Phase-locked loop frequency fast switching circuit, phase-locked loop and control method

Abstract

The present invention provides a phase-locked loop frequency fast switching circuit, a phase-locked loop and a control method. The circuit includes a charge pump, a loop filter, a voltage-controlled oscillator, a switch module, a level conversion module and a controller; the switch module and the charge pump are both controlled by the controller; the output end of the charge pump is connected to the loop filter; the first end of the switch module is connected to the loop filter, the second end of the switch module is connected to the voltage-controlled oscillator, and the third end of the switch module is connected to the level conversion module; the level conversion module is also connected to the controller. The present invention can minimize the frequency switching time by presetting the voltage of the voltage-controlled oscillator and increasing the working current of the charge pump, so that the frequency switching time of the phase-locked loop is controlled within ten microseconds, and the frequency can be switched arbitrarily.

Description

Technical Field

[0001] The present invention relates to the technical field of phase-locked loops, and in particular to a phase-locked loop frequency fast switching circuit, a phase-locked loop and a control method. Background Art

[0002] With the development of technology, communication systems and other systems have increasingly higher requirements for the frequency switching time of phase-locked loops. Frequency switching time of tens of microseconds can no longer meet system requirements.

[0003] At present, the commonly used frequency fast switching technology cannot reach less than ten microseconds, and most of them can only meet the fast switching from low to high frequency, but cannot achieve fast switching from high to low frequency. Summary of the invention

[0004] The embodiment of the present invention provides a phase-locked loop frequency fast switching circuit, a phase-locked loop and a control method to solve the problem that the prior art cannot simultaneously meet the requirements of controlling the frequency switching time of the phase-locked loop within ten microseconds and realizing arbitrary frequency switching.

[0005] In a first aspect, an embodiment of the present invention provides a phase-locked loop frequency fast switching circuit, including a charge pump, a loop filter, a voltage-controlled oscillator, a switch module, a level conversion module and a controller;

[0006] The switch module and the charge pump are both controlled by the controller; the output end of the charge pump is connected to the loop filter; the first end of the switch module is connected to the loop filter, the second end of the switch module is connected to the voltage-controlled oscillator, and the third end of the switch module is connected to the level conversion module; the level conversion module is also connected to the controller;

[0007] The controller is used to control the charge pump to work in a high current working mode when receiving a frequency switching instruction or detecting that the phase-locked loop is unlocked, and to control the switch module to disconnect the loop filter and the voltage-controlled oscillator, and to connect the voltage-controlled oscillator and the level conversion module, and to generate a digital signal according to the electric adjustment voltage corresponding to the target frequency, and send the digital signal to the level conversion module;

[0008] The level conversion module is used to convert the digital signal into an analog signal, and send the analog signal to the voltage-controlled oscillator so that the oscillation frequency of the voltage-controlled oscillator is the target frequency;

[0009] The controller is also used to control the switch module to put the loop filter and the voltage-controlled oscillator in an on state and the voltage-controlled oscillator and the level conversion module in a disconnected state after a preset period of time after sending the digital signal, and to control the charge pump to operate in a normal current operating mode after detecting that the phase-locked loop is locked; wherein, when the output current of the charge pump is greater than a first preset current, the charge pump operates in a high current operating mode, and when the output current of the charge pump is less than or equal to a second preset current, the charge pump operates in a normal current operating mode; the first preset current is greater than or equal to the second preset current.

[0010] In a possible implementation, the charge pump includes a first current source, a second current source, a third current source, a fourth current source, a first switch, a second switch, a third switch, and a fourth switch;

[0011] The first switch and the second switch are controlled by an external phase detector, and the third switch and the fourth switch are controlled by a controller;

[0012] The first end of the first current source is used to connect to an external power source, and the second end of the first current source is respectively connected to the first end of the first switch and the second end of the third switch;

[0013] The first end of the second current source is respectively connected to the second end of the second switch and the first end of the fourth switch, and the second end of the second current source is grounded; the second end of the first switch is respectively connected to the first end of the second switch and the output end of the charge pump;

[0014] A first end of the third current source is used to connect to an external power source, and a second end of the third current source is connected to a first end of the third switch; a first end of the fourth current source is connected to a second end of the fourth switch, and a second end of the fourth current source is grounded;

[0015] The controller is specifically used to control the third switch and the fourth switch to be turned on so that the charge pump works in a high current working mode, or to control the third switch and the fourth switch to be turned off so that the charge pump works in a normal current working mode.

[0016] In a possible implementation, the switch module includes a fifth switch and a sixth switch;

[0017] The fifth switch and the sixth switch are both controlled by the controller;

[0018] A first end of the fifth switch is connected to a first end of the switch module, and a second end of the fifth switch is connected to a second end of the switch module; a first end of the sixth switch is connected to a third end of the switch module, and a second end of the sixth switch is connected to a second end of the switch module;

[0019] The controller is specifically used to control the fifth switch to be disconnected, and control the sixth switch to be turned on, so that the loop filter and the voltage-controlled oscillator are in a disconnected state, and the voltage-controlled oscillator and the level conversion module are in a turned-on state, or control the fifth switch to be turned on, and control the sixth switch to be disconnected, so that the loop filter and the voltage-controlled oscillator are in a turned-on state, and the voltage-controlled oscillator and the level conversion module are in a disconnected state.

