Improved composite voltage stabilizing circuit in high-precision power supply

Abstract

This invention discloses an improved composite voltage regulator circuit for high-precision power supplies, comprising a switching regulator circuit and a linear regulator circuit. The switching regulator circuit first performs power factor correction (PFC), outputting a DC voltage higher than 250V. Then, an isolated switching circuit converts the voltage to a DC voltage slightly higher than the downstream voltage, serving as the system's pre-regulation voltage. The linear regulator circuit acts as the second stage of regulation, feeding back the sampled signal through a feedback channel. After comparing the feedback signal with the set value, the signal is output to the regulating transistor. The regulating transistor adjusts the output voltage based on the error signal, resulting in a preliminary stable current / voltage. Both the switching and linear regulator circuits are programmable. The switching regulator circuit has low power consumption during adjustment, while the linear regulator has a short adjustment time. The adjustment takes into account the regulation characteristics of both circuits, intelligently adjusting the regulated voltage values ​​to achieve a balance between power consumption, accuracy, and adjustment speed. This solves many problems of traditional voltage regulator circuits, such as low regulation accuracy, lack of programmability, poor reliability, and slow response time.

Description

Technical Field

[0001] This invention relates to voltage regulator circuits, and more particularly to an improved composite voltage regulator circuit for high-precision power supplies. Background Technology

[0002] A voltage regulator circuit is an electronic circuit that converts an unstable DC voltage into a fixed, stable DC voltage. It is used to offset voltage deviations caused by input voltage fluctuations and load changes, and is widely used in power supplies, home appliances, industrial control equipment, and other devices.

[0003] In the existing technology, the traditional voltage regulation circuit scheme is implemented by using a transformer, rectifier module and voltage regulator module. The voltage regulation accuracy is low, it is not programmable, has poor reliability and slow response time.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] The purpose of this invention is to provide an improved composite voltage regulator circuit for high-precision power supplies to solve the aforementioned technical problems in the prior art.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] An improved composite voltage regulator circuit for high-precision power supplies includes a switching voltage regulator circuit and a linear voltage regulator circuit.

[0008] The switching regulator circuit first performs PFC power factor correction and outputs DC power higher than 250V. Then, it uses an isolated switching circuit to convert the voltage into DC voltage slightly higher than the downstream voltage as the pre-regulation voltage of the system.

[0009] The linear voltage regulator circuit serves as the second stage of voltage regulation. It feeds back the sampled signal through a feedback channel. After comparing the feedback signal with the set value, it outputs the signal to the regulating transistor. The regulating transistor adjusts the output voltage based on the error signal, and outputs a preliminary stable current / voltage.

[0010] Both the switching regulator circuit and the linear regulator circuit can be programmable. The switching regulator circuit has low power consumption during adjustment, while the linear regulator has a short adjustment time. The adjustment takes into account the voltage regulation characteristics of both circuits and intelligently adjusts the voltage values ​​between them to achieve a balance between power consumption, accuracy, and adjustment speed.

[0011] Compared with existing technologies, the improved composite voltage regulator circuit in the high-precision power supply provided by this invention has low power consumption for switching voltage regulator circuit adjustment and short adjustment time for linear voltage regulator. During adjustment, it intelligently adjusts the voltage value between the two by taking into account the voltage regulation characteristics of both, so as to achieve a perfect balance between power consumption, accuracy and adjustment speed. It solves many problems of traditional voltage regulator circuit schemes, which use transformer, rectifier module + voltage regulator module, resulting in low voltage regulation accuracy, lack of programmability, poor reliability and slow response time. Attached Figure Description

[0012] Figure 1 A schematic diagram of an improved composite voltage regulator circuit in a high-precision power supply is provided for embodiments of the present invention.

[0013] Figure 2 This is a schematic diagram of the full-bridge control and isolation rectifier circuit according to an embodiment of the present invention.

[0014] Figure 3 This is a schematic diagram of the PWM control circuit in an embodiment of the present invention.

[0015] Figure 4 This is a schematic diagram of an optocoupler isolation driving circuit according to an embodiment of the present invention.

[0016] Figure 5 This is a schematic diagram of a linear voltage regulator circuit according to an embodiment of the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them, and do not constitute a limitation on the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the protection scope of the present invention.

