A low phase noise LC type voltage-controlled oscillator and electronic equipment

Abstract

The present invention discloses a low phase noise LC type voltage-controlled oscillator and electronic equipment. The LC type voltage-controlled oscillator comprises a resonance unit, a negative resistance unit and a feedback unit. The resonance unit and the negative resistance unit are respectively connected in parallel with two differential output terminals; the first input terminal of the feedback unit is connected to the resonance unit, the second input terminal is connected to the reference voltage terminal, and the output terminal is connected to the negative resistance unit. The LC type voltage-controlled oscillator adopts a technical solution of cross-coupling the negative resistance unit to bias the gate voltage of the tube separately, so that all MOS tubes can work in a suitable working area, ensure the normal operation of the LC type voltage-controlled oscillator, and reduce the phase noise of the voltage-controlled oscillator circuit, which is particularly suitable for application scenarios with low power supply voltage.

Description

Technical Field

[0001] The invention relates to an LC type voltage-controlled oscillator with low phase noise, and also relates to electronic equipment comprising the LC type voltage-controlled oscillator, belonging to the technical field of integrated circuits. Background Art

[0002] The function of the voltage controlled oscillator (VCO) is to output an AC signal of a certain frequency, and its application range is very wide. According to the different oscillation circuit structures, it can be divided into inductor capacitor type (LC-VCO), resistor capacitor type (RC-VCO) and crystal oscillation type. In wireless communication systems, the RF transceiver chip requires a phase-lock loop (PLL) to provide LO (local oscillator) signal for RF transceiver. Among them, VCO is the frequency generation module of PLL and is the most critical and core component of PLL. Therefore, the performance indicators of VCO are very important. Among them, lower phase noise can improve the sensitivity of the receiver while reducing the spectrum occupancy of the transmitter and improving EVM (error vector magnitude) and other performance.

[0003] In the prior art, a typical LC voltage-controlled oscillator circuit is as follows: Figure 1 As shown, it mainly includes PMOS tube PM0, PMOS tube PM1 and NMOS tube NM0, NMOS tube NM1, as well as inductor L0, variable capacitor C1 and variable capacitor C2. Among them, two NMOS tubes and two PMOS tubes form a negative resistance tube, and inductor L0 and two variable capacitors form a resonant circuit. When the input control voltage Vc changes, the capacitance values ​​of variable capacitors C1 and C2 change accordingly, so as to adjust the output frequency.

[0004] With the continuous development of semiconductor process technology, the process technology has transitioned from 180nm to 90nm and then to 40nm and below, and the channel length of the MOS tube has become smaller and smaller, and its voltage resistance has become lower and lower. Therefore, the voltage for providing power to it has also been reduced. When the power supply voltage Vdd is low, in the above-mentioned LC-VCO circuit, if it cannot be guaranteed that the power supply voltage value is greater than the sum of the gate-source threshold voltages (Vgs_th) of the PMOS tube and the NMOS tube (i.e. PM0 and NM0, or PM1 and NM1) connected to the differential output terminal under all process angles (PVT), it will cause the PMOS tube and / or NMOS tube to be not fully turned on, and its drain current is relatively small, and the transconductance Gm value is also relatively small, so that the phase noise performance of the LC-VCO is significantly reduced. Therefore, how to overcome the problems existing in the above-mentioned prior art and provide a low phase noise LC type voltage-controlled oscillator to meet the requirements of the phase noise performance index of PLL and other application integrated circuits is a very important technical research topic in this field.

[0005] In the Chinese patent application with application number 201910183529.4, a LC voltage-controlled oscillator with dynamic bias adjustment is disclosed. The LC voltage-controlled oscillator includes a cross-coupling pair, an LC resonant cavity, a frequency tuning module, and a peak detection module; wherein the two differential output ports of the cross-coupling pair are respectively connected in parallel with the two input ports of the LC resonant cavity, the frequency tuning module, and the peak detection module, and the two differential output ports are used as the output ports of the LC voltage-controlled oscillator; the differential input port of the cross-coupling pair is connected to the output port of the peak detection module, and the cross-coupling pair detects the peak value of the output signal in real time according to the peak detection module to realize dynamic bias adjustment. Summary of the invention

[0006] The primary technical problem to be solved by the present invention is to provide an LC type voltage-controlled oscillator with low phase noise.

