Simulation circuit and simulation method of charge pump in phase-locked loop, equipment and medium

Abstract

The invention relates to the technical field of circuits, in particular to a simulation circuit and simulation method of a charge pump in a phase-locked loop, equipment and a medium. The system comprises a variable delay controller, a phase frequency detector, a charge pump to be simulated, a loop filter, a voltage control unit and a voltage-controlled oscillator which are connected in sequence, wherein the output end of the charge pump to be simulated is also connected with a current source; the variable delay controller is used for generating two paths of test clock signals with dynamic time difference based on a target clock signal output by the voltage-controlled oscillator, and inputting the two paths of test clock signals into the phase frequency detector; wherein the dynamic time difference is linearly changed; the phase frequency detector is used for detecting the phase difference of the two paths of test clock signals and generating a voltage pulse signal corresponding to the phase difference; the to-be-simulated charge pump is used for outputting a corresponding first current signal based on the voltage pulse signal, so that the voltage-controlled oscillator updates the output target clock signal. And comprehensive and accurate quantitative evaluation of the linearity of the charge pump is realized.

Description

Technical Field

[0001] The present application relates to the field of circuit technology, and in particular to a simulation circuit and simulation method, device, and medium for a charge pump in a phase-locked loop. Background Art

[0002] As semiconductor process technology continues to evolve and power supply voltages continue to decrease, the channel modulation effect of MOS transistors becomes increasingly pronounced under low voltage conditions, leading to mismatches in the charge and discharge currents in the charge pump, which in turn introduces phase noise and jitter. Furthermore, the demand for high-speed data transmission (such as Wi-Fi 6 / 7) is driving the reference frequency of phase-locked loops (PLLs) to over 100MHz, extending the loop bandwidth to several MHz. This requires the charge pump to output high currents in the milliampere range for fast response. However, to reduce area and power consumption, the capacitors in the charge pump are becoming increasingly miniaturized, significantly increasing the voltage swing at the charge pump output, further exacerbating the channel modulation effect and causing increasingly severe dynamic current mismatch in the charge pump within the PLL. Effective control measures are urgently needed.

[0003] For example, the invention patent application with patent application publication number CN118054785 A discloses a wide-swing, low-mismatch charge pump circuit for a phase-locked loop, including a discharge current compensation circuit, a charge pump main circuit, and a charging current compensation circuit. It uses PMOS and NMOS tubes to form complementary switches and unit-gain connected amplifier A3 to suppress charge injection and charge sharing-induced charge pump output jitter. It uses a composite MOS tube current mirror structure to effectively suppress the channel modulation effect and improve the mirror accuracy of the current mirror. It uses PMOS tubes M17, PMOS tubes M18, and amplifier A2 to implement charging current technology and NMOS tubes M13, NMOS tubes M14, and amplifier A1 to implement discharging current technology to improve the matching accuracy of charging and discharging currents. It uses charging current compensation circuit and discharge current compensation circuit technology to improve the matching range of charging current and discharging current of the charge pump.

[0004] For example, the utility model patent with authorization publication number CN 219627697 U discloses a charge pump circuit and a phase-locked loop for compensating for current mismatch. The charge pump circuit for compensating for current mismatch includes a current mirror bias branch, a first feedback bias branch, a second feedback bias branch, a first charge and discharge branch, and a second charge and discharge branch. A current mirror bias branch based on replica feedback bias is adopted, and the first feedback bias branch and the second feedback bias branch achieve double compensation.

[0005] However, existing control methods have limited effects in practical applications, and the dynamic current mismatch problem remains prominent, resulting in a decrease in phase-locked loop performance and affecting system stability and accuracy. Summary of the Invention

[0006] The main purpose of this application is to provide a simulation circuit and simulation method, device and medium for a charge pump in a phase-locked loop. In order to solve the above-mentioned technical problems, this application specifically adopts the following technical solutions: A first aspect of the present application is to provide a simulation circuit for a charge pump in a phase-locked loop, the simulation circuit comprising a variable delay controller, a phase frequency detector, a charge pump to be simulated, a loop filter, a voltage control unit, and a voltage-controlled oscillator connected in sequence, wherein an output end of the charge pump to be simulated is further connected to a current source, and the current source is configured to output a second current signal; The variable delay controller is used to generate two test clock signals with a dynamic time difference based on the target clock signal output by the voltage-controlled oscillator, and input the two test clock signals into the phase and frequency detector; wherein the dynamic time difference changes linearly; The phase frequency detector is used to detect the phase difference between the two test clock signals and generate a voltage pulse signal corresponding to the phase difference; The charge pump to be simulated is used to output a corresponding first current signal based on the voltage pulse signal, so that the voltage-controlled oscillator updates the output target clock signal.

