Dual-loop two-dimensional regulated isolating power supply control system and method

Abstract

The application discloses a double-loop two-dimensional regulation isolating transformer power supply control system and method, and relates to the technical field of switching power supply.The system comprises a two-dimensional PWM modulation module for driving a power switch tube, having a duty cycle control end and a frequency control end, the power switch tube being connected to the primary side of an isolating transformer, and the secondary side of the isolating transformer being connected to a rectifier filter unit to generate an output voltage for power supply; a fast loop regulation loop, the output voltage being fed back to the duty cycle control end after being isolated and filtered by an optical coupler; a slow loop digital regulation loop, a 1-bit pulse modulation signal being generated after the output voltage is sampled, DEM randomization processing and Sigma-Delta modulation, and the frequency control end being adjusted after being isolated by an optical coupler; the double-loop can be two-dimensionally linked or independently adjusted to regulate the duty cycle and the frequency of the two-dimensional PWM modulation module, and then to regulate the output voltage.The application realizes the comprehensive optimization goal of fast response and high-precision voltage stabilization through the cooperation of the fast loop and the slow loop.

Description

Technical Field

[0001] This application relates to the field of switching power supply technology, and more specifically, to a dual-loop two-dimensional adjustable isolation switching power supply control system and method, applicable to power supply scenarios. Background Technology

[0002] In traditional control schemes, the duty cycle of PWM (Pulse Width Modulation) is adjusted at a fixed frequency. However, the duty cycle adjustment range is limited, efficiency decreases under light load, and dynamic response is limited by the bandwidth of the error amplifier. Using a fixed duty cycle to adjust the frequency results in a large frequency variation range, which leads to difficulties in EMI (Electromagnetic Interference) filtering and complex transformer core design.

[0003] In EMI suppression schemes for switching power supplies, patent CN201210282249.7 proposes a PWM modulation method and system based on direct spread spectrum technology. This method XORs the PWM signal with a spread spectrum sequence to obtain a random direct spread spectrum PWM signal used to drive the switching transistor. The randomness of the spread spectrum sequence expands the spectrum to suppress EMI. However, the spread spectrum operation targets the PWM signal itself, directly superimposing random disturbances onto the PWM waveform. Essentially, it still falls under the category of single-parameter adjustment, without involving independent control of duty cycle and frequency. Although the randomness of the spread spectrum sequence can expand the spectrum, the expanded spectrum still contains certain discrete components, making it impossible to achieve a completely flat white noise substrate.

[0004] To overcome the limitations of single-loop circuits, existing technologies have proposed dual-loop control schemes. Patent CN110299843A describes a composite DC-DC circuit employing a dual-loop architecture, adding a compensation loop to improve output voltage accuracy without compromising the stability of the original loop. Its drive control unit includes a fast current-voltage feedback loop and a slow loop to correct voltage changes. If the slow loop cannot correct fast voltage changes, compensation is provided by the loop compensation unit. However, although both the fast and slow loops in this scheme achieve voltage regulation by adjusting the PWM drive signal, it actually performs one-dimensional adjustment through the dual loops, with the two loops superimposed to adjust the duty cycle of the same PWM modulator.

[0005] Furthermore, in the implementation of dual-loop circuits, patent US7141956 also proposes a switching power supply regulation circuit with dual digital loop control. The fast loop uses a low-resolution ADC (Analog-to-Digital Converter) for high-speed tracking, while the slow loop uses a high-resolution ADC for precise calibration. Both loops in this scheme are digital loops, requiring ADC sampling and digital processing. The response speed of the fast digital loop is limited by the ADC sampling rate and digital filter delay. Both loops adjust the duty cycle, similarly using a dual-loop superposition for one-dimensional adjustment.