[0007] Another technical problem to be solved by the present invention is to provide an electronic device including the low phase noise LC type voltage-controlled oscillator.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] According to a first aspect of an embodiment of the present invention, a low phase noise LC type voltage controlled oscillator is provided. The LC type voltage controlled oscillator comprises a resonance unit, a negative resistance unit and a feedback unit; wherein:

[0010] The resonance unit and the negative resistance unit are respectively connected in parallel to the two differential output terminals; the first input terminal of the feedback unit is connected to the resonance unit, the second input terminal is connected to the reference voltage terminal, and the output terminal is connected to the negative resistance unit;

[0011] The resonance unit adopts a parallel structure of inductance and capacitance to generate an AC signal with a certain resonance frequency; the negative resistance unit adopts a complementary structure of PMOS cross-coupled pair of tubes and NPOS cross-coupled pair of tubes to compensate for the energy loss in each oscillation cycle; the feedback unit adopts a closed-loop feedback structure to provide a first bias voltage for the negative resistance unit.

[0012] Preferably, two ends of the first inductor in the resonance unit are connected to the first differential output end and the second differential output end respectively, and a middle tap end of the first inductor is connected to the first input end of the feedback unit.

[0013] Preferably, the feedback unit is composed of an operational amplifier, whose inverting input terminal is connected to the middle tap terminal of the first inductor in the resonance unit, its non-inverting input terminal is connected to the reference voltage terminal, and its output terminal is connected to the first bias voltage terminal in the negative resistance unit.

[0014] Preferably, the feedback unit is composed of a third NMOS transistor NM2, a fourth NMOS transistor NM3, a fifth NMOS transistor NM4 and a third PMOS transistor PM2; wherein,

[0015] The source of the third PMOS tube PM2 is connected to the power supply voltage terminal, the gate and drain of the third PMOS tube PM2 are short-circuited and connected to the first bias voltage terminal of the negative resistance unit on the one hand, and to the drain of the fifth NMOS tube NM4 on the other hand, and the gate of the fifth NMOS tube NM4 is connected to the reference voltage terminal; the drain of the fourth NMOS tube NM3 is connected to the power supply voltage terminal, the gate of the fourth NMOS tube NM3 is connected to the middle tap terminal of the first inductor in the resonance unit, the source of the fourth NMOS tube NM3 is connected to the source of the fifth NMOS tube NM4 and then connected to the drain of the third NMOS tube NM2, the gate of the third NMOS tube NM2 is connected to the third bias voltage terminal, and the source of the third NMOS tube NM2 is connected to the ground potential terminal.

[0016] Preferably, when the LC voltage-controlled oscillator operates stably, the voltage at the middle tap end of the first inductor in the resonance unit is equal to the input reference voltage of the feedback unit.

[0017] Preferably, the negative resistance unit includes a first PMOS transistor PM0, a second PMOS transistor PM1, a first NMOS transistor NM0 and a second NMOS transistor NM1; wherein,

[0018] The first NMOS transistor NM0 and the second NMOS transistor NM1 form an NMOS cross-coupled pair of transistors, and the first PMOS transistor PM0 and the second PMOS transistor PM1 form a PMOS cross-coupled pair of transistors.

[0019] Preferably, the negative resistance unit further includes a third capacitor C2, a fourth capacitor C3, a third resistor R2 and a fourth resistor R3; wherein,

[0020] One end of the third capacitor C2 and the fourth capacitor C3 are respectively connected to the gate of the second PMOS transistor PM1 and the first PMOS transistor PM0, and the other end is respectively connected to the first differential output terminal and the second differential output terminal;

[0021] One end of the third resistor R2 and the fourth resistor R3 are respectively connected to the gate of the second PMOS transistor PM1 and the first PMOS transistor PM0 , and the other ends are connected to each other and then connected to the output end of the feedback unit as a first bias voltage end.