[0020] In one possible implementation, the switch module includes a single-pole double-throw switch;

[0021] The SPDT switch is controlled by the controller;

[0022] The moving end of the single-pole double-throw switch is connected to the second end of the switch module, the first fixed end of the single-pole double-throw switch is connected to the first end of the switch module, and the second fixed end of the single-pole double-throw switch is connected to the third end of the switch module;

[0023] The controller is specifically used to control the disconnection between the moving end and the first fixed end of the single-pole double-throw switch, and control the conduction between the moving end and the second fixed end of the single-pole double-throw switch, so that the loop filter and the voltage-controlled oscillator are in a disconnected state, and the voltage-controlled oscillator and the level conversion module are in a conductive state, or control the conduction between the moving end and the first fixed end of the single-pole double-throw switch, and control the disconnection between the moving end and the second fixed end of the single-pole double-throw switch, so that the loop filter and the voltage-controlled oscillator are in a conductive state, and the voltage-controlled oscillator and the level conversion module are in a disconnected state.

[0024] In a possible implementation, a corresponding relationship between the oscillation frequency of the voltage-controlled oscillator and the electrically adjustable voltage is pre-stored in the controller;

[0025] The controller is also used to determine the electric adjustment voltage corresponding to the target frequency according to the pre-stored correspondence between the oscillation frequency of the voltage-controlled oscillator and the electric adjustment voltage.

[0026] In a possible implementation, the level conversion module is further used to collect a voltage analog signal from a voltage-controlled oscillator, convert the voltage analog signal into a voltage digital signal, and send the voltage digital signal to the controller.

[0027] In a possible implementation, the controller includes a micro control unit.

[0028] In a second aspect, an embodiment of the present invention provides a phase-locked loop, comprising a phase-locked loop frequency fast switching circuit as described in the first aspect or any possible implementation manner of the first aspect.

[0029] In a possible implementation, the phase-locked loop further includes a phase detector;

[0030] The phase detector is connected to the charge pump.

[0031] In a third aspect, an embodiment of the present invention provides a control method, which is applied to the phase-locked loop frequency fast switching circuit described in the first aspect or any possible implementation of the first aspect, or to the phase-locked loop described in the second aspect or any possible implementation of the second aspect;

[0032] The above control method includes:

[0033] When a frequency switching instruction is received or a phase-locked loop is detected to be unlocked, the charge pump is controlled to work in a high-current working mode, and the loop filter and the voltage-controlled oscillator are disconnected and the voltage-controlled oscillator and the level conversion module are connected by controlling the switch module;

[0034] Generate a digital signal according to the electric adjustment voltage corresponding to the target frequency, and send the digital signal to the level conversion module; the digital signal is used to instruct the level conversion module to convert the digital signal into an analog signal, and send the analog signal to the voltage-controlled oscillator, so that the oscillation frequency of the voltage-controlled oscillator is the target frequency;

[0035] After the digital signal is sent, after a preset time, the switch module is controlled to make the loop filter and the voltage-controlled oscillator in an on state, and the voltage-controlled oscillator and the level conversion module in an off state;

[0036] After detecting that the phase-locked loop is locked, the charge pump is controlled to operate in a normal current operating mode; wherein, when the output current of the charge pump is greater than a first preset current, the charge pump operates in a high current operating mode, and when the output current of the charge pump is less than or equal to a second preset current, the charge pump operates in a normal current operating mode; the first preset current is greater than or equal to the second preset current.

[0037] The embodiment of the present invention provides a phase-locked loop frequency fast switching circuit, a phase-locked loop and a control method. The circuit includes a charge pump, a loop filter, a voltage-controlled oscillator, a switch module, a level conversion module and a controller. When the controller receives a frequency switching instruction or detects that the phase-locked loop is unlocked, the controller controls the charge pump to work in a high-current working mode, and controls the switch module to make the loop filter and the voltage-controlled oscillator in a disconnected state, and the voltage-controlled oscillator and the level conversion module in a conducting state, and generates a digital signal according to an electric adjustment voltage corresponding to a target frequency, and sends the digital signal to the level conversion module, and sends the digital signal to the voltage-controlled oscillator after conversion by the level conversion module, so that the vibration frequency of the voltage-controlled oscillator is switched to the target frequency by presetting a voltage to the voltage-controlled oscillator. After the presetting is completed, the controller controls the loop filter and the voltage-controlled oscillator to be in a conducting state, and controls the voltage-controlled oscillator and the level conversion module to be in a disconnected state. At this time, the charge pump still works in the high-current working mode, and the frequency can be quickly locked. After locking, the controller controls the charge pump to work in a normal current working mode, and the loop enters a normal locking state, completing the fast switching of the frequency. The embodiment of the present invention can minimize the frequency switching time by presetting the voltage of the voltage-controlled oscillator and increasing the working current of the charge pump, so that the frequency switching time of the phase-locked loop is controlled within ten microseconds and arbitrary frequency switching can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0039] Figure 1 It is a structural schematic diagram of a phase-locked loop frequency fast switching circuit provided by an embodiment of the present invention;

