Oscillator

Abstract

The present application provides an oscillator, which relates to the field of circuit design and achieves the purpose of reducing the phase noise of the oscillator. The oscillator includes an oscillation circuit, a negative resistance differential pair circuit, a tail current circuit and an amplitude adjustment circuit, the oscillation circuit is used to generate an oscillation signal, the input end of the negative resistance differential pair circuit is connected to the output end of the oscillation circuit, the negative resistance differential pair circuit is used to compensate for the equivalent resistance generated by the oscillation circuit, the input end of the tail current circuit is connected to the output end of the negative resistance differential pair circuit, the output end of the tail current circuit is grounded, the tail current circuit includes a first field effect transistor, the tail current circuit is used to provide a tail current for the oscillator, the input end of the amplitude adjustment circuit is connected to the output end of the oscillation circuit, the output end of the amplitude adjustment circuit is connected to the gate of the first field effect transistor, the amplitude adjustment circuit is used to adjust the size of the tail current to adjust the amplitude of the oscillation signal, and the tail current can suppress the noise of the power supply ground from entering the resonant cavity, thereby reducing the phase noise of the oscillator.

Description

Technical Field

[0001] The present application relates to the field of circuit design, and in particular to an oscillator. Background Art

[0002] High-performance clocks are the key to many application areas, such as high-speed and high-precision digital-to-analog / analog-to-digital converters, high-speed serial communication circuits, high-performance wireless transceivers, etc. Its jitter noise is the core indicator, and the main noise contribution of high-performance clocks comes from the oscillator.

[0003] In the existing oscillation circuit, since the oscillation circuit is grounded, the noise of the power ground will enter the resonant cavity, and the phase noise of the oscillator is usually large. Summary of the invention

[0004] One purpose of the present application is to reduce the phase noise of the oscillator to a certain extent.

[0005] To solve the above problems, the present application provides an oscillator on the one hand, including: an oscillation circuit for generating an oscillation signal; a negative resistance differential pair circuit, the input end of the negative resistance differential pair circuit is connected to the output end of the oscillation circuit, and the negative resistance differential pair circuit is used to compensate for the equivalent resistance generated by the oscillation circuit; a tail current circuit, the input end of the tail current circuit is connected to the output end of the negative resistance differential pair circuit, the output end of the tail current circuit is grounded, the tail current circuit includes a first field effect transistor, and the tail current circuit is used to provide a tail current for the oscillator; an amplitude adjustment circuit, the input end of the amplitude adjustment circuit is connected to the output end of the oscillation circuit, the output end of the amplitude adjustment circuit is connected to the gate of the first field effect transistor, and the amplitude adjustment circuit is used to adjust the size of the tail current to adjust the amplitude of the oscillation signal.

[0006] In one embodiment of the present application, the output end of the oscillation circuit includes a positive output end and a negative output end, and the oscillation circuit includes: a first inductor, a first end of the first inductor is connected to a first DC power supply, and a second end of the first inductor serves as the positive output end of the oscillation circuit; a second inductor, a first end of the second inductor is connected to the first DC power supply, and a second end of the second inductor serves as the negative output end of the oscillation circuit; and a variable capacitor array, a first end of the variable capacitor array is connected to the positive output end of the oscillation circuit, and a second end of the variable capacitor array is connected to the negative output end of the oscillation circuit.

[0007] In one embodiment of the present application, the variable capacitor array includes a plurality of variable capacitors connected in parallel.

[0008] In one embodiment of the present application, the negative resistance differential pair circuit includes: a second field effect transistor, the source of the second field effect transistor is connected to the positive output end of the oscillation circuit, the gate of the second field effect transistor is connected to the negative output end of the oscillation circuit, and the drain of the second field effect transistor serves as the output end of the negative resistance differential pair circuit; a third field effect transistor, the source of the third field effect transistor is connected to the negative output end of the oscillation circuit, the gate of the third field effect transistor is connected to the positive output end of the oscillation circuit, and the drain of the third field effect transistor is connected to the drain of the second field effect transistor.