[0022] Preferably, the negative resistance unit further includes a first capacitor C0, a second capacitor C1, a first resistor R0 and a second resistor R1; wherein,

[0023] One end of the first capacitor C0 and the second capacitor C1 are respectively connected to the gate of the second NMOS transistor NM1 and the first NMOS transistor NM0, and the other end is respectively connected to the first differential output terminal and the second differential output terminal;

[0024] One end of the first resistor R0 and the second resistor R1 are respectively connected to the gates of the second NMOS transistor NM1 and the first NMOS transistor NM0 , and the other ends are connected to each other and then to the second bias voltage terminal.

[0025] According to a second aspect of an embodiment of the present invention, there is provided an electronic device, comprising the above-mentioned LC type voltage-controlled oscillator with low phase noise.

[0026] Compared with the prior art, the low phase noise LC type voltage controlled oscillator provided by the present invention adopts a technical solution of biasing the gate voltage of the cross-coupled pair of tubes of the negative resistance unit separately, so as to ensure that the cross-coupled pair of tubes can work in a suitable working area under all process angles (PVT) to provide a larger transconductance Gm, thereby effectively improving the phase noise performance. Therefore, the low phase noise LC type voltage controlled oscillator provided by the present invention has the beneficial effects of ingenious and reasonable structural design, low cost and excellent circuit performance, and is particularly suitable for application scenarios with low power supply voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A typical LC voltage-controlled oscillator circuit schematic diagram in the prior art;

[0028] Figure 2 A structural block diagram of a low phase noise LC voltage-controlled oscillator provided by the present invention;

[0029] Figure 3A circuit schematic diagram of an LC voltage-controlled oscillator in an embodiment of the present invention;

[0030] Figure 4 A circuit schematic diagram of a feedback unit in an embodiment of the present invention;

[0031] Figure 5 This is a simulation test diagram of the phase noise of the LC type voltage-controlled oscillator in an embodiment of the present invention;

[0032] Figure 6 The schematic diagram of an electronic device using the LC voltage-controlled oscillator provided by the present invention is shown in FIG. DETAILED DESCRIPTION

[0033] The technical content of the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] like Figure 2 As shown, the low phase noise LC type voltage-controlled oscillator provided by the embodiment of the present invention includes a resonance unit, a negative resistance unit and a feedback unit. The resonance unit and the negative resistance unit are respectively connected in parallel with the two differential output terminals (Pout, Nout) of the voltage-controlled oscillator; the first input terminal of the feedback unit is connected to the resonance unit, the second input terminal is connected to the reference voltage terminal, and the output terminal is connected to the negative resistance unit.

[0035] The resonance unit adopts a parallel structure of inductance and capacitance to generate an AC signal with a certain resonant frequency; the negative resistance unit adopts a complementary structure of PMOS cross-coupled pair of tubes and NPOS cross-coupled pair of tubes to compensate for the energy loss in each oscillation cycle; the feedback unit adopts a closed-loop feedback structure to provide a bias voltage for the negative resistance unit.

[0036] The low phase noise LC-type voltage-controlled oscillator provided by the embodiment of the present invention adopts a technical solution of biasing the gate voltage of the cross-coupled pair of tubes (NMOS pair and PMOS pair) of the negative resistance unit separately, so that all MOS tubes can work in a suitable working area, provide a larger transconductance Gm, ensure the normal operation of the LC-type voltage-controlled oscillator, and reduce the phase noise of the LC-VCO circuit. It is particularly suitable for application scenarios with low power supply voltage Vdd.

[0037] like Figure 3As shown, in one embodiment of the present invention, the resonant unit is composed of a first inductor L0, a first variable capacitor Cv1 and a second variable capacitor Cv2. The two ends of the first inductor L0 are respectively connected to the first differential output terminal Pout and the second differential output terminal Nout, and the middle tap end of the first inductor L0 is connected to the first input end of the feedback unit; the first variable capacitor Cv1 and the second variable capacitor Cv2 are connected in series, the series node is connected to the control voltage Vc terminal, and the two ends of the variable capacitor series branch are respectively connected to the first differential output terminal Pout and the second differential output terminal Nout.

