Simulation circuit and simulation chip of DC-DC converter

Abstract

The invention discloses a simulation circuit and a simulation chip of a DC-DC converter, the simulation circuit comprises a switch module, a feedback module, a voltage selection module and an error adjustment module, the feedback module collects a DC conversion voltage and outputs a feedback voltage; the voltage selection module outputs a starting signal when the input voltage is within a preset voltage range; when the error adjusting module receives the starting signal, a control signal is generated according to the feedback voltage and the reference voltage, and the switch module is adjusted through the control signal, so that the direct-current conversion voltage is a preset voltage value; according to the technical scheme, dynamic response modeling of closed-loop control can be realized, the consistency of a simulation result and an actual circuit behavior is effectively improved, the accuracy and reliability of a system design stage are improved, and the debugging cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of voltage conversion, and particularly relates to a simulation circuit and a simulation chip of a direct current-direct current converter. BACKGROUND

[0002] With the continuous development of power electronics technology and electronic circuit design, direct current-direct current converters are widely used in various electronic devices, such as central air conditioners, electric vehicles, power modules and the like. In order to improve the efficiency and accuracy of circuit design, more and more engineers introduce simulation technology in the early stage of design to estimate circuit performance and find potential problems. However, in the current mainstream simulation platforms (such as Pspice, LTspice, Simulink), although basic power module simulation models are provided, the tools for modeling the control characteristics of DC-DC converters are still limited, especially the behavior level modeling for specific IC chips is difficult. In the prior art, ideal switch models or fixed topology structures are mostly used for simplified simulation, which is difficult to reflect key characteristics such as negative feedback regulation and dynamic response in complex circuits, resulting in a large difference between the simulation results and the actual circuit performance. At the same time, the design of complex models often needs to manually adjust a large number of parameters, which is tedious and prone to errors, and lacks reusability, which is not conducive to popularization and use. SUMMARY

[0003] The embodiment of the present application provides a simulation circuit and a simulation chip of a direct current-direct current converter to solve the above technical problems.

[0004] The first aspect of the embodiment of the present application provides a simulation circuit of a direct current-direct current converter, comprising:

[0005] a switch module, one end of which is connected to an input voltage, and the other end of which outputs a direct current conversion voltage;

[0006] a feedback module, an input end of which is connected to the other end of the switch module, and the feedback module is configured to collect the direct current conversion voltage and output a feedback voltage;

[0007] a voltage selection module, an input end of which is connected to one end of the switch module, and the voltage selection module is configured to output a start signal when the input voltage is within a preset voltage range;

[0008] an error adjustment module, a control end of which is connected to an output end of the voltage selection module, a first input end of the error adjustment module is connected to an output end of the feedback module, a second input end of the error adjustment module receives a reference voltage, and an output end of the error adjustment module is connected to a control end of the switch module;

[0009] The error adjustment module is configured to generate a control signal according to the feedback voltage and the reference voltage when receiving the start signal, and adjust the switch module by the control signal so that the DC conversion voltage is a preset voltage value.

[0010] In the embodiment of the present application, by constructing a DC-DC converter simulation circuit including a switching module, a feedback module, a voltage selection module and an error adjustment module, the working mechanism of the DC-DC converter can be accurately simulated in the simulation platform, especially the key control processes such as negative feedback regulation, error amplification, dynamic response and input voltage judgment; compared with the existing solutions that only have idealized modeling functions, this solution can realize dynamic response modeling of closed-loop control, effectively improve the consistency between simulation results and actual circuit behavior, improve the accuracy and reliability of the system design stage, and reduce debugging costs. At the same time, the modular modeling method supports flexible parameter adjustment and rapid reuse, reduces the complexity of modeling and debugging, and improves system development efficiency and the applicability of simulation models.

[0011] In some embodiments, the voltage selection module includes:

[0012] A first power supply module is configured to output a high-level signal;

[0013] a voltage comparison module, whose input terminal is the input terminal of the voltage selection module, and the voltage comparison module is configured to output a high-level signal when the input voltage is within a preset voltage range, and output a low-level signal when the input voltage is not within the preset voltage range;

[0014] A multiplier module, wherein a first input end is connected to the output end of the first power supply module, and a second input end of the multiplier module is connected to the output end of the voltage comparison module. The multiplier module is configured to perform a multiplication operation on the signal output by the first power supply module and the signal output by the voltage comparison module to output or not output a start signal.

[0015] In the embodiment of the present application, by setting up a voltage selection module, effective identification of whether the input voltage is within a preset range is achieved, and the output of the start signal is controlled by the multiplier module, which triggers the subsequent control module to start only when the input voltage is normal, avoiding the problem of false start under abnormal voltage conditions and improving the reliability and stability of the system.

[0016] In some embodiments, the feedback module includes:

[0017] a first resistor module, a first end of which is an input end of the feedback module;

[0018] a second resistor module, a first end of which and a second end of the first resistor module are commonly connected to the output end of the feedback module, and a second end of the second resistor module is grounded;

[0019] The first resistance module and the second resistance module are configured to divide the DC conversion voltage to obtain and output the feedback voltage.

[0020] In the embodiment of the present application, by providing the first resistor module 121 and the second resistor module 122 to form a voltage divider circuit, effective sampling and voltage scaling of the DC conversion voltage are achieved, so that the feedback voltage stably falls within the voltage range recognizable by the control module, thereby ensuring the precise control of the error adjustment module 104 and improving the voltage regulation accuracy and stability of the entire DC-DC converter system.

[0021] In some embodiments, the error adjustment module includes:

[0022] A second power supply module is configured to provide a reference voltage;

[0023] An operational amplifier module, whose inverting input terminal is the first input terminal of the error adjustment module, the non-inverting input terminal of the operational amplifier module is connected to the second power supply module and constitutes the second input terminal of the error adjustment module, the output terminal of the operational amplifier module is the output terminal of the error adjustment module, and the operational amplifier module is configured to obtain the difference voltage between the feedback voltage and the reference voltage to generate a control signal.