[0040] Figure 2 It is a schematic diagram of the frequency switching time when the output current of the charge pump is 500 μA provided by an embodiment of the present invention;

[0041] Figure 3 is a schematic diagram of frequency switching time when the output current of the charge pump is 2500 μA provided by an embodiment of the present invention;

[0042] Figure 4 The present invention provides a circuit diagram of a phase-locked loop frequency fast switching circuit. DETAILED DESCRIPTION

[0043] In order to enable people in the technical field to better understand the present solution, the technical solution in the embodiment of the present solution will be clearly described below in conjunction with the drawings in the embodiment of the present solution. Obviously, the described embodiment is an embodiment of a part of the present solution, not all of the embodiments. Based on the embodiments in the present solution, all other embodiments obtained by ordinary technicians in the field without creative work should fall within the scope of protection of the present solution.

[0044] The term "including" and any other variations in the specification and claims of this solution and the above drawings mean "including but not limited to", and is intended to cover non-exclusive inclusions and is not limited to the examples listed in the text. In addition, the terms "first" and "second" are used to distinguish different objects, not to describe a specific order.

[0045] At present, for phase-locked loops, the commonly used frequency fast switching technology cannot simultaneously meet the requirements of controlling the frequency switching time of the phase-locked loop within ten microseconds and realizing arbitrary frequency switching. For example, ADI's fast switching technology is to increase the startup charging current of the second-order capacitor of the loop filter, which can reduce the frequency switching time, but can only realize the frequency change from low to high, and cannot realize the frequency change from high to low; another commonly used frequency fast switching technology is to change the loop filter bandwidth, by switching to an ultra-wide loop filter before locking, and then switching back to a normal loop filter after locking, to achieve fast frequency switching. This method can realize fast frequency switching, and switching in any direction can be realized, but the frequency switching time cannot reach less than ten microseconds.

[0046] In view of the above problems, an embodiment of the present invention proposes a phase-locked loop frequency fast switching circuit. The implementation of the present invention is described in detail below with reference to specific drawings:

[0047] Figure 1 A schematic diagram of a phase-locked loop frequency fast switching circuit provided by an embodiment of the present invention. Figure 1 The phase-locked loop frequency fast switching circuit includes a charge pump 11, a loop filter 12, a voltage-controlled oscillator 14, a switch module 13, a level conversion module 15 and a controller 16;

[0048] The switch module 13 and the charge pump 11 are both controlled by the controller 16; the output end of the charge pump 11 is connected to the loop filter 12; the first end of the switch module 13 is connected to the loop filter 12, the second end of the switch module 13 is connected to the voltage-controlled oscillator 14, and the third end of the switch module 13 is connected to the level conversion module 15; the level conversion module 15 is also connected to the controller 16;

[0049] The controller 16 is used to control the charge pump 11 to work in a high current working mode when receiving a frequency switching instruction or detecting that the phase-locked loop is unlocked, and to control the switch module 13 to disconnect the loop filter 12 and the voltage-controlled oscillator 14, and to connect the voltage-controlled oscillator 14 and the level conversion module 15, and to generate a digital signal according to the electric adjustment voltage corresponding to the target frequency, and send the digital signal to the level conversion module 15;

[0050] The level conversion module 15 is used to convert the digital signal into an analog signal, and send the analog signal to the voltage-controlled oscillator 14, so that the oscillation frequency of the voltage-controlled oscillator 14 is the target frequency;

[0051] The controller 16 is also used to control the switch module 13 after a preset period of time after sending the digital signal, so that the loop filter 12 and the voltage-controlled oscillator 14 are in an on state, and the voltage-controlled oscillator 14 and the level conversion module 15 are in a disconnected state, and after detecting that the phase-locked loop is locked, control the charge pump 11 to operate in a normal current operating mode; wherein, when the output current of the charge pump 11 is greater than a first preset current, the charge pump 11 operates in a high current operating mode, and when the output current of the charge pump 11 is less than or equal to a second preset current, the charge pump 11 operates in a normal current operating mode; the first preset current is greater than or equal to the second preset current.

[0052] In this embodiment, the charge pump 11 has two working modes, namely a high current working mode and a normal current working mode. The output current of the charge pump 11 in the high current working mode is greater than the output current of the charge pump 11 in the normal working mode.

[0053] When frequency switching is performed, the charge pump 11 is controlled to operate in a high current operating mode, which can shorten the frequency switching time. Figure 2 and Figure 3 , Figure 2 and Figure 3 When other conditions remain unchanged, only the output current of the charge pump 11 is changed to obtain the frequency switching time. Figure 2 It can be seen that when the output current of the charge pump 11 is 500μA, the frequency switching time is 40μs. Figure 3 It can be seen that when the output current of the charge pump 11 is 2500 μA, the frequency switching time is 7 μs. Therefore, it can be seen that when the output current of the charge pump 11 is increased, the frequency switching time will be significantly reduced.