[0038] In other embodiments of the present invention, the capacitor series branch of the resonance unit may also contain a fixed capacitor, or may be in the form of an array of capacitor series branches, which are used to form an oscillation circuit together with the inductor.

[0039] like Figure 3 As shown, in one embodiment of the present invention, the negative resistance unit includes a first PMOS transistor PM0, a second PMOS transistor PM1, a first NMOS transistor NM0 and a second NMOS transistor NM1, as well as a first capacitor C0, a second capacitor C1, a third capacitor C2 and a fourth capacitor C3, and a first resistor R0, a second resistor R1, a third resistor R2 and a fourth resistor R3. Among them, the source of the first PMOS transistor PM0 and the second PMOS transistor PM1 are both connected to the power supply voltage Vdd terminal; the gate of the first PMOS transistor PM0 is connected to the drain of the second PMOS transistor PM1 through the fourth capacitor C3 on the one hand, and is connected to the first bias voltage Vbp terminal through the third resistor R2 on the other hand; the gate of the second PMOS transistor PM1 is connected to the drain of the first PMOS transistor PM0 through the third capacitor C2 on the one hand, and is connected to the first bias voltage Vbp terminal through the fourth resistor R3 on the other hand. The drain of the first PMOS transistor PM0 is connected to the drain of the first NMOS transistor NM0 as the first differential output terminal Pout, and the drain of the second PMOS transistor PM1 is connected to the drain of the second NMOS transistor NM1 as the second differential output terminal Nout. The sources of the first NMOS transistor NM0 and the second NMOS transistor NM1 are both connected to the ground potential terminal; the gate of the first NMOS transistor NM0 is connected to the drain of the second NMOS transistor NM1 through the second capacitor C1 on the one hand, and is connected to the second bias voltage Vbn terminal through the first resistor R0 on the other hand; the gate of the second NMOS transistor NM1 is connected to the drain of the first NMOS transistor NM0 through the first capacitor C0 on the one hand, and is connected to the second bias voltage Vbn terminal through the second resistor R1 on the other hand.

[0040] In the negative resistance unit, the first NMOS transistor NM0 and the second NMOS transistor NM1 form an NMOS cross-coupled pair, and the first PMOS transistor PM0 and the second PMOS transistor PM1 form a PMOS cross-coupled pair, which are used to compensate for the energy loss generated on the resistor in each LC oscillation cycle. This complementary structure of the NMOS differential pair and the PMOS differential pair can provide a larger negative resistance, which is beneficial to the oscillation of the VCO.

[0041] like Figure 3 As shown, in one embodiment of the present invention, the feedback unit is composed of an operational amplifier OP, whose first input terminal, i.e., the reverse output terminal, is connected to the middle tap terminal of the first inductor L0 in the resonance unit, whose second input terminal, i.e., the same direction input terminal, is connected to the reference voltage Vref terminal, and whose output terminal is connected to the first bias voltage Vbp terminal in the negative resistance unit.

[0042] In the LC-type voltage-controlled oscillator circuit provided by the embodiment of the present invention, the NMOS cross-coupled pair of tubes of the negative resistance unit, namely the first NMOS tube NM0 and the second NMOS tube NM1, have their gates respectively isolated by the first capacitor C0 and the second capacitor C1, and then the second bias voltage Vbn provides a suitable bias voltage through the first resistor R0 and the second resistor R1, so that the gate-source voltage Vgs of the first NMOS tube NM0 and the second NMOS tube NM1 are both greater than their threshold voltage Vgs_th, ensuring that the first NMOS tube NM0 and the second NMOS tube NM1 can be fully turned on and work normally.