[0018] First, the following explanations are provided for the terms that may be used in this article:

[0019] The terms “including,” “contains,” “comprising,” “having,” or other similar semantic descriptions shall be interpreted as non-exclusive inclusion.

[0020] The term "composed of" excludes any technical feature elements not explicitly listed.

[0021] The technical solution provided by this invention will be described in detail below. Contents not described in detail in the embodiments of this invention are prior art known to those skilled in the art. Where specific conditions are not specified in the embodiments of this invention, they shall be performed according to conventional conditions in the art or conditions recommended by the manufacturer. Reagents or instruments used in the embodiments of this invention whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0022] like Figure 1 As shown, an improved composite voltage regulator circuit for a high-precision power supply includes a switching voltage regulator circuit and a linear voltage regulator circuit.

[0023] The switching regulator circuit first performs PFC power factor correction and outputs DC power higher than 250V. Then, it uses an isolated switching circuit to convert the voltage into DC voltage slightly higher than the downstream voltage as the pre-regulation voltage of the system.

[0024] The linear voltage regulator circuit serves as the second stage of voltage regulation. It feeds back the sampled signal through a feedback channel. After comparing the feedback signal with the set value, it outputs the signal to the regulating transistor. The regulating transistor adjusts the output voltage based on the error signal, and outputs a preliminary stable current / voltage.

[0025] Both the switching regulator circuit and the linear regulator circuit can be programmable. The switching regulator circuit has low power consumption during adjustment, while the linear regulator has a short adjustment time. The adjustment takes into account the voltage regulation characteristics of both circuits and intelligently adjusts the voltage values ​​between them to achieve a balance between power consumption, accuracy, and adjustment speed.

[0026] The switching regulator circuit comprises the following components:

[0027] EMI filters are used to filter out high-frequency interference noise in the power grid, allowing low-frequency signals to pass through smoothly. At the same time, they also prevent high-frequency harmonic signals generated by switching from feeding back into the power grid and causing interference.

[0028] PFC (Power Factor Correction) circuit: used to improve the power factor of the power supply and reduce harmonic pollution of the power grid by the instrument; it performs full-bridge rectification on the input AC power supply, and then uses the PFC control circuit to shape the input current waveform to make the voltage and current waveforms consistent, thereby improving the power factor of the instrument; after conversion by the PFC power factor correction circuit, a smoother DC power is obtained through filtering to supply the next stage of conversion.

[0029] Sampling circuit: Samples the voltage and current output from the output terminal, and obtains the sampling signal amplitude suitable for PWM circuit control through a voltage divider network and signal conditioning circuit, thus completing the sampling and signal conditioning for PWM control; based on the sampling values ​​obtained from the test circuit, it provides reference signals for various protection circuits, thereby providing protection measures.

[0030] PWM control circuit: generates the PWM control signal required for chopping; the PWM control circuit first samples the output through the sampling circuit, compares the sampled signal with the reference signal as a comparison value to obtain a certain error voltage; then amplifies the error signal and transmits the amplified error voltage to the pulse width modulator. The width of the PWM output pulse square wave will change with the change of the error voltage. After the pulse square wave passes through the frequency divider, it will generate two signals with opposite phases, thus completing the entire adjustment process;

[0031] Optical isolation drive circuit: Optical isolation electrical connections are used to achieve complete isolation between the input and output of the entire module, and to drive the high voltage signal of the regulating tube switch.

[0032] The linear voltage regulator circuit comprises: a regulating transistor, a feedback circuit, an error comparison circuit, and a filter;

[0033] The output power accuracy is 0.01%, and the power supply rejection ratio is 80dB to 100dB.

[0034] It also includes protection circuits, including hardware overvoltage and overcurrent protection circuits and software protection mechanisms.

[0035] In summary, the improved composite voltage regulator circuit in the high-precision power supply of this invention can be programmable for both switching voltage regulator circuit and linear voltage regulator circuit. The switching voltage regulator circuit has low power consumption, while the linear voltage regulator has a short adjustment time. When adjusting, the voltage regulation characteristics of both should be taken into account, and the voltage regulation value between the two should be intelligently adjusted to achieve a perfect balance between power consumption, accuracy and adjustment speed.

