Multi-band voltage-controlled oscillator
By designing a voltage-controlled oscillator including a cross-coupled pair circuit, a first capacitor circuit, a first inductor, a second inductor, a second capacitor circuit and a first switching circuit, the problem of large area consumption of the existing multi-band voltage-controlled oscillator circuit is solved, and the oscillation signal output and frequency of the multi-band are greatly changed.
Patent Information
- Application Number
- CN202311838998.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-10-16
- Filing Date
- 2023-12-28
- Publication Date
- 2025-04-18
AI Technical Summary
The existing multi-band voltage-controlled oscillators need to use multiple voltage-controlled oscillators of different frequency bands when the frequency band changes, resulting in excessive circuit area consumption.
A voltage controlled oscillator including a cross-coupling pair circuit, a first capacitor circuit, a first inductor, a second inductor, a second capacitor circuit and a first switching circuit is designed. Through the mutual inductance of the first inductor and the second inductor and the cooperation between the second capacitor circuit and the first switching circuit, the oscillation signal output in multiple frequency bands is realized.
It realizes the output of multi-band oscillation signal without increasing the circuit area, and can greatly change the oscillation frequency, which is suitable for multi-band applications.
Smart Images
Figure CN119853613A_ABST
Abstract
Description
Technical Field
[0001] The present invention provides a voltage-controlled oscillator, in particular a multi-band voltage-controlled oscillator. Background Art
[0002] When using a voltage-controlled oscillator, the frequency of the oscillation signal can be changed by fine-tuning the capacitance value. However, when the frequency band used by the signal changes significantly, it is necessary to use more than two voltage-controlled oscillators with different frequency bands. Although this can achieve multi-band signal output, it will consume a lot of area in circuit production. Summary of the invention
[0003] A voltage-controlled oscillator includes a cross-coupled pair circuit; a first capacitor circuit, arranged in parallel with the cross-coupled pair circuit; a first inductor, arranged in parallel with the cross-coupled pair circuit, the first inductor having an intermediate tap point for receiving a power supply voltage; a second inductor, arranged in mutual inductance with the first inductor, the second inductor having an intermediate tap point for receiving a first control voltage; a second capacitor circuit, arranged in parallel with the second inductor; and a first switch circuit, arranged in parallel with the second inductor, for receiving a second control voltage to be turned on or off. The first control voltage changes synchronously with the second control voltage. BRIEF DESCRIPTION OF THE DRAWINGS
[0004] Figure 1A is a circuit diagram of a voltage-controlled oscillator in an embodiment of the present invention. Figure 1B yes Figure 1A Equivalent circuit diagram of a voltage-controlled oscillator operating in the high-frequency band. Figure 1C yes Figure 1A Equivalent circuit diagram of a voltage-controlled oscillator operating in the low-frequency band. Figure 2 yes Figure 1A A circuit diagram of another second capacitor circuit of a voltage controlled oscillator. Figure 3 yes Figure 1A Schematic diagram of the mutual inductance arrangement of the first inductor and the second inductor of the voltage controlled oscillator. Figure 4 yes Figure 1A Circuit diagram of the second resonant circuit of the voltage controlled oscillator.
Explanation of symbols
[0005] Figure 1A 1 is a circuit diagram of a voltage-controlled oscillator (VCO) 100 in an embodiment of the present invention. The voltage-controlled oscillator 100 includes a cross coupled pair circuit 101, a first capacitor circuit 105, a first inductor 112, a second inductor 114, a second capacitor circuit 115 and a first switch circuit 117. The first capacitor circuit 105, the first inductor 112 and the cross coupled pair circuit 101 are arranged in parallel, and the first inductor 112 has a center tapped node for receiving a power supply voltage VDD. The second inductor 114 is arranged in mutual inductance with the first inductor 112, and the second inductor 114 has a center tapped node for receiving a first control voltage VCTRL1. The second capacitor circuit 115, the second inductor 114 and the first switch circuit 117 are arranged in parallel, and the first switch circuit 117 is used to receive the second control voltage VCTRL2 and be turned on or off.
[0006] The cross-coupled pair circuit 101 includes a first transistor 102 and a second transistor 104. The first transistor 102 includes a first terminal, a second terminal coupled to a reference voltage terminal, and a control terminal, and the second transistor 104 includes a first terminal coupled to the control terminal of the first transistor 102, a second terminal coupled to the reference voltage terminal, and a control terminal coupled to the first terminal of the first transistor 102. The cross-coupled pair circuit 101 formed by the first transistor 102 and the second transistor 104 is used to provide a negative impedance to the reference voltage terminal. The reference voltage terminal is, for example, a ground terminal or a common terminal. In the present embodiment, the first transistor 102 and the second transistor 104 are coupled to the reference voltage terminal through a current source.