[0007] In some embodiments, the voltage control unit includes an operational amplifier, and the system includes: the input end of the variable delay controller is connected to the output end of the voltage-controlled oscillator, the output end of the variable delay controller is connected to the input end of the phase frequency detector, and the output end of the phase frequency detector is connected to the input end of the charge pump to be simulated; the output end of the charge pump to be simulated is connected to the input end of the loop filter and the current source; the output end of the loop filter is connected to the positive input end of the operational amplifier; the negative input end of the operational amplifier is connected to a reference voltage, and the output end of the operational amplifier is connected to the input end of the voltage-controlled oscillator.

[0008] In some embodiments, the system includes: the loop filter is used to generate a smooth voltage corresponding to the first current signal; the operational amplifier is used to compare the smooth voltage with the reference voltage to generate a control voltage; and the voltage-controlled oscillator is used to update the target clock signal based on the control voltage.

[0009] A second aspect of the present application is to provide a method for simulating a charge pump in a phase-locked loop, the method comprising: Simulating the charge pump to be simulated based on the simulation circuit to obtain a first current signal output by the charge pump to be simulated, a second current signal generated by the current source, and a period of a target clock signal output by a voltage-controlled oscillator under different dynamic time differences; Based on a preset calculation formula, the linearity of the charge pump to be simulated is determined according to the dynamic time difference, the first current signal, the second current signal, and the period of the target clock signal.

[0010] In some embodiments, the preset calculation formula is: ; in, is the first current signal; is the dynamic time difference; is the second current signal; is the period of the target clock signal.

[0011] In some embodiments, the method further includes: obtaining a reference frequency of a phase-locked loop of the target application of the charge pump to be simulated; determining a value range of the output frequency of the voltage-controlled oscillator according to the reference frequency based on a preset locking duration; and determining a value range of the dynamic time difference according to the output frequency value range of the voltage-controlled oscillator based on the preset calculation formula.

[0012] In some embodiments, the method further includes: when the output frequency of the voltage controlled oscillator is in the range of [ ], the value range of the dynamic time difference is: ;in, is the reference frequency, 、 is an integer or fractional value, and Less than .

[0013] A third aspect of the present application is to provide a computer device, comprising: memory for storing computer programs; A processor is used to execute the computer program and implement the steps of the simulation method of the charge pump in the phase-locked loop provided in any embodiment of the present application when executing the computer program.

[0014] The fourth aspect of the present application is to provide a corresponding computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the processor performs the steps of the method for simulating a charge pump in a phase-locked loop as provided in any embodiment of the present application.

[0015] Beneficial effects: The embodiments of the present application provide a simulation circuit and simulation method, device and medium for a charge pump in a phase-locked loop. Through loop simulation driven by dynamic time difference, combined with a mathematical model based on the law of conservation of charge, the linearity index of the charge pump is quantitatively calculated, thereby achieving a comprehensive and accurate quantitative evaluation of the linearity of the charge pump, improving the sensitivity of nonlinear detection, providing a theoretical basis for circuit nonlinear mismatch compensation, and enhancing the development reliability of the phase-locked loop system.

[0016] Specifically, a loop simulation architecture consisting of a variable delay controller, a frequency detector, a charge pump, a loop filter, an op amp, and a voltage-controlled oscillator is constructed. Two test clock signals with a linearly varying time difference are dynamically generated by the variable delay controller, thereby simulating the current response of the charge pump under different working conditions, thereby capturing the nonlinear relationship between the charge and phase output of the charge pump. Then, based on the law of conservation of charge, a The core formula is to convert the pulse current output by the charge pump into The current of the current source Through dynamic time difference and target clock cycle By correlating the complex and random current mismatch, the system can transform it into observable clock cycle parameters, which improves the interpretability of the simulation results.

[0017] Furthermore, by introducing dynamic range constraints on the reference frequency and the voltage-controlled oscillator output frequency, the value range of the dynamic time difference is limited, avoiding an excessively large simulation range that leads to a long locking time or an inability to lock, reducing the time consumption of each round of loop simulation, and accurately adapting to the actual application scenarios of the charge pump, taking into account both simulation efficiency and engineering practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the embodiments or the description of the prior art. In all drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the various elements or parts are not necessarily drawn according to the actual scale. Obviously, the drawings described below are some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without paying any creative work.

[0019] Figure 1 is a schematic diagram of an ideal charge pump output current waveform provided by an embodiment of the present application; Figure 2 is a curve diagram of charge and phase of an ideal charge pump provided in an embodiment of the present application; Figure 3 1 is a schematic diagram of a charge pump output current waveform under current mismatch provided in an embodiment of the present application; Figure 4 is a schematic diagram of the phase relationship between CLK_Td0 and CLK_Td1 provided in an embodiment of the present application; Figure 5 This is a schematic block diagram of a simulation circuit of a charge pump in a phase-locked loop provided in an embodiment of the present application; Figure 6 is a schematic flow chart of a method for simulating a charge pump in a phase-locked loop provided in an embodiment of the present application; Figure 7 is a curve diagram of charge and phase of a charge pump under current mismatch provided by an embodiment of the present application; Figure 8 This is a schematic block diagram of the structure of a computer device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0020] To make the purpose, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0021] Herein, suffixes such as "module," "component," or "unit" used to represent elements are only used to facilitate the description of the present application and have no specific meaning. Therefore, "module," "component," or "unit" can be used interchangeably.