[0009] In one embodiment of the present application, the tail current circuit further includes: a first resistor, a first end of the first resistor is connected to the drain of the first field effect transistor, and a second end of the first resistor is grounded.

[0010] In one embodiment of the present application, the amplitude adjustment circuit includes: a rectifier circuit, the input end of the rectifier circuit is connected to the output end of the oscillation circuit; a filter circuit, the input end of the filter circuit is connected to the output end of the rectifier circuit; an operational amplifier, the first input end of the operational amplifier is connected to the output end of the filter circuit, the second input end of the operational amplifier inputs a comparison voltage, and the output end of the operational amplifier is connected to the control end of the tail current circuit.

[0011] In one embodiment of the present application, the rectifier circuit includes: a fourth field effect transistor, the source of the fourth field effect transistor is connected to the second DC power supply, the gate of the fourth field effect transistor is connected to the positive output end of the oscillation circuit, and the drain of the fourth field effect transistor serves as the output end of the rectifier circuit; a fifth field effect transistor, the source of the fifth field effect transistor is connected to the second DC power supply, the gate of the fifth field effect transistor is connected to the negative output end of the oscillation circuit, and the drain of the fifth field effect transistor is connected to the drain of the fourth field effect transistor.

[0012] In one embodiment of the present application, the filtering circuit includes: a second resistor, a first end of the second resistor is connected to the output end of the rectifier circuit, a second end of the second resistor is grounded through a negative resistance, and a second end of the second resistor is connected to the first input end of the operational amplifier; a first capacitor, a first end of the first capacitor is connected to the second end of the second resistor, and a second end of the first capacitor is grounded.

[0013] In one embodiment of the present application, the second end of the second resistor is grounded through a sixth field effect transistor, the source of the sixth field effect transistor is connected to the second end of the second resistor, the drain of the sixth field effect transistor is grounded, and the gate of the sixth field effect transistor is connected to the sixth field effect transistor bias voltage.

[0014] In one embodiment of the present application, the amplitude adjustment circuit also includes: a third resistor, a first end of the third resistor is connected to the second DC power supply, and a second end of the third resistor is connected to the second input terminal of the operational amplifier; a fourth resistor, a first end of the fourth resistor is connected to the second end of the third resistor, and a second end of the fourth resistor is grounded.

[0015] It can be seen from the above technical solution that the present application has at least the following advantages and positive effects:

[0016] An oscillator proposed in the present application includes an oscillation circuit, a negative resistance differential pair circuit, and a tail current circuit. The oscillation circuit is used to generate an oscillation signal. The input end of the negative resistance differential pair circuit is connected to the output end of the oscillation circuit. The negative resistance differential pair circuit is used to compensate for the equivalent resistance generated by the oscillation circuit, and acts as a negative resistance to compensate for the equivalent resistance, so as to perform energy compensation on the oscillation circuit. The input end of the tail current circuit is connected to the output end of the negative resistance differential pair circuit, and the output end of the tail current circuit is grounded. The tail current circuit is used to provide a bias current for the negative resistance differential pair circuit, thereby providing a tail current for the oscillator. The tail current can suppress the noise of the power supply ground from entering the resonant cavity, thereby reducing the phase noise of the oscillator. In addition, the tail current circuit includes a first field effect transistor, and the oscillator also includes an amplitude adjustment circuit. The input end of the oscillator tail current amplitude adjustment circuit The end is connected to the output end of the oscillation circuit, and the output end of the amplitude adjustment circuit is connected to the gate of the first field effect tube to control the resistance of the first field effect tube, thereby controlling the size of the tail current. The larger the tail current is, the smaller the voltage required for the negative resistance differential pair circuit to be turned on is, and the larger the amplitude of the oscillation signal is; the smaller the tail current is, the larger the voltage required for the negative resistance differential pair circuit to be turned on is, and the smaller the amplitude of the oscillation signal is. When the amplitude of the oscillation signal is too large, the amplitude adjustment circuit is adjusted to reduce the tail current, and the amplitude of the oscillation signal is reduced; when the amplitude of the oscillation signal is too small, the amplitude adjustment circuit is adjusted to increase the tail current, and the amplitude of the oscillation signal is increased. The amplitude adjustment circuit can adjust the size of the tail current to adjust the amplitude of the oscillation signal. By using a low-noise self-biased analog control loop to adjust the tail current resistance, the low noise of the oscillator is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of a circuit diagram of an oscillator provided in an embodiment of the present application;