[0054] The values ​​of the first preset current and the second preset current can be set according to actual needs. For example, both can be 2000 μA; or, the first preset current is 2000 μA, the second preset current is 600 μA, and so on.

[0055] In a possible implementation, when the charge pump 11 operates in a high current operation mode, its output current may be 2500 μA, and when the charge pump 11 operates in a normal current operation mode, its output current may be 500 μA.

[0056] It should be noted that the above is only an example of the first preset current and the second preset current, and no specific limitation is imposed on them. The values ​​of the first preset current and the second preset current can be set arbitrarily according to actual needs. For example, the value of the first preset current can be several times or even dozens of times the value of the second preset current, and no specific limitation is imposed here.

[0057] In this embodiment, the host computer or the upper system may send an instruction to the controller 16. When frequency switching is required, the host computer or the upper system sends a frequency switching instruction to the controller 16, and the frequency switching instruction may carry a target frequency. The target frequency is the frequency to be switched, that is, the frequency switching instruction is used to instruct the controller 16 to switch the current frequency to the target frequency.

[0058] In this embodiment, the host computer or the upper system may detect whether the phase-locked loop is unlocked, and send the detection result to the controller 16; or the controller 16 may directly detect whether the phase-locked loop is unlocked.

[0059] A lock indication voltage is generated inside the phase-locked loop, which reports a high level signal when the phase-locked loop is locked and a low level signal when the phase-locked loop is unlocked, or a low level signal when the phase-locked loop is locked and a high level signal when the phase-locked loop is unlocked. The host computer or upper system, controller 16 can determine whether the phase-locked loop is locked or unlocked by detecting the signal.

[0060] When the controller 16 detects that the phase-locked loop is unlocked, or receives a frequency switching instruction, it can start to control the phase-locked loop frequency fast switching circuit to start frequency switching. First, the charge pump 11 is controlled to work in a high current working mode, and the switch module 13 is controlled to make the loop filter 12 and the voltage-controlled oscillator 14 in a disconnected state, and the voltage-controlled oscillator 14 and the level conversion module 15 in a conductive state, so that the preset voltage output by the controller 16 can be added to the electrical adjustment end of the voltage-controlled oscillator 14. Specifically, the controller 16 generates a digital signal according to the electrical adjustment voltage corresponding to the target frequency, and sends the digital signal to the level conversion module 15. The electrical adjustment voltage corresponding to the target frequency is the voltage that needs to be added to the electrical adjustment end of the voltage-controlled oscillator 14, and the digital signal generated according to the electrical adjustment voltage is used to control the voltage added to the electrical adjustment end of the voltage-controlled oscillator 14 to be the electrical adjustment voltage.

[0061] The level conversion module 15 can convert the digital signal into an analog signal, and send the analog signal to the voltage-controlled oscillator 14, so that the preset voltage of the electrical adjustment end of the voltage-controlled oscillator 14 is the electrical adjustment voltage, and the oscillation frequency of the voltage-controlled oscillator 14 is the target frequency. Since the voltage-controlled oscillator 14 controls the oscillation frequency by adjusting the voltage of the electrical adjustment end, the controller 16 adjusts the voltage of the electrical adjustment end of the voltage-controlled oscillator 14 to adjust the oscillation frequency of the voltage-controlled oscillator 14 in this embodiment.

[0062] The level conversion module 15 may include a level conversion circuit that can perform analog-to-digital conversion or digital-to-analog conversion. The level conversion circuit can be designed according to actual needs and is not specifically limited here. For example, it can be an existing bidirectional analog-to-digital conversion circuit.

[0063] After the controller 16 sends the digital signal, after a preset time, it can control the switch module 13 to make the loop filter 12 and the voltage-controlled oscillator 14 in a conducting state, and the voltage-controlled oscillator 14 and the level conversion module 15 in a disconnected state, so that the loop filter 12 is connected to the circuit, and the entire feedback system starts to work. At this time, the charge pump 11 is still in a high-current working mode, which can shorten the frequency conversion time, and the sweep frequency is the target frequency or near the target frequency, and the frequency can be quickly locked.

[0064] Among them, since the time required to adjust the preset voltage of the voltage-controlled oscillator 14 is very short, which can be completed in nanoseconds, the delay time of the controller 16 is used to manage whether the preset is completed. When the digital signal is sent for a preset time, it is considered that the preset voltage has been completed. The preset time is a very short time, which is a nanosecond time, and can be set according to actual needs, and no specific setting is made here.

[0065] After detecting that the phase-locked loop is locked, the controller 16 controls the charge pump 11 to operate in the normal current operating mode. At this time, the loop filter 12 and the voltage-controlled oscillator 14 are still in the on state, and the voltage-controlled oscillator 14 and the level conversion module 15 are still in the off state. The loop enters the normal locking state and completes the rapid frequency switching.