[0007] The first capacitor circuit 105 includes a first capacitor 110. In one embodiment, the capacitance of the first capacitor circuit 105 is variable and controlled by a fourth control voltage VCTRL4. For example, the first capacitor circuit 105 may also include a first variable capacitor 106, a second variable capacitor 108, and a contact for receiving the fourth control voltage VCTRL4, the first variable capacitor 106 and the second variable capacitor 108 are arranged in series, and the serial circuit formed by the two is arranged in parallel with the first capacitor 110. With the adjustment of the fourth control voltage VCTRL4, the capacitance values of the first variable capacitor 106 and the second variable capacitor 108 will also change accordingly, thereby achieving the purpose of adjusting the frequency of the output oscillation signal of the voltage-controlled oscillator 100. The capacitance value of the first capacitor circuit 105 is the result of the first capacitor 110 and the first variable capacitor 106 being connected in series with the second variable capacitor 108.
[0008] The first inductor 112 has a middle tap point for receiving the power supply voltage VDD and generating an oscillation signal of a single frequency band at two end points. In order to achieve a multi-band effect different from that of a conventional voltage-controlled oscillator, the first inductor 112 and the second inductor 114 are arranged in mutual inductance, and the second inductor 114 has a middle tap point for receiving the first control voltage VCTRL1. Since the first control voltage VCTRL1 can control the equivalent impedance formed by the second inductor 114, the second capacitor circuit 115 and the first switch circuit 117, by means of the mutual inductance effect of the first inductor 112 and the second inductor 114, the voltage-controlled oscillator 100 can not only adjust the capacitance values of the first variable capacitor 106 and the second variable capacitor 108 to change the oscillation frequency slightly, but also adjust the equivalent impedance formed by the second inductor 114, the second capacitor circuit 115 and the first switch circuit 117 to change the oscillation frequency significantly.
[0009] The second capacitor circuit 115 includes a second capacitor 116 for providing a capacitance value. If it can be properly adjusted, the second capacitor circuit 115 can more easily adjust the frequency of the voltage controlled oscillator 100. In one embodiment, the first switch circuit 117 includes a first switch 118. The control end of the first switch 118 is used to receive a control voltage related to the first control voltage VCTRL1 to turn the first switch 118 on or off. The control voltage can change synchronously with the first control voltage VCTRL1. In this embodiment, the first switch circuit 117 further includes an inverter 120. The control end of the first switch 118 is connected to the output end of the inverter 120. The inverter 120 is used to receive the second control voltage VCTRL2 to turn the first switch 118 on or off. The first control voltage VCTRL1 and the second control voltage VCTRL2 can be the same control voltage and can change synchronously.
[0010] Figure 1B 1 is a circuit diagram of the voltage controlled oscillator 100 operating in the high frequency band. Figure 1B As shown, when the first control voltage VCTRL1 is a first voltage (e.g., a low voltage, VCTRL1=0V), the second control voltage VCTRL2 is also a first voltage (VCTRL2=0V), and the control end of the first switch 118 therefore receives a second voltage (e.g., a high voltage). At this time, the first end and the second end of the first switch 118 receive the first voltage, and the voltage difference between the first voltage and the second voltage further ensures the conduction degree of the first switch 118, so that a predetermined equivalent small resistance 122 is formed between the first end and the second end of the first switch 118. At this time, it is equivalent to the mutual inductance of the voltage-controlled oscillator 100 in the RLC parallel circuit, so that the first inductor 112 outputs an oscillation signal in the high frequency band. In an alternative embodiment, the middle tap point of the second inductor 114 omits to receive the first control voltage VCTRL1. Then, when the control end of the first switch 118 receives the second voltage and is to be turned on, since the voltages at the first end and the second end of the first switch 118 are not defined, the conduction degree of the first switch 118 is affected, so that a predetermined equivalent resistance value cannot be formed between the first end and the second end of the first switch 118, and even the first switch 118 cannot be turned on, causing the voltage-controlled oscillator 100 to be unable to operate in a predetermined frequency band.