[0006] In summary, there is currently no novel switching power supply control system and its control method that urgently requires independent or coordinated adjustment in two dimensions: duty cycle and frequency, and that works in collaboration between fast-loop analog and slow-loop digital, while introducing randomization processing to achieve spectrum whitening. Summary of the Invention

[0007] To address the shortcomings of existing technologies and the problems of power supply ripple and regulation interference, this application provides a dual-loop two-dimensional regulation isolated switching power supply control system, including a primary side circuit and a secondary side circuit, and: a two-dimensional PWM regulation module, located in the primary side circuit, for generating a pulse width modulation signal to drive a power switch, the two-dimensional PWM regulation module including a duty cycle control terminal and a frequency control terminal; a power switch, the control terminal of which is connected to the output terminal of the two-dimensional PWM regulation module, for switching the pulse width modulation to generate a pulse voltage; an isolation transformer, connected between the power switch and the secondary side circuit, for transmitting the pulse voltage from the primary side circuit to the secondary side circuit; and a rectification and filtering module, connected to the secondary winding of the isolation transformer, for rectifying the pulse voltage. The output voltage is filtered and converted into an output voltage for power supply. The fast-loop adjustment module includes a first isolation module and a filtering module. The output voltage is isolated by the first isolation module and transmitted to the primary side circuit, then filtered by the filtering module, and output to the duty cycle control terminal for real-time adjustment of the output duty cycle of the two-dimensional PWM adjustment module. The slow-loop adjustment module includes a processing module and a second isolation module. The processing module samples the output voltage, processes it, and converts it into a 1-bit pulse density modulation signal. This signal is then isolated by the second isolation module and connected to the frequency control terminal for real-time adjustment of the frequency of the two-dimensional PWM adjustment module. The fast-loop and slow-loop adjustment modules act on the duty cycle control terminal and frequency control terminal of the two-dimensional PWM adjustment module, respectively, forming two independent and interconnected adjustment loops.

[0008] Optionally, the first isolation module in the fast-loop adjustment module is a first optocoupler module, and the filtering module is a low-pass filter module; the output voltage is transmitted to the primary side circuit through the isolation of the first optocoupler module, and after being filtered by the low-pass filter module, it is applied to the duty cycle control terminal of the two-dimensional PWM adjustment module.

[0009] Optionally, the second isolation module in the slow loop adjustment module is a second optocoupler module, the output terminal of the processing module is connected to the primary input terminal of the second optocoupler module, and the secondary output terminal of the second optocoupler module is directly connected to the frequency control terminal of the two-dimensional PWM adjustment module.

[0010] Optionally, the processing module includes: an analog-to-digital converter for sampling the output voltage; a difference calculation unit connected to the output terminal of the analog-to-digital converter for comparing the sampled value of the output voltage with a reference voltage to generate an error signal; a DEM randomization processing unit connected to the output terminal of the difference calculation unit for performing dynamic element matching randomization processing on the error signal to convert the error signal into a memoryless random distribution sequence; and a Sigma-Delta modulator connected to the output terminal of the DEM randomization processing unit for converting the memoryless random distribution sequence into a 1-bit pulse density modulation signal.

[0011] Optionally, the DEM randomization processing unit is specifically a mismatch shaping filter.

[0012] Optionally, the mismatch shaping filter includes: a discretization module, used to discretize the error signal into at least one unit step size, map the error signal to the number of unit step sizes to be activated, and calculate the quantization error; a mismatch shaping filter, connected to the output of the discretization module, used to perform mismatch shaping filtering on the quantization error, pushing the error energy from the low-frequency band to the high-frequency band; a random code disk construction and shuffling module, used to construct a binary array of length one unit step size, and randomly arrange the binary array using a pseudo-random sequence; and a time slot output and physical limiting module, used to sequentially extract one element from the arranged binary array and output it in each time slot period, and perform physical safety limiting on the output.

[0013] Optionally, the fast-loop adjustment module and the slow-loop adjustment module work together according to the linkage direction and linkage ratio; when the linkage coefficient is zero, the two loops work independently.

[0014] This application also proposes a dual-loop two-dimensional regulation method for controlling an isolated switching power supply, comprising the following steps:

[0015] Step S1: Sample the output voltage, and transmit the output voltage to the sampling terminal of the processing module in the fast loop adjustment module and the slow loop digital adjustment module;

[0016] Step S2: The fast-loop adjustment module transmits the output voltage to the primary side circuit through the first isolation module, and then filters it through the filter module before applying it to the duty cycle control terminal of the two-dimensional PWM adjustment module. This closed-loop adjustment of the output duty cycle of the two-dimensional PWM adjustment module changes the on-time of the power switch and adjusts the energy transferred from the isolation transformer to the secondary side circuit, thereby achieving rapid adjustment of the output voltage.