[0024] In the embodiment of the present application, an error adjustment module is provided to enable the system to dynamically adjust in real time according to the deviation between the output feedback voltage and the set target voltage, thereby effectively improving the voltage regulation accuracy, response speed and system stability of the DC-DC converter, and ensuring that the output voltage is always maintained within the set range.

[0025] In some embodiments, the error adjustment module further includes:

[0026] A phase adjustment module is connected between the inverting input terminal and the output terminal of the operational amplifier module. The phase adjustment module is configured to compensate for the phase delay that occurs during the operation of the error adjustment module.

[0027] In the embodiment of the present application, by providing a phase adjustment module in the feedback path of the operational amplifier module, the phase delay occurring during the operation of the error adjustment module can be effectively compensated, the stability of the system can be enhanced, oscillation can be prevented, and the dynamic response characteristics can be optimized, thereby improving the voltage regulation performance of the DC-DC converter under load changes or input disturbances.

[0028] In some embodiments, the phase adjustment module includes:

[0029] a third resistor module, one end of which is connected to the output end of the operational amplifier module;

[0030] A first capacitor module has one end connected to the other end of the third resistor module, and the other end connected to the inverting input end of the operational amplifier module.

[0031] In the embodiment of the present application, by providing a third resistor module and a first capacitor module, the phase margin of the error adjustment module can be effectively improved, the control loop oscillation phenomenon can be suppressed, and the stability of the system during high-frequency operation can be enhanced; at the same time, the dynamic response performance of the power supply system can be optimized, overshoot and oscillation can be reduced, and the voltage regulation accuracy and robustness of the DC-DC converter can be improved.

[0032] In some embodiments, the simulation circuit further includes:

[0033] An overcurrent protection module is connected between the switch module and the feedback module. The overcurrent protection module is configured to adjust the conduction state of the switch module according to the current output by the switch module so that the current flowing through the switch module is a preset current value.

[0034] In the embodiment of the present application, by setting up an overcurrent protection module, the current flowing through the switch module can be detected in real time, and the conduction state of the switch module can be adjusted in time when the current exceeds a preset threshold, thereby effectively preventing overcurrent from damaging the device and improving the safety and stability of the system.

[0035] In some embodiments, the switch module includes:

[0036] a first triode module, wherein the collector of the first triode module is one end of the switch module, and the emitter of the first triode module is the other end of the switch module;

[0037] A fourth resistor module has one end connected to the base of the first transistor module, and the other end of the fourth resistor module is the control end of the switch module.

[0038] In the embodiment of the present application, by introducing a first transistor module and a fourth resistor module into the switch module, the current amplification characteristics of the transistor are utilized in conjunction with base current limiting control to achieve linear regulation capability of the output current, enabling the system to dynamically adjust the output state according to the error signal, thereby improving the voltage stability, load response speed and overall control accuracy of the DC-DC converter.

[0039] In some embodiments, the overcurrent protection module includes:

[0040] a second triode module, a collector of which is connected to one end of the fourth resistor module;

[0041] A fifth resistor module has one end connected to the emitter of the first transistor module and the base of the second transistor module respectively, and the other end of the fifth resistor module is connected to the emitter of the second transistor module and then connected to the input end of the feedback module.

[0042] In the embodiment of the present application, by providing a current limiting control structure composed of a second transistor module and a fifth resistor module, it is possible to automatically limit the output current to prevent overcurrent from damaging the main switching transistor or load devices; when the output current exceeds the set value, the second transistor module self-feedback suppresses the conduction state, so that the output current is stably maintained within a safe value range, realizing a dynamic, self-recovering overcurrent protection mechanism, and improving the safety and reliability of the system.

[0043] A second aspect of the present application provides a simulation chip of a DC-DC converter, wherein the simulation chip includes the simulation circuit described in the first aspect.

[0044] It can be understood that the beneficial effects of the second aspect mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0046] Figure 1 This is a first structural schematic diagram of a simulation circuit of a DC-DC converter provided in the first embodiment of the present invention;

[0047] Figure 2 This is a schematic structural diagram of a voltage selection module in a simulation circuit of a DC-DC converter provided in the first embodiment of the present invention;

[0048] Figure 3 1 is a schematic structural diagram of a feedback module in a simulation circuit of a DC-DC converter provided in a first embodiment of the present invention;

[0049] Figure 4 This is a schematic diagram of a first structure of an error adjustment module in a simulation circuit of a DC-DC converter provided in the first embodiment of the present invention;

[0050] Figure 5 This is a second structural diagram of an error adjustment module in a simulation circuit of a DC-DC converter provided in the first embodiment of the present invention;

[0051] Figure 6This is a third structural diagram of an error adjustment module in a simulation circuit of a DC-DC converter provided in the first embodiment of the present invention;

[0052] Figure 7 This is a second structural diagram of a simulation circuit of a DC-DC converter provided in the first embodiment of the present invention;

[0053] Figure 8 This is a structural diagram of a switch module in a simulation circuit of a DC-DC converter provided in the first embodiment of the present invention;

[0054] Figure 9 This is a structural diagram of the connection between a switch module and an overcurrent protection module in a simulation circuit of a DC-DC converter provided in the first embodiment of the present invention;

[0055] Figure 10 This is a circuit diagram of a simulation circuit of a DC-DC converter provided in the first embodiment of the present invention;

[0056] Figure 11 This is a simulation waveform diagram of a simulation circuit of a DC-DC converter provided in the first embodiment of the present invention;

[0057] Figure 12 This is another simulation waveform diagram of a simulation circuit of a DC-DC converter provided in the first embodiment of the present invention;

[0058] Figure 13 This is a schematic structural diagram of a simulation chip for a DC-DC converter provided in a second embodiment of the present invention;

[0059] In the figure: 101, switch module; 102, feedback module; 103, voltage selection module; 104, error adjustment module; 105, overcurrent protection module; 111, first transistor module; 112, fourth resistor module; 121, first resistor module; 122, second resistor module; 131, first power supply module; 132, voltage comparison module; 133, multiplier module; 141, operational amplifier module; 142, second power supply module; 143, phase adjustment module; 144, third resistor module; 145, first capacitor module; 151, second transistor module; 152, fifth resistor module. DETAILED DESCRIPTION

[0060] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0061] It should be understood that the present invention can be embodied in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to make the disclosure thorough and complete and to fully convey the scope of the invention to those skilled in the art. In the drawings, the dimensions and relative dimensions of layers and regions may be exaggerated for clarity. Like reference numerals denote like elements throughout.