[0022] As used herein, terms such as "upper," "lower," "inner," "outer," "front," "back," "one end," and "the other end" indicate positions or locations based on those shown in the accompanying drawings. These terms are intended solely to facilitate the description of this application and simplify the description. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0023] As used herein, unless otherwise expressly specified or limited, the terms "installed," "provided with," "connected," etc., should be understood broadly. For example, "connected" may refer to a fixed connection, a detachable connection, or an integral connection; it may refer to a mechanical connection, a direct connection, an indirect connection through an intermediate medium, or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this application.

[0024] As used herein, "and / or" includes any and all combinations of one or more of the associated listed items.

[0025] Herein, "plurality" means two or more than two, ie, it includes two, three, four, five, etc.

[0026] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or apparatus comprising the element.

[0027] In this context, a clock signal is a periodically varying voltage or current waveform, which can be a square wave, sine wave, or pulse wave, and is used to coordinate the synchronous operation of various circuit units. A clock signal has properties such as period, frequency, and duty cycle. For example, the target clock signal is a periodic waveform output by a voltage-controlled oscillator, and the test clock signal is a paired periodic waveform generated by a variable delay controller.

[0028] In this article, a phase-locked loop (PLL) is a feedback control system whose core components include a phase frequency detector (PFD), a charge pump (CP), a loop filter (LF), and a voltage-controlled oscillator (VCO). The charge pump converts the phase error signal output by the PFD into current pulses, which are then used by the loop filter to adjust the frequency of the VCO.

[0029] See also Figures 1 to 2 , Figure 1 is a schematic diagram of an ideal charge pump output current waveform provided by an embodiment of the present application; Figure 2 This is a graph of charge and phase of an ideal charge pump provided by an embodiment of the present application. Figure 1 As shown, under ideal conditions, the current output by the charge pump presents a constant amplitude of The charge pump generates a square wave, and the amount of charge is proportional to the phase error, such as Figure 2 As shown, the relationship between the charge pump output charge and the phase error is linear.

[0030] However, with the continuous evolution of semiconductor process technology and the continuous reduction of power supply voltage, the channel modulation effect of MOS transistors has become increasingly significant under low voltage conditions, leading to mismatch in the charge and discharge currents in the charge pump, which in turn introduces phase noise and jitter. Furthermore, the demand for high-speed data transmission (such as Wi-Fi 6 / 7) has driven the reference frequency of phase-locked loops to above 100MHz, and the loop bandwidth has expanded to several MHz. This requires the charge pump to output high currents in the milliampere range for fast response. To reduce area and power consumption, the capacitor design in the charge pump has been gradually miniaturized, resulting in a significant increase in the voltage swing at the charge pump output, further exacerbating the channel modulation effect and causing even more severe dynamic current mismatch in the charge pump in the phase-locked loop.

[0031] See also Figure 3 , Figure 3 FIG is a schematic diagram of a charge pump output current waveform under a current mismatch provided by an embodiment of the present application. Figure 3 As shown in the figure, when facing the current mismatch problem in actual application, the charge output by the charge pump in two adjacent cycles is 、 They are not equal, which will introduce great noise and affect the performance of the phase-locked loop.

[0032] Existing dynamic current mismatch control methods are typically designed based on static or locally linear assumptions, making it difficult to track the nonlinear dynamic characteristics of the charge pump in real time. If linearity is not accurately modeled, the compensation algorithm will not be able to effectively eliminate the dynamic mismatch, resulting in increased phase noise and jitter. Furthermore, traditional charge pump simulation techniques typically clamp the charge pump output to a fixed voltage source. This fixed voltage source causes the charge pump voltage to remain stable, making it impossible to characterize the charge pump's swing voltage and effectively reflect the current nonlinearity caused by dynamic voltage changes.

[0033] Based on this, the embodiments of the present application provide a simulation circuit and simulation method, device and medium for a charge pump in a phase-locked loop. Through loop simulation driven by dynamic time difference, combined with a mathematical model based on the law of conservation of charge, the linearity index of the charge pump is quantitatively calculated, thereby achieving a comprehensive and accurate quantitative evaluation of the linearity of the charge pump, improving the sensitivity of nonlinear detection, providing a theoretical basis for circuit nonlinear mismatch compensation, and enhancing the development reliability of the phase-locked loop system.

[0034] The following describes some embodiments of the present application in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features therein may be combined with each other.