[0017] Step S3: In the slow loop regulation module, the analog-to-digital converter of the processing module samples the output voltage. The difference calculation unit compares the output voltage with the reference voltage to generate an error signal. The DEM randomization processing unit randomizes the error signal. The Sigma-Delta modulator converts the processed signal into a 1-bit pulse density modulation signal. After being isolated and transmitted to the primary side circuit through the second isolation module, it drives the frequency control terminal of the two-dimensional PWM regulation module to adjust the frequency of the two-dimensional PWM regulation module, change the switching frequency of the power switch, and adjust the energy transferred to the secondary side circuit by the isolation transformer, thereby achieving high-precision steady-state regulation of the output voltage.

[0018] Step S4: The fast loop adjustment module and the slow loop adjustment module work simultaneously, and the two loops coordinate to adjust the output voltage according to the linkage direction and linkage ratio; when the linkage coefficient is zero, the two loops work independently.

[0019] The beneficial effects of this application are:

[0020] 1. This invention constructs a two-dimensional linkage coupling mechanism between duty cycle and frequency, enabling the two parameters to influence and coordinate each other during adjustment, thereby achieving comprehensive optimal control through two-dimensional linkage adjustment parameters. Compared to single-loop adjustment schemes that can only adjust a single control parameter, and mixed adjustment schemes that simply superimpose two parameters without linkage, this invention establishes a controllable feedback loop linkage relationship between duty cycle and frequency, resulting in significantly higher adjustment efficiency than independent adjustment or simple superposition adjustment.

[0021] 2. In this invention, the fast loop adjusts the duty cycle and the slow loop adjusts the frequency. These two dimensions are connected to different functional nodes on the PWM. The two loops can work simultaneously to achieve linkage adjustment, or they can work independently without interfering with each other. The control strategy design is simple and does not require complex loop compensation. Compared with the existing dual-loop scheme where the fast and slow loops are superimposed on the duty cycle and there are problems of coupling and competition, this invention achieves true two-dimensional adjustment, and the linkage coefficient can be flexibly configured to adapt to different operating conditions.

[0022] 3. The slow loop of this invention processes the error signal through a cascaded combination of DEM (Dynamic Element Matching) mismatch shaping and Sigma-Delta modulation. DEM mismatch shaping attenuates the error at low frequencies, ensuring long-term accuracy of the output frequency; Sigma-Delta modulation converts the signal into a 1-bit pulse width modulation signal, achieving high-frequency noise shaping. The synergistic effect of these two technologies enables the frequency control link to achieve high accuracy in the low-frequency band and spectral whitening in the high-frequency band. It also solves the problems of insufficient low-frequency accuracy and severe high-frequency EMI in traditional solutions, a comprehensive effect that cannot be achieved by existing single spread spectrum technology or single digital control technology. Attached Figure Description

[0023] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0024] Figure 1 This is a schematic diagram of the structure of a dual-loop two-dimensional adjustable isolation switching power supply control system according to this application;

[0025] Figure 2 This is a schematic diagram of the circuit implementation structure of a dual-loop two-dimensional adjustable isolation switching power supply control system in an embodiment of this application;

[0026] Figure 3 This is a schematic diagram of the internal structure of the processing module of the present invention;

[0027] Figure 4 This is a flowchart of the method when the DEM randomization processing unit of the present invention is a mismatch shaping filter.

[0028] The above figures include the following reference numerals:

[0029] 1-Two-dimensional PWM regulation module, 2-Power switching transistor, 3-Isolation transformer, 4-First optocoupler module, 5-Low-pass filter module, 6-MCU (Microcontroller Unit), 7-Second optocoupler module. Detailed Implementation

[0030] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are merely some, not all, of the embodiments of the present application. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative effort should fall within the scope of protection of the present application.

