Voltage controlled oscillator, phase locked loop circuit, light detection device and laser radar

Abstract

The application discloses a voltage-controlled oscillator, a phase-locked loop circuit, an optical detection device and a laser radar, wherein the voltage-controlled oscillator comprises an inductance unit, a variable capacitance unit and a temperature compensation unit; the inductance unit is coupled between a first output end and a second output end of the voltage-controlled oscillator; the variable capacitance unit is coupled between the first output end and the second output end of the voltage-controlled oscillator and comprises a plurality of parallel variable capacitance branches, each of the plurality of variable capacitance branches is respectively coupled with the temperature compensation unit and is adapted to cover a preset target frequency of the voltage-controlled oscillator; and the temperature compensation unit is respectively coupled with the plurality of variable capacitance branches and is adapted to change a temperature compensation voltage according to a detected ambient temperature and adjust capacitance values of the plurality of variable capacitance branches. The above scheme can reduce the influence of the ambient temperature on the voltage-controlled oscillator.

Description

Technical Field

[0001] This specification relates to the field of voltage-controlled oscillator technology, and in particular to a voltage-controlled oscillator, a phase-locked loop circuit, a photodetector, and a lidar. Background Technology

[0002] Phase-locked loop (PLL) circuits are widely used in radio frequency transceiver systems. They can provide local oscillator signals or clock signals to data converters and digital circuits. The signal quality of the local oscillator signal or clock signal has a direct impact on the key indicators of radio frequency systems and high-speed, high-precision data converters.

[0003] The core component that enables a PLL to maintain good frequency signal quality is the voltage-controlled oscillator (VCO). Due to its stable oscillation frequency and wide tuning range, the LC-type VCO is widely used in PLLs. The LC-type VCO is a positive feedback amplifier. When the circuit starts operating, the amplifier cyclically amplifies the noise in the circuit. If the amplifier meets the Barkhausen start-up condition, the oscillator will eventually oscillate, thus obtaining the desired oscillation signal. Figure 1 The schematic diagram of the LC-type VCO shown indicates that the signal frequency can be determined by the inductance value of the spiral inductor L and the total capacitance value, which includes the capacitance C provided by the varactor diode. v And parasitic capacitances C1 and C2. Change the Vctrl value ( Figure 1 (Not shown in the image) The voltage difference U across the variable capacitor can be changed. c This causes a change in the capacitance of the variable capacitor, thereby altering the oscillation frequency ω. The voltage signal that changes the Vctrl value is provided by the loop filter (LPF) in the PLL.

[0004] However, when the external temperature changes, the parasitic capacitance and inductance inside the LC-type VCO exhibit significant temperature characteristics. If the real-time tuning gain K of the VCO... VCO If the voltage is very low, the PLL will undergo a relocking process, which requires a stabilization time of tens of microseconds. During this relocking period, the PLL's working state is abnormal, which is not allowed in system applications. Summary of the Invention

[0005] In view of this, embodiments of this specification provide a voltage-controlled oscillator, a phase-locked loop circuit, a photodetector, and a lidar, which can reduce the impact of ambient temperature changes on the voltage-controlled oscillator.

[0006] First, this specification provides a voltage-controlled oscillator, including: an inductor unit, a variable capacitor unit, and a temperature compensation unit, wherein:

[0007] The inductor unit is coupled between the first output terminal and the second output terminal of the voltage-controlled oscillator;

[0008] The variable capacitor unit is coupled between the first and second output terminals of the voltage-controlled oscillator and includes multiple variable capacitor branches connected in parallel. Each of the multiple variable capacitor branches is coupled to the temperature compensation unit, which is suitable for enabling the voltage-controlled oscillator to cover a preset target frequency.

[0009] The temperature compensation unit is coupled to the plurality of variable capacitor branches respectively, and is adapted to change the temperature compensation voltage accordingly based on the detected ambient temperature, thereby adjusting the capacitance value of the plurality of variable capacitor branches.

[0010] Optionally, the voltage-controlled oscillator further includes a voltage control unit coupled to the variable capacitor unit, the voltage control unit comprising:

[0011] A voltage control module is adapted to adjust its own output voltage in order to adjust the capacitance value of the plurality of variable capacitor branches;

[0012] A resistor module is coupled between the voltage control module and the variable capacitor unit.

[0013] Optionally, the variable capacitor branch includes: a variable capacitor module and a fixed capacitor module, wherein:

[0014] The variable capacitor module is coupled to the temperature compensation unit and the voltage control unit, respectively;

[0015] The fixed capacitor module is coupled between the variable capacitor module and the first and second output terminals of the voltage-controlled oscillator, and is suitable for providing a basic capacitance value.

[0016] Optionally, the voltage-controlled oscillator further includes a cross-coupling unit, which is coupled between the power supply and ground, and is coupled to the first output terminal and the second output terminal of the voltage-controlled oscillator, and is adapted to provide negative resistance.

[0017] Optionally, the cross-coupling unit includes: a first cross-coupling module and a second cross-coupling module, wherein:

[0018] The first cross-coupling module is located at the ground terminal of the voltage-controlled oscillator and is coupled to the first and second output terminals of the voltage-controlled oscillator.

[0019] The second cross-coupling module is located at the power supply terminal of the voltage-controlled oscillator and is coupled to the first and second output terminals of the voltage-controlled oscillator.

[0020] Optionally, the inductor unit is directly connected to the power supply; the cross-coupling unit includes a cross-coupling module disposed at the ground terminal, the cross-coupling module being coupled to the first output terminal and the second output terminal of the voltage-controlled oscillator respectively.

[0021] Optionally, the voltage-controlled oscillator further includes a frequency coarse adjustment unit, the frequency coarse adjustment unit comprising:

[0022] Digital control code module, suitable for outputting digital control codes;

[0023] Multiple frequency coarse adjustment branches connected in parallel, the frequency coarse adjustment branches including:

[0024] A switch module, the control terminal of which is coupled to the digital control code module, is adapted to perform on / off control based on the digital control code;

[0025] At least two fixed capacitors are coupled between the switching module and the first or second output terminal of the voltage-controlled oscillator, and are adapted to be connected to the circuit of the voltage-controlled oscillator when the switching module is turned on, so as to adjust the sub-band frequency of the voltage-controlled oscillator.

[0026] This specification also provides a phase-locked loop circuit, including:

[0027] The voltage-controlled oscillator described in any of the foregoing embodiments is suitable for generating an oscillation signal within a preset frequency range;

[0028] A phase detector, coupled to the voltage-controlled oscillator, is adapted to determine, based on an input reference signal, whether the frequency of the oscillation signal output by the voltage-controlled oscillator is the same as that of the reference signal, and when they are different, output a control voltage signal to adjust the oscillation frequency of the voltage-controlled oscillator.