[0066] The phase-locked loop frequency fast switching circuit provided in this embodiment includes a charge pump 11, a loop filter 12, a voltage-controlled oscillator 14, a switch module 13, a level conversion module 15 and a controller 16; when the controller 16 receives a frequency switching instruction or detects that the phase-locked loop is unlocked, the charge pump 11 is controlled to work in a high-current working mode, and the loop filter 12 and the voltage-controlled oscillator 14 are disconnected and the voltage-controlled oscillator 14 and the level conversion module 15 are connected by controlling the switch module 13, and a digital signal is generated according to the electric adjustment voltage corresponding to the target frequency, and the digital signal is sent to the level conversion module 15. 5, after being converted by the level conversion module 15, it is sent to the voltage-controlled oscillator 14, so that the vibration frequency of the voltage-controlled oscillator 14 is switched to the target frequency by presetting the voltage to the voltage-controlled oscillator 14; after the presetting is completed, the controller 16 controls the loop filter 12 and the voltage-controlled oscillator 14 to be in a conducting state, and controls the voltage-controlled oscillator 14 and the level conversion module 15 to be in a disconnected state. At this time, the charge pump 11 still works in a large current working mode and can quickly lock the frequency; after locking, the controller 16 controls the charge pump 11 to work in a normal current working mode, and the loop enters a normal locking state, completing the rapid switching of the frequency. The embodiment of the present invention can minimize the frequency switching time by presetting the voltage-controlled oscillator 14 and increasing the working current of the charge pump 11, so that the frequency switching time of the phase-locked loop is controlled within ten microseconds, and the frequency can be switched arbitrarily, that is, not only the switching from low to high frequency can be realized, but also the switching from high to low frequency can be realized.

[0067] In some embodiments, see Figure 4 , the charge pump 11 includes a first current source Icp1, a second current source Icp2, a third current source Icp_f1, a fourth current source Icp_f2, a first switch K1, a second switch K2, a third switch K3 and a fourth switch K4;

[0068] The first switch K1 and the second switch K2 are controlled by an external phase detector, and the third switch K3 and the fourth switch K4 are controlled by a controller 16;

[0069] A first end of the first current source Icp1 is used to connect to an external power source, and a second end of the first current source Icp1 is connected to a first end of the first switch K1 and a second end of the third switch K3 respectively;

[0070] The first end of the second current source Icp2 is respectively connected to the second end of the second switch K2 and the first end of the fourth switch K4, and the second end of the second current source Icp2 is grounded; the second end of the first switch K1 is respectively connected to the first end of the second switch K2 and the output end of the charge pump 11;

[0071] A first end of the third current source Icp_f1 is used to connect to an external power source, and a second end of the third current source Icp_f1 is connected to a first end of the third switch K3; a first end of the fourth current source Icp_f2 is connected to a second end of the fourth switch K4, and a second end of the fourth current source Icp_f2 is grounded;

[0072] The controller 16 is specifically used to control the third switch K3 and the fourth switch K4 to be turned on so that the charge pump 11 works in the high current working mode, or to control the third switch K3 and the fourth switch K4 to be turned off so that the charge pump 11 works in the normal current working mode.

[0073] The conventional charge pump 11 only includes a first current source Icp1, a second current source Icp2, a first switch K1, and a second switch K2. The charge pump 11 provided in this embodiment is provided with a third current source Icp_f1, a fourth current source Icp_f2, a third switch K3, and a fourth switch K4 on the basis of the conventional charge pump 11, so that when frequency switching is performed, the output current of the charge pump 11 can be increased by closing the third switch K3 and the fourth switch K4, and the frequency switching time can be reduced. After the frequency switching is completed, the third switch K3 and the fourth switch K4 can be closed without affecting the final loop characteristics.

[0074] The third switch K3 and the fourth switch K4 are controlled by the controller 16, and both are turned on and off at the same time. The controller 16 sends a control signal CTRL1 to the third switch K3 and the fourth switch K4, thereby controlling the switch states of the third switch K3 and the fourth switch K4. When both are turned on, the charge pump 11 works in a high current working mode, and when both are turned off, the charge pump 11 works in a normal current working mode.

[0075] The first switch K1 and the second switch K2 are controlled by an external phase detector. The phase detector compares the reference signal and the feedback signal, and generates an UP signal and a DOWN signal according to the phase difference between the feedback signal and the reference signal, so as to finally make the phase of the feedback signal consistent with the phase of the reference signal. The UP signal is used to control the switching state of the first switch K1, and the DOWN signal is used to control the switching state of the second switch K2. Regardless of whether the phase-locked loop is in a locked state or an unlocked state, the first switch K1 and the second switch K2 are controlled by the phase detector.