[0031] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0032] Reference Figure 1 This invention provides a schematic diagram of a dual-loop two-dimensional adjustable isolation switching power supply control system, including a primary side circuit and a secondary side circuit.

[0033] The primary side circuit includes: a two-dimensional PWM regulation module, a power switching transistor, the primary winding of an isolation transformer, a filter module in the fast-loop regulation module, and a second isolation module in the slow-loop regulation module.

[0034] The secondary circuit includes: the secondary winding of the isolation transformer, the rectifier and filter module, the first isolation module of the fast-loop regulation module, and the processing module in the slow-loop digital regulation module.

[0035] The two-dimensional PWM regulation module includes a duty cycle control terminal and a frequency control terminal. The output terminal of the two-dimensional PWM regulation module is connected to the control terminal of the power switching transistor, and the other end is connected to the primary winding of the isolation transformer. The secondary winding of the isolation transformer is connected to the rectifier and filter module. The output terminal of the rectifier and filter module is the output voltage Vout, which supplies power to the load.

[0036] The output voltage Vout is connected to the sampling terminal of the fast loop regulation module and the sampling terminal of the processing module in the slow loop regulation module, respectively.

[0037] In the fast-loop regulation module, the output voltage Vout is sampled and then enters the first isolation module. After being isolated by the first isolation module, it is transmitted to the primary side circuit. After being filtered by the filter module, it is output to the duty cycle control terminal of the two-dimensional PWM regulation module.

[0038] In the slow-loop regulation module, the output voltage Vout is sampled and then enters the processing module. The processing module processes the sampled voltage and converts it into a 1-bit pulse density modulation signal. After being isolated by the second isolation module, the signal is transmitted to the primary side circuit and then connected to the frequency control terminal of the two-dimensional PWM regulation module.

[0039] The specific working principle includes: a two-dimensional PWM regulation module generates a pulse width modulation signal to drive a power switching transistor. The power switching transistor switches the pulse width modulation signal to generate a pulse voltage. The pulse voltage is transmitted from the primary side to the secondary side via an isolation transformer, and then converted into a DC output voltage Vout by a rectifier and filter module to supply power to the load.

[0040] When the output voltage Vout changes, both the fast-loop and slow-loop regulation modules respond simultaneously:

[0041] The fast-loop regulation module isolates and transmits the output voltage change signal to the primary side through the first isolation module. After being filtered by the filtering module, it directly acts on the duty cycle control terminal of the two-dimensional PWM regulation module, adjusting the output duty cycle in real time, changing the conduction time of the power switch, thereby adjusting the energy transferred to the secondary side by the isolation transformer, and realizing rapid regulation of the output voltage.

[0042] In the slow-loop regulation module, the processing module samples the output voltage, processes it, and generates a 1-bit pulse density modulation signal. After being isolated by the second isolation module, the signal is transmitted to the primary side and drives the frequency control terminal of the two-dimensional PWM regulation module to adjust the frequency, thereby changing the switching frequency of the power switch and adjusting the energy transferred from the isolation transformer to the secondary side, thus achieving high-precision steady-state regulation of the output voltage.

[0043] The two loops act on the duty cycle control terminal and the frequency control terminal of the two-dimensional PWM adjustment module, respectively, forming two independent adjustment loops that can be linked together.

[0044] Based on the system structure proposed in the above embodiments, referring to Figure 2 A circuit implementation diagram of a dual-loop two-dimensional regulation isolated switching power supply control system is proposed, specifically including:

[0045] Primary side circuit: 2D PWM adjustment module 1, power switch 2, primary winding of isolation transformer 3, secondary side of first optocoupler module 4, low-pass filter module 5, secondary side of second optocoupler module 7.

[0046] The secondary side circuit includes: the secondary winding of the isolation transformer 3, the rectifier and filter module, the primary side of the first optocoupler module 4, the MCU 6, and the primary side of the second optocoupler module 7.

[0047] The fast-loop regulation module includes a first optocoupler module and a low-pass filter module. The output voltage Vout, after sampling, drives the primary-side LED (Light Emitting Diode) of the first optocoupler module. The output current of the secondary-side phototransistor of the first optocoupler module, after being filtered by the low-pass filter module, is applied to the duty cycle control terminal of the two-dimensional PWM regulation module.