[0035] An embodiment of the present application provides a simulation circuit for a charge pump in a phase-locked loop, the simulation circuit comprising a variable delay controller, a phase frequency detector, a charge pump to be simulated, a loop filter, a voltage control unit, and a voltage-controlled oscillator, which are connected in sequence. The output end of the charge pump to be simulated is further connected to a current source, and the current source is used to output a second current signal. The variable delay controller is used to generate two test clock signals with a dynamic time difference based on the target clock signal output by the voltage-controlled oscillator, and input the two test clock signals into the phase and frequency detector; wherein the dynamic time difference changes linearly; The phase frequency detector is used to detect the phase difference between the two test clock signals and generate a voltage pulse signal corresponding to the phase difference; The charge pump to be simulated is used to output a corresponding first current signal based on the voltage pulse signal, so that the voltage-controlled oscillator updates the output target clock signal.

[0036] Specifically, a loop simulation architecture consisting of a variable delay controller, a frequency and phase detector, a charge pump to be simulated, a loop filter, a voltage control unit and a voltage-controlled oscillator is constructed. Two test clock signals with a linearly varying time difference are dynamically generated through the variable delay controller, and then the current response of the charge pump under different working states is simulated, thereby capturing the nonlinear relationship between the output charge and phase of the charge pump to be simulated.

[0037] In some embodiments, the variable delay controller is used to adjust the delay time according to the dynamic time difference (i.e. ) delays the target clock signal (i.e., CLK_OUT) output by the voltage-controlled oscillator to obtain two test clock signals (i.e., CLK_Td1 and CLK_Td0).

[0038] See also Figure 4 , Figure 4 Schematic diagram of the phase relationship between CLK_Td0 and CLK_Td1 provided in an embodiment of the present application. Figure 4 As shown, the frequencies of CLK_Td1 and CLK_Td0 are the same as CLK_OUT, and the phases between CLK_Td1 and CLK_Td0 are different. The phase difference between the two (i.e., dynamic time difference, delay time) is It should be understood that in each round of loop simulation, the delay time is adjusted based on the linearly changing dynamic time difference to achieve precise control of the phase difference of the test clock signal to detect the nonlinear behavior of the charge pump.

[0039] In some embodiments, the dynamic time difference changes linearly with time, and can be linearly increasing or linearly decreasing. The specific value range can be determined according to the actual application scenario and is not limited here.

[0040] In some embodiments, a phase frequency detector is used to detect the phase difference between two test clock signals and output a voltage pulse signal of corresponding width, whose pulse width is proportional to the phase difference between the two test clock signals and is used to adjust the working state of subsequent circuits (such as the charge pump to be simulated).

[0041] In some embodiments, the charge pump to be simulated is the object of the linearity test required in this simulation, which receives the voltage pulse signal output by the frequency detector and converts the voltage pulse signal into the corresponding charge pump current, that is, the first current signal .

[0042] In some embodiments, the current source is an electronic component that provides a constant current, and its output current is not affected by changes in the load resistance. One end of the current source is connected in parallel with the output end of the charge pump to be simulated, providing a constant current signal, i.e., the second current signal , as the benchmark reference quantity in the law of conservation of charge; the other end can be connected to an external power supply or ground to form a complete current path.

[0043] In some embodiments, the loop filter is located after the charge pump to be simulated and is used to generate a smoothed voltage corresponding to the first current signal. That is, the loop filter is used to smooth the current signal output by the charge pump to be simulated. Specifically, it can be a low-pass filter or other filter with a smoothing effect, which is not limited here.

[0044] In some embodiments, the voltage control unit is used to adjust the output smoothing voltage of the loop filter to a preset specific range to improve the stability of the simulation circuit. The specific electronic components corresponding to the voltage control unit are not limited here.

[0045] Exemplarily, the voltage control unit includes an operational amplifier (op amp), which is used to compare the smoothed voltage with a reference voltage based on a pre-provided reference voltage and generate a control voltage. Exemplarily, the voltage control unit can also be an analog-to-digital converter (ADC), which is used to convert the analog voltage corresponding to the smoothed voltage into a digital signal, and then convert the digital signal into an analog signal using a digital-to-analog converter (DAC) to output the control voltage.

[0046] It should be understood that the combination of a charge pump and a loop filter is commonly used in systems such as phase-locked loops to regulate the output frequency of a voltage-controlled oscillator. However, when the gain of both is too large, the system may oscillate due to excessive loop gain or insufficient phase margin. In this case, a voltage control unit is used to stabilize the circuit voltage within the operating range of the simulation circuit.

[0047] In some embodiments, the voltage-controlled oscillator is used to update the target clock signal based on the control voltage to form a closed-loop feedback, and the target clock signal corresponding to the control voltage is modulated and output, and is fed back to the variable delay controller closed loop, and the period of the target clock signal is recorded. , as the key parameter for observing the nonlinearity of the charge pump.

[0048] See also Figure 5 , Figure 5 is a schematic block diagram of a simulation circuit of a charge pump in a phase-locked loop provided by an embodiment of the present application, such as Figure 5 As shown, an embodiment of the present application provides a simulation circuit of a charge pump in a phase-locked loop.

