.
10. The resonance circuit according to claim 7 , wherein the second capacitive unit is a parasitic capacitance.
11. The resonance circuit according to claim 1 , wherein the capacitive unit is connected in parallel to the second inductive element.
12. The resonance circuit according to claim 1 , wherein the capacitive unit has a settable capacitance value and the resonance circuit is designed to set the settable capacitance value of the first capacitive unit as a function of at least one additional control signal.
13. The resonance circuit according to claim 1 , wherein the capacitive unit has at least one metal-insulator-metal capacitor, a varactor, a switched MIM capacitor, or a switched capacitor bank.
14. The resonance circuit according to claim 1 , wherein the capacitive unit is designed as a distributed capacitance.
15. The resonance circuit according to claim 1 , wherein the second inductive element has two series-connected inductive subelements.
16. The resonance circuit according to claim 1 , further comprising:
a third inductive element, which is mutually coupled to the first inductive element,
a second switching unit connected in parallel to the third inductive element, and having at least a second switch, wherein the second switch is connected in parallel to the third inductive element.
17. The resonance circuit according to claim 1 , wherein at least one first resonance circuit and a second resonance circuit according to claim 1 is provided, wherein a separate parallel resonance circuit of the second resonance circuit is connected in parallel to the first inductive element of the first resonance circuit.
18. A Voltage-controlled oscillator comprising at least one resonance circuit according to claim 1 .
19. An integrated circuit comprising at least one resonance circuit according to claim 1 .
20. The integrated circuit according to claim 19 , wherein the integrated circuit is designed as a monolithically integrated circuit, a hybrid circuit, or a multilayer-ceramic circuit.
21. An integrated circuit comprising at least one voltage-controlled oscillator according to claim 18 .
22. An integrated tunable resonance circuit for providing a high-frequency output signal with a frequency that is dependent on a control signal, the circuit comprising:
a parallel resonance circuit with a first inductive element and an output for providing the high-frequency output signal;
a switching unit with a controlled path and a control terminal for switching between states, wherein the switching unit exhibits a capacitive behavior in a first state and a resistive behavior in a second state, the resonance circuit driving the control terminal of the switching unit as a function of the control signal; and
a second inductive element, which is coupled mutually to the first inductive element,
wherein the controlled path is connected in parallel to the second inductive element,
wherein the second inductive element has two series-connected inductive subelements, and
wherein a first potential value is applied at the connection point of the inductive subelements when the switching unit is in the first state, and a different second potential value is applied when the switching unit is in the second state.