[0062] It should be understood that when an element or layer is referred to as being "on," "adjacent to," "connected to," or "coupled to" another element or layer, it may be directly on, adjacent to, connected to, or coupled to the other element or layer, or there may be intervening elements or layers. Conversely, when an element is referred to as being "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" another element or layer, there may be no intervening elements or layers. It should be understood that although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers, and / or parts, these elements, components, regions, layers, and / or parts should not be limited by these terms. These terms are merely used to distinguish one element, component, region, layer, or part from another element, component, region, layer, or part. Thus, a first element, component, region, layer, or part discussed below may be represented as a second element, component, region, layer, or part without departing from the teachings of the present invention.

[0063] The purpose of the terms used herein is only to describe specific embodiments and is not intended to limit the present invention. When used herein, the singular forms "a", "an", and "the" are intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "comprising" and / or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0064] In order to fully understand the present invention, detailed structures and steps will be provided in the following description to illustrate the technical solutions proposed by the present invention. Preferred embodiments of the present invention are described in detail below. However, in addition to these detailed descriptions, the present invention may also have other implementations.

[0065] Example 1

[0066] This embodiment provides a simulation circuit of a DC-DC converter, such as Figure 1 As shown, including:

[0067] A switch module 101 , one end of which is connected to an input voltage VIN and the other end of which outputs a DC conversion voltage VOUT;

[0068] A feedback module 102 , whose input terminal is connected to the other end of the switch module 101 , and the feedback module 102 is configured to collect the DC conversion voltage VOUT and output a feedback voltage;

[0069] A voltage selection module 103 , whose input end is connected to one end of the switch module 101 , and the voltage selection module 103 is configured to output a start signal when the input voltage VIN is within a preset voltage range;

[0070] an error adjustment module 104 , wherein a control terminal of the error adjustment module 104 is connected to the output terminal of the voltage selection module 103 , a first input terminal of the error adjustment module 104 is connected to the output terminal of the feedback module 102 , a second input terminal of the error adjustment module 104 receives a reference voltage, and an output terminal of the error adjustment module 104 is connected to the control terminal of the switch module 101 ;

[0071] The error adjustment module 104 is configured to generate a control signal according to the feedback voltage and the reference voltage when receiving the start signal, and adjust the switch module 101 through the control signal so that the DC conversion voltage is a preset voltage value.

[0072] The switch module 101 performs the primary switching operation for power conversion, controlling the on / off switching of the input voltage to output a stable DC voltage. The switch module 101 receives a control signal from the error adjustment module 104 and adjusts the conduction level based on the control signal to achieve voltage regulation. The feedback module 102 monitors the DC conversion voltage at the output in real time and converts it into a feedback voltage signal, which is fed back to the error adjustment module 104. This provides the necessary input for closed-loop control, ensuring that the system adjusts to the actual output voltage. The voltage selection module 103 determines whether the input voltage is within a set operating range to prevent the system from starting when the input voltage is too high or too low. Only when the input voltage is within a safe and effective preset range does it output a start signal to activate the entire circuit. The error adjustment module 104 executes the core closed-loop control logic, comparing the difference between the feedback voltage and the reference voltage. Based on this difference, it generates a control signal, which is output to the control terminal of the switch module 101. This signal adjusts the conduction level, frequency, or duty cycle of the switch module 101, thereby regulating the DC conversion voltage to stabilize it at the target value corresponding to the reference voltage, achieving automatic voltage regulation.

[0073] The modules selected in the simulation system are as follows: Switch module 101 is used to control the on / off switching of the input DC voltage, thereby regulating the output voltage. In this embodiment, switch module 101 is modeled as a power MOSFET device in the simulation system. Its source is connected to ground, its drain is connected to the load circuit, and its control terminal (gate) receives the PWM control signal output by the error adjustment module 104 to control its on / off switching. Feedback module 102 is used to sample the DC voltage output by switch module 101 in real time. In this embodiment, feedback module 102 is modeled using a voltage divider network formed by two series resistors. Its input is connected to the output voltage node, and its output uses the voltage at the divider point as feedback voltage, which is sent to the error adjustment module 104. Voltage selection module 103 is used to output a start signal to the error adjustment module 104 when the input voltage is within a preset effective range. In this embodiment, voltage selection module 103 is modeled as a window comparator structure composed of a comparator, which compares the input voltage with a set upper and lower voltage limits. Only when the input voltage is between the upper and lower limits does the comparator output a high level, generating a start signal that is then output to the control terminal of the error adjustment module 104. The error adjustment module 104 is configured to generate a control signal based on the deviation between the reference voltage and the feedback voltage, and output the control signal to the switch module 101 to implement closed-loop regulation. In this embodiment, the error adjustment module 104 is modeled using an operational amplifier module, with the reference voltage and feedback voltage received at its input to form a differential amplifier loop. This simulation circuit enables dynamic simulation of the DC-DC conversion process and verification of the control process, providing an effective means for the design and debugging of DC-DC control systems.

[0074] The technical effect of the technical solution provided in the first embodiment is that: by constructing a DC-DC converter simulation circuit including a switching module, a feedback module, a voltage selection module and an error adjustment module, the working mechanism of the DC-DC converter can be accurately simulated in the simulation platform, especially the key control processes such as negative feedback adjustment, error amplification, dynamic response and input voltage judgment; compared with the existing solutions that only have idealized modeling functions, this solution can realize dynamic response modeling of closed-loop control, effectively improve the consistency between simulation results and actual circuit behavior, improve the accuracy and reliability of the system design stage, and reduce debugging costs. At the same time, the modular modeling method supports flexible parameter adjustment and rapid reuse, reduces the complexity of modeling and debugging, and improves system development efficiency and the applicability of simulation models.