[0029] Optionally, the phase-locked loop circuit further includes a low-pass filter coupled between the phase detector and the voltage-controlled oscillator, adapted to filter the control voltage signal output by the phase detector.

[0030] This specification also provides an embodiment of a light detection device, including:

[0031] Photoelectric sensors are suitable for converting light signals reflected from a target object into analog electrical signals;

[0032] An analog-to-digital converter module, adapted to convert the analog electrical signal into a digital signal;

[0033] The phase-locked loop circuit described in any of the foregoing embodiments is adapted to provide a clock signal to the analog-to-digital conversion module.

[0034] Optionally, the photodetector further includes: an electrical signal preprocessing module, coupled between the photoelectric sensor and the analog-to-digital conversion module, adapted to perform at least one of the following preprocessing steps on the analog electrical signal:

[0035] The analog electrical signal is filtered;

[0036] The analog electrical signal is amplified.

[0037] This specification also provides a lidar system, including a light emitting device, an optical system, and a computing system, and further including the light detection device described in any of the foregoing embodiments, wherein:

[0038] The light emitting device is adapted to provide detection light;

[0039] The optical system is adapted to transmit the detection light to the detection target and to transmit the reflected light from the detection target to the optical detection device;

[0040] The light detection device is adapted to obtain the reception time of the reflected light;

[0041] The computing system is adapted to calculate the distance to the target object based on the emission time of the detection light and the reception time of the reflected light.

[0042] The voltage-controlled oscillator (VCO) in this embodiment includes an inductor unit, a variable capacitor unit, and a temperature compensation unit. Since the variable capacitor unit uses multiple variable capacitor branches connected in parallel, the temperature compensation unit adjusts the temperature compensation voltage according to the detected ambient temperature, thereby adjusting the capacitance values ​​of the multiple variable capacitor branches. This achieves adaptive adjustment of the VCO's oscillation frequency, reducing the impact of ambient temperature changes on the VCO, and thus improving the frequency output accuracy and stability of the VCO. Furthermore, the variable capacitor unit, including multiple parallel variable capacitor branches, can reduce the kickback effect caused by the high-frequency vibration signal output by the VCO with a smaller variable capacitor unit area, improving the stability of the VCO's temperature compensation. In summary, using the VCO in this embodiment can ensure the stability of temperature compensation with a smaller chip area.

[0043] Furthermore, the voltage-controlled oscillator (VCO) also includes a voltage control unit coupled to the variable capacitor unit. That is, the voltage control unit and the temperature compensation unit share the variable capacitor unit, and both can adjust the capacitance value of the variable capacitor unit. This eliminates the need for a separate variable capacitor to be adapted for the voltage control unit, thus further reducing the circuit area and the area of ​​the chip packaging the VCO, and correspondingly reducing chip power consumption. Moreover, the voltage control unit includes a voltage control module and a resistor module. Since the resistor module is coupled between the voltage control module and the variable capacitor unit, it can cancel the oscillation current generated by the variable capacitor unit, preventing the oscillation current from affecting the output voltage of the voltage control module, thereby further improving the stability of the VCO output frequency.

[0044] Furthermore, the variable capacitor branch of the voltage-controlled oscillator includes a variable capacitor module and a fixed capacitor module. On the one hand, the temperature compensation unit and the voltage control unit can adjust the oscillation frequency of the voltage-controlled oscillator by adjusting the variable capacitor module; on the other hand, the linearity of the frequency adjustment of the voltage-controlled oscillator can be improved by the fixed capacitor module.

[0045] Furthermore, the cross-coupling unit is coupled between the power supply and ground, and is also coupled to the first and second output terminals of the voltage-controlled oscillator (VCO), providing negative resistance to the VCO. This balances the resistance of the capacitors and inductors within the VCO, reduces the attenuation of the oscillation amplitude, and further improves the stability of the VCO's output frequency.

[0046] Furthermore, the input terminal of the voltage-controlled oscillator is directly connected to the power supply through the inductor unit, and the cross-coupling unit only includes a cross-coupling module disposed at the ground terminal. Therefore, the power supply voltage can be applied directly to the voltage-controlled oscillator without passing through the cross-coupling unit, thereby reducing the power supply voltage required for the voltage-controlled oscillator to operate and thus reducing the power consumption of the voltage-controlled oscillator. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0048] Figure 1 This is a schematic diagram of the principle of an LC-type VCO;

[0049] Figure 2This is a simplified structural diagram of an LC-type VCO.

[0050] Figure 3 A simplified structural diagram of another type of LC VCO;

[0051] Figure 4 The waveform diagram shows the oscillation amplitude of an LC-type VCO.

[0052] Figure 5 This is a circuit diagram of a voltage-controlled oscillator;

[0053] Figure 6 This is a circuit diagram of a voltage-controlled oscillator as described in the embodiments of this specification;

[0054] Figure 7 The diagram shows a mapping curve showing the relationship between the output frequency of the voltage-controlled oscillator and the output voltage of the voltage control unit in some embodiments of this specification;

[0055] Figure 8 This specification shows a mapping curve illustrating the relationship between the output frequency of a voltage-controlled oscillator and the output voltage of a voltage control unit in a specific example.

[0056] Figure 9 for Figure 5 and Figure 6 The waveform of the oscillation frequency of the example circuit shown as a function of temperature;

[0057] Figure 10 This is a circuit diagram of another voltage-controlled oscillator in the embodiments of this specification;

[0058] Figure 11 This is a schematic diagram of a phase-locked loop circuit in one of the embodiments of this specification;

[0059] Figure 12 This is a schematic diagram of the structure of a photodetector as described in the embodiments of the specification;

[0060] Figure 13 This is a schematic diagram of the structure of a lidar in the embodiments of the specification. Detailed Implementation

[0061] As is known from the background art, the voltage-controlled oscillator is the core component of a PLL. Among them, the LC type VCO is widely used in PLLs due to its stable oscillation frequency and wide frequency modulation range.

[0062] However, the parasitic capacitance and inductance inside an LC-type VCO have significant temperature characteristics, which can cause the oscillation frequency to shift during operation.

[0063] To enable those skilled in the art to better understand and implement the embodiments of this specification, the working principle of the voltage-controlled oscillator involved in the embodiments of this specification will be explained below with reference to a simplified structural diagram of the voltage-controlled oscillator.

[0064] Reference Figure 2 The diagram shown is a simplified structural diagram of a voltage-controlled oscillator. The voltage-controlled oscillator can be considered as consisting of a parasitic capacitance C. p and equivalent inductance L eq The LC oscillating circuit consists of circuits whose operating principle is based on the parasitic capacitance C. p and the equivalent inductance L eq Causes current oscillation:

[0065]

[0066] However, capacitors and inductors are subject to temperature effects. In the operating environment temperature of the voltage-controlled oscillator (e.g., -40 to 125°C), as the temperature rises, the capacitance and inductance values ​​in the circuit will increase, resulting in a decrease in the oscillation frequency. This causes the control voltage of the voltage-controlled oscillator to deviate from the intermediate value, resulting in a reduction in circuit performance. Moreover, if the oscillation frequency changes too much, it may cause the PLL to lose lock.