[0076] In some embodiments, see Figure 4 , the switch module 13 includes a fifth switch K5 and a sixth switch K6;

[0077] The fifth switch K5 and the sixth switch K6 are both controlled by the controller 16;

[0078] A first end of the fifth switch K5 is connected to a first end of the switch module 13, and a second end of the fifth switch K5 is connected to a second end of the switch module 13; a first end of the sixth switch K6 is connected to a third end of the switch module 13, and a second end of the sixth switch K6 is connected to a second end of the switch module 13;

[0079] The controller 16 is specifically used to control the fifth switch K5 to be disconnected, and control the sixth switch K6 to be turned on, so that the loop filter 12 and the voltage-controlled oscillator 14 are in a disconnected state, and the voltage-controlled oscillator 14 and the level conversion module 15 are in a conductive state, or control the fifth switch K5 to be turned on, and control the sixth switch K6 to be disconnected, so that the loop filter 12 and the voltage-controlled oscillator 14 are in a conductive state, and the voltage-controlled oscillator 14 and the level conversion module 15 are in a disconnected state.

[0080] In this embodiment, two switches are added between the loop filter 12 and the voltage controlled oscillator 14, namely the fifth switch K5 and the sixth switch K6. The control signals ~CTRL2 and CTRL2 of the two are generated by the controller 16, and ~CTRL2 is opposite to CTRL2.

[0081] When the fifth switch K5 is disconnected and the sixth switch K6 is turned on, the loop filter 12 and the voltage-controlled oscillator 14 are in a disconnected state, and the voltage-controlled oscillator 14 and the level conversion module 15 are in a connected state. At this time, the controller 16 can send a preset voltage to the voltage-controlled oscillator 14 through the level conversion module 15.

[0082] When the fifth switch K5 is turned on and the sixth switch K6 is turned off, the loop filter 12 and the voltage-controlled oscillator 14 are in a conducting state, and the voltage-controlled oscillator 14 and the level conversion module 15 are in a disconnected state. At this time, the loop filter 12 is connected to the circuit.

[0083] In some embodiments, the switch module 13 includes a single-pole double-throw switch;

[0084] The single-pole double-throw switch is controlled by a controller 16;

[0085] The moving end of the single-pole double-throw switch is connected to the second end of the switch module 13, the first fixed end of the single-pole double-throw switch is connected to the first end of the switch module 13, and the second fixed end of the single-pole double-throw switch is connected to the third end of the switch module 13;

[0086] The controller 16 is specifically used to control the disconnection between the moving end and the first fixed end of the single-pole double-throw switch, and control the connection between the moving end and the second fixed end of the single-pole double-throw switch, so that the loop filter 12 and the voltage-controlled oscillator 14 are in a disconnected state, and the voltage-controlled oscillator 14 and the level conversion module 15 are in a conductive state, or control the connection between the moving end and the first fixed end of the single-pole double-throw switch, and control the disconnection between the moving end and the second fixed end of the single-pole double-throw switch, so that the loop filter 12 and the voltage-controlled oscillator 14 are in a conductive state, and the voltage-controlled oscillator 14 and the level conversion module 15 are in a disconnected state.

[0087] In addition to being implemented in the form of the fifth switch K5 and the sixth switch K6 as described above, the switch module 13 may also be implemented in the form of a single-pole double-throw switch, which is controlled by the controller 16 .

[0088] When the moving end of the single-pole double-throw switch is disconnected from the first fixed end, and the moving end of the single-pole double-throw switch is connected to the second fixed end, the loop filter 12 and the voltage-controlled oscillator 14 are in a disconnected state, and the voltage-controlled oscillator 14 and the level conversion module 15 are in a connected state. At this time, the controller 16 can send a preset voltage to the voltage-controlled oscillator 14 through the level conversion module 15.

[0089] When the moving end of the single-pole double-throw switch is connected to the first fixed end, and the moving end of the single-pole double-throw switch is disconnected from the second fixed end, the loop filter 12 and the voltage-controlled oscillator 14 are in a conducting state, and the voltage-controlled oscillator 14 and the level conversion module 15 are in a disconnected state. At this time, the loop filter 12 is connected to the circuit.

[0090] In some embodiments, the controller 16 pre-stores the corresponding relationship between the oscillation frequency of the voltage-controlled oscillator 14 and the electrically adjustable voltage;

[0091] The controller 16 is further configured to determine the electrical adjustment voltage corresponding to the target frequency according to the pre-stored correspondence between the oscillation frequency of the voltage-controlled oscillator 14 and the electrical adjustment voltage.

[0092] In this embodiment, the voltage-controlled oscillator 14 can be controlled in advance to work at different oscillation frequencies, and the corresponding electrical adjustment voltage can be sampled, so as to obtain the corresponding relationship between the oscillation frequency of the voltage-controlled oscillator 14 and the electrical adjustment voltage, and the corresponding relationship can be pre-stored in the controller 16. Therefore, when performing frequency switching, the controller 16 can determine the corresponding electrical adjustment voltage according to the target frequency, and control the electrical adjustment voltage to be preset to the electrical adjustment end of the voltage-controlled oscillator 14.

[0093] In some embodiments, the level conversion module 15 is further used to collect the voltage analog signal of the voltage controlled oscillator 14 , convert the voltage analog signal into a voltage digital signal, and send the voltage digital signal to the controller 16 .

[0094] In this embodiment, see Figure 4 In addition to being connected via the switch module 13 (sixth switch K6 ), the level conversion module 15 and the voltage controlled oscillator 14 may also be directly connected.