[0036] It solves many problems of traditional voltage regulation circuits, which use transformers, rectifier modules and voltage regulator modules, resulting in low voltage regulation accuracy, lack of programmability, poor reliability and slow response time.

[0037] To more clearly demonstrate the technical solution and its effects provided by the present invention, the improved composite voltage regulator circuit in the high-precision power supply provided by the present invention will be described in detail below with reference to specific embodiments.

[0038] Example 1

[0039] An improved composite voltage regulator circuit for high-precision power supplies combines traditional solutions with a design based on semiconductor switching devices.

[0040] like Figure 1 As shown:

[0041] The improved composite voltage regulator circuit in high-precision power supplies consists of two stages: a switching voltage regulator circuit and a linear voltage regulator circuit.

[0042] The principle of the improved composite voltage regulator circuit is as follows:

[0043] The switching regulator circuit first performs power factor correction (PFC), outputting a DC voltage higher than 250V. Then, using an isolated switching circuit structure, it converts the voltage to a DC voltage slightly higher than the downstream voltage, serving as the system's pre-regulation voltage. The linear regulator circuit acts as the second stage of regulation, feeding back the sampled signal through a feedback channel. After comparing the feedback signal with the set value, it outputs it to the regulating transistor. The regulating transistor adjusts the output voltage based on the error signal, resulting in a preliminary stable current / voltage.

[0044] The innovation of the invention lies in:

[0045] The improved composite voltage regulator circuit uses an isolated switching circuit structure as the pre-regulation of the power supply, and a linear voltage regulator circuit as the second-stage regulator. The sampled signal is fed back through a feedback channel and then output to the regulating transistor. Both the switching voltage regulator circuit and the linear voltage regulator circuit can be programmable. The switching voltage regulator circuit has low power consumption, while the linear voltage regulator has a short adjustment time. When adjusting, the voltage regulation characteristics of both circuits must be taken into account, and the voltage values ​​of the two circuits should be intelligently adjusted to achieve a perfect balance between power consumption, accuracy, and adjustment speed.

[0046] Switching regulator circuit:

[0047] This circuit converts AC power into a preset DC regulated current / voltage output, achieving pre-regulation. It not only achieves input-output isolation in a compact size but also allows for easy switching between voltage levels. Furthermore, the switching regulator circuit easily implements overheat protection, overcurrent protection, and overvoltage protection, improving circuit reliability.

[0048] The structure of a switching regulator circuit includes:

[0049] EMI filter: Its function is to filter out high-frequency interference noise in the power grid, allowing low-frequency signals to pass smoothly, while also preventing high-frequency harmonic signals generated by switching from feeding back into the power grid and causing interference to the power grid;

[0050] PFC (Power Factor Correction) Circuit: The PFC circuit is used to improve the power factor of the power supply and reduce harmonic pollution to the power grid. The input AC power supply is rectified by a full-bridge rectifier, and then the PFC control circuit shapes the input current waveform to ensure consistency between voltage and current waveforms, thereby improving the instrument's power factor. After conversion by the PFC circuit, a smoother DC power supply is obtained through filtering, which is then used for the next stage of conversion.

[0051] Full-bridge circuit:

[0052] Direct current (DC) is chopped into a square wave with a specific duty cycle. After chopping, the DC becomes high-frequency alternating current (AC), facilitating isolation, voltage reduction, and filtering. Chopping is the core of a high-frequency switching power supply. Higher chopping frequencies result in higher power conversion efficiency; however, as the chopping frequency increases, the switching losses of the power devices also rise. Therefore, it is necessary to select a suitable switching frequency to balance the switching losses of the power transistors and the efficiency of the magnetic components. The chopping topology has a significant impact on the ripple coefficient of the entire switching regulator output.

[0053] The chopper method selected is a full-bridge design, and its circuit diagram is as follows: Figure 2 As shown.

[0054] This structure has many advantages, such as simple structure, high DC voltage utilization, and easy control. The advantages are as follows:

[0055] The main circuit topology is relatively simple, but the control methods are varied.

[0056] High utilization rate of input DC voltage.