[0067] In practical work, such as Figure 3 As shown, the parasitic capacitance C of the voltage-controlled oscillator p There is a parasitic resistance R C Equivalent inductance L eq There is a parasitic resistance R L The presence of these two parasitic resistances causes the oscillation amplitude of the voltage-controlled oscillator to gradually weaken within one oscillation cycle. To reduce the amplitude decay caused by the resistance of parasitic capacitance and equivalent inductance, a negative resistance -R can be added to the voltage-controlled oscillator circuit to balance the parasitic resistance R. C and R L This can reduce the attenuation of oscillation amplitude.

[0068] Reference Figure 4 The graph shows the amplitude variation curve of the LC-type voltage-controlled oscillator. The vertical axis A represents the amplitude, and the horizontal axis t represents time. The input pulse P0 is input to... Figure 2 and Figure 3 The input terminal Vin of the LC-type VCO circuit shown outputs corresponding oscillation waveforms at the output terminal Vout, as follows: Figure 4 The waveforms f1 and f2 shown are shown below, where waveform f1 represents the oscillation amplitude change curve without negative resistance and waveform f2 represents the oscillation amplitude change curve with negative resistance.

[0069] Depend on Figure 4 It can be seen that the adoption Figure 3 The circuit structure shown can reduce the attenuation of oscillation amplitude caused by the resistance of parasitic capacitance and equivalent inductance. However, when the operating temperature of the voltage-controlled oscillator changes, the inductance and capacitance values ​​in the voltage-controlled oscillator circuit will change, thereby affecting the oscillation frequency output by the voltage-controlled oscillator.

[0070] To address the aforementioned issues, a voltage-controlled oscillator (VCO) circuit exists that can reduce the impact of operating temperature variations on the VCO's oscillation frequency.

[0071] like Figure 5 The circuit diagram of the voltage-controlled oscillator 50 is shown above. The voltage-controlled oscillator 50 includes: a first cross-coupled transistor 51, a second cross-coupled transistor 52, an inductor L, and a variable capacitor C. C1 C C2 C C3 C C4 53. Voltage control module 54. Temperature compensation module 55. Frequency coarse adjustment unit 56. and stabilizing capacitor C S The compensation principle of temperature compensation module 54 is briefly described below:

[0072] Assume the equivalent capacitance of the preset voltage-controlled oscillator is C, and the inductance is L, where the equivalent capacitance C is the capacitance C. C1 C C2 C C3 C C4 C DC1 C DC2 The equivalent capacitance value. When the operating temperature of the voltage-controlled oscillator 50 changes, the inductance changes accordingly to ΔL, and the temperature compensation module 54 can adjust the temperature compensation voltage V. TH Change C C3 and C C4 The capacitance value is such that the capacitance value of the equivalent capacitance becomes ΔC. Ideally, this would make:

[0073] C·L=ΔC·ΔL (2)

[0074] That is, the temperature compensation module 54 changes the temperature compensation voltage V TH The size of the value is such that the oscillation frequency output by the voltage-controlled oscillator 50 does not change with temperature before and after temperature changes, thereby reducing the impact of temperature changes on the oscillation frequency.

[0075] Using the voltage-controlled oscillator described above, the temperature compensation module can output different temperature compensation voltages V when the temperature changes. TH By changing the variable capacitor C C3 C C4The capacitance value can be changed to alter the equivalent capacitance value of the voltage-controlled oscillator, thereby enabling the voltage-controlled oscillator to output a preset oscillation frequency and reducing the impact of temperature changes on the oscillation frequency of the voltage-controlled oscillator.

[0076] However, in actual operation, voltage-controlled oscillators (VCOs) must not only cover variations within the normal operating temperature range, but also the oscillation frequency drift caused by changes in the operating parameters of other electronic components due to temperature variations and other factors. Therefore, the variable capacitor C used for temperature compensation... C3 Or C C4 In addition to compensating for the frequency change of the voltage-controlled oscillator itself due to temperature variations, it is also necessary to compensate for the frequency drift caused by other electronic components. Therefore, in practical design, in order to provide sufficient variable capacitance value to compensate for the frequency shift caused by temperature changes, Figure 5 The variable capacitor C in C3 Or C C4 The area will be relatively large.

[0077] Furthermore, since the voltage-controlled oscillator outputs a high-frequency oscillation signal, it affects the variable capacitor coupled between the power supply VCC and the output terminal Out, causing the current or voltage at the output terminal Out to be fed back to the voltage input terminal, such as the output terminal Vctrl of the voltage control module 53 and the output terminal V of the temperature compensation module 54. TH This can cause a kickback effect, for example, it may cause damage to the output of the temperature compensation module 54. Figure 5 The capacitor C in C3 and C C4 The temperature compensation module 54 generates significant fluctuations. To reduce these fluctuations at its output, a stabilizing capacitor C is used. S It will be designed to have a larger area.

[0078] As can be seen from the above, although the voltage-controlled oscillator can reduce the problem of vibration frequency drift caused by temperature changes, the excessively large area of ​​the variable capacitor and the stable capacitor not only increases the area of ​​the chip, but also reduces the stability of temperature compensation.

[0079] To address the aforementioned issues, the voltage-controlled oscillator (VCO) provided in this embodiment is employed. In this VCO, multiple variable capacitor branches are connected in parallel within the variable capacitor unit. A temperature compensation unit adjusts the temperature compensation voltage based on the detected ambient temperature, thereby adjusting the capacitance values ​​of the multiple variable capacitor branches. This achieves adaptive adjustment of the VCO's oscillation frequency, reducing the impact of ambient temperature changes on the VCO and improving its frequency output accuracy and stability. Furthermore, the parallel connection of multiple variable capacitor branches reduces the area of ​​the variable capacitor unit, thus reducing the chip area. This also minimizes the kickback effect caused by the high-frequency vibration signal output by the VCO, improving the stability of the VCO's temperature compensation.

[0080] To enable those skilled in the art to better understand the concept, advantages, and implementation schemes of the solutions provided in this specification, the following detailed description and examples of the principles of the voltage-controlled oscillator, phase-locked loop, and other solutions provided in the embodiments of this specification are given with reference to the accompanying drawings and through specific examples.