[0018] Figure 2 A schematic circuit diagram of an amplitude adjustment circuit provided in an embodiment of the present application.

[0019] The following are the descriptions of the reference numerals:

[0020] V0+, a positive output terminal of the oscillation circuit, V0-, a negative output terminal of the oscillation circuit, L1, a first inductor, 111, a first end of the first inductor, 112, a second end of the first inductor, L2, a first inductor, 121, a first end of the second inductor, 122, a second end of the second inductor, Vdd1, a first DC power supply, 131, a first end of the variable capacitor array, 132, a second end of the variable capacitor array;

[0021] M1, a first field effect transistor, R1, a first resistor, 211, a first end of the first resistor, 212, a second end of the first resistor;

[0022] M2, the second field effect transistor, M3, the third field effect transistor;

[0023] Vdd2, a second DC power supply, M4, a fourth field effect transistor, M5, a fifth field effect transistor, R2, a second resistor, 311, a first end of the second resistor, 312, a second end of the second resistor, C1, a first capacitor, 321, a first end of the first capacitor, 322, a second end of the first capacitor, M6, a sixth field effect transistor, a sixth field effect transistor bias voltage Vbias2, Vref, a regulation voltage, Vdet, a DC voltage, Comp, an operational amplifier, S-, a first input end of the operational amplifier, S+, a second input end of the operational amplifier, and a tail current regulation voltage Vbias1;

[0024] R3, a third resistor, 411, a first end of the third resistor, 412, a second end of the third resistor, R4, a fourth resistor, 421, a first end of the fourth resistor, 422, a second end of the fourth resistor;

[0025] C2, a second capacitor, 511, a first end of the second capacitor, 512, a second end of the second capacitor. DETAILED DESCRIPTION

[0026] Typical implementations that embody the features and advantages of the present application will be described in detail in the following description. It should be understood that the present application can have various changes in different implementations without departing from the scope of the present application, and the descriptions and illustrations therein are essentially used for illustrative purposes rather than for limiting the present application.

[0027] An oscillator provided by this embodiment includes an oscillation circuit, a negative resistance differential pair circuit, a tail current circuit and an amplitude adjustment circuit.

[0028] In one embodiment of the present application, the oscillation circuit includes a first inductor L1, a second inductor L2 and a variable capacitor array, the first end 111 of the first inductor is connected to the first DC power supply Vdd1, the second end 112 of the first inductor serves as the positive output terminal V0+ of the oscillation circuit, the first end 121 of the second inductor is connected to the first DC power supply Vdd1, the second end 122 of the second inductor serves as the negative output terminal V0- of the oscillation circuit, the first end 131 of the variable capacitor array is connected to the positive output terminal V0+ of the oscillation circuit, and the second end 132 of the variable capacitor array is connected to the negative output terminal V0- of the oscillation circuit.

[0029] In this embodiment, the first inductor L1, the second inductor L2 and the variable capacitor array form an LC resonant network for generating an oscillation signal.

[0030] In one embodiment of the present application, the variable capacitor array may include a plurality of variable capacitors connected in parallel.