[0057] Sampling circuit: Samples the voltage and current output from the output terminal, and obtains the sampling signal amplitude suitable for PWM circuit control through a voltage divider network and signal conditioning circuit, thus completing the sampling and signal conditioning for PWM control; based on the sampling values ​​obtained from the test circuit, it provides reference signals for various protection circuits, thereby providing protection measures.

[0058] PWM Control Circuit: Generates the PWM control signal required for chopping. A switching power supply first chops the DC current into a square wave pulse with a constant period, then filters it back to DC. The amplitude and duty cycle of the square wave determine the output voltage. By changing the duty cycle of the square wave in each pulse cycle, the output voltage is adjusted to achieve the desired voltage value. The PWM control circuit generates the PWM control signal needed for chopping; this is the core circuit of the entire switching regulator. Its working principle is as follows: Figure 3 As shown.

[0059] The PWM control circuit first samples the output and compares the sampled signal with the reference signal to obtain a certain error voltage. Then, the error signal is amplified and the amplified error voltage is transmitted to the pulse width modulator. The width of the pulse square wave output by the PWM will change with the change of the error voltage. After the pulse square wave passes through the frequency divider, it will generate two signals with opposite phases, thus completing the entire adjustment process.

[0060] Optocoupler isolation drive circuit: To achieve control signal isolation, the power transistor also needs to be isolated and driven. This invention uses optocoupler isolation. Using optocoupler-isolated electrical connections achieves complete input-output isolation of the entire module, while simultaneously driving the high-voltage signal of the regulating transistor switch. This is significant for miniaturizing the module and enabling cascadable expansion of the instrument. The optocoupler isolation drive circuit is as follows: Figure 4 As shown.

[0061] Linear voltage regulator circuit: Employing a regulating transistor linear voltage regulator structure, this circuit performs secondary voltage regulation on the output of the switching regulator / current regulator, thereby improving output accuracy, reducing output noise, and achieving preliminary voltage / current regulation. Because of the pre-regulation by the switching regulator circuit, the regulating transistor linear voltage regulator structure eliminates the need for bulky transformers or rectifiers. Furthermore, the two-stage regulation significantly improves the accuracy and noise levels of the source output. Switching regulators typically have an accuracy of only 1% and a power supply rejection ratio (PSRR) of only 40dB. A transformer-rectifier + linear power supply typically achieves an accuracy of 0.1% and a PSRR of only 60dB. However, the improved linear voltage regulator structure of this invention achieves an accuracy of 0.01% and a PSRR of 80dB–100dB. The linear voltage regulator circuit is as follows: Figure 5 As shown.

[0062] Furthermore, both switching and linear voltage regulators can be programmable. Switching regulators have low power consumption during adjustment, while linear regulators have short adjustment times. Adjustment must consider the characteristics of both, intelligently adjusting the regulated voltage between them to achieve a perfect balance between power consumption, accuracy, and adjustment speed. The structure of a linear voltage regulator includes: a regulating transistor, a feedback circuit, an error comparator circuit, and a filter.

[0063] Protection Circuit: For power supply products, even short-lived overvoltage or overcurrent faults can cause devastating damage to the load connected to the power supply, and prolonged operation under overtemperature conditions can also damage internal components. Therefore, overvoltage, overcurrent, and overtemperature protection are crucial for the high reliability of a power supply. The hardware protection circuit adds an extra hardware monitoring circuit to monitor the power supply's output voltage and current in real time. When a fault occurs, it provides a fault protection signal and shuts down the PWM signal of the power semiconductor devices, thereby cutting off the output voltage and current. Hardware overvoltage and overcurrent protection can achieve very short times, providing excellent protection. Software protection can achieve very high protection accuracy, within 10mV and 10mA. However, limited by the sampling speed of high-precision ADCs, the effective action time of software protection may exceed 100ms. This time is unacceptable for sensitive loads, but it can serve as an effective backup protection mechanism. This invention combines the above advantages, employing a combination of hardware and software methods for protection.

[0064] The beneficial effects of the technical solution of this invention are as follows:

[0065] This invention solves many problems in traditional voltage regulator circuits, such as low voltage regulation accuracy, lack of programmability, poor reliability, and slow response time. The switching voltage regulator and linear voltage regulator in this invention can both be programmable. The switching voltage regulator has low power consumption during adjustment, while the linear voltage regulator has a short adjustment time. The adjustment process takes into account the voltage regulation characteristics of both, intelligently adjusting the voltage values ​​between them to achieve a perfect balance between power consumption, accuracy, and adjustment speed.