[0081] Reference Figure 6 The structural diagram of the voltage-controlled oscillator circuit of the embodiment shown in this specification is as follows: Figure 6 As shown, the voltage-controlled oscillator 60 may include an inductor unit 6A, a variable capacitor unit 63, and a temperature compensation unit 64, wherein:

[0082] The inductor unit 6A is coupled between the first output terminal Out1 and the second output terminal Out2 of the voltage-controlled oscillator 60;

[0083] The variable capacitor unit 63 is coupled between the first output terminal Out1 and the second output terminal Out2 of the voltage-controlled oscillator 60. The variable capacitor unit 63 includes multiple variable capacitor branches 63i connected in parallel. Each of the multiple variable capacitor branches 63i is coupled to the temperature compensation unit 64, which is suitable for enabling the voltage-controlled oscillator 60 to cover a preset target frequency.

[0084] The temperature compensation unit 64 is coupled to the plurality of variable capacitor branches 63i respectively, and is adapted to change the temperature compensation voltage V accordingly based on the detected ambient temperature. TH Adjust the capacitance values ​​of the multiple variable capacitor branches 63i.

[0085] Employing the aforementioned voltage-controlled oscillator 60, the variable capacitor unit 63 includes multiple parallel variable capacitor branches 63i. The temperature compensation unit 64 can adjust its temperature compensation voltage V according to the detected ambient temperature. THThis allows adjustment of the capacitance values ​​of the multiple variable capacitor branches 63i, thereby adjusting the oscillation frequency of the voltage-controlled oscillator 60 and compensating for frequency drift caused by changes in ambient temperature. Furthermore, the variable capacitor unit 63 includes multiple parallel variable capacitor branches 63i, which can reduce the backlash effect caused by the high-frequency vibration signal output by the voltage-controlled oscillator 60 with a smaller variable capacitor unit 63, thus improving the stability of temperature compensation of the voltage-controlled oscillator 60.

[0086] As can be seen from the above, the voltage-controlled oscillator in the embodiments of this specification can ensure the stability of temperature compensation with a smaller chip area.

[0087] Therefore, when the operating temperature of the voltage-controlled oscillator 60 changes, the temperature compensation unit 64 can automatically adjust the capacitance value of the variable capacitor unit 63 to compensate for the oscillation frequency drift caused by temperature changes, thereby reducing the impact of ambient temperature changes on the voltage-controlled oscillator.

[0088] In a specific implementation, the voltage-controlled oscillator may further include a voltage control unit 65, which is coupled to the variable capacitor unit 63 and is adapted to adjust its own output voltage Vctrl to adjust the capacitance value of the plurality of variable capacitor branches 63i.

[0089] In the above embodiment, the voltage control unit 65 and the temperature compensation unit 64 share the variable capacitor unit 63, and both can adjust the capacitance value of the variable capacitor unit 63. Therefore, it is not necessary to specially adapt different variable capacitors for the voltage control unit 65. As a result, the circuit area and the area of ​​the chip packaging the voltage-controlled oscillator 60 can be further reduced, and the chip power consumption can also be reduced accordingly.

[0090] To clearly illustrate the temperature compensation process described above, the working principle of the voltage-controlled oscillator is explained in detail below through specific application examples, including how to adjust the capacitance value of the variable capacitor unit to reduce the impact of ambient temperature changes on the voltage-controlled oscillator.

[0091] First, in some embodiments of the present invention, the parasitic capacitance of the voltage-controlled oscillator can be coarsely adjusted first, and then finely adjusted. (Continue to refer to...) Figure 6 In practical implementation, the sub-band frequency range of the voltage-controlled oscillator output can be determined first, and then adjusted by the voltage control unit 65 to stabilize the output oscillation frequency at a certain fixed value. Therefore, a coarse frequency adjustment operation can be performed on the voltage-controlled oscillator first to ensure that the oscillation frequency meets the preset frequency range. To achieve graded adjustment of the voltage-controlled oscillator oscillation frequency, such as... Figure 6As shown, the voltage-controlled oscillator 60 may further include a frequency coarse adjustment unit 66. After the frequency coarse adjustment unit 66 determines the sub-band frequency range of the voltage-controlled oscillator output, the voltage control unit 65 is adjusted to obtain the adjusted Vctrl. By adjusting Vctrl, the capacitance value of the variable capacitor unit 63 is adjusted, thereby indirectly and precisely adjusting the oscillation frequency of the voltage-controlled oscillator and locking it at the target frequency. Here, the target frequency can be understood as the frequency desired by the user.

[0092] In some embodiments of this specification, the frequency coarse adjustment unit 66 may include a digital control code module 661 and multiple frequency coarse adjustment branches 66j connected in parallel. Wherein: the digital control code module 661 is adapted to output digital control codes; as a specific example, the frequency coarse adjustment branch 66j may include a switching module K and at least two fixed capacitors (such as capacitor C). DC1 C DC2 The switching module K, whose control terminal is coupled to the digital control code module 661, is adapted to perform on / off control based on the digital control code; the at least two fixed capacitors are coupled between the switching module K and the first output terminal Out1 or the second output terminal Out2 of the voltage-controlled oscillator (e.g., fixed capacitor C). DC1 A fixed capacitor C is coupled between the switching module K and the first output terminal Out1 of the voltage-controlled oscillator. DC2 (Coupled between the switch module K and the second output terminal Out2 of the voltage-controlled oscillator), adapted to be connected to the circuit of the voltage-controlled oscillator 60 when the switch module K is turned on, so as to adjust the sub-band frequency of the voltage-controlled oscillator 60.

[0093] The working principle of the multiple parallel frequency coarse adjustment branches 66i is briefly described below: When the switching module K is turned on, the fixed capacitor C... DC1 and C DC2 The circuit connected to the voltage-controlled oscillator (VCO) increases the equivalent capacitance of the VCO and decreases the sub-band frequency of the VCO; when the switching module K is disconnected, the fixed capacitor C... DC1 and C DC2 Disconnecting from the voltage-controlled oscillator circuit increases the sub-band frequency of the voltage-controlled oscillator. Therefore, by controlling the on / off state of each of the frequency coarse adjustment branches 66i, a suitable sub-band frequency can be selected.

[0094] In a specific implementation, the digital control code module 661 can be provided by a PLL loop to output digital control codes to select a suitable sub-band frequency of the voltage-controlled oscillator, thereby coarsely adjusting the frequency of the voltage-controlled oscillator.

[0095] In a specific implementation, the voltage-controlled oscillator may further include a cross-coupling unit, coupled between the power supply VCC and ground GND, and coupled to the first output terminal Out1 and the second output terminal Out2 of the voltage-controlled oscillator 60, which is suitable for providing negative resistance.

[0096] In some embodiments of this specification, reference continues to be made to... Figure 6 The cross-coupling unit may include a first cross-coupling module 61 and a second cross-coupling module 62, wherein: the first cross-coupling module 61 is disposed at the ground terminal and coupled to the first output terminal Out1 and the second output terminal Out2 of the voltage-controlled oscillator 60; the second cross-coupling module 62 is disposed at the power supply VCC terminal and coupled to the first output terminal Out1 and the second output terminal Out2 of the voltage-controlled oscillator 60.