[0095] The level conversion module 15 can be directly connected to the voltage-controlled oscillator 14 to collect the voltage analog signal of the electrical adjustment end of the voltage-controlled oscillator 14 , convert the voltage analog signal into a voltage digital signal, and send the voltage digital signal to the controller 16 .

[0096] When the controller 16 needs to preset voltage to the voltage-controlled oscillator 14, the sixth switch K6 should be closed, so that the voltage-controlled oscillator 14 can be preset voltage through the level conversion module 15 and the sixth switch K6. The level conversion module 15 converts the digital level (generally 0 to 3.3) output by the controller 16 into the analog level (generally 0 to 3.3 or higher) required by the voltage-controlled oscillator 14.

[0097] In some embodiments, the controller 16 includes a micro control unit (MCU).

[0098] Corresponding to the above-mentioned phase-locked loop frequency fast switching circuit, an embodiment of the present invention further provides a phase-locked loop, including the phase-locked loop frequency fast switching circuit as described in any of the above embodiments, which has the same beneficial effects as the phase-locked loop frequency fast switching circuit.

[0099] In some embodiments, the phase-locked loop further includes a phase detector;

[0100] The phase detector is connected to the charge pump.

[0101] The phase detector can control the switching states of the first switch and the second switch of the charge pump.

[0102] In a possible implementation, the phase-locked loop further includes a frequency divider, and the voltage-controlled oscillator is connected to the phase detector via the frequency divider.

[0103] Corresponding to the above-mentioned phase-locked loop frequency fast switching circuit or phase-locked loop, an embodiment of the present invention provides a control method, which is applied to the phase-locked loop frequency fast switching circuit as described in any of the above embodiments, or to the phase-locked loop as described in any of the above embodiments;

[0104] The above control method includes:

[0105] When a frequency switching instruction is received or a phase-locked loop is detected to be unlocked, the charge pump is controlled to work in a high-current working mode, and the loop filter and the voltage-controlled oscillator are disconnected and the voltage-controlled oscillator and the level conversion module are connected by controlling the switch module;

[0106] Generate a digital signal according to the electric adjustment voltage corresponding to the target frequency, and send the digital signal to the level conversion module; the digital signal is used to instruct the level conversion module to convert the digital signal into an analog signal, and send the analog signal to the voltage-controlled oscillator, so that the oscillation frequency of the voltage-controlled oscillator is the target frequency;

[0107] After the digital signal is sent, after a preset time, the switch module is controlled to make the loop filter and the voltage-controlled oscillator in an on state, and the voltage-controlled oscillator and the level conversion module in an off state;

[0108] After detecting that the phase-locked loop is locked, the charge pump is controlled to operate in a normal current operating mode; wherein, when the output current of the charge pump is greater than a first preset current, the charge pump operates in a high current operating mode, and when the output current of the charge pump is less than or equal to a second preset current, the charge pump operates in a normal current operating mode; the first preset current is greater than or equal to the second preset current.

[0109] The detailed description of the control method can refer to the specific description of the aforementioned phase-locked loop frequency fast switching circuit, which will not be repeated here.

[0110] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A phase-locked loop frequency fast switching circuit, characterized in that: Includes a charge pump, a loop filter, a voltage-controlled oscillator, a switch module, a level conversion module and a controller; The switch module and the charge pump are both controlled by the controller; the output end of the charge pump is connected to the loop filter; the first end of the switch module is connected to the loop filter, the second end of the switch module is connected to the voltage-controlled oscillator, and the third end of the switch module is connected to the level conversion module; the level conversion module is also connected to the controller; The controller is used to control the charge pump to work in a high current working mode when receiving a frequency switching instruction or detecting that the phase-locked loop is unlocked, and to control the switch module so that the loop filter and the voltage-controlled oscillator are in a disconnected state, and the voltage-controlled oscillator and the level conversion module are in a conductive state, and to generate a digital signal according to the electric adjustment voltage corresponding to the target frequency, and send the digital signal to the level conversion module; The level conversion module is used to convert the digital signal into an analog signal, and send the analog signal to the voltage-controlled oscillator, so that the oscillation frequency of the voltage-controlled oscillator is the target frequency; The controller is also used to control the switch module to make the loop filter and the voltage-controlled oscillator in an on state and the voltage-controlled oscillator and the level conversion module in a disconnected state after a preset time period after sending the digital signal, and control the charge pump to operate in a normal current operating mode after detecting that the phase-locked loop is locked; wherein, when the output current of the charge pump is greater than a first preset current, the charge pump operates in the high current operating mode, and when the output current of the charge pump is less than or equal to a second preset current, the charge pump operates in the normal current operating mode; the first preset current is greater than or equal to the second preset current.