[0066] The components within the circuit designed in this invention can be replaced with similar components to achieve the same function.

[0067] Key technical points of this invention:

[0068] 1. The improved composite voltage regulator circuit structure and the control relationship between circuits.

[0069] 2. Both switching and linear voltage regulators can be programmable. Switching voltage regulators have low power consumption during adjustment, while linear voltage regulators have short adjustment time. When adjusting, the voltage regulation characteristics of both should be taken into account. The voltage values ​​of the two can be intelligently adjusted to achieve a perfect balance between power consumption, accuracy, and adjustment speed.

[0070] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims. The information disclosed in the background section is intended only to enhance the understanding of the overall background technology of the present invention and should not be construed as an admission or implication in any way that such information constitutes prior art known to those skilled in the art.

Claims

1. An improved composite voltage regulator circuit for high-precision power supplies, characterized in that, Including switching regulator circuits and linear regulator circuits; The switching regulator circuit first performs PFC power factor correction and outputs DC power higher than 250V. Then, it uses an isolated switching circuit to convert the voltage into DC voltage slightly higher than the downstream voltage as the pre-regulation voltage of the system. The linear voltage regulator circuit serves as the second stage of voltage regulation. It feeds back the sampled signal through a feedback channel. After comparing the feedback signal with the set value, it outputs the signal to the regulating transistor. The regulating transistor adjusts the output voltage based on the error signal, and outputs a preliminary stable current / voltage. Both the switching regulator circuit and the linear regulator circuit can be programmable. The switching regulator circuit has low power consumption during adjustment, while the linear regulator has a short adjustment time. The adjustment takes into account the voltage regulation characteristics of both circuits and intelligently adjusts the voltage values ​​between them to achieve a balance between power consumption, accuracy, and adjustment speed.

2. The improved composite voltage regulator circuit in a high-precision power supply according to claim 1, characterized in that, The switching regulator circuit comprises the following components: EMI filters are used to filter out high-frequency interference noise in the power grid, allowing low-frequency signals to pass through smoothly. At the same time, they also prevent high-frequency harmonic signals generated by switching from feeding back into the power grid and causing interference. PFC (Power Factor Correction) circuit: used to improve the power factor of the power supply and reduce harmonic pollution of the power grid by the instrument; it performs full-bridge rectification on the input AC power supply, and then uses the PFC control circuit to shape the input current waveform to make the voltage and current waveforms consistent, thereby improving the power factor of the instrument; after conversion by the PFC power factor correction circuit, a smoother DC power is obtained through filtering to supply the next stage of conversion. Sampling circuit: Samples the voltage and current output from the output terminal, and obtains the sampling signal amplitude suitable for PWM circuit control through a voltage divider network and signal conditioning circuit, thus completing the sampling and signal conditioning for PWM control; based on the sampling values ​​obtained from the test circuit, it provides reference signals for various protection circuits, thereby providing protection measures. PWM control circuit: generates the PWM control signal required for chopping; the PWM control circuit first samples the output through the sampling circuit, compares the sampled signal with the reference signal as a comparison value to obtain a certain error voltage; then amplifies the error signal and transmits the amplified error voltage to the pulse width modulator. The width of the PWM output pulse square wave will change with the change of the error voltage. After the pulse square wave passes through the frequency divider, it will generate two signals with opposite phases, thus completing the entire adjustment process; Optical isolation drive circuit: Optical isolation electrical connections are used to achieve complete isolation between the input and output of the entire module, and to drive the high voltage signal of the regulating tube switch.

3. The improved composite voltage regulator circuit in a high-precision power supply according to claim 2, characterized in that, The linear voltage regulator circuit comprises: a regulating transistor, a feedback circuit, an error comparison circuit, and a filter; The output power accuracy is 0.01%, and the power supply rejection ratio is 80dB to 100dB.

4. The improved composite voltage regulator circuit in a high-precision power supply according to any one of claims 1 to 3, characterized in that, It also includes protection circuits, including hardware overvoltage and overcurrent protection circuits and software protection mechanisms.

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