[0031] In one embodiment of the present application, the variable capacitor array may include four variable capacitors as a first variable capacitor, a second variable capacitor, a third variable capacitor and a fourth variable capacitor, four fixed capacitors as a first fixed capacitor, a second fixed capacitor, a third fixed capacitor and a fourth fixed capacitor, and four resistors as a first array resistor, a second array resistor, a third array resistor and a fourth array resistor, wherein the first end of the first variable capacitor is connected to a control voltage, the second end of the first variable capacitor is connected to a first reference voltage through a first array resistor, the first end of the second variable capacitor is connected to the control voltage, the second end of the second variable capacitor is connected to the first reference voltage through a second array resistor, the first end of the third variable capacitor is connected to the control voltage, the second end of the third variable capacitor is connected to the second reference voltage through a third array resistor, the first end of the fourth variable capacitor is connected to the control voltage, and the second end of the fourth variable capacitor is connected to the second reference voltage through a fourth array resistor. A distributed varactor structure circuit is adopted. Compared with a single bias varactor structure, the loop stability and loop noise performance deterioration are reduced, thereby achieving a high linear gain of the oscillator.

[0032] In one embodiment of the present application, the oscillation circuit may include an inductor and a variable capacitor array, the variable capacitor array may include two variable capacitors and two fixed capacitors, the anodes of the two variable capacitors may be connected to a capacitor adjustment voltage, the cathodes of the two variable capacitors may be respectively connected to the first ends of the two fixed capacitors, the second ends of the two fixed capacitors may respectively serve as the positive output terminal V0+ and the negative output terminal of the oscillation circuit, and the two ends of the inductor may respectively be connected to the positive output terminal V0+ and the negative output terminal of the oscillation circuit.

[0033] In one embodiment of the present application, the input end of the negative resistance differential pair circuit is connected to the output end of the oscillation circuit. The LC oscillation circuit will be equivalent to a resistance in parallel with the distributed varactor structure circuit. The equivalent resistance consumes energy and increases the power consumption of the circuit. The negative resistance differential pair circuit is used to compensate for the equivalent resistance generated by the oscillation circuit. The negative resistance differential pair circuit acts as a negative resistance to compensate for the equivalent resistance, thereby performing energy compensation on the oscillation circuit.

[0034] In one embodiment of the present application, the negative resistance differential pair circuit includes a second field effect transistor M2 and a third field effect transistor M3, the source of the second field effect transistor M2 is connected to the positive output terminal V0+ of the oscillation circuit, the gate of the second field effect transistor M2 is connected to the negative output terminal V0- of the oscillation circuit, and the drain of the second field effect transistor M2 serves as the output terminal of the negative resistance differential pair circuit; the source of the third field effect transistor M3 is connected to the negative output terminal V0- of the oscillation circuit, the gate of the third field effect transistor M3 is connected to the positive output terminal V0+ of the oscillation circuit, and the drain of the third field effect transistor M3 is connected to the drain of the second field effect transistor M2. The negative resistance differential pair circuit uses a pair of cross-complementary coupled field effect transistors to act as negative resistance to compensate for the energy of the oscillation circuit, so that the entire oscillator can oscillate without attenuation and reduce power consumption.

[0035] In one embodiment of the present application, the input end of the tail current circuit is connected to the output end of the negative resistance differential pair circuit, the output end of the tail current circuit is grounded, and the tail current circuit provides a bias current for the negative resistance differential pair circuit, thereby providing a tail current for the oscillator, wherein, the larger the tail current, the smaller the voltage required for the negative resistance differential pair circuit to be turned on, and the larger the amplitude of the oscillation signal; the smaller the tail current, the larger the voltage required for the negative resistance differential pair circuit to be turned on, and the smaller the amplitude of the oscillation signal.

[0036] In one embodiment of the present application, the input end of the amplitude adjustment circuit is connected to the output end of the oscillation circuit, the output end of the amplitude adjustment circuit is connected to the control end of the tail current circuit, and the amplitude adjustment circuit is used to adjust the size of the tail current to adjust the amplitude of the oscillation signal.