[0048] The slow-loop regulation module includes an MCU and a second optocoupler module. The MCU samples the output voltage Vout, processes it, and converts it into a 1-bit pulse density modulation signal. After being isolated by the second optocoupler module, the signal drives the frequency control terminal of the two-dimensional PWM regulation module.

[0049] refer to Figure 3 Another schematic diagram of the specific structure of the processing module is presented, which includes the following internal components of the MCU:

[0050] An ADC (Analog-to-Digital Converter) 61 is used to sample the output voltage Vout; a difference operation unit, specifically a comparator 62, is used to compare the sampled value of the output voltage with a reference voltage to generate an error signal; a DEM randomization processing unit 63, connected to the output of the comparator 62, is used to perform dynamic element matching randomization processing on the error signal; and a Sigma-Delta modulator 64, connected to the output of the DEM randomization processing unit 63, is used to convert the processed signal into a 1-bit pulse density modulation signal.

[0051] The specific working principle includes: the output terminal of the two-dimensional PWM regulation module is connected to the gate of the power switch transistor, the source of the power switch transistor is grounded, and the drain of the power switch transistor is connected to the primary winding of the isolation transformer. The secondary winding of the isolation transformer is connected to the rectifier and filter module, which specifically consists of diodes, inductors, and resistors. The output terminal of the rectifier and filter module is connected to the output voltage Vout.

[0052] After the output voltage Vout is sampled, one path drives the primary-side LED of the first optocoupler module for fast-loop regulation, and the other path sends it to the ADC sampling terminal of the MCU for slow-loop regulation.

[0053] In one embodiment, in the fast-loop regulation circuit, after the output voltage Vout is regulated by the primary side of the first optocoupler module, the output current of the phototransistor on the secondary side is filtered by the low-pass filter module and then applied to the duty cycle control terminal of the two-dimensional PWM regulation module 1 to change the charging and discharging time constant of the timing capacitor and adjust the output duty cycle. The transfer function of the fast-loop regulation circuit is formula (1):

[0054] (1)

[0055] In another embodiment, in the slow-loop regulation circuit, the output voltage Vout is sampled by the ADC and sent to a comparator for comparison with the reference voltage Vref to generate an error signal. Specifically, the transfer function is given by formula (2):

[0056] (2)

[0057] The error signal is sent to the DEM randomization processing unit, and after randomization, a memoryless random distribution sequence is output. Specifically, the noise transfer function is given by formula (3):

[0058] (3)

[0059] The sequence is fed into a Sigma-Delta modulator, converted into a 1-bit pulse density modulated signal, and output from the MCU. The transfer function of the Sigma-Delta is given by formula (4):

[0060] (4)

[0061] The overall transfer function after DEM randomization and cascading with a Sigma-Delta modulator is given by formula (5):

[0062] (5)

[0063] The overall transfer function of the slow loop is given by formula (6):

[0064] (6)

[0065] Where T_slot is the time slot period of the DEM.

[0066] The MCU's output is connected to the primary input of the second optocoupler module; the secondary output of the second optocoupler module is directly connected to the frequency control of the two-dimensional PWM adjustment module.

[0067] The two loops adjust the duty cycle and frequency respectively. The fast loop is responsible for transient response, and the slow loop is responsible for steady-state accuracy. Together, they achieve high-precision voltage regulation. The parameters can be adjusted simultaneously or independently as needed to achieve comprehensive optimization.

[0068] In another embodiment, the fast loop and slow loop interact based on their linkage ratio and direction. When the fast loop adjusts its duty cycle, it proportionally affects the frequency through the forward coupling branch:

[0069] (7)

[0070] in: The positive linkage coefficient is 0 ≤ |K1| ≤ 1, when When the clock is in the same direction, the frequency also increases as the duty cycle increases. This is a reverse linkage, meaning that as the duty cycle increases, the frequency decreases. At this time, there is no linkage, meaning that the two loops are adjusted independently.

[0071] When the slow loop adjusts the frequency, the duty cycle is proportionally affected through the reverse coupling branch:

[0072] (8)

[0073] in, This is the reverse linkage coefficient.