[0097] As a specific example, such as Figure 6 As shown, the first cross-coupling module 61 may include a first transistor NM1 and a second transistor NM2, wherein the sources of both the first transistor NM1 and the second transistor NM2 are coupled to ground; the drain of the first transistor NM1 is coupled to the gate of the second transistor NM2 and the first output terminal Out1 of the voltage-controlled oscillator 60, respectively; the drain of the second transistor NM2 is coupled to the gate of the first transistor NM1 and the first output terminal Out2 of the voltage-controlled oscillator, respectively. The first transistor NM1 and the second transistor NM2 are cross-coupled, serving as the negative resistance of the ground terminal.

[0098] Continue to refer to Figure 6 The second cross-coupling module 62 may include a third transistor PM1 and a fourth transistor PM2, wherein the sources of both the third transistor PM1 and the fourth transistor PM2 are coupled to the power supply VCC; the drain of the third transistor PM1 is coupled to the gate of the fourth transistor PM2 and the first output terminal Out1 of the voltage-controlled oscillator 60, respectively; the drain of the fourth transistor PM2 is coupled to the gate of the third transistor PM1 and the second output terminal Out2 of the voltage-controlled oscillator 60, respectively. The third transistor PM1 and the fourth transistor PM2 are cross-coupled as a negative resistor at the power supply terminal.

[0099] In a specific implementation, the transistors in the second cross-coupling module 62 can be either P-type transistors or N-type transistors.

[0100] It should be noted that the oscillation signals output by the first output terminal Out1 and the second output terminal Out2 are 180° out of phase.

[0101] In practical applications, users can individually couple the first output terminal Out1 or the second output terminal Out2 of the voltage-controlled oscillator 60 to other circuit modules to provide the oscillation signal required by other circuit modules. Alternatively, the first output terminal Out1 and the second output terminal Out2 of the voltage-controlled oscillator 60 can be coupled to different circuit modules to provide the oscillation signal required by the corresponding circuit modules.

[0102] By setting a first cross-coupling module 61 and a second cross-coupling module 62 between the power supply and ground as negative resistors, the resistance of the capacitor and inductor in the voltage-controlled oscillator circuit can be balanced, thereby reducing the attenuation of the oscillation amplitude.

[0103] The inductor unit 6A, such as Figure 6 As shown, it may specifically include an inductor L, which is suitable for providing the inductance required by the voltage-controlled oscillator.

[0104] Using the voltage-controlled oscillator 60 described above, each variable capacitor branch 63i of the variable capacitor unit 63 is coupled to the voltage control unit 65 and the temperature compensation unit 64 respectively. That is, the voltage control unit 65 and the temperature compensation unit 64 share the variable capacitor unit 63. On the one hand, the voltage control unit 65 can adjust its own output voltage Vctrl, thereby adjusting the capacitance value of the multiple variable capacitor branches 63i, and thus adjusting the oscillation frequency of the voltage-controlled oscillator 60. On the other hand, the temperature compensation unit 64 can adaptively adjust the temperature compensation voltage V based on the ambient temperature. TH This allows for adjustment of the capacitance values ​​of each variable capacitor branch 63i in the variable capacitor unit 63 coupled to it, thereby adjusting the oscillation frequency of the voltage-controlled oscillator 60 and reducing the impact of ambient temperature changes on the voltage-controlled oscillator 60.

[0105] In some embodiments of this specification, the variable capacitor branch 63i may include a variable capacitor module 631 and a fixed capacitor module 632, wherein the variable capacitor module 631 is coupled to the temperature compensation unit 64 and the voltage control unit 65 respectively, and the fixed capacitor module 632 is coupled between the variable capacitor module 631 and the first output terminal Out1 and the second output terminal Out2 of the voltage-controlled oscillator 60, and is adapted to provide a base capacitance value.

[0106] As mentioned earlier, the voltage control unit 65 can adjust the capacitance values ​​of the plurality of variable capacitor branches 63i, thereby adjusting the oscillation frequency of the voltage-controlled oscillator 60. The adjustment principle of the voltage control unit is explained below with reference to the accompanying drawings and specific examples:

[0107] As a specific example, such as Figure 6 As shown, the variable capacitor module 631 may include a variable capacitor C.C1 C C2 The fixed capacitor module 632 may include fixed capacitors C1 and C2, wherein the fixed capacitors C1 and C2 provide the current required by the variable capacitor branch in which the fixed capacitor module 632 is located, and the temperature compensation unit 64 can change the capacitance C according to temperature changes. C1 C C2 The capacitance value is used to indirectly adjust the oscillation frequency of the voltage-controlled oscillator to obtain the preset oscillation frequency.

[0108] By coupling the fixed capacitor module 632 into the variable capacitor branch 63i, the linearity of the voltage-controlled oscillator output frequency can be significantly improved compared to the case where the fixed capacitor module 632 is not coupled. Figure 7 The diagram shows the relationship between the output frequency and output voltage of a voltage-controlled oscillator (VCO). Curve f4 represents the output frequency f as a function of the output voltage Vctrl of the voltage control unit 65 in the variable capacitor branch 63i without the fixed capacitor module 632. Curve f3 represents the output frequency f as a function of the output voltage Vctrl of the voltage control unit 65 in the variable current branch including the fixed capacitor module 632. Figure 7 As shown, the slope of curve f3 changes more slowly, and its linearity is higher.

[0109] In specific implementations, by configuring the capacitor parameters in the variable capacitor module 631 and fixed capacitor module 632 of each variable capacitor branch 63i, the output frequency of the voltage-controlled oscillator can be made to change linearly with the output voltage Vctrl of the voltage control unit 65. For example... Figure 8 The diagram shows a mapping curve f5 between the output frequency of the voltage-controlled oscillator and the output voltage of the voltage control unit in one embodiment of this specification. It can be seen that the output frequency f of the voltage-controlled oscillator is linearly related to the output voltage Vctrl of the voltage control unit. Therefore, by using the above-mentioned voltage-controlled oscillator and adjusting the voltage control unit, the required oscillation frequency can be easily obtained.

[0110] In some embodiments of this specification, the voltage control unit 65 may include a voltage control module 651 and a resistor module 652. The resistor module 652 may be coupled between the voltage control module 651 and the variable capacitor unit 63 to prevent the oscillation current from affecting the output voltage Vctr1 of the voltage control unit 65, thereby further improving the stability of the output frequency of the voltage-controlled oscillator 60.

[0111] In a specific implementation, a matching resistor submodule can be set for each variable capacitor branch 63i, and each resistor submodule is part of the resistor module 652. As a specific example, such as... Figure 6 The resistor submodules shown are R1 and R2, configured for each variable capacitor branch 63i.