[0049] The input end of the variable delay controller is connected to the output end of the voltage controlled oscillator, and is used to receive the target clock signal CLK_OUT output by the voltage controlled oscillator; the output end of the variable delay controller is connected to the input end of the frequency detector, and is used to convert the target clock signal CLK_OUT, the dynamic time difference The two test clock signals CLK_Td1 and CLK_Td0 are generated and input to the input terminal A and input terminal B of the frequency detector respectively; the output terminal of the frequency detector is connected to the input terminal of the charge pump to be simulated; the output terminal of the charge pump to be simulated is connected to the input terminal of the loop filter and the current source (for outputting the second current signal The output of the loop filter is connected to the positive input of the operational amplifier; the negative input of the operational amplifier is connected to a reference voltage to receive reference voltage VREF; the output of the operational amplifier is connected to the input of the voltage-controlled oscillator to input a control voltage VTUNE generated by the operational amplifier into the voltage-controlled oscillator. VTUNE refers to the voltage used for tuning in the voltage-controlled oscillator, i.e., the control voltage applied to the voltage-controlled oscillator. The value of VTUNE can be used to adjust the frequency of the target clock signal CLK_OUT output by the voltage-controlled oscillator.

[0050] See also Figure 6 , Figure 6 FIG. 1 is a schematic flow chart of a method for simulating a charge pump in a phase-locked loop provided in an embodiment of the present application. Figure 6 As shown, an embodiment of the present application provides a simulation method for a charge pump in a phase-locked loop, which is applied to a simulation circuit for a charge pump in a phase-locked loop provided by any embodiment of the present application, and the method includes S101 to S102.

[0051] S101, simulating the charge pump to be simulated based on the simulation circuit to obtain a first current signal output by the charge pump to be simulated, a second current signal generated by the current source, and a period of a target clock signal output by a voltage-controlled oscillator under different dynamic time differences; S102 , determining the linearity of the charge pump to be simulated based on a preset calculation formula and according to the dynamic time difference, the first current signal, the second current signal, and the period of the target clock signal.

[0052] Specifically, under the linearly changing dynamic time difference output by the variable delay controller, a closed-loop simulation circuit is run to simulate the process of the charge pump converting the phase error signal into a current pulse in the phase-locked loop. In this process, for each dynamic time difference Simultaneously record the simulation results: the pulse current output by the charge pump to be simulated , the constant current provided by the current source , the target clock period of the voltage controlled oscillator output According to the working principle of the simulation circuit and the law of charge conservation, the key parameters collected are substituted into the preset calculation formula. Follow The change relationship of the charge pump current phase response is calculated to determine the degree of deviation from the ideal proportional characteristic (such as slope deviation and nonlinear error) and to quantify the linearity of the charge pump current phase response.

[0053] In some embodiments, the preset calculation formula is: ; in, is the first current signal; is the dynamic time difference; is the second current signal; is the period of the target clock signal.

[0054] Specifically, a single cycle of the voltage controlled oscillator output in each round of loop simulation is used. is the observation window, the charge pump current Only in dynamic time difference Internal charge injection; current source Throughout Continuously absorbs charge during the cycle. In dynamic time difference Injected charge for: ; At the target clock cycle Internally absorbed charge for: .

[0055] Pulse current output by the charge pump With the current source providing a constant current At the same node (i.e., the input of the loop filter), charge balance is formed, and the charges accumulated by the two current signals in the same cycle time are equal, that is, , and then the preset calculation formula can be converted. It should be understood that the preset calculation formula is determined based on the working principle of the simulation circuit and the law of conservation of charge.

[0056] Among them, when the circuit working state meets the preset calculation formula, the control voltage is a stable value, and the dynamic time difference is linearly changed. When you can get different The value of .

[0057] It should be understood that the charge pump concentrates the charge injected during the pulse period, and then is continuously absorbed by the current source throughout the cycle, so that the node charge state is reset at the end of the cycle and returns to the cycle start value, achieving zero net charge accumulation and maintaining the locked state. If the charge pump has nonlinearity, in order to maintain charge equality and ensure periodic reset, The nonlinearity is inferred from the period offset by the adaptive adjustment.

[0058] In some embodiments, the following calculation formula can be used: ; It should be understood that In the process of linear change over time, the value will undergo N linear changes, and the corresponding simulation circuit will be simulated N times. According to the preset calculation formula, we can further obtain: ; Where N is The number of simulations is a positive integer; is the dynamic time difference during the Nth simulation; The first current signal collected for the Nth simulation; is the second current signal; The period of the target clock signal acquired for the Nth simulation.

[0059] It should be understood that due to is a linearly changing value, and is a constant current, that is, a constant, so or By taking two derivatives, we can get the linearity of the charge pump. The linearity of the charge pump to be simulated can be expressed as: ; in, is the symbol for the second-order derivative formula.