2. The phase-locked loop frequency fast switching circuit as claimed in claim 1, characterized in that: The charge pump comprises a first current source, a second current source, a third current source, a fourth current source, a first switch, a second switch, a third switch and a fourth switch; The first switch and the second switch are controlled by an external phase detector, and the third switch and the fourth switch are controlled by the controller; The first end of the first current source is used to connect to an external power source, and the second end of the first current source is respectively connected to the first end of the first switch and the second end of the third switch; The first end of the second current source is respectively connected to the second end of the second switch and the first end of the fourth switch, and the second end of the second current source is grounded; the second end of the first switch is respectively connected to the first end of the second switch and the output end of the charge pump; The first end of the third current source is used to connect to the external power supply, and the second end of the third current source is connected to the first end of the third switch; the first end of the fourth current source is connected to the second end of the fourth switch, and the second end of the fourth current source is grounded; The controller is specifically used to control the third switch and the fourth switch to be turned on so that the charge pump operates in the high current operation mode, or to control the third switch and the fourth switch to be turned off so that the charge pump operates in the normal current operation mode.

3. The phase-locked loop frequency fast switching circuit as claimed in claim 1, characterized in that: The switch module includes a fifth switch and a sixth switch; The fifth switch and the sixth switch are both controlled by the controller; The first end of the fifth switch is connected to the first end of the switch module, and the second end of the fifth switch is connected to the second end of the switch module; the first end of the sixth switch is connected to the third end of the switch module, and the second end of the sixth switch is connected to the second end of the switch module; The controller is specifically used to control the fifth switch to be disconnected, and control the sixth switch to be turned on, so that the loop filter and the voltage-controlled oscillator are in a disconnected state, and the voltage-controlled oscillator and the level conversion module are in a connected state, or control the fifth switch to be turned on, and control the sixth switch to be disconnected, so that the loop filter and the voltage-controlled oscillator are in a connected state, and the voltage-controlled oscillator and the level conversion module are in a disconnected state.

4. The phase-locked loop frequency fast switching circuit as claimed in claim 1, characterized in that: The switch module includes a single-pole double-throw switch; The single-pole double-throw switch is controlled by the controller; The movable end of the single-pole double-throw switch is connected to the second end of the switch module, the first fixed end of the single-pole double-throw switch is connected to the first end of the switch module, and the second fixed end of the single-pole double-throw switch is connected to the third end of the switch module; The controller is specifically used to control the disconnection between the moving end of the single-pole double-throw switch and the first fixed end, and control the connection between the moving end of the single-pole double-throw switch and the second fixed end, so that the loop filter and the voltage-controlled oscillator are in a disconnected state, and the voltage-controlled oscillator and the level conversion module are in a connected state, or control the connection between the moving end of the single-pole double-throw switch and the first fixed end, and control the disconnection between the moving end of the single-pole double-throw switch and the second fixed end, so that the loop filter and the voltage-controlled oscillator are in a connected state, and the voltage-controlled oscillator and the level conversion module are in a disconnected state.

5. The phase-locked loop frequency fast switching circuit as claimed in claim 1, characterized in that: The controller pre-stores a correspondence between the oscillation frequency of the voltage-controlled oscillator and the electrically adjustable voltage; The controller is further configured to determine the electrical adjustment voltage corresponding to the target frequency according to a pre-stored correspondence between the oscillation frequency of the voltage-controlled oscillator and the electrical adjustment voltage.

6. The phase-locked loop frequency fast switching circuit as claimed in claim 1, characterized in that: The level conversion module is also used to collect the voltage analog signal of the voltage-controlled oscillator, convert the voltage analog signal into a voltage digital signal, and send the voltage digital signal to the controller.

7. The phase-locked loop frequency fast switching circuit according to any one of claims 1 to 6, characterized in that: The controller includes a micro control unit.

8. A phase-locked loop, characterized in that: It comprises the phase-locked loop frequency fast switching circuit as claimed in any one of claims 1 to 7.

9. The phase-locked loop according to claim 8, characterized in that: The phase-locked loop also includes a phase detector; The phase detector is connected to the charge pump.

10. A control method, characterized in that: Applicable to the phase-locked loop frequency fast switching circuit as claimed in any one of claims 1 to 7, or, applied to the phase-locked loop as claimed in claim 8 or 9; The control method comprises: When a frequency switching instruction is received or a phase-locked loop is detected to be unlocked, the charge pump is controlled to work in a high-current working mode, and the loop filter and the voltage-controlled oscillator are disconnected and the voltage-controlled oscillator and the level conversion module are connected by controlling the switch module; Generate a digital signal according to the electric adjustment voltage corresponding to the target frequency, and send the digital signal to the level conversion module; the digital signal is used to instruct the level conversion module to convert the digital signal into an analog signal, and send the analog signal to the voltage-controlled oscillator, so that the oscillation frequency of the voltage-controlled oscillator is the target frequency; After the digital signal is sent, after a preset time, the switch module is controlled to make the loop filter and the voltage-controlled oscillator in an on state, and the voltage-controlled oscillator and the level conversion module in an off state; After detecting that the phase-locked loop is locked, the charge pump is controlled to operate in a normal current operating mode; wherein, when the output current of the charge pump is greater than a first preset current, the charge pump operates in the high current operating mode, and when the output current of the charge pump is less than or equal to a second preset current, the charge pump operates in the normal current operating mode; the first preset current is greater than or equal to the second preset current.

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