[0011] Figure 1C 1 is a circuit diagram of the voltage controlled oscillator 100 operating in a low frequency band. Figure 1CAs shown, when the first control voltage VCTRL1 is a second voltage (e.g., a high voltage, VCTRL1=VCC), the second control voltage VCTRL2 is also a second voltage (e.g., a high voltage, VCTRL2=VCC), and the control end of the first switch 118 receives the first voltage. At this time, the first end and the second end of the first switch 118 receive the second voltage. The voltage difference between the first voltage and the second voltage further ensures the cut-off degree of the first switch 118, so that a nearly infinite resistance is formed between the first end and the second end of the first switch 118. At this time, it is equivalent to the mutual inductance of the voltage-controlled oscillator 100 in the LC parallel circuit, so that the first inductor 112 outputs an oscillation signal of a lower frequency band. In an alternative embodiment, the middle tap point of the second inductor 114 omits to receive the first control voltage VCTRL1. Then, when the control end of the first switch 118 receives the first voltage and is to be turned off, since the voltages at the first end and the second end of the first switch 118 are not defined, the degree of cut-off of the first switch 118 is affected, so that a resistance close to infinite cannot be formed between the first end and the second end of the first switch 118, and the first switch 118 may even be turned on, causing the voltage-controlled oscillator 100 to be unable to operate in a predetermined frequency band.
[0012] Figure 2 FIG. 1 is a circuit diagram of another second capacitor circuit 115 of the voltage-controlled oscillator in an embodiment of the present invention. Figure 2 In the embodiment, the second capacitor circuit 115 includes two capacitors 206 and 208 and a second switch circuit 202 is disposed between the two capacitors 206 and 208. The second switch circuit 202 includes a second switch 204 for receiving a third control voltage VCTRL3 and then being turned on or off. In the present embodiment, both ends of the second switch 204 may further include two endpoints for receiving a bias voltage VB1 to ensure the degree of turning on or off of the second switch 204. When the first control voltage VCTRL1 is a first voltage (e.g., a low voltage), the first switch 118 receives a second voltage (e.g., a high voltage) and is turned on, and if the third control voltage VCTRL3 is a second voltage, the second switch 204 is controlled by the third control voltage VCTRL3 and is turned on. At this time, the voltage controlled oscillator 100 has a first frequency. When the first control voltage VCTRL1 is the second voltage, the first switch 118 receives the first voltage and is turned off, and if the third control voltage VCTRL3 is the second voltage, the second switch 204 is controlled by the third control voltage VCTRL3 and is turned on, and the voltage controlled oscillator 100 has a second frequency. When the first control voltage VCTRL1 is the second voltage, the first switch 118 receives the first voltage and is turned off, and if the third control voltage VCTRL3 is the first voltage, the second switch 204 is controlled by the third control voltage VCTRL3 and is turned off, and the voltage controlled oscillator 100 has a third frequency. The first frequency is higher than the third frequency and the third frequency is higher than the second frequency. When Figure 1AThe second capacitor circuit 115 is Figure 2 When the second capacitor circuit 115 is replaced by the second capacitor circuit 115, the user can turn on or off the second switch circuit 202 by the third control voltage VCTRL3 to change the equivalent capacitance value of the second capacitor circuit 115, thereby changing the oscillation signal frequency of the voltage controlled oscillator 100 to achieve a multi-band effect.
[0013] Figure 3 FIG. 1 is a schematic diagram of a mutual inductance arrangement of the first inductor 112 and the second inductor 114 . Figure 3 The first inductor 112, the second inductor 114, the first switch circuit 117 and the second capacitor circuit 115 are shown. The first inductor 112 is a polygonal coil, and the center point of the line length is used to receive the power supply voltage VDD. The second inductor 114 is also a polygonal coil corresponding to the shape of the first inductor 112. The first inductor 112 and the second inductor 114 are arranged on the same plane of the circuit board, and the second inductor 114 is arranged inside the first inductor 112 and reversely configured, so as to achieve the effect of mutual inductance. In other words, the first inductor 112 and the second inductor 114 have similar routing shapes and are arranged on the same plane, and the first inductor 112 is arranged outside the second inductor 114. In another embodiment, the first inductor 112 can also be arranged inside the second inductor 114. The first switch circuit 117 is connected in parallel with the second inductor 114. The first switch circuit 117 includes a first switch 118 and an inverter 120, which are used to receive a second control voltage VCTRL2 to turn the first switch on or off. The second capacitor circuit 115 can also be connected in parallel with the second inductor 114 and the first switch circuit 117. Figure 2 The second capacitor circuit 115 in the embodiment is replaced to achieve the effect of having more frequency bands. Figure 3 This is just one implementation method of the present invention. The first inductor 112 and the second inductor 114 may also be in different shapes or located in different planes to achieve the mutual inductance effect. Figure 3 The octagon and the configuration method of the inner and outer sides are shown.