[0060] See also Figure 7, Figure 7 is a graph of charge and phase of a charge pump under current mismatch provided by an embodiment of the present application. Figure 7 As shown, the simulation circuit and simulation method provided in the embodiment of the present application can restore the nonlinear behavior of the charge pump, thereby accurately improving the linearity of the charge pump by optimizing design parameters or adopting compensation technology, thereby improving the performance of the phase-locked loop.

[0061] It should be understood that the preset calculation formula is derived based on the working principle of the simulation circuit and the law of conservation of charge, and the data used in the formula strictly depends on the closed-loop simulation output to accurately restore the nonlinear behavior of the current caused by the dynamic change of voltage.

[0062] In some embodiments, the dynamic time difference grows linearly with time, by continuously changing The possible operating points of the charge pump are covered and used as independent variables to drive the frequency detector to generate pulses with varying widths, thereby detecting the nonlinear defects of current mismatch in the charge pump.

[0063] The embodiment of the present application also introduces dynamic range constraints on the reference frequency and the output frequency of the voltage-controlled oscillator to limit the value range of the dynamic time difference, thereby avoiding excessive simulation range leading to excessive locking time or inability to lock, reducing the time consumption of each round of loop simulation, and accurately adapting to the actual application scenario of the charge pump, taking into account both simulation efficiency and engineering practicality. It should be understood that since the simulation circuit provided in the embodiment of the present application is a loop, and It is linearly variable and requires multiple complete loop runs to cover different working conditions, which takes a certain amount of simulation time. To improve efficiency, it can be combined with actual application scenarios and specific simulation constraints. to dynamically adjust the simulation strategy. In some embodiments, the range of the dynamic time difference is determined based on a preset simulation speed, so that the actual simulation speed is less than the preset simulation speed. The simulation speed is the length of time required to complete a preset number of loop simulation rounds per unit time. Correspondingly, the preset simulation speed is the maximum length of time required to complete a preset number of loop simulation rounds per unit time. The specific value can be set based on the speed and accuracy requirements for simulation efficiency in actual applications. The preset number of rounds can be one or more, and is not limited herein.

[0064] In some embodiments, the simulation parameters are optimized through the application scenario of the phase-locked loop, and the method further includes: obtaining a reference frequency of the phase-locked loop of the target application of the charge pump to be simulated; determining the output frequency value range of the voltage-controlled oscillator according to the reference frequency based on a preset locking duration; and determining the value range of the dynamic time difference according to the output frequency value range of the voltage-controlled oscillator based on the preset calculation formula.

[0065] The phase-locked loop reference frequency is the reference signal frequency used for phase comparison with the voltage-controlled oscillator output signal and is a core parameter for the phase-locked loop to achieve frequency lock and phase synchronization. It should be understood that the choice of reference frequency varies depending on system requirements, performance indicators, and hardware limitations. For example, in wireless communications (such as GSM, Wi-Fi, and 5G), the reference frequency must meet high frequency resolution (i.e., small step size) and low phase noise to ensure signal modulation / demodulation accuracy and anti-interference capabilities.

[0066] The preset lock time refers to the maximum allowable time required for the system to stabilize from an initial state (such as an unlocked state) to a target frequency during the design or simulation of the phase-locked loop system.

[0067] Specifically, the reference frequency of the phase-locked loop of the charge pump to be simulated in the target application scenario is obtained, and the response time required for the phase-locked loop to go from initial startup to the phase-locked state at the reference frequency is determined through pre-testing or empirical values ​​of the phase-locked loop. The output frequency whose response time is less than or equal to the preset locking duration is recorded to obtain the output frequency value range of the voltage-controlled oscillator. At the same time, the first current signal output by the charge pump at different output frequencies can be recorded. In other words, the frequency variation range of the voltage-controlled oscillator that can be adjusted within the limited preset locking duration is determined, thereby determining the output frequency value range of the voltage-controlled oscillator that meets the simulation speed requirements.

[0068] Furthermore, the output frequency of the voltage-controlled oscillator is the frequency range of the target clock signal. At this time, the value range of the dynamic time difference can be reversed through the preset calculation formula. When the dynamic time difference is within the value range, the voltage-controlled oscillator can output the target clock signal more quickly. On the one hand, it enables the simulation to cover the key working state, and on the other hand, it avoids the simulation speed being too low due to an excessively wide time difference range, thereby improving the overall simulation efficiency while ensuring accuracy.

[0069] In some embodiments, ,in, is the frequency of the target clock signal; is the period of the target clock signal.

[0070] The formula Substitute into the formula In this case, we can get: ; Since the output frequency of the voltage controlled oscillator is the frequency range of the target clock signal, the output frequency range of the voltage controlled oscillator is [ ]Substitute into the above formula to obtain the value range of the dynamic time difference.

[0071] Exemplarily, the method further includes: when the output frequency of the voltage controlled oscillator is in the range of [ ], the value range of the dynamic time difference is: ; in, is the reference frequency, 、 is an integer or fractional value, and Less than .