[0075] As an implementation method, Figure 2 As shown, the voltage selection module 103 includes:

[0076] The first power supply module 131 is configured to output a high-level signal;

[0077] A voltage comparison module 132, whose input terminal is the input terminal of the voltage selection module 103, and the voltage comparison module 132 is configured to output a high-level signal when the input voltage is within a preset voltage range, and output a low-level signal when the input voltage is not within the preset voltage range;

[0078] The multiplier module 133 has a first input end connected to the output end of the first power supply module 131, and a second input end of the multiplier module 133 is connected to the output end of the voltage comparison module 132. The multiplier module 133 is configured to perform a multiplication operation on the signal output by the first power supply module 131 and the signal output by the voltage comparison module 132 to output or not output a start signal.

[0079] The first power supply module 131 is used to provide a constant high-level signal as a reference signal for use in the subsequent startup signal control logic. Regardless of the input voltage state, the first power supply module 131 always outputs a stable high-level signal, ensuring that the system can reliably generate a startup signal when the voltage comparison module 132 determines that the input is valid. The voltage comparison module 132 is used to determine whether the input voltage is within a preset voltage range. Its input terminal is connected to the input terminal of the voltage selection module 103 and receives the input voltage signal. When the input voltage is within the set normal operating range, the voltage comparison module 132 outputs a high-level signal; when the input voltage is below the lower threshold or above the upper threshold, the voltage comparison module 132 outputs a low-level signal. The multiplier module 133 is used to generate the final startup signal. Its first input terminal receives the high-level signal output by the first power supply module 131, and its second input terminal receives the judgment signal output by the voltage comparison module 132. The multiplier module 133 performs a multiplication operation on the two input signals: if the voltage comparison module 132 outputs a high level (value is 1), the multiplier outputs a high level (value is 1×1=1), that is, it outputs a start signal; if the voltage comparison module 132 outputs a low level (value is 0), the multiplier outputs a low level (value is 1×0=0), that is, it does not output a start signal.

[0080] The voltage selection module 103 includes: a first power supply module 131, a voltage comparison module 132, and a multiplier module 133, which can be modeled as follows in the simulation environment:

[0081] The first power supply module 131 provides a fixed logic-high signal (e.g., 5V or 3.3V) as the base input for the multiplier module 133. In PSpice simulation, a constant DC voltage source is used, set to DC = 5V or 3.3V. In Simulink, a constant block is used, with a value set to 1 (normalized) or 5V. The output is a constant high level, always valid regardless of the input voltage. The voltage comparison module 132 detects whether the input voltage is within the set upper and lower voltage limits; it outputs a high level if it is within the range and a low level if it is outside the range. If a SPICE-type simulator is used, a window comparator structure can be constructed using two comparators. The upper comparator is an op amp with its positive input connected to the input voltage and its negative input connected to the set upper voltage limit. When the input voltage is less than the upper limit, it outputs a high level. The lower comparator is an op amp with its negative input connected to the input voltage and its positive input connected to the set lower voltage limit. When the input voltage is greater than the lower voltage limit, it outputs a high level. The two outputs are connected via an AND gate (implemented using MOS or a simple multiplication scheme), which outputs a high level only when the input voltage is between the upper and lower limits. If using Simulink, two comparison modules are used to determine whether the value is greater than the lower limit or less than the upper limit; then a logical AND module is used to obtain the final judgment result (1 or 0). The multiplier module 133 receives the output signals of the first power supply module 131 and the voltage comparison module 132 and performs a multiplication operation. Simulation modeling method: There is no native multiplier module 133 in SPICE, so a controlled voltage source (such as an E element) can be used to simulate the multiplier output. In Simulink, a product module is used to directly implement the product calculation of the two inputs. A high-level start signal is output only when the input voltage is valid, otherwise the output is 0.

[0082] The technical effect of this embodiment is that by setting up a voltage selection module, it is possible to effectively identify whether the input voltage is within a preset range, and by controlling the output of the start signal through the multiplier module, the subsequent control module is triggered to start only when the input voltage is normal, avoiding the problem of false start-up under abnormal voltage conditions, and improving the reliability and stability of the system.

[0083] As an implementation method, Figure 3 As shown, the feedback module 102 includes:

[0084] A first resistor module 121 , a first end of which is an input end of the feedback module 102 ;

[0085] A second resistor module 122, a first end of which and a second end of the first resistor module 121 are connected to the output end of the feedback module 102, and a second end of the second resistor module 122 is grounded;

[0086] The first resistance module 121 and the second resistance module 122 are configured to divide the DC conversion voltage to obtain and output a feedback voltage.

[0087] The feedback module 102 includes a first resistor module 121 and a second resistor module 122, which are connected in series to form a voltage divider circuit for scaling the output voltage of the DC converter and outputting a feedback voltage signal to the error adjustment module 104 to achieve closed-loop voltage regulation control. The first end of the first resistor module 121 is the input end of the feedback module 102, which is connected to the output end of the switch module 101, that is, receives the DC conversion voltage (Vout). The second end of the first resistor module 121 is connected to the first end of the second resistor module 122, forming a voltage divider node for the feedback voltage. The second end of the second resistor module 122 is grounded to complete the voltage divider path. In a simulation system (such as LTspice or Simulink), the first resistor module 121 and the second resistor module 122 are both modeled as ideal resistor elements; one end of the first resistor module 121 is connected to the output voltage node, and the other end of the second resistor module 122 is grounded; the middle connection point between the two is the feedback voltage node, which can be connected to the error adjustment module 104 for closed-loop comparison.

[0088] The technical effect of this embodiment is that by providing the first resistor module 121 and the second resistor module 122 to form a voltage divider circuit, effective sampling and voltage scaling of the DC conversion voltage are achieved, so that the feedback voltage is stably within the voltage range recognizable by the control module, thereby ensuring the precise control of the error adjustment module 104 and improving the voltage regulation accuracy and stability of the entire DC-DC converter system.