[0074] when or At this time, there is a controllable linkage between the two dimensions. The off-diagonal elements of the system matrix determine the direction and intensity of the linkage: when At that time, positive feedback linkage occurs, and the two parameters change in the same direction; When negative feedback occurs, the two parameters change in opposite directions; when At that time, it is completely decoupled and can be adjusted independently.

[0075] The direction and intensity of the linkage are determined by the signs and magnitudes of K1 and K2. The value of the linkage coefficient can be configured by the MCU, without the need for additional hardware circuitry, thus achieving software-adjustable two-dimensional linkage control.

[0076] Reference Figure 4 In the slow-loop adjustment circuit, when the DEM randomization processing unit 63 is specifically a mismatch shaping filter, the specific processing method flowchart includes the following steps:

[0077] Step S631: Discretization and quantization error generation. Discretize the error signal into N unit steps, map the error signal to the number of unit steps M to be activated, and calculate the quantization error, where N is an integer greater than 1.

[0078] Step S632: Mismatch shaping filter, perform mismatch shaping filter on the quantization error to push the error energy from the low frequency band to the high frequency band.

[0079] Step S633: Random code disk construction and shuffling. Construct a binary array of length N, in which M elements are in active state and NM elements are inactive state. Use a pseudo-random sequence to randomly arrange the array.

[0080] Step S634: Time-slot output and physical limiting. Within each time-slot period, one element is sequentially taken from the arranged array to determine the positive or negative frequency step. Physical safety limiting is applied to the output to restrict the single-step rate of change and the absolute frequency range.

[0081] Specifically, the working principle applied to the structure of the embodiments of this application includes:

[0082] The MCU first discretizes the input error signal e(k) into N unit steps, where N is preferably an integer between 8 and 32. Assuming the amplitude range of the error signal is ±E_max, the unit step size is given by formula (9):

[0083] (9)

[0084] Map the error signal e(k) to the number of unit steps M(k) that need to be activated:

[0085] (10)

[0086] The value of M(k) is restricted to be between 0 and N. The quantization error is specifically defined by formula (11):

[0087] (11)

[0088] The quantization error reflects the difference between the precise value of the error signal and the actual value after discretization.

[0089] At this point, the mismatch shaping filter performs second-order shaping on the quantization error, attenuating the low-frequency components and enhancing the high-frequency components of the quantization error, thereby ensuring the low-frequency accuracy of the output frequency.

[0090] First, the error is accumulated using formula (12):

[0091] (12)

[0092] Then, second-order difference shaping is performed using formula (13):

[0093] (13)

[0094] When the error after shaping exceeds one unit step Δe, compensation correction is performed on M(k):

[0095] If err_shaped(k) > Δe / 2, then M(k) is incremented by 1 and err_acc(k) is decremented by Δe; if err_shaped(k) < -Δe / 2, then M(k) is decremented by 1 and err_acc(k) is incremented by Δe; otherwise, M(k) remains unchanged.

[0096] Mismatch shaping is performed after error accumulation. Second-order mismatch shaping is selected. In the low-frequency range, when f approaches 0, the quantization error is significantly attenuated. In the high-frequency range, when f approaches 1 / (2×T_slot), the quantization error is enhanced. However, due to the randomization effect of DEM, the enhanced error energy is distributed as white noise.

[0097] The value M_comp after mismatch shaping compensation is used to construct a random code disk. When filling the code disk, a binary array Array[0:N-1] of length N is constructed in the MCU memory. The first M_comp elements are filled with logic "1", and the remaining N-M_comp elements are filled with logic "0".

[0098] A 16-bit Linear Feedback Shift Register (LFSR) is used to generate a pseudo-random sequence. Each call to the LFSR generates a pseudo-random number, which is modulo (i+1) and used as the shuffle index.

[0099] Decrementing from i=N-1 to 1 each time, a pseudo-random index is generated. Swap Array[i] with Array[j]. This shuffle operation is performed once at the beginning of each complete code disk cycle.