[0112] In other embodiments of this specification, the resistor module 652 may be coupled between the voltage control module 651 and the entire variable capacitor unit 63, that is, a common resistor module 652 is provided for all variable capacitor branches 63i, thereby further reducing the area occupied by the circuit.

[0113] In this embodiment of the invention, by connecting multiple variable capacitor branches in parallel as a variable capacitor unit 63, when the operating temperature of the voltage-controlled oscillator changes, the temperature compensation unit 64 can adaptively change the voltage at one end of the parallel variable capacitor branches based on the change in operating temperature, and can simultaneously adjust the capacitance values ​​of multiple variable capacitor branches to cover the preset target frequency of the voltage-controlled oscillator.

[0114] Moreover, by connecting multiple variable capacitor branches in parallel, the area occupied by the entire variable capacitor unit can be reduced. While reducing the chip area, the kickback effect caused by the high-frequency vibration signal output by the voltage-controlled oscillator can be reduced, thus improving the stability of the voltage-controlled oscillator temperature compensation.

[0115] In this embodiment of the specification, the temperature compensation unit 64 can detect the real-time operating temperature of the voltage-controlled oscillator 60 and automatically adjust its temperature compensation voltage, i.e., the temperature compensation voltage V of the temperature compensation unit, is... TH This can change the voltage difference across the variable capacitor module 631, thereby changing the capacitance value of the variable capacitor module 631 to compensate for the oscillation frequency drift caused by temperature changes.

[0116] In specific implementation, in order to stabilize the temperature compensation voltage V of the temperature compensation unit 64 TH A voltage regulator unit can be coupled to the output terminal of the temperature compensation unit 64 to stabilize the temperature compensation voltage V of the temperature compensation unit 64. TH As mentioned earlier, the voltage-controlled oscillator 60 generates a backlash effect during operation, causing fluctuations at the output of the temperature compensation unit 64. Therefore, a stabilizing capacitor Cs can be coupled to the output of the temperature compensation unit 64 to stabilize its output voltage. The stabilizing capacitor Cs... S The first end is coupled to the output end of the temperature compensation unit 64, and the second end is coupled to ground.

[0117] It should be noted that, because the voltage-controlled oscillator uses multiple variable capacitor units connected in parallel, the back kick effect is reduced, thus decreasing the fluctuation at the output of the temperature compensation unit 64. Therefore, the area of ​​the voltage-regulating capacitor Cs is similar to that of the voltage regulator. Figure 5 Compared to the voltage regulator capacitor in the circuit, it can be designed to be smaller, thereby reducing the area of ​​the entire voltage-controlled oscillator circuit and thus reducing the overall size of the voltage-controlled oscillator.

[0118] As can be seen from the above embodiments, when the voltage-controlled oscillator 60 is working normally, refer to Figure 6 The frequency coarse adjustment unit 66 selects the sub-band frequency output by the voltage-controlled oscillator 60, and the output voltage Vctrl is adjusted by the voltage control unit 65, thereby adjusting the capacitance value of the variable capacitor module 631 so that the voltage-controlled oscillator 60 outputs a preset oscillation frequency. The first transistor NM1 and the second transistor NM2 in the first cross-coupling module 61, and the third transistor PM1 and the fourth transistor PM2 in the second cross-coupling module, act as negative resistors in the circuit. They are used to balance the resistance of the capacitors and inductors in the entire voltage-controlled oscillator circuit, reducing the attenuation of the oscillation amplitude and improving the stability and reliability of the voltage-controlled oscillator output frequency.

[0119] When the operating temperature changes, the temperature compensation unit 64 automatically adjusts the temperature compensation voltage V at the output terminal according to the ambient temperature. TH Therefore, the variable capacitor C in the variable capacitor unit 63 C1 and C C2 The voltage across the two ends changes, creating a voltage difference, which causes the C C1 and C C2 The capacitance value changes; simultaneously, the voltage control module 651 can be manually adjusted. Its output voltage Vtr1, after being divided by resistors R1 and R2, partially charges the fixed capacitors C1 and C2 in the fixed capacitor module 632, generating current in the variable capacitor branch 63i where the variable capacitor unit 63 is located. The other part flows to the variable capacitor module 631, changing the variable capacitor C... C1 and C C2 The capacitance value is adjusted by changing the output voltage of the temperature compensation unit 64 and the voltage control unit 65, thereby changing the voltage difference across the variable capacitor unit 63, so that the capacitance value of C... C1 and C C2 The change in capacitance value can alter the equivalent capacitance value of the voltage-controlled oscillator, thereby adjusting the oscillation frequency of the voltage-controlled oscillator.

[0120] Furthermore, in order to reduce voltage jitter at the output terminal of the temperature compensation unit 64, a stabilizing capacitor C can be coupled to the output terminal of the temperature compensation unit 64. S .

[0121] use Figure 6 The voltage-controlled oscillator circuit shown, because the voltage control unit 65 and the temperature compensation unit 64 share a single variable capacitor unit 63, and the variable capacitor unit 63 uses multiple variable capacitor branches connected in parallel, allows for a very small capacitance area in each variable capacitor branch. Therefore, it reduces the kickback effect caused by the high-frequency vibration signal output by the voltage-controlled oscillator. Figure 5 Compared to the voltage-controlled oscillator circuit shown, this circuit has better temperature compensation and can improve the stability of temperature compensation in voltage-controlled oscillators.

[0122] Reference Figure 9 The waveform diagram shown illustrates the variation of the oscillation frequency of a voltage-controlled oscillator with temperature. The horizontal axis T represents temperature (°C), and the vertical axis f represents the oscillation frequency (GHz). Curve fa represents... Figure 5 The waveform of the oscillation frequency of the voltage-controlled oscillator as a function of temperature is shown in the figure. Curve fb represents... Figure 6 The waveform shown illustrates the oscillation frequency of a voltage-controlled oscillator as a function of temperature. Figure 9 It can be seen that the oscillation frequency corresponding to curve fb is less affected by temperature than that of curve fa. Therefore, by using the variable capacitor unit formed by multiple parallel variable capacitor branches, which is shared by the voltage control unit and temperature compensation unit described in this specification, the influence of temperature drift on the output frequency of the voltage-controlled oscillator can be reduced.

[0123] Further experiments revealed that by sharing the variable capacitor unit, which consists of multiple parallel variable capacitor branches, between the voltage control unit and the temperature compensation unit, the circuit area can be significantly reduced. For example, with two variable capacitor branches, the circuit area can be reduced by approximately 50%.