[0043] The PMOS cross-coupled pair of transistors of the negative resistance unit, i.e., the first PMOS transistor PM0 and the second PMOS transistor PM1, have their gates isolated by the third capacitor C2 and the fourth capacitor C3, respectively. The first bias voltage Vbp output by the feedback unit provides a suitable bias voltage through the third resistor R2 and the fourth resistor R3, respectively, so that the gate-source voltage Vgs of the first PMOS transistor PM0 and the second PMOS transistor PM1 are both greater than their threshold voltage Vgs_th, ensuring that the first PMOS transistor PM0 and the second PMOS transistor PM1 can be fully turned on and work in the saturation region, effectively providing a larger transconductance Gm and a sufficiently large drain current, and reducing the phase noise of the LC-VCO.

[0044] Among them, the first bias voltage Vbp is provided by the output voltage of the operational amplifier OP of the feedback unit, the reverse input terminal of the operational amplifier OP inputs the voltage Vt of the middle tap terminal of the first inductor L0 in the resonance unit, and the voltage is the common mode voltage of the two differential output terminal signals, and the same direction input terminal inputs the reference voltage Vref, forming a closed-loop feedback network. When the LC-VCO circuit works stably, the voltage Vt of the middle tap terminal of the first inductor L0 is equal to the reference voltage Vref. Therefore, by reasonably setting the voltage value of the reference voltage Vref, a suitable first bias voltage Vbp can be obtained, and according to the common mode voltage Vt being equal to the reference voltage Vref, the voltage values ​​of the first differential output terminal Pout and the second differential output terminal Nout are adjusted to ensure that the first PMOS tube PM0 and the second PMOS tube PM1 as well as the first NMOS tube NM0 and the second NMOS tube NM1 can be fully turned on and work in the saturation region, thereby improving the phase noise performance of the LC-VCO circuit.

[0045] like Figure 4 As shown, in another embodiment of the present invention, the LC voltage-controlled oscillator includes a resonance unit, a negative resistance unit and a feedback unit. The difference from the above embodiment is that the feedback unit is composed of a simple operational amplifier composed of four tubes.

[0046] In this embodiment, the feedback unit is composed of a third NMOS transistor NM2, a fourth NMOS transistor NM3, a fifth NMOS transistor NM4 and a third PMOS transistor PM2. The source of the third PMOS transistor PM2 is connected to the power supply voltage Vdd terminal, the gate and drain of the third PMOS transistor PM2 are short-circuited and connected to the first bias voltage Vbp terminal of the negative resistance unit as an output terminal, and connected to the drain of the fifth NMOS transistor NM4 on the other hand, and the gate of the fifth NMOS transistor NM4 is connected to the reference voltage Vref terminal as a second input terminal; the drain of the fourth NMOS transistor NM3 is connected to the power supply voltage Vdd terminal, the gate of the fourth NMOS transistor NM3 is connected to the middle tap terminal of the first inductor L0 in the resonance unit as a first input terminal, the source of the fourth NMOS transistor NM3 is connected to the source of the fifth NMOS transistor NM4 and then connected to the drain of the third NMOS transistor NM2, the gate of the third NMOS transistor NM2 is connected to the third bias voltage Vbn1 terminal, and the source of the third NMOS transistor NM2 is connected to the ground potential terminal.

[0047] In the feedback unit, the third PMOS tube PM2 (load tube) is connected in the form of a diode, and its gate terminal serves as the output terminal of the operational amplifier to provide the first bias voltage Vbp for the negative resistance unit. This structure is conducive to the current matching between the VCO and the operational amplifier. The fourth NMOS tube NM3 and the fifth NMOS tube NM4 form an input pair tube, which respectively inputs the voltage Vt at the middle tap end of the first inductor L0 and the reference voltage Vref to form a closed-loop feedback network. When the LC-VCO circuit works stably, the voltage Vt at the middle tap end of the first inductor L0 is equal to the reference voltage Vref. The gate of the third NMOS tube NM2 inputs the third bias voltage Vbn1 to provide the amplifier with working current. The simple operational amplifier solution provided in the embodiment of the present invention has a simple structure and a small number of transistors, which is conducive to improving the phase noise performance of the LC-VCO.