[0100] Set the time slot period T_slot. At the beginning of each time slot, take one element from the array in sequence, with the current position indicated by the pointer ptr. Increment ptr by 1 for each element taken. When ptr reaches N, ptr is reset to zero, and the code disk filling and LFSR shuffling operations are re-executed.

[0101] If the extracted element value is 1, the frequency jitter is F_dither = +Δf; if the extracted element value is 0, the frequency jitter is F_dither = -Δf. The instantaneous frequency setpoint is F_set = f_center + F_dither, and F_set is fed into a second-order Σ-Δ modulator to be converted into a 1-bit PDM (Pulse Density Modulation) stream. The second-order Σ-Δ modulator's judgment logic is: if the accumulator value is greater than 0, it outputs 1; otherwise, it outputs 0.

[0102] Set a physical safety limiter in the time slot output stage:

[0103] If |F_set(k)-F_set(k-1)|>Δf_max, then F_set(k) is forcibly limited to F_set(k-1) plus the sign function multiplied by Δf_max, where Δf_max is the maximum allowable jump amplitude in a single step.

[0104] If F_set(k) is greater than f_max, then the limit is f_max; if F_set(k) is less than f_min, then the limit is f_min.

[0105] A 1-bit PDM signal is output from the MCU to drive the primary-side LED of the second optocoupler module, and then transmitted to the primary-side circuit through the isolation of the second optocoupler module.

[0106] The 1-bit PDM signal output from the secondary side of the second optocoupler module is directly connected to the frequency control terminal of the two-dimensional PWM modulation module. The oscillation frequency of the two-dimensional PWM modulation module directly follows the pulse density of the PDM signal. The frequency increases when the density is high and decreases when the density is low.

[0107] When Vout is lower than the set value, the error signal e(t) is positive, the value of M increases, the proportion of logic "1" in the random sequence output by DEM increases, the PDM density of the Sigma-Delta modulator output increases, the average voltage output of the optocoupler secondary side increases, the voltage at the control voltage input terminal of the two-dimensional PWM modulation module increases, the oscillation frequency increases, the output energy increases, and Vout increases.

[0108] When Vout is higher than the set value, the above process is reversed: the error signal e(t) is negative, the M value decreases, the PDM density decreases, the frequency decreases, the output energy decreases, and Vout decreases.

[0109] In summary, the two loops work simultaneously, with the fast loop responsible for transient response and the slow loop responsible for steady-state accuracy, working together to achieve high-precision voltage regulation.

[0110] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0111] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0112] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0113] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0114] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A dual-loop two-dimensional adjustable isolation switching power supply control system, characterized in that, Includes primary-side circuitry and secondary-side circuitry, and: A two-dimensional PWM adjustment module is located in the primary side circuit and is used to generate a pulse width modulation signal to drive the power switching transistor. The two-dimensional PWM adjustment module includes a duty cycle control terminal and a frequency control terminal. The power switching transistor, with its control terminal connected to the output terminal of the two-dimensional PWM regulation module, is used to switch the pulse width modulation signal to generate a pulse voltage. An isolation transformer is connected between the power switch and the secondary side circuit to transmit the pulse voltage from the primary side circuit to the secondary side circuit. The rectifier and filter module is connected to the secondary winding of the isolation transformer and is used to rectify and filter the pulse voltage and convert it into an output voltage for power supply. The fast-loop regulation module includes a first isolation module and a filter module. The output voltage is isolated and transmitted to the primary side circuit through the first isolation module, then filtered by the filter module, and output to the duty cycle control terminal for real-time adjustment of the output duty cycle of the two-dimensional PWM regulation module. The slow-loop adjustment module includes a processing module and a second isolation module. The processing module is used to sample the output voltage, process it, and convert it into a 1-bit pulse density modulation signal. After being isolated by the second isolation module, it is connected to the frequency control terminal for real-time adjustment of the frequency of the two-dimensional PWM adjustment module. The fast-loop adjustment module and the slow-loop adjustment module act on the duty cycle control terminal and the frequency control terminal of the two-dimensional PWM adjustment module, respectively, forming two independent adjustment loops that can be linked together.