[0089] As an implementation method, Figure 4 As shown, the error adjustment module 104 includes:

[0090] A second power supply module 142 is configured to provide a reference voltage;

[0091] The operational amplifier module 141 has an inverting input terminal that serves as the first input terminal of the error adjustment module 104. The non-inverting input terminal of the operational amplifier module 141 is connected to the second power supply module 142 and constitutes the second input terminal of the error adjustment module 104. The output terminal of the operational amplifier module 141 serves as the output terminal of the error adjustment module 104. The operational amplifier module 141 is configured to obtain a difference voltage between the feedback voltage and the reference voltage to generate a control signal.

[0092] Among them, the second power supply module 142 is used to provide a constant reference voltage signal as the target reference voltage for error judgment. In this embodiment, the reference voltage can be a stable voltage value set by the system, and its output is connected to the non-inverting input terminal of the operational amplifier module 141, serving as the second input terminal of the error adjustment module 104. In the simulation system, the second power supply module 142 can be modeled as a constant voltage source (such as Vref in LTspice or the constant module in Simulink) for stably outputting a preset voltage value. The operational amplifier module 141 is the core unit of the error adjustment module 104, used to compare the feedback voltage with the reference voltage and output a control signal based on the difference between the two. The inverting input terminal of the operational amplifier module 141 is the first input terminal of the error adjustment module 104, receiving the feedback voltage signal from the feedback module 102; the non-inverting input terminal is connected to the second power supply module 142, receiving the reference voltage signal; its output terminal is the output terminal of the error adjustment module 104, outputting the control signal to the switch module 101. In the PSpice system modeling, the operational amplifier module 141 can be modeled using an ideal operational amplifier model; in the Simulink system, an adder, a gain block, and a transfer function module or a PID controller module can be used for modeling, and the output error signal is used as the power switch control signal source.

[0093] The technical effect of this embodiment is that by setting the error adjustment module 104, the system can be dynamically adjusted in real time according to the deviation between the output feedback voltage and the set target voltage, thereby effectively improving the voltage regulation accuracy, response speed and system stability of the DC-DC converter, and ensuring that the output voltage is always maintained within the set range.

[0094] As an implementation method, Figure 5 As shown, the error adjustment module 104 further includes:

[0095] The phase adjustment module 143 is connected between the inverting input terminal and the output terminal of the operational amplifier module 141 . The phase adjustment module 143 is configured to compensate for the phase delay that occurs during the operation of the error adjustment module 104 .

[0096] The phase adjustment module 143 is used to improve the dynamic response characteristics of the error adjustment module 104 during closed-loop control. Specifically, it adjusts the phase characteristics of the negative feedback path of the operational amplifier module 141 to enhance the system's phase margin, improving the system's stability and anti-oscillation capability. This module is connected between the inverting input and output of the operational amplifier module 141, forming a negative feedback loop. Its structure typically consists of a series or parallel resistor and capacitor, forming a proportional-integral (PI) or proportional-integral-differential (PID) compensation network. By adjusting the pole and zero distribution of the feedback network, the system's open-loop gain and phase response are optimized. Specific functions include: improving the mid-frequency phase response by introducing zeros to prevent the system from experiencing premature phase lead in the high-frequency range and avoiding oscillation; enhancing the system's phase safety distance near the unity-gain crossover frequency to ensure stable control under sudden load changes or input disturbances; and improving system response speed while ensuring system stability, reducing output voltage overshoot and adjustment time. If the error adjustment module 104 lacks compensation, the response to a certain frequency range may be delayed (e.g., by 135°), resulting in a very small overall phase margin. This means that if the input voltage is disturbed or the load changes, the system may self-oscillate or lose control. By adding a phase adjustment module (e.g., by adding an RC network to the amplifier feedback terminal), the phase delay can be partially compensated (e.g., by only 90°), resulting in a more stable control system with a shorter recovery time and stronger anti-interference capabilities.

[0097] The technical effect of this embodiment is that by setting the phase adjustment module 143 in the feedback path of the operational amplifier module 141, the phase margin of the error adjustment module 104 can be effectively improved, the phase delay can be compensated, the stability of the system can be enhanced, and oscillation can be prevented. At the same time, the dynamic response characteristics can be optimized, and the voltage regulation performance of the DC-DC converter under load changes or input disturbances can be improved.

[0098] As an implementation method, Figure 6 As shown, the phase adjustment module 143 includes:

[0099] A third resistor module 144 , one end of which is connected to the output end of the operational amplifier module 141 ;

[0100] The first capacitor module 145 has one end connected to the other end of the third resistor module 144 , and the other end connected to the inverting input end of the operational amplifier module 141 .

[0101] Among them, the third resistor module 144 is used to construct a negative feedback path and is connected in series with the first capacitor module 145 to form an RC phase compensation network. In the system frequency response analysis, the third resistor module 144 and the first capacitor module 145 jointly determine the position of the compensation zero point, and their resistance values ​​affect the frequency range of the phase advance in the control loop. Reasonable selection of this resistance value can enable the system to have sufficient phase margin near the unity gain crossover frequency, thereby avoiding oscillation of the system due to insufficient advance. In the simulation platform, the third resistor module 144 can be modeled as a standard resistor element, such as the resistor in the PSpice system modeling, or using a resistor module in the Simulink environment. The first capacitor module 145 can be modeled as a standard capacitor element, such as the capacitor in SPICE or the capacitor module in Simulink.

[0102] The technical effect of this embodiment is that, by providing the third resistor module 144 and the first capacitor module 145, the phase margin of the error adjustment module 104 can be effectively improved, the control loop oscillation can be suppressed, and the stability of the system during high-frequency operation can be enhanced. At the same time, the dynamic response performance of the power supply system can be optimized, overshoot and oscillation can be reduced, and the voltage regulation accuracy and robustness of the DC-DC converter can be improved.

[0103] As an implementation method, Figure 7 As shown, the simulation circuit also includes:

[0104] The overcurrent protection module 105 is connected between the switch module 101 and the feedback module 102 . The overcurrent protection module 105 is configured to adjust the conduction state of the switch module 101 so that the current flowing through the switch module 101 is a preset current value.