[0072] Specifically, is the minimum value of the output frequency of the voltage controlled oscillator, is the maximum value of the output frequency of the voltage controlled oscillator, is a value less than 1, A value greater than 1. is 0.85, It should be understood that in practical applications, the closer the output frequency range of the voltage-controlled oscillator is to the reference frequency, the shorter the required locking time is.

[0073] In some embodiments, when the voltage controlled oscillator operates within the output frequency range, the charge pump outputs a first current signal accordingly. The first current signal output by the charge pump at different output frequencies can be recorded. Among them, the output frequency of the voltage controlled oscillator is hour The value of , the output frequency of the voltage controlled oscillator is hour The value of , the value range of dynamic time difference is: .

[0074] It should be understood that in the process of determining the dynamic time difference value, It can be the first current signal output by the charge pump when the voltage-controlled oscillator operates at the maximum or minimum output frequency, or it can be an empirical value or a preset value corresponding to the charge pump performance, which is not limited here.

[0075] In some embodiments, The linear change is divided into discrete intervals, giving priority to covering high-probability conditions and reducing the computational effort of traversing the full range.

[0076] In some embodiments, during the simulation process, the linearity of the charge pump to be simulated is calculated based on the dynamic time difference, the first current signal, the second current signal, and the period of the target clock signal acquired in real time; the calculated historical linearity is monitored; if the charge and the phase difference in the historical linearity within a first preset time length continue to maintain a linear relationship, the linearly changing dynamic time difference is divided into multiple intervals according to a preset step size; a representative time difference is selected from each interval, and simulation is performed based on the representative time difference, that is, the variable delay controller is controlled to generate two test clock signals based on the representative time difference; when nonlinear results appear in the charge and phase difference in the historical linearity, the interval division is canceled, and the simulation is continued based on the linearly changing dynamic time difference.

[0077] Among them, the first preset duration and the preset step size can be flexibly set according to the simulation requirements and are not limited here; the representative time difference can take a representative value such as the mean within the interval, which is not limited here.

[0078] It should be understood that the charge pump should be able to accurately generate the corresponding output charge according to the phase difference, that is, there is a direct and linear relationship between the output and the phase difference. Dividing the simulation into discrete intervals can reduce unnecessary simulation times and avoid traversing the entire continuous range, which can significantly improve simulation efficiency while ensuring the accuracy of key performance evaluation.

[0079] In some embodiments, the method further includes: obtaining a target representative time difference corresponding to the nonlinear result, and determining a target interval corresponding to the target representative time difference; and re-simulating based on the dynamic time difference within the target interval to update the linearity of the charge pump to be simulated in the calculated target interval.

[0080] In some embodiments, the simulation circuit also includes a signal acquisition unit and a data processing unit; the signal acquisition unit is used to collect the periods of the first current signal, the second current signal, and the target clock signal under different dynamic time differences to determine the linearity of the charge pump to be simulated; the data processing unit is used to execute the simulation method of the charge pump in the phase-locked loop provided in any embodiment of the present application based on multiple sets of simulation data to determine the linearity of the charge pump to be simulated. For details, please refer to the aforementioned embodiments and will not be repeated here.

[0081] It should be understood that after each dynamic time difference is simulated through the simulation circuit, the corresponding first current signal, second current signal, and target clock signal period will be obtained. The signal acquisition unit can be one or more and can be arranged at a specific location in the circuit or integrated within the electrical component to be monitored. This is not limited here. The signal acquisition unit collects and transmits a set of collected simulation data (i.e., the dynamic time difference, the first current signal, the second current signal, and the target clock signal period) to the data processing unit. Correspondingly, the data processing unit can be any device with data computing capabilities, which is used to perform subsequent operations on the multiple sets of simulation data to obtain the linearity of the charge pump to be simulated.

[0082] See also Figure 8 , Figure 8 1 is a schematic block diagram of a computer device according to an embodiment of the present application. The computer device may be a terminal device or a server, or may be the data processing unit in the aforementioned embodiment.

[0083] For example, the above method can be implemented in the form of a computer program. Figure 8 Runs on the computer device shown.

[0084] like Figure 8 As shown, the computer device includes a processor, a memory, and a network interface connected via a system bus, wherein the memory may include a non-volatile storage medium and an internal memory.

[0085] The non-volatile storage medium can store an operating system and a computer program. The computer program includes program instructions, and when the program instructions are executed, the processor can execute any one of the simulation methods for a charge pump in a phase-locked loop.

[0086] The processor is used to provide computing and control capabilities and support the operation of the entire computer equipment.

[0087] The internal memory provides an environment for the operation of the computer program in the non-volatile storage medium. When the computer program is executed by the processor, the processor can execute any simulation method of the charge pump in the phase-locked loop.

[0088] This network interface is used for network communication, such as sending assigned tasks.