[0037] In one embodiment of the present application, the tail current circuit may include a first field effect transistor M1, the source of the first field effect transistor M1 is connected to the output end of the negative resistance differential pair circuit, the gate of the first field effect transistor M1 serves as the control end of the tail current circuit, and the first field effect transistor M1 using a variable resistor in the tail current adjusts the amplitude of the oscillation signal, thereby reducing the noise of the oscillation signal.

[0038] In one embodiment of the present application, the tail current circuit may also include a first resistor R1, the first end 211 of the first resistor is connected to the drain of the first field effect transistor M1, the second end 212 of the first resistor is grounded, the first resistor R1 provides a bias current for the first field effect transistor M1, which is beneficial to the conduction of the first field effect transistor M1, and a low-noise passive resistor is combined with the variable resistor of the first field effect transistor M1 to serve as a tail current source, thereby blocking the noise of the power ground and reducing the noise of the oscillation signal.

[0039] In this embodiment, a low-noise passive resistor is combined with the first field effect transistor M1 variable resistor to serve as a tail current source, and the first field effect transistor M1 variable resistor is controlled by a low-noise self-biased analog control loop, thereby achieving low noise of the oscillator.

[0040] In one embodiment of the present application, the smaller the current input to the control end of the tail current circuit, the larger the resistance of the first field effect transistor M1, the smaller the tail current generated by the tail current circuit, the larger the voltage required for the negative resistance differential pair circuit to be turned on, and the smaller the amplitude of the oscillation signal; the larger the current input to the gate of the first field effect transistor M1, the smaller the resistance of the first field effect transistor M1, the larger the tail current generated by the tail current circuit, the smaller the voltage required for the negative resistance differential pair circuit to be turned on, and the larger the amplitude of the oscillation signal.

[0041] In one embodiment of the present application, the tail current circuit may include multiple resistors connected in parallel and switches corresponding to the multiple resistors one by one. A control signal of the switch can be generated according to the amplitude of the oscillation signal, and the number of resistors connected to the tail current can be adjusted according to the amplitude, thereby adjusting the size of the tail current and further adjusting the amplitude of the oscillation signal.

[0042] In one embodiment of the present application, the amplitude adjustment circuit may include a rectifier circuit, a filter circuit and an operational amplifier Comp, the input end of the rectifier circuit is connected to the output end of the oscillation circuit, the input end of the filter circuit is connected to the output end of the rectifier circuit, the first input end S- of the operational amplifier is connected to the output end of the filter circuit, the second input end S+ of the operational amplifier inputs the comparison voltage Vref, the output end of the operational amplifier Comp outputs the tail current adjustment voltage Vbias1, the output end of the operational amplifier Comp is connected to the control end of the tail current circuit, the rectifier circuit and the filter circuit convert the oscillation signal output by the oscillation circuit into a DC voltage Vdet, the operational amplifier Comp calculates the DC voltage Vdet obtained according to the oscillation signal and the comparison voltage Vref, the calculation result is input into the control end of the tail current, the resistance of the tail current circuit is adjusted, and thus the size of the tail current is adjusted to achieve the purpose of adjusting the amplitude of the oscillation signal.

[0043] In one embodiment of the present application, the first input terminal S- of the operational amplifier receives a DC voltage Vdet obtained according to the oscillation signal, and the second input terminal S+ of the operational amplifier receives a comparison voltage Vref. The calculation formula of the operational amplifier Comp can be: [(S+)-(S-)]*x, where x is the operational gain factor, which can be set as needed.

[0044] In this embodiment, when the amplitude of the oscillation signal is too large, the voltage received by the first input terminal S- of the operational amplifier is too large, and the voltage output by the output terminal of the operational amplifier Comp is too small, the resistance of the tail current increases, and the tail current decreases, and the voltage required for the negative resistance differential pair circuit to be turned on increases, and the amplitude of the oscillation signal decreases, and finally the amplitude of the oscillation signal is within a moderate range. This amplitude adjustment circuit automatically adjusts in real time and is an analog control loop. Compared with the digital control loop, it has better robustness and does not require the introduction of additional signals for calibration.