[0014] In another embodiment, the first inductor 112 and the second inductor 114 are located in different planes to achieve a mutual inductance effect. The first inductor 112 is a polygonal coil, and the second inductor 114 is also a polygonal coil corresponding to the shape of the first inductor 112, and the two coils can be located in different and mutually parallel planes and have a distance. The shape of the first inductor 112 and the shape of the second inductor 114 roughly overlap on a projection plane to form a mutual inductance effect. In other words, the first inductor 112 and the second inductor 114 have similar routing shapes and are arranged in different planes, and the first inductor 112 and the second inductor 114 have similar external dimensions. In addition, the relative positions of the first inductor 112, the second inductor 114, the first switch circuit 117 and the second capacitor circuit 115 can be the same as each other. Figure 3 The same or similar ones will not be repeated here.
[0015] If the second inductor 114, the second capacitor circuit 115 and the first switch circuit 117 of the voltage controlled oscillator 100 form a first resonant circuit, then Figure 4 is a circuit diagram of the second resonant circuit 400 of the voltage-controlled oscillator 100. In the embodiment of the present invention, it is not limited to using only one resonant circuit. The mutual inductance object of the first inductor 112 can be multiple resonant circuits, and the frequency of the voltage-controlled oscillator 100 is determined according to whether the switch of each resonant circuit is turned on or off. The second resonant circuit 400 includes a third inductor 402, a third capacitor circuit 404 and a third switch circuit 406, and the three are arranged in parallel. The first inductor 112 can be simultaneously arranged with the second inductor 114 and the third inductor 402 in mutual inductance. The third inductor 402 also has an intermediate tap point for receiving the fifth control voltage VCTRL5. The specific effect of the fifth control voltage VCTRL5 is similar to that of the first control voltage VCTRL1. The third capacitor circuit 404 can be replaced as follows Figure 2 The third switch circuit 406 includes a third switch 408 and an inverter 410. The sixth control voltage VCTRL6 can turn on or off the third switch 408. The fifth control voltage VCTRL5 and the sixth control voltage VCTRL6 can be the same control voltage and can change synchronously.
[0016] In summary, the voltage-controlled oscillator 100 of the present invention can control the equivalent impedance formed by the second inductor 114, the second capacitor circuit 115 and the first switch circuit 117, and greatly change the oscillation frequency by the mutual inductance effect of the first inductor 112 and the second inductor 114. The voltage-controlled oscillator 100 can also include fine-tunable variable capacitors 106 and 108 to fine-tune the oscillation signal frequency, or further include a second resonant circuit 400, more resonant circuits and change the capacitance value of the second capacitor circuit 115 to achieve a large change in more oscillation signal frequency bands. The present invention can be used to realize a multi-band voltage-controlled oscillator, and the effect of reducing the consumption of circuit area is achieved by setting the resonant circuit. In addition, the present invention can make the voltage-controlled oscillator 100 operate in a predetermined frequency band by receiving a control signal that changes synchronously with the control end of the first switch 118 at the middle tap point of the second inductor 114.
[0017] The above descriptions are only preferred embodiments of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should fall within the scope of the present invention.
Claims
1. A voltage-controlled oscillator, characterized in that: Include: a cross-coupled pair circuit; a first capacitor circuit, arranged in parallel with the cross-coupling pair circuit; a first inductor, arranged in parallel with the cross-coupling pair circuit, the first inductor having an intermediate tap point for receiving a power supply voltage; a second inductor, arranged in mutual inductance with the first inductor, the second inductor having an intermediate tap point for receiving a first control voltage; a second capacitor circuit, arranged in parallel with the second inductor; and a first switch circuit, arranged in parallel with the second inductor, for receiving a second control voltage to be turned on or off; The first control voltage and the second control voltage change synchronously.
2. The voltage controlled oscillator according to claim 1, characterized in that: in: When the first control voltage is a first voltage and the first switch circuit is controlled by the second control voltage to be turned on, the oscillation signal of the voltage-controlled oscillator has a first frequency; When the first control voltage is a second voltage and the first switch circuit is controlled by the second control voltage to be turned off, the oscillation signal of the voltage-controlled oscillator has a second frequency; and The first frequency is higher than the second frequency.