[0105] Among them, the overcurrent protection module 105 is used to monitor the current in the switch module 101 in real time and adjust the conduction state of the switch module 101 when the current exceeds a preset threshold, thereby limiting the current size and preventing the circuit from damaging the device or causing system instability due to overcurrent. The overcurrent protection module 105 is set between the switch module 101 and the feedback module 102, and can collect the main current path signal flowing through the switch device (such as MOSFET or IGBT) in real time and compare the signal with the set current threshold: when the current in the switch module 101 does not exceed the preset value, the overcurrent protection module 105 does not interfere with the switch control and the system operates normally; when the current exceeds the preset current value, the overcurrent protection module 105 outputs a shutdown signal to limit the switch module 101 from continuing to conduct, thereby reducing the current and achieving the protection purpose. The overcurrent protection module 105 can be implemented in conjunction with a current sampling resistor, a current detection amplifier, a Hall element, or a transistor, and can dynamically adjust the conduction or shutdown of the switch module 101 based on the feedback, thereby forming a closed-loop current limiting logic.

[0106] The technical effect of this embodiment is that by setting the overcurrent protection module 105, the current flowing through the switch module 101 can be detected in real time, and the conduction state of the switch module 101 can be adjusted in time when the current exceeds the preset threshold, thereby effectively preventing overcurrent from damaging the device and improving the safety and stability of the system.

[0107] As an implementation method, Figure 8 As shown, the switch module 101 includes:

[0108] A first triode module 111, whose collector is one end of the switch module 101 and whose emitter is the other end of the switch module 101;

[0109] One end of the fourth resistor module 112 is connected to the base of the first transistor module 111 , and the other end of the fourth resistor module 112 is the control end of the switch module 101 .

[0110] The first transistor module 111 is an NPN transistor. Its collector is one end of the switch module 101 and is connected to the power supply. Its emitter is the other end of the switch module 101 and is connected to the load or output node. This transistor acts as a linear amplification regulator, controlling its collector current based on its base current to adjust the output voltage. During the control process, the error adjustment module 104 compares the reference voltage with the feedback voltage and outputs a difference voltage. This voltage is driven by the second stage and applied to the transistor base. The transistor's collector current Ic is determined by the base current Ib, satisfying the following: Ic = Ib × β. Simulation modeling method: In PSpice system modeling, a standard NPN transistor model is used. Its β value is set (typically 200 to 1000) to simulate its current amplification characteristics. In Simulink, an NPN transistor module can be used and parameters such as β and saturation voltage can be set. Fourth resistor module 112 is connected between the base and control terminal of first transistor module 111. One end of the resistor is connected to the base, and the other end is connected to the control terminal of switch module 101 (i.e., it receives the voltage signal from the error amplifier). This resistor acts as an emitter-level current-limiting resistor, controlling the current applied to the transistor base, thereby indirectly controlling the main current path. Simulation modeling method: In PSpice system modeling, standard resistor elements are used; in Simulink, resistor modules are used.

[0111] The technical effect of this embodiment is that by introducing the first transistor module 111 and the fourth resistor module 112 into the switch module 101, the current amplification characteristics of the transistor are combined with the base current limiting control to achieve linear regulation of the output current, enabling the system to dynamically adjust the output state according to the error signal, thereby improving the voltage stability, load response speed and overall control accuracy of the DC-DC converter.

[0112] As an implementation method, Figure 9 As shown, the overcurrent protection module 105 includes:

[0113] The second triode module 151 has a collector connected to one end of the fourth resistor module 112;

[0114] One end of the fifth resistor module 152 is connected to the emitter of the first transistor module 111 and the base of the second transistor module 151 . The other end of the fifth resistor module 152 and the emitter of the second transistor module 151 are connected to the input end of the feedback module 102 .

[0115] The second transistor module 151 is an NPN transistor, used to monitor the voltage across the fifth resistor module 152. When the output current is excessive (i.e., the current flowing through the fifth resistor exceeds the set value), the voltage drop across the resistor exceeds the transistor conduction threshold (approximately 0.6-0.7V), causing the second transistor module 151 to conduct, reducing the base current of the first transistor module 111, causing it to cut off and thus interrupting the main current path. This negative feedback action automatically limits the output current to a preset value, achieving dynamic current limiting. Simulation modeling methods: In PSpice system modeling, a standard NPN transistor model is used; in Simulink system modeling, an NPN transistor module is used, with an appropriate conduction voltage and β value set. The fifth resistor module 152 is placed between the emitter of the first transistor module 111 and the system output (i.e., the input of the feedback module 102) to sample the output current in real time. When the output current is lower than the preset value, the voltage drop across the fifth resistor module 152 is insufficient to turn on the second transistor module 151, allowing the first transistor module 111 to conduct normally and the system output voltage to remain normal. Once the output current exceeds the set value, the base-emitter voltage difference of the second transistor module 151 exceeds the conduction threshold, causing the second transistor module 151 to begin conducting, thereby limiting the base drive current of the first transistor module 111 and turning off the first transistor module 111. This reduces the output current and causes the second transistor module 151 to turn off again, forming a dynamic self-recovery current limiter. Simulation modeling method: In the PSpice system modeling, it is modeled as a normal resistor element, connected in series between the emitter of the first transistor module 111 and the output path; in the Simulink system modeling, a resistor module is used, connected to the output terminal in the current path, and its voltage drop is calculated to control the conduction behavior of the second transistor module 151.

[0116] The technical effect of this embodiment is that: by setting up a current limiting control structure composed of the second transistor module 151 and the fifth resistor module 152, it is possible to automatically limit the output current to avoid overcurrent damage to the main switch transistor or load devices; when the output current exceeds the set value, the second transistor module 151 self-feedback suppresses the conduction state, so that the output current is stably maintained within a safe value range, realizing a dynamic, self-recovering overcurrent protection mechanism, and improving the safety and reliability of the system.