[0045] In one embodiment of the present application, the rectifier circuit includes a fourth field effect transistor M4 and a fifth field effect transistor M5, the source of the fourth field effect transistor M4 is connected to the second DC power supply Vdd2, the gate of the fourth field effect transistor M4 is connected to the positive output terminal V0+ of the oscillation circuit, the drain of the fourth field effect transistor M4 outputs a half-wave rectifier circuit of an oscillation signal output from the positive output terminal V0+ of the oscillation circuit, the drain of the fourth field effect transistor M4 serves as the output terminal of the rectifier circuit, the source of the fifth field effect transistor M5 is connected to the second DC power supply Vdd2, the gate of the fifth field effect transistor M5 is connected to the negative output terminal V0- of the oscillation circuit, the drain of the fifth field effect transistor M5 is connected to the drain of the fourth field effect transistor M4, the drain of the fifth field effect transistor M5 outputs a half-wave rectifier circuit of an oscillation signal output from the negative output terminal V0- of the oscillation circuit, and the oscillation signal output from the positive output terminal V0+ of the oscillation circuit is equal in amplitude and opposite in phase to the oscillation signal output from the negative output terminal V0- of the oscillation circuit, therefore, the output terminal of the rectifier circuit outputs a pulsating DC voltage.

[0046] In one embodiment of the present application, the filtering circuit may include a second resistor R2 and a first capacitor C1, the first end 311 of the second resistor is connected to the output end of the rectifier circuit, the second end 312 of the second resistor is grounded through a negative resistance, the second end 312 of the second resistor is connected to the first input terminal S- of the operational amplifier, the first end 321 of the first capacitor is connected to the second end 312 of the second resistor, the second end 322 of the first capacitor is grounded, the second resistor R2 and the first capacitor C1 convert the pulsating DC voltage into a smooth DC voltage Vdet, the smooth DC voltage Vdet carries the amplitude information in the oscillation signal, and the smooth DC voltage Vdet is easy to calculate using the operational amplifier Comp, so that the amplitude of the oscillation signal can be adjusted according to the calculation result of the operational amplifier Comp.

[0047] In one embodiment of the present application, the second end 312 of the second resistor can be grounded through a resistor, and the resistor connected to the second end 312 of the second resistor provides a bias current for the fourth field effect transistor M4 and the fifth field effect transistor M5, which is beneficial to the conduction of the fourth field effect transistor M4 and the fifth field effect transistor M5.

[0048] In one embodiment of the present application, the second end 312 of the second resistor can be grounded through the sixth field effect transistor M6, the source of the sixth field effect transistor M6 is connected to the second end 312 of the second resistor, the drain of the sixth field effect transistor M6 is grounded, and the gate of the sixth field effect transistor M6 is connected to the bias voltage of the sixth field effect transistor M6. The sixth field effect transistor M6 provides a bias current for the fourth field effect transistor M4 and the fifth field effect transistor M5, which is beneficial to the conduction of the fourth field effect transistor M4 and the fifth field effect transistor M5. Since the bias voltage of the sixth field effect transistor M6 can be set as needed, the bias voltage of the sixth field effect transistor M6 can be adjusted to adjust the voltage input to the first end of the operational amplifier Comp, thereby adjusting the voltage output from the amplitude adjustment circuit to the control end of the tail current circuit, thereby changing the amplitude of the oscillation signal.

[0049] In one embodiment of the present application, the amplitude adjustment circuit may also include a third resistor R3 and a fourth resistor R4 connected in series, the first end 411 of the third resistor is connected to the second DC power supply Vdd2, the second end 412 of the third resistor is connected to the second input terminal S+ of the operational amplifier, the first end 421 of the fourth resistor is connected to the second end 412 of the third resistor, the second end 422 of the fourth resistor is grounded, the third resistor R3 is a voltage divider for the fourth resistor R4, the voltage input to the second input terminal S+ of the operational amplifier is the voltage divided by the fourth resistor R4, and the size of the comparison voltage Vref can be changed by adjusting the size of the third resistor R3 or the fourth resistor R4, thereby changing the operation result of the operational amplifier Comp, and then changing the amplitude of the oscillation signal.