[0048] It can be seen from the analysis and description of the above embodiments that the low phase noise LC type voltage-controlled oscillator provided by the embodiments of the present invention, when the power supply voltage is low, adopts a technical solution of separately biasing the gate voltages of the cross-coupled pairs of tubes (NMOS pairs and PMOS pairs) of the negative resistance unit, so that all MOS tubes can operate in a suitable working area to provide a larger transconductance Gm, thereby effectively suppressing the noise in the circuit.

[0049] In order to verify the working performance of the LC voltage-controlled oscillator provided by the embodiment of the present invention, the inventors conducted phase noise simulation tests on the LC voltage-controlled oscillator and the prior art solution respectively. The power supply voltage of the LC_VCO circuit in the test was 1V. The test results are as follows: Figure 5 shown. Figure 5 The horizontal axis is the output frequency, and the vertical axis is the phase noise. It can be seen from the figure that the phase noise performance of the LC voltage-controlled oscillator provided by the embodiment of the present invention is significantly improved compared with the prior art solution, wherein the phase noise at a frequency of 10KHz is improved by 4dB, and the phase noise at a frequency of 100KHz is improved by 2dB.

[0050] An embodiment of the present invention further provides an electronic device, which includes the above-mentioned LC type voltage-controlled oscillator with low phase noise, and the LC type voltage-controlled oscillator is used as a frequency generating module in a communication component to provide an AC signal of a certain frequency for an application integrated circuit in the electronic device. Figure 6As shown, the electronic device at least includes a processor, a memory and a communication component, and may further include a sensor component, a multimedia component, a power component and an input / output interface according to actual needs. Among them, the memory, the communication component, the sensor component, the power component, the multimedia component and the input / output interface are all connected to the processor. The memory may be a static random access memory (SRAM), an electrically erasable programmable read-only memory (EEPROM), an erasable programmable read-only memory (EPROM), a programmable read-only memory (PROM), a read-only memory (ROM), a magnetic memory, a flash memory, etc., and the processor may be a central processing unit (CPU), a graphics processing unit (GPU), a field programmable gate array (FPGA), an application-specific integrated circuit (ASIC), a digital signal processing (DSP) chip, etc. Other power components, sensor components, multimedia components, etc. may all be implemented using general components, which will not be specifically described here.

[0051] In summary, compared with the prior art, the low phase noise LC type voltage controlled oscillator provided by the present invention adopts a technical solution of biasing the gate voltage of the cross-coupled pair of tubes of the negative resistance unit separately, so as to ensure that the cross-coupled pair of tubes can work in a suitable working area under all process angles (PVT) to provide a larger transconductance Gm, thereby effectively improving the phase noise performance. Therefore, the low phase noise LC type voltage controlled oscillator provided by the present invention has the beneficial effects of ingenious and reasonable structural design, low cost and excellent circuit performance, and is particularly suitable for application scenarios with low power supply voltage.

[0052] It should be noted that the above-mentioned multiple embodiments are only examples, and the technical solutions of various embodiments can be combined, all of which are within the protection scope of the present invention.

[0053] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0054] The above is a detailed description of the low phase noise LC voltage-controlled oscillator and electronic device provided by the present invention. For those skilled in the art, any obvious changes made to it without departing from the essence of the present invention will constitute an infringement of the patent right of the present invention and will bear the corresponding legal liability.