[0117] As an implementation to further enhance the system's adaptability and flexibility, the error adjustment module's reference voltage is provided by an adjustable reference voltage generation module instead of a fixed reference source. This module dynamically adjusts the reference voltage based on external input or control parameters, adapting to different output voltage targets and improving the versatility of the simulation system.

[0118] The adjustable reference voltage generation module may include: a voltage source module (such as a DAC module); a control logic unit (such as a microcontroller); and a voltage selection interface (such as a switch dial, an analog voltage input, or a digital bus control interface).

[0119] The control process is as follows: according to the preset target output voltage, the target reference value is set; the control logic converts the set value into an analog voltage; the analog voltage is sent to the error adjustment module as a new reference voltage; the error adjustment module performs closed-loop comparison control based on the new reference voltage and the feedback voltage.

[0120] The technical effect of this embodiment is that: this embodiment allows the same simulation circuit to adapt to multiple output target requirements, improves the reuse capability and adaptability of the simulation chip, is suitable for modeling and simulation of multi-voltage level DC-DC control chips, and enhances the versatility and flexibility of the chip.

[0121] As an implementation method, based on the existing voltage selection module, this implementation method introduces a delayed start unit to control the output delay of the start signal to ensure that the subsequent module is triggered to start after the input voltage stabilizes, thereby preventing misjudgment caused by voltage jitter or interference.

[0122] The delayed start unit may include: a monostable trigger, an RC delay network, and a programmable timer module.

[0123] The working process is as follows: when the voltage comparison module determines that the input voltage is within the valid range, it outputs a high level; the start signal enters the delay start module; after the delay module timing reaches the set time, the start signal is transmitted to the error adjustment module; if the input voltage falls out of the valid range during the delay period, the delay timing is canceled or reset to avoid false start.

[0124] The technical effect of this embodiment is that the structure effectively enhances the robustness of input voltage judgment, avoids frequent system startup at the initial power-on or when voltage fluctuates, improves system stability and reliability of the startup process, and is particularly suitable for DC-DC chip modeling with high requirements for startup accuracy and anti-interference.

[0125] The present embodiment is described in detail below through a specific circuit structure: Figure 10 As shown, the first transistor module 111 is a transistor Q1, the fourth resistor module 112 is a resistor R6, the second transistor module 151 is a transistor Q2, the fifth resistor module 152 is a resistor R5, the first power supply module 131 is a battery V1, the voltage comparison module 132 is a comparator U2, the multiplier module 133 is a multiplier U3, the first resistor module 121 is a resistor R3, the second resistor module 122 is a resistor R4, the operational amplifier module 141 is an operational amplifier U1, the second power supply module 142 is a battery V2, the third resistor module 144 is a resistor R2, the first capacitor module 145 is a capacitor C1, the resistor R7 is a load, and the battery V3 provides the input voltage.

[0126] The specific working mode of this circuit structure is as follows: This embodiment provides a DC-DC converter simulation circuit, which mainly includes a switch module, a feedback module, a voltage selection module, an error adjustment module, and an overcurrent protection module. The output voltage adjustment and control process of the simulation circuit is as follows:

[0127] 1. The feedback module performs DC conversion voltage division sampling:

[0128] The DC conversion voltage Vout is sampled through a voltage divider network formed by resistors R3 and R4 to form a feedback voltage Vfb, satisfying the following relationship: Vout = Vfb × (1 + R3 / R4). For example, a negative feedback voltage Vfb of 2.5V corresponds to Vout = 5V (when R3 = R4 = 1kΩ).

[0129] 2. The error adjustment module performs error detection and amplification:

[0130] The error adjustment module includes a PSpice-emulated operational amplifier U1, which implements the error detection function. One input receives the reference voltage Vref, and the other receives the feedback voltage Vfb. The difference (ΔV) between the two is amplified by the open-loop gain Aol to form the adjustment drive signal. This process satisfies:

[0131] The difference voltage ΔV = (Vref - Vfb) × Aol (open-loop gain), (for example, Aol = 10^5, and the driver current changes by 1mA for every 1mV change in ΔV).

[0132] 3. Error adjustment module performs current regulation and output control:

[0133] The difference voltage ΔV is amplified in the second stage and used to drive the base current Ib of the adjustment transistor Q1, specifically satisfying:

[0134] The base current Ib = ΔV / Re, Re is the emitter resistance, and the collector current Ic = β×Ib.

[0135] 4. Simulate the circuit to adjust the load dynamic response:

[0136] In the event of a sudden change in the current across load resistor R7, the simulation circuit can achieve dynamic voltage response regulation. For example, when the load current suddenly increases by 100mA, the output voltage Vout will instantly drop by approximately 50mV (with an equivalent output impedance of approximately 0.5Ω), and the feedback voltage Vfb will simultaneously drop to 2.23V. Operational amplifier U1 generates ΔV = 20mV. Assuming the emitter resistor Re is 10kΩ, the base drive current increases to: ΔIb = 20mV / 10kΩ = 2μA, and the collector current Ic increases by ΔIc = β × ΔIb = 2000 × 2μA = 4mA. The response time is limited by the compensation capacitor and can be adjusted according to the actual system conditions. Dynamic response allows for real-time adjustment to achieve a stable output voltage.

[0137] 5. Overcurrent protection module implements overcurrent protection mechanism:

[0138] To prevent device damage caused by excessive output current, this simulation circuit designs an overcurrent protection module based on transistors Q1 and Q2 and resistor R5. Its working principle is as follows:

[0139] When the output current is lower than the preset threshold value XmA, transistor Q1 is turned on and transistor Q2 is turned off. At this time, due to the small voltage across resistor R5, the voltage difference between the base and emitter of transistor Q2 is insufficient to drive it to turn on.

[0140] When the output current exceeds XmA, the voltage across resistor R5 increases, turning on transistor Q2. Its collector current rapidly reduces the base current of transistor Q1, causing transistor Q1 to turn off. If transistor Q1 is turned off, transistor Q2 will also turn off due to the lack of continuous drive current. The above process will occur repeatedly, thereby limiting the output current to near XmA and entering the current limiting maintenance state to ensure safe operation of the system.