[0089] It should be understood that the processor may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0090] In one embodiment, the processor is configured to execute a computer program stored in the memory to implement the following steps: Simulating the charge pump to be simulated based on the simulation circuit to obtain a first current signal output by the charge pump to be simulated, a second current signal generated by the current source, and a period of a target clock signal output by a voltage-controlled oscillator under different dynamic time differences; Based on a preset calculation formula, the linearity of the charge pump to be simulated is determined according to the dynamic time difference, the first current signal, the second current signal, and the period of the target clock signal.

[0091] Exemplarily, the processor is used to run a computer program stored in the memory, and is also used to implement the steps of the simulation method of the charge pump in the phase-locked loop provided in any embodiment of the present application, which will not be repeated here.

[0092] A computer-readable storage medium is also provided in an embodiment of the present application, wherein the computer-readable storage medium stores a computer program, wherein the computer program includes program instructions, and the processor executes the program instructions to implement the steps of the simulation method of the charge pump in the phase-locked loop provided in any one of the embodiments of the present application.

[0093] The computer-readable storage medium may be an internal storage unit of the computer device described in the aforementioned embodiment, such as a hard disk or memory of the computer device. The computer-readable storage medium may also be an external storage device of the computer device, such as a plug-in hard disk, a SmartMedia Card (SMC), a Secure Digital (SD) card, a flash memory card, etc., equipped on the computer device.

[0094] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present application, and such modifications or substitutions should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A simulation circuit for a charge pump in a phase-locked loop, characterized in that: The simulation circuit includes a variable delay controller, a phase frequency detector, a charge pump to be simulated, a loop filter, a voltage control unit, and a voltage controlled oscillator connected in sequence, and the output end of the charge pump to be simulated is also connected to a current source, and the current source is used to output a second current signal; The variable delay controller is used to generate two test clock signals with a dynamic time difference based on the target clock signal output by the voltage-controlled oscillator, and input the two test clock signals into the phase and frequency detector; wherein the dynamic time difference changes linearly; The phase frequency detector is used to detect the phase difference between the two test clock signals and generate a voltage pulse signal corresponding to the phase difference; The charge pump to be simulated is used to output a corresponding first current signal based on the voltage pulse signal, so that the voltage-controlled oscillator updates the output target clock signal.

2. The simulation circuit according to claim 1, wherein: The voltage control unit includes an operational amplifier, and the system includes: The input end of the variable delay controller is connected to the output end of the voltage controlled oscillator, the output end of the variable delay controller is connected to the input end of the phase frequency detector, and the output end of the phase frequency detector is connected to the input end of the charge pump to be simulated; The output end of the charge pump to be simulated is connected to the input end of the loop filter and the current source; The output terminal of the loop filter is connected to the positive input terminal of the operational amplifier; The negative input terminal of the operational amplifier is connected to a reference voltage, and the output terminal of the operational amplifier is connected to the input terminal of the voltage-controlled oscillator.

3. The simulation circuit according to claim 2, wherein: The system comprises: The loop filter is used to generate a smooth voltage corresponding to the first current signal; The operational amplifier is used to compare the smoothed voltage with the reference voltage to generate a control voltage; The voltage-controlled oscillator is configured to update the target clock signal based on the control voltage.

4. A method for simulating a charge pump in a phase-locked loop, characterized in that: The method applied to the emulation circuit of the charge pump in the phase-locked loop according to any one of claims 1 to 3 comprises: Simulating the charge pump to be simulated based on the simulation circuit to obtain a first current signal output by the charge pump to be simulated, a second current signal generated by the current source, and a period of a target clock signal output by a voltage-controlled oscillator under different dynamic time differences; Based on a preset calculation formula, the linearity of the charge pump to be simulated is determined according to the dynamic time difference, the first current signal, the second current signal, and the period of the target clock signal.

5. The method according to claim 4, wherein The preset calculation formula is: ； in, is the first current signal; is the dynamic time difference; is the second current signal; is the period of the target clock signal.

6. The method according to claim 5, wherein The method further comprises: Obtaining a reference frequency of a phase-locked loop of a target application of the charge pump to be simulated; Based on a preset locking time, determining an output frequency value range of the voltage controlled oscillator according to the reference frequency; Based on the preset calculation formula and according to the output frequency value range of the voltage-controlled oscillator, the value range of the dynamic time difference is determined.

7. The method according to claim 6, wherein The method further comprises: When the output frequency of the voltage controlled oscillator is in the range of [ ], the value range of the dynamic time difference is: ； in, is the reference frequency, 、 is an integer or fractional value, and Less than .

8. The method according to claim 7, wherein described is 0.85, is 1.

15.

9. A computer device, characterized in that: The device comprises: memory for storing computer programs; A processor, configured to execute the computer program and implement the method for simulating a charge pump in a phase-locked loop according to any one of claims 4 to 8 when executing the computer program.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, which, when executed by a processor, enables the processor to implement the method for simulating a charge pump in a phase-locked loop according to any one of claims 4 to 8.

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