[0050] In this embodiment, the comparison voltage Vref is generated by dividing the second DC power source Vdd2, and no additional comparison voltage needs to be introduced, so that the structure is simple and the robustness is better.

[0051] In one embodiment of the present application, the amplitude adjustment circuit may further include a second capacitor C2, the first end 511 of the second capacitor is connected to the output end of the amplitude adjustment circuit, the second end 512 of the second capacitor is grounded, and the second capacitor C2 filters the output of the amplitude adjustment circuit to make the output of the amplitude adjustment circuit more stable.

[0052] An oscillator proposed in the present application includes an oscillation circuit, a negative resistance differential pair circuit, and a tail current circuit. The oscillation circuit is used to generate an oscillation signal. The input end of the negative resistance differential pair circuit is connected to the output end of the oscillation circuit. The negative resistance differential pair circuit is used to compensate for the equivalent resistance generated by the oscillation circuit, and acts as a negative resistance to compensate for the equivalent resistance, so as to perform energy compensation on the oscillation circuit. The input end of the tail current circuit is connected to the output end of the negative resistance differential pair circuit. The output end of the tail current circuit is grounded. The tail current circuit is used to provide a bias current for the negative resistance differential pair circuit, thereby providing a tail current for the oscillator. The tail current can suppress the noise of the power supply ground from entering the resonant cavity, thereby reducing the phase noise of the oscillator. In addition, the tail current circuit includes a first field effect transistor M1, and the oscillator also includes an amplitude adjustment circuit. The input end of the oscillator tail current amplitude adjustment circuit The output end of the oscillation circuit is connected, and the output end of the amplitude adjustment circuit is connected to the gate of the first field effect transistor M1, and the resistance of the first field effect transistor M1 is controlled, thereby controlling the size of the tail current. The larger the tail current is, the smaller the voltage required for the negative resistance differential pair circuit to be turned on is, and the larger the amplitude of the oscillation signal is; the smaller the tail current is, the larger the voltage required for the negative resistance differential pair circuit to be turned on is, and the smaller the amplitude of the oscillation signal is. When the amplitude of the oscillation signal is too large, the amplitude adjustment circuit is adjusted to reduce the tail current, and the amplitude of the oscillation signal is reduced; when the amplitude of the oscillation signal is too small, the amplitude adjustment circuit is adjusted to increase the tail current, and the amplitude of the oscillation signal is increased. The amplitude adjustment circuit can adjust the size of the tail current to adjust the amplitude of the oscillation signal. The tail current resistance is controlled by using a low-noise self-biased analog control loop, thereby achieving low noise of the oscillator.

[0053] Although the present application has been described with reference to several typical embodiments, it should be understood that the terms used are illustrative and exemplary, rather than restrictive. Since the present application can be implemented in a variety of forms without departing from the spirit or essence of the application, it should be understood that the above-mentioned embodiments are not limited to any of the aforementioned details, but should be widely interpreted within the spirit and scope defined by the attached claims, so all changes and modifications falling within the scope of the claims or their equivalents should be covered by the attached claims.

Claims

1. An oscillator, characterized in that: include: An oscillation circuit, for generating an oscillation signal; A negative resistance differential pair circuit, wherein an input end of the negative resistance differential pair circuit is connected to an output end of the oscillation circuit, and the negative resistance differential pair circuit is used to compensate for an equivalent resistance generated by the oscillation circuit; A tail current circuit, wherein the input end of the tail current circuit is connected to the output end of the negative resistance differential pair circuit, the output end of the tail current circuit is grounded, the tail current circuit comprises a first field effect transistor, and the tail current circuit is used to provide a tail current for the oscillator; an amplitude adjustment circuit, wherein the input end of the amplitude adjustment circuit is connected to the output end of the oscillation circuit, the output end of the amplitude adjustment circuit is connected to the gate of the first field effect transistor, and the amplitude adjustment circuit is used to adjust the size of the tail current to adjust the amplitude of the oscillation signal; Wherein, the amplitude adjustment circuit comprises: A rectifier circuit, wherein an input end of the rectifier circuit is connected to an output end of the oscillator circuit; A filter circuit, wherein an input end of the filter circuit is connected to an output end of the rectifier circuit; An operational amplifier, wherein a first input terminal of the operational amplifier is connected to an output terminal of the filter circuit, a second input terminal of the operational amplifier is input with a comparison voltage, and an output terminal of the operational amplifier is connected to a control terminal of the tail current circuit.