[0141] The above control process fully describes the entire closed-loop control process from error detection and signal conditioning to dynamic response and overcurrent protection. It is suitable for modeling DC-DC converter control ICs and used in verification environments in simulation platforms such as PSpice. The simulation structure design has good adjustability and versatility.

[0142] like Figure 11 and Figure 12The following are simulation results of the DC-DC converter simulation circuit of the present invention under different load conditions. The following is a summary of the simulation data of these two figures, which can illustrate the performance characteristics and overcurrent protection effect of the simulation circuit:

[0143] like Figure 11 As shown, the input voltage is 24V, the load is 50Ω (normal working state), the output voltage is about 5V; the output current is about 100mA; the feedback voltage Vfb is about 2.5V; the system status is stable, the feedback regulation is effective, and the output voltage fluctuation is small; the error amplifier and compensation network control are normal; the overcurrent protection mechanism is not triggered.

[0144] like Figure 12 As shown in the figure, the input voltage is 24V, the load is 5Ω (overload state), the theoretical load current is about 1000mA (5V / 5Ω), the actual output current is about 508mA, the output voltage drops slightly, and remains in the safe range. The system status is: the overcurrent protection mechanism is triggered. When the output current exceeds the set threshold (such as 500mA), the transistor Q1 / Q2 protection circuit in the simulation takes effect, limiting the output current to about 508mA to prevent further increase. The feedback and control module still maintains the regulation function, but the control is intervened by the protection circuit.

[0145] These simulation results verify the closed-loop stability and overcurrent protection capabilities of this technical solution under different load conditions, effectively improving the practicality and engineering reference value of the simulation model.

[0146] Example 2

[0147] The second embodiment provides a simulation chip of a DC-DC converter, and the simulation chip includes the simulation circuit provided in the first embodiment.

[0148] like Figure 13 As shown in the figure, from the internal block point of view, PIN 1 is the input voltage, PIN 2 is the output voltage, and PIN 3 is connected to GND.

[0149] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the scope of protection of the present invention.

Claims

1. A simulation circuit of a DC-DC converter, characterized in that: include: A switch module, one end of which is connected to the input voltage and the other end of which outputs the DC conversion voltage; a feedback module, an input end of which is connected to the other end of the switch module, and the feedback module is configured to collect the DC conversion voltage and output a feedback voltage; a voltage selection module, whose input end is connected to one end of the switch module, and the voltage selection module is configured to output a start signal when the input voltage is within a preset voltage range; an error adjustment module, wherein a control end of the error adjustment module is connected to the output end of the voltage selection module, a first input end of the error adjustment module is connected to the output end of the feedback module, a second input end of the error adjustment module receives a reference voltage, and an output end of the error adjustment module is connected to the control end of the switch module; The error adjustment module is configured to generate a control signal according to the feedback voltage and the reference voltage when receiving the start signal, and adjust the switch module by the control signal so that the DC conversion voltage is a preset voltage value.

2. The simulation circuit according to claim 1, wherein: The voltage selection module includes: A first power supply module is configured to output a high-level signal; a voltage comparison module, whose input terminal is the input terminal of the voltage selection module, and the voltage comparison module is configured to output a high-level signal when the input voltage is within a preset voltage range, and output a low-level signal when the input voltage is not within the preset voltage range; A multiplier module, wherein a first input end is connected to the output end of the first power supply module, and a second input end of the multiplier module is connected to the output end of the voltage comparison module. The multiplier module is configured to perform a multiplication operation on the signal output by the first power supply module and the signal output by the voltage comparison module to output or not output a start signal.

3. The simulation circuit according to claim 1, wherein: The feedback module includes: a first resistor module, a first end of which is an input end of the feedback module; a second resistor module, a first end of which and a second end of the first resistor module are commonly connected to the output end of the feedback module, and a second end of the second resistor module is grounded; The first resistance module and the second resistance module are configured to divide the DC conversion voltage to obtain and output the feedback voltage.

4. The simulation circuit according to claim 1, wherein: The error adjustment module includes: A second power supply module is configured to provide a reference voltage; An operational amplifier module, whose inverting input terminal is the first input terminal of the error adjustment module, the non-inverting input terminal of the operational amplifier module is connected to the second power supply module and constitutes the second input terminal of the error adjustment module, the output terminal of the operational amplifier module is the output terminal of the error adjustment module, and the operational amplifier module is configured to obtain the difference voltage between the feedback voltage and the reference voltage to generate a control signal.

5. The simulation circuit according to claim 4, wherein: The error adjustment module further includes: A phase adjustment module is connected between the inverting input terminal and the output terminal of the operational amplifier module. The phase adjustment module is configured to compensate for the phase delay that occurs during the operation of the error adjustment module.

6. The simulation circuit according to claim 5, wherein: The phase adjustment module includes: a third resistor module, one end of which is connected to the output end of the operational amplifier module; A first capacitor module has one end connected to the other end of the third resistor module, and the other end connected to the inverting input end of the operational amplifier module.

7. The simulation circuit according to claim 1, wherein: The simulation circuit further includes: An overcurrent protection module is connected between the switch module and the feedback module. The overcurrent protection module is configured to adjust the conduction state of the switch module according to the current output by the switch module so that the current flowing through the switch module is a preset current value.

8. The simulation circuit according to claim 7, wherein: The switch module includes: a first triode module, wherein the collector of the first triode module is one end of the switch module, and the emitter of the first triode module is the other end of the switch module; A fourth resistor module has one end connected to the base of the first transistor module, and the other end of the fourth resistor module is the control end of the switch module.

9. The simulation circuit according to claim 8, wherein: The overcurrent protection module includes: a second triode module, a collector of which is connected to one end of the fourth resistor module; A fifth resistor module has one end connected to the emitter of the first transistor module and the base of the second transistor module respectively, and the other end of the fifth resistor module is connected to the emitter of the second transistor module and then connected to the input end of the feedback module.

10. A DC-DC converter simulation chip, characterized in that: The simulation chip includes the simulation circuit according to any one of claims 1 to 9.

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