2. The dual-loop two-dimensional adjustable isolation switching power supply control system according to claim 1, characterized in that, The first isolation module in the fast-loop adjustment module is a first optocoupler module, and the filtering module is a low-pass filter module. The output voltage is transmitted to the primary side circuit through the isolation of the first optocoupler module, and after being filtered by the low-pass filter module, it is applied to the duty cycle control terminal of the two-dimensional PWM adjustment module.

3. The dual-loop two-dimensional adjustable isolation switching power supply control system according to claim 1, characterized in that, The second isolation module in the slow loop adjustment module is a second optocoupler module. The output terminal of the processing module is connected to the primary input terminal of the second optocoupler module, and the secondary output terminal of the second optocoupler module is directly connected to the frequency control terminal of the two-dimensional PWM adjustment module.

4. The dual-loop two-dimensional adjustable isolation switching power supply control system according to claim 1, characterized in that, The processing module includes: an analog-to-digital converter for sampling the output voltage; a difference calculation unit connected to the output of the analog-to-digital converter for comparing the sampled value of the output voltage with a reference voltage to generate an error signal; a DEM randomization processing unit connected to the output of the difference calculation unit for performing dynamic element matching randomization processing on the error signal to convert the error signal into a memoryless random distribution sequence; and a Sigma-Delta modulator connected to the output of the DEM randomization processing unit for converting the memoryless random distribution sequence into a 1-bit pulse density modulation signal.

5. The dual-loop two-dimensional adjustable isolation switching power supply control system according to claim 4, characterized in that, The DEM randomization processing unit is specifically a mismatch shaping filter.

6. The dual-loop two-dimensional adjustable isolation switching power supply control system according to claim 5, characterized in that, The mismatch shaping filter includes: The discretization module is used to discretize the error signal into at least one unit step size, map the error signal to the number of unit step sizes to be activated, and calculate the quantization error. A mismatch shaping filter, connected to the output of the discretization module, is used to perform mismatch shaping filtering on the quantization error, pushing the error energy from the low-frequency band to the high-frequency band; The random code disk construction and shuffling module is used to construct a binary array with a length of unit step and to randomly arrange the binary array using a pseudo-random sequence; The time-slot output and physical limiting module is used to sequentially extract one element from the arranged binary array and output it in each time-slot period, and to physically limit the output.

7. The dual-loop two-dimensional adjustable isolation switching power supply control system according to claim 1, characterized in that, The fast-loop adjustment module and the slow-loop adjustment module work together according to the linkage direction and linkage ratio; when the linkage coefficient is zero, the two loops work independently.

8. A dual-loop two-dimensional regulation isolation switching power supply control method, applied to the control system according to any one of claims 4 to 6, characterized in that, Includes the following steps: Step S1: Sample the output voltage, and transmit the output voltage to the sampling terminal of the processing module in the fast loop adjustment module and the slow loop digital adjustment module; Step S2: The fast-loop adjustment module transmits the output voltage to the primary side circuit through the first isolation module, and then filters it through the filter module before applying it to the duty cycle control terminal of the two-dimensional PWM adjustment module. This closed-loop adjustment of the output duty cycle of the two-dimensional PWM adjustment module changes the on-time of the power switch and adjusts the energy transferred from the isolation transformer to the secondary side circuit, thereby achieving rapid adjustment of the output voltage. Step S3: In the slow loop regulation module, the analog-to-digital converter of the processing module samples the output voltage. The difference calculation unit compares the output voltage with the reference voltage to generate an error signal. The DEM randomization processing unit randomizes the error signal. The Sigma-Delta modulator converts the processed signal into a 1-bit pulse density modulation signal. After being isolated and transmitted to the primary side circuit through the second isolation module, it drives the frequency control terminal of the two-dimensional PWM regulation module to adjust the frequency of the two-dimensional PWM regulation module, change the switching frequency of the power switch, and adjust the energy transferred to the secondary side circuit by the isolation transformer, thereby achieving high-precision steady-state regulation of the output voltage. Step S4: The fast loop adjustment module and the slow loop adjustment module work simultaneously, and the two loops coordinate to adjust the output voltage according to the linkage direction and linkage ratio; when the linkage coefficient is zero, the two loops work independently.

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