3. The voltage controlled oscillator according to claim 1, characterized in that: The second capacitor circuit includes two capacitors and a second switch circuit disposed between the two capacitors. The second switch circuit is used to receive a third control voltage to be turned on or off.
4. The voltage controlled oscillator according to claim 3, characterized in that: in: When the first control voltage is a first voltage, the first switch circuit is controlled to be turned on by the second control voltage, and the second switch circuit is controlled to be turned on by the third control voltage, the oscillation signal of the voltage-controlled oscillator has a first frequency; When the first control voltage is a second voltage, the first switch circuit is controlled by the second control voltage to be turned off, and the second switch circuit is controlled by the third control voltage to be turned on, the oscillation signal of the voltage-controlled oscillator has a second frequency; When the first control voltage is the second voltage, the first switch circuit is controlled to be turned off by the second control voltage, and the second switch circuit is controlled to be turned off by the third control voltage, the oscillation signal of the voltage-controlled oscillator has a third frequency; and The first frequency is higher than the third frequency and the third frequency is higher than the second frequency.
5. The voltage controlled oscillator according to claim 3, characterized in that: The second switch circuit includes a transistor disposed between the two capacitors.
6. The voltage controlled oscillator according to claim 5, characterized in that: The second switch circuit further includes two terminals for receiving bias voltage, which are respectively arranged between the transistor and the two capacitors.
7. The voltage controlled oscillator according to claim 1, characterized in that: The first inductor and the second inductor have similar routing shapes and are arranged on the same plane, and the first inductor is arranged on the inner side or the outer side of the second inductor.
8. The voltage controlled oscillator according to claim 1, characterized in that: The first inductor and the second inductor have similar routing shapes and are arranged on different planes, and the first inductor and the second inductor have similar external dimensions.
9. The voltage controlled oscillator according to claim 1, characterized in that: The cross-coupling circuit comprises: A first transistor comprising: a first end; a second terminal coupled to a reference voltage terminal; and a control terminal; and a second transistor, comprising: a first terminal coupled to the control terminal of the first transistor; a second terminal coupled to the reference voltage terminal; and A control terminal is coupled to the first terminal of the first transistor.
10. The voltage controlled oscillator according to claim 1, characterized in that: The first capacitor circuit is controlled by a fourth control voltage and has different capacitance values.
11. The voltage controlled oscillator according to claim 10, characterized in that: The first capacitor circuit includes: A first variable capacitor, comprising: a first end; and a second terminal, for receiving the fourth control voltage; A second variable capacitor, comprising: a first terminal coupled to the second terminal of the first variable capacitor and configured to receive the fourth control voltage; and a second end; and A first capacitor, comprising: a first terminal coupled to the first terminal of the first variable capacitor; and A second end is coupled to the second end of the second variable capacitor.
12. The voltage controlled oscillator according to claim 1, characterized in that: The second capacitor circuit includes a second capacitor.
13. The voltage controlled oscillator according to claim 1, characterized in that: The first switch circuit includes a transistor, which is arranged in parallel with the second inductor and is turned on or off by the second control voltage.
14. The voltage controlled oscillator according to claim 13, characterized in that: The first switch circuit further includes an inverter coupled to a control terminal of the transistor.
15. The voltage controlled oscillator according to claim 14, characterized in that: The inverter is used to receive the second control voltage, and the second control voltage is the same as the first control voltage.
16. The voltage controlled oscillator according to claim 1, characterized in that: The two ends of the first inductor are used to output an oscillation signal.
17. The voltage controlled oscillator according to claim 1, characterized in that: The two ends of the second inductor are used to output an oscillation signal.
18. The voltage controlled oscillator according to claim 1, characterized in that: The second capacitor circuit is controlled by a third control voltage and has different capacitance values.
19. The voltage controlled oscillator according to claim 1, characterized in that: Also includes: a third inductor, arranged in mutual inductance with the first inductor, the third inductor having an intermediate tap point for receiving a fifth control voltage; a third capacitor circuit, arranged in parallel with the third inductor; a third switch circuit, arranged in parallel with the third inductor, for receiving a sixth control voltage to be turned on or off; The fifth control voltage changes synchronously with the sixth control voltage.
20. The voltage controlled oscillator according to claim 19, characterized in that: The first inductor, the second inductor and the third inductor have similar routing shapes and are arranged on different planes, and the first inductor is arranged between the second inductor and the third inductor.