2. The oscillator according to claim 1, characterized in that The output end of the oscillator circuit includes a positive output end and a negative output end, and the oscillator circuit includes: a first inductor, wherein a first end of the first inductor is connected to a first DC power supply, and a second end of the first inductor serves as a positive output end of the oscillation circuit; a second inductor, wherein a first end of the second inductor is connected to the first DC power supply, and a second end of the second inductor serves as a negative output end of the oscillation circuit; A variable capacitor array, wherein a first end of the variable capacitor array is connected to the positive output end of the oscillation circuit, and a second end of the variable capacitor array is connected to the negative output end of the oscillation circuit.

3. The oscillator according to claim 2, characterized in that The variable capacitor array includes a plurality of variable capacitors connected in parallel.

4. The oscillator according to claim 1, characterized in that The negative resistance differential pair circuit comprises: a second field effect transistor, wherein the drain of the second field effect transistor is connected to the positive output end of the oscillation circuit, the gate of the second field effect transistor is connected to the negative output end of the oscillation circuit, and the source of the second field effect transistor serves as the output end of the negative resistance differential pair circuit; A third field effect transistor, wherein the drain of the third field effect transistor is connected to the negative output end of the oscillation circuit, the gate of the third field effect transistor is connected to the positive output end of the oscillation circuit, and the source of the third field effect transistor is connected to the source of the second field effect transistor.

5. The oscillator according to claim 1, characterized in that The tail current circuit further includes: A first resistor, wherein a first end of the first resistor is connected to a source of the first field effect transistor, and a second end of the first resistor is grounded.

6. The oscillator according to claim 1, characterized in that The rectifier circuit comprises: a fourth field effect transistor, wherein the drain of the fourth field effect transistor is connected to the second DC power supply, the gate of the fourth field effect transistor is connected to the positive output end of the oscillation circuit, and the source of the fourth field effect transistor serves as the output end of the rectifier circuit; A fifth field effect transistor, wherein the drain of the fifth field effect transistor is connected to the second DC power supply, the gate of the fifth field effect transistor is connected to the negative output end of the oscillation circuit, and the source of the fifth field effect transistor is connected to the source of the fourth field effect transistor.

7. The oscillator according to claim 1, characterized in that The filtering circuit comprises: a second resistor, wherein a first end of the second resistor is connected to the output end of the rectifier circuit, a second end of the second resistor is grounded via a negative resistor, and a second end of the second resistor is connected to the first input end of the operational amplifier; A first capacitor, wherein a first end of the first capacitor is connected to the second end of the second resistor, and a second end of the first capacitor is grounded.

8. The oscillator according to claim 7, characterized in that The second end of the second resistor is grounded through a sixth field effect transistor, the drain of the sixth field effect transistor is connected to the second end of the second resistor, the source of the sixth field effect transistor is grounded, and the gate of the sixth field effect transistor is connected to the sixth field effect transistor bias voltage.

9. The oscillator according to claim 6, characterized in that The amplitude adjustment circuit also includes: a third resistor, wherein a first end of the third resistor is connected to the second DC power supply, and a second end of the third resistor is connected to the second input end of the operational amplifier; A fourth resistor, wherein a first end of the fourth resistor is connected to the second end of the third resistor, and a second end of the fourth resistor is grounded.

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