[0124] This specification provides another voltage-controlled oscillator, such as... Figure 10 The voltage-controlled oscillator 100 shown may include an inductor unit 10A, a variable capacitor unit 103, and a temperature compensation unit 104, etc. As a specific example, it may also include a voltage control unit 105, a frequency coarse adjustment unit 106, and a cross-coupling unit, wherein the cross-coupling unit only includes a cross-coupling module 101 at the ground terminal, combined with... Figure 6 and Figure 10 As shown, the difference between voltage-controlled oscillator 100 and voltage-controlled oscillator 60 is that the cross-coupled module at the power supply terminal is omitted. Specifically, as shown... Figure 10 As shown, the power supply voltage VCC is directly coupled to the inductor unit 10A and only the cross-coupled module 101 composed of transistors NM3 and NM4 is used as the negative resistance to compensate for the resistance of the inductor and capacitor in the circuit of the voltage-controlled oscillator 100 and reduce the attenuation of the oscillation amplitude.

[0125] In specific implementation, such as Figure 10 As shown, the voltage-controlled oscillator 100 is coupled to the power supply VCC through the inductor L, and the cross-coupling unit only includes the cross-coupling module 101 disposed at the ground terminal. Since the power supply VCC is directly coupled to the voltage-controlled oscillator 100, the power supply voltage of the voltage-controlled oscillator 100 during normal operation can be reduced, thereby reducing the power consumption of the voltage-controlled oscillator 100.

[0126] In some embodiments of this specification, reference continues to be made to... Figure 10 The cross-coupling module 101 may include a first transistor NM1 and a second transistor NM2, wherein the sources of both the first transistor NM1 and the second transistor NM2 are coupled to ground; the drain of the first transistor NM1 is coupled to the gate of the second transistor NM2 and the first output terminal Out1 of the voltage-controlled oscillator 100, respectively; and the drain of the second transistor NM2 is coupled to the gate of the first transistor NM1 and the second output terminal Out2 of the voltage-controlled oscillator 100, respectively.

[0127] because Figure 10 The voltage-controlled oscillator 100 shown uses only one cross-coupling module, namely cross-coupling module 101. Therefore, the equivalent negative resistance of the voltage-controlled oscillator is relatively small. Thus, in specific implementations, to increase the equivalent negative resistance, Figure 10 The first transistor NM1 and the second transistor NM2 can be selected to be transistors with larger sizes.

[0128] The embodiments in this specification also provide corresponding phase-locked loop circuits, such as... Figure 11 The schematic diagram of the phase-locked loop circuit shown indicates that the phase-locked loop circuit 110 may include: a phase detector 111 and a voltage-controlled oscillator 112, wherein:

[0129] The phase detector 111 is coupled to the voltage-controlled oscillator 112 and is adapted to determine whether the frequency of the oscillation signal output by the voltage-controlled oscillator 112 is the same as that of the reference signal based on the input reference signal, and when they are different, output a control voltage signal to adjust the oscillation frequency of the voltage-controlled oscillator 112.

[0130] The voltage-controlled oscillator 112 is adapted to generate an oscillation signal within a preset frequency range. In specific implementations, the voltage-controlled oscillator described in any of the foregoing embodiments can be used. The specific structure, working principle, advantages, etc. can be found in the foregoing embodiments and will not be repeated here.

[0131] In the embodiments described in this specification, reference continues to be made to... Figure 11The phase-locked loop circuit 110 may further include a low-pass filter 113, which may be coupled between the phase detector 111 and the voltage-controlled oscillator 112 and is suitable for filtering the control voltage signal output by the phase detector 111.

[0132] In specific implementation, refer to Figure 11 The schematic diagram of the phase-locked loop circuit shown illustrates that the output signal of the voltage-controlled oscillator 112 is acquired and fed back to the phase detector 111. Simultaneously, a reference signal is input to the phase detector 111. The phase detector 111 compares the frequency difference between the output signal θ2(t) and the reference signal θ1(t) and outputs a DC pulse voltage u. d (t), the DC pulse voltage u d (t) After being filtered by low-pass filter 113, the output control voltage u c (t) to the voltage-controlled oscillator 112, changing the oscillation frequency of the output signal of the voltage-controlled oscillator 112, so that the oscillation frequency θ2(t) of the output signal is consistent with the oscillation frequency θ1(t) of the reference signal.

[0133] In practical implementation, the phase-locked loop (PLL) circuit can be applied to various fields, such as optical detection. Specifically, for pulsed optical detection devices, a high-precision clock is a key factor in ensuring their detection accuracy. Therefore, a PLL circuit can be built into the optical detection device to provide a stable and high-frequency pulse signal. To this end, this specification provides an embodiment of an optical detection device, such as... Figure 12 As shown, the optical detection device 120 may include a phase-locked loop circuit 110. In specific implementations, the phase-locked loop circuit described in any of the foregoing embodiments can be used, and details can be found in the foregoing embodiments, which will not be repeated here.

[0134] Reference Figure 12 The schematic diagram shown is of a light detection device. In some embodiments of this specification, such as... Figure 12 As shown, the light detection device 120 may include: a photoelectric sensor 121, an analog-to-digital converter module 122, and a phase-locked loop circuit 110, wherein:

[0135] The photoelectric sensor 121 is adapted to convert the light signal reflected by the target object into an analog electrical signal;

[0136] The analog-to-digital converter module 122 is adapted to convert the analog electrical signal into a digital signal;

[0137] The phase-locked loop circuit 110 is adapted to provide a clock signal to the analog-to-digital converter module.

[0138] The specific implementation of the phase-locked loop circuit 110 can be found in the aforementioned embodiments, and will not be repeated here.

[0139] Because the voltage-controlled oscillator (VCO) used in the embodiments of this specification can reduce the impact of temperature drift, the phase-locked loop (PLL) can output a clock signal with higher accuracy and stability, thereby improving the detection accuracy of the photodetector. Furthermore, since the VCO can be reduced in size, the size of the PLL circuit containing the VCO and the photodetector can be further reduced, and power consumption can be lowered.

[0140] In specific implementation, we will continue to refer to Figure 12 The photodetector 120 may also include an electrical signal preprocessing module 123, which can be coupled between the photoelectric sensor 121 and the analog-to-digital conversion module 122, and is adapted to preprocess the analog electrical signal according to specific circumstances. As a specific example, the electrical signal preprocessing module 123 can filter the analog electrical signal to reduce noise interference; as another specific example, the electrical signal preprocessing module 123 can amplify the analog electrical signal to facilitate subsequent signal processing.

[0141] In a specific implementation, the analog-to-digital conversion module 122 may include at least one of the following:

[0142] Analog-to-digital converter;

[0143] Time-to-digital converter.

[0144] The analog-to-digital converter or time-to-digital converter can convert the received analog electrical signal into a digital signal, which contains a lot of information, including the time information of the optical signal received by the optical detection device 120.

[0145] Therefore, the phase-locked loop circuit in the foregoing embodiments of this specification is used in the optical detection device 120 to provide a clock signal to the analog-to-digital conversion module 122. The clock signal is equivalent to a scale for measuring the time of flight of light. Therefore, by using the optical detection device in the embodiments of this specification, more accurate optical signal reception time information can be obtained.