Claims

1. A low phase noise LC voltage controlled oscillator, characterized in that It includes a resonance unit, a negative resistance unit and a feedback unit; wherein, The resonance unit and the negative resistance unit are respectively connected in parallel to the two differential output terminals; the first input terminal of the feedback unit is connected to the resonance unit, the second input terminal is connected to the reference voltage terminal, and the output terminal is connected to the negative resistance unit; The resonant unit adopts a parallel structure of an inductor and a capacitor to generate an AC signal with a certain resonant frequency; the negative resistance unit adopts a complementary structure of a PMOS cross-coupled pair of transistors and an NPOS cross-coupled pair of transistors to compensate for the energy loss in each oscillation cycle; the feedback unit adopts a closed-loop feedback structure to provide a first bias voltage for the negative resistance unit; The feedback unit is composed of a third NMOS tube (NM2), a fourth NMOS tube (NM3), a fifth NMOS tube (NM4) and a third PMOS tube (PM2); the source of the third PMOS tube (PM2) is connected to the power supply voltage terminal, the gate and drain of the third PMOS tube (PM2) are short-circuited and connected to the first bias voltage terminal of the negative resistance unit on the one hand, and to the drain of the fifth NMOS tube (NM4) on the other hand, and the gate of the fifth NMOS tube (NM4) is connected to the power supply voltage terminal. The fourth NMOS tube (NM3) is connected to the reference voltage terminal; the drain of the fourth NMOS tube (NM3) is connected to the power supply voltage terminal, the gate of the fourth NMOS tube (NM3) is connected to the middle tap terminal of the first inductor in the resonant unit, the source of the fourth NMOS tube (NM3) is connected to the source of the fifth NMOS tube (NM4) and then connected to the drain of the third NMOS tube (NM2), the gate of the third NMOS tube (NM2) is connected to the third bias voltage terminal, and the source of the third NMOS tube (NM2) is connected to the ground potential terminal.

2. The LC voltage-controlled oscillator according to claim 1, characterized in that: Two ends of the first inductor in the resonance unit are connected to the first differential output end and the second differential output end respectively, and a middle tap end of the first inductor is connected to the first input end of the feedback unit.

3. The LC voltage-controlled oscillator according to claim 1, wherein: The feedback unit is composed of an operational amplifier, whose inverting input terminal is connected to the middle tap terminal of the first inductor in the resonance unit, its non-inverting input terminal is connected to the reference voltage terminal, and its output terminal is connected to the first bias voltage terminal in the negative resistance unit.

4. The LC voltage-controlled oscillator according to claim 1, wherein: When the LC voltage-controlled oscillator operates stably, the voltage at the middle tap end of the first inductor in the resonance unit is equal to the input reference voltage of the feedback unit.

5. The LC voltage-controlled oscillator according to claim 1, wherein: The negative resistance unit includes a first PMOS tube (PM0), a second PMOS tube (PM1), a first NMOS tube (NM0) and a second NMOS tube (NM1); wherein, The first NMOS transistor (NM0) and the second NMOS transistor (NM1) form an NMOS cross-coupled pair of transistors, and the first PMOS transistor (PM0) and the second PMOS transistor (PM1) form a PMOS cross-coupled pair of transistors.

6. The LC voltage-controlled oscillator according to claim 5, characterized in that: The negative resistance unit further includes a third capacitor (C2), a fourth capacitor (C3), a third resistor (R2) and a fourth resistor (R3); wherein, One end of the third capacitor (C2) and the fourth capacitor (C3) are respectively connected to the gate of the second PMOS transistor (PM1) and the first PMOS transistor (PM0), and the other end is respectively connected to the first differential output terminal and the second differential output terminal; One end of the third resistor (R2) and the fourth resistor (R3) are respectively connected to the gate of the second PMOS transistor (PM1) and the first PMOS transistor (PM0), and the other ends are connected to each other and connected to the output end of the feedback unit as a first bias voltage end.

7. The LC voltage-controlled oscillator according to claim 5, characterized in that: The negative resistance unit further includes a first capacitor (C0), a second capacitor (C1), a first resistor (R0) and a second resistor (R1); wherein, One end of the first capacitor (C0) and the second capacitor (C1) are respectively connected to the gate of the second NMOS transistor (NM1) and the first NMOS transistor (NM0), and the other end is respectively connected to the first differential output terminal and the second differential output terminal; One end of the first resistor (R0) and the second resistor (R1) are respectively connected to the gate of the second NMOS transistor (NM1) and the first NMOS transistor (NM0), and the other ends are connected to each other and then connected to the second bias voltage terminal.

8. An electronic device, characterized in that The invention comprises the LC type voltage controlled oscillator as claimed in any one of claims 1 to 7.

Images