[0146] This specification also provides a lidar that can be used in the optical detection device described in the foregoing embodiments.

[0147] Reference Figure 13 The schematic diagram of the lidar shown is illustrated in the embodiments of this specification, as follows: Figure 13 As shown, the lidar 130 may include a light emitting device 131, an optical system 132, a computing system 133, and a light detection device 120, wherein:

[0148] The light emitting device 131 is adapted to provide detection light;

[0149] The optical system 132 is adapted to transmit the detection light to the detection target 13A and transmit the reflected light from the detection target 13A to the light detection device 120;

[0150] The light detection device 120 is adapted to convert the reflected light into a digital signal to obtain the reception time of the reflected light;

[0151] The computing system 133 is adapted to calculate the distance of the detection target 13A based on the emission time of the detection light and the reception time of the reflected light.

[0152] In a specific implementation, the computing system 133 can obtain the time of flight of light based on the emission time of the detection light and the reception time of the reflected light, and then calculate the distance to the detection target 13A. Specifically, the computing system 133 can obtain the time of flight of light by calculating how many clock cycles the light travels through and the specific time of each clock cycle.

[0153] For details on the specific implementation of the optical detection device, please refer to the foregoing embodiments, which will not be repeated here.

[0154] As mentioned above, the phase-locked loop circuit of the embodiments of this specification can improve the accuracy of the clock signal. Therefore, the lidar using the phase-locked loop circuit can improve the ranging accuracy. Furthermore, the lidar using the embodiments of this specification has a smaller size and lower power consumption.

[0155] It should be noted that, in specific implementation, the various embodiments shown in this specification can be combined, selected, or further optimized according to requirements.

[0156] While the embodiments of the present invention have been disclosed above, the present invention is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A voltage-controlled oscillator, characterized in that, include: The unit consists of an inductor, a variable capacitor, and a temperature compensation unit, wherein: The inductor unit is coupled between the first output terminal and the second output terminal of the voltage-controlled oscillator; The variable capacitor unit is coupled between the first and second output terminals of the voltage-controlled oscillator and includes multiple variable capacitor branches connected in parallel. The multiple variable capacitor branches are respectively coupled to the temperature compensation unit, which is suitable for enabling the voltage-controlled oscillator to cover a preset target frequency. The temperature compensation unit is coupled to the plurality of variable capacitor branches respectively, and is adapted to change the temperature compensation voltage accordingly based on the detected ambient temperature, thereby adjusting the capacitance value of the plurality of variable capacitor branches. The voltage-controlled oscillator also includes a voltage control unit coupled to the variable capacitor unit; The voltage control unit and the temperature compensation unit share the variable capacitor unit. The voltage control unit adjusts its own output voltage to adjust the capacitance value of the multiple variable capacitor branches.

2. The voltage-controlled oscillator according to claim 1, characterized in that, The voltage control unit includes: A voltage control module is adapted to adjust its own output voltage in order to adjust the capacitance value of the plurality of variable capacitor branches; A resistor module is coupled between the voltage control module and the variable capacitor unit.

3. The voltage-controlled oscillator according to claim 2, characterized in that, The variable capacitor branch includes: a variable capacitor module and a fixed capacitor module, wherein: The variable capacitor module is coupled to the temperature compensation unit and the voltage control unit, respectively; The fixed capacitor module is coupled between the variable capacitor module and the first and second output terminals of the voltage-controlled oscillator, and is suitable for providing a basic capacitance value.

4. The voltage-controlled oscillator according to claim 1, characterized in that, It also includes a cross-coupling unit, which is coupled between the power supply and ground, and is coupled to the first and second output terminals of the voltage-controlled oscillator, and is adapted to provide negative resistance.

5. The voltage-controlled oscillator according to claim 4, characterized in that, The cross-coupling unit includes: a first cross-coupling module and a second cross-coupling module, wherein: The first cross-coupling module is located at the ground terminal of the voltage-controlled oscillator and is coupled to the first and second output terminals of the voltage-controlled oscillator. The second cross-coupling module is located at the power supply terminal of the voltage-controlled oscillator and is coupled to the first and second output terminals of the voltage-controlled oscillator.

6. The voltage-controlled oscillator according to claim 4, characterized in that, The inductor unit is directly connected to the power supply; the cross-coupling unit includes a cross-coupling module disposed at the ground terminal, the cross-coupling module being coupled to the first output terminal and the second output terminal of the voltage-controlled oscillator respectively.

7. The voltage-controlled oscillator according to claim 1, characterized in that, It also includes a frequency coarse adjustment unit, which includes: Digital control code module, suitable for outputting digital control codes; Multiple frequency coarse adjustment branches connected in parallel, the frequency coarse adjustment branches including: A switch module, the control terminal of which is coupled to the digital control code module, is adapted to perform on / off control based on the digital control code; At least two fixed capacitors are coupled between the switching module and the first or second output terminal of the voltage-controlled oscillator, and are adapted to be connected to the circuit of the voltage-controlled oscillator when the switching module is turned on, so as to adjust the sub-band frequency of the voltage-controlled oscillator.

8. A phase-locked loop circuit, characterized in that, include: The voltage-controlled oscillator according to any one of claims 1-7 is suitable for generating an oscillation signal within a preset frequency range; A phase detector, coupled to the voltage-controlled oscillator, is adapted to determine, based on an input reference signal, whether the frequency of the oscillation signal output by the voltage-controlled oscillator is the same as that of the reference signal, and when they are different, output a control voltage signal to adjust the oscillation frequency of the voltage-controlled oscillator.

9. The phase-locked loop circuit according to claim 8, characterized in that, Also includes: A low-pass filter, coupled between the phase detector and the voltage-controlled oscillator, is suitable for filtering the control voltage signal output by the phase detector.

10. A light detection device, characterized in that, include: Photoelectric sensors are suitable for converting light signals reflected from a target object into analog electrical signals; An analog-to-digital converter module, adapted to convert the analog electrical signal into a digital signal; The phase-locked loop circuit of claim 8 or 9 is adapted to provide a clock signal to the analog-to-digital conversion module.

11. The photodetector according to claim 10, characterized in that, Also includes: An electrical signal preprocessing module, coupled between the photoelectric sensor and the analog-to-digital conversion module, is adapted to perform at least one of the following preprocessing steps on the analog electrical signal: The analog electrical signal is filtered; The analog electrical signal is amplified.

12. A lidar system, comprising a light emitting device, an optical system, and a computing system, characterized in that, It also includes the light detection device as described in claim 10 or 11, wherein: The light emitting device is adapted to provide detection light; The optical system is adapted to transmit the detection light to the detection target and to transmit the reflected light from the detection target to the optical detection device; The light detection device is adapted to obtain the reception time of the reflected light; The computing system is adapted to calculate the distance to the target object based on the emission time of the detection light and the reception time of the reflected light.

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