A small-signal reference source and voltage stabilizing circuit

Abstract

The utility model discloses a small signal reference source and voltage stabilizing circuit, including by triode Q1 and resistance R1 constitute's output drive circuit, and reference voltage source U1, triode Q1's collector connects input voltage VIN, and emitter as voltage stabilizing output end VOUT (output >2.5V voltage), and reference voltage source U1 output end is connected with triode Q1 base, and resistance R1 is established between triode Q1 base and collector, and the second signal input of reference voltage source U1 is with voltage stabilizing output end VOUT and is established by resistance R2~resistance R5 constitute's voltage divider circuit, and the first signal input of reference voltage source U1 is connected with the connecting node of resistance R3 and resistance R4, and the connecting node of resistance R4 and resistance R5 is small signal reference source VREF (output <2.5V voltage). The circuit structure is simple, and the cost is low, and the precision is high, realizes voltage stabilizing and small signal reference source double -output linkage steady, adapts multiple scene demand.

Description

Technical Field

[0001] This utility model relates to the field of constant current output control technology for intelligent power supplies or ordinary power supplies, specifically to a small signal reference source and voltage regulator circuit. Background Technology

[0002] In constant current output control scenarios for both intelligent and conventional power supplies, the reference source and voltage regulator are core components, directly impacting the power supply's control performance and cost. Current technologies suffer from the following significant drawbacks: 1. The reference source voltage is singular and lacks accuracy. Existing reference sources are mostly designed based on standard reference devices (such as voltage regulators with an internal reference fixed at 2.5V). The output voltage is single and fixed, which makes it difficult to meet the needs of some scenarios for "high-precision reference sources below 2.5V", thus limiting the application of power supplies in low-signal control scenarios.

[0003] 2. High circuit complexity and high cost For the existing 2.5V reference source, in order to improve power supply efficiency, the current sampling resistor of the constant current source needs to be designed to be as small as possible. This means that the small-signal constant current feedback signal must go through an additional amplification circuit to achieve the comparison function. At the same time, smart power supplies often need to have the function of a voltage source. Existing solutions require the design of an additional independent voltage source circuit, which not only increases the overall complexity of the circuit, but also increases the component cost and production and debugging cost.

[0004] 3. Poor control performance Additional amplifier circuits and independent voltage source circuits introduce more signal interference and losses, resulting in slower response speed and decreased stability of constant current feedback control, ultimately affecting the overall control performance of the power supply.

[0005] In view of the shortcomings of the existing technology, there is an urgent need for a solution that can simultaneously achieve a "small signal reference source below 2.5V" and a "regulated source above 2.5V", and that has a simple circuit and low cost. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by providing a small-signal reference source and voltage regulator circuit that has fewer components, more flexible adjustment, and higher precision. This circuit can convert a DC voltage source into a small-signal reference source below 2.5V while simultaneously outputting a voltage regulator source above 2.5V.

[0007] The objective of this utility model is achieved through the following solution: A small-signal reference source and voltage regulator circuit, characterized in that it includes an output driving circuit composed of a transistor Q1 and a resistor R1, and a reference voltage source U1, wherein the output terminal of the reference voltage source U1 is connected to the base of the transistor Q1, and a resistor R1 is provided between the base and the collector of the transistor Q1, and the collector of the transistor Q1 is connected to the input voltage VIN. The emitter of transistor Q1 serves as the regulated output terminal VOUT, used to output a regulated voltage higher than 2.5V. A voltage divider circuit is provided between the second signal input terminal and the regulated output terminal VOUT of the reference voltage source U1. The voltage divider circuit includes resistors R2, R3, R4, and R5. Resistor R5 is connected to the second signal input terminal of the reference voltage source U1 and grounded. The connection node of resistors R3 and R4 is connected to the first signal input terminal of the reference voltage source U1, and the connection node of resistors R4 and R5 serves as a small signal reference source VREF, used to output a reference voltage lower than 2.5V.

[0008] Preferably, the transistor Q1 is an NPN transistor.

[0009] Preferably, the NPN transistor is any one of 9014, BC547, BC548, BC549, 2SC1815, or 2N5551.

[0010] Preferably, the reference voltage source U1 is a shunt regulator.

[0011] Preferably, the shunt regulator is any one of TL431, LT1431, TS1431, ATL431, ATL431LI, and NCP431.

[0012] Preferably, the resistors R2, R3, R4, and R5 can be resistors with fixed resistance values ​​or resistors with adjustable resistance values.

[0013] Preferably, the ratio of the total resistance of resistors R2 and R3 to the total resistance of resistors R4 and R5 is adjusted according to the magnitude of the input voltage VIN, so that the magnitude of the regulated output voltage at the regulated output terminal VOUT meets the requirements.

[0014] Preferably, the resistance ratio of resistor R4 to resistor R5 is adjusted according to the magnitude of the input voltage VIN so that the output voltage of the small signal reference source meets the requirements.

[0015] Preferably, when the input voltage VIN is 12V, the resistance of resistor R2 is 22KΩ, the resistance of resistor R3 is 3KΩ, the resistance of resistor R4 is 22KΩ, the resistance of resistor R5 is 3KΩ, the regulated output terminal VOUT is stable at 5V, and the voltage of the small signal reference source is 0.3V.

[0016] The beneficial effects of this utility model are as follows: A small-signal reference source and voltage regulator circuit, characterized in that it includes an output driving circuit composed of a transistor Q1 and a resistor R1, and a reference voltage source U1, wherein the output terminal of the reference voltage source U1 is connected to the base of the transistor Q1, and a resistor R1 is provided between the base and the collector of the transistor Q1, and the collector of the transistor Q1 is connected to the input voltage VIN. The emitter of transistor Q1 serves as the regulated output terminal VOUT, used to output a regulated voltage higher than 2.5V. A voltage divider circuit is provided between the second signal input terminal and the regulated output terminal VOUT of the reference voltage source U1. The voltage divider circuit includes resistors R2, R3, R4, and R5. Resistor R5 is connected to the second signal input terminal of the reference voltage source U1 and grounded. The connection node of resistors R3 and R4 is connected to the first signal input terminal of the reference voltage source U1, and the connection node of resistors R4 and R5 serves as a small signal reference source VREF, used to output a reference voltage lower than 2.5V.

[0017] This invention utilizes an output drive circuit consisting of transistor Q1 and resistor R1, and connects the output terminal of reference voltage source U1 to the base of transistor Q1. By leveraging the current amplification characteristics of the transistor, it enhances the load-carrying capacity of the regulated output terminal VOUT (i.e., the emitter of transistor Q1), ensuring that the regulated output voltage above 2.5V remains stable under varying load conditions. Simultaneously, the resistor R1 provides current-limiting protection for the base and collector of transistor Q1, preventing damage to the transistor due to overcurrent and improving the overall reliability of the circuit. Furthermore, this invention utilizes a voltage divider circuit (resistors R2 to R5) between the second signal input terminal and the regulated output terminal VOUT of the reference voltage source U1, and the connection node of resistors R3 and R4 to the first signal input terminal, to construct a precise feedback regulation mechanism. This mechanism can correct the voltage deviation of the regulated output terminal VOUT in real time, significantly improving the voltage regulation accuracy. Simultaneously, it cleverly utilizes the voltage divider node of resistors R4 and R5 to output a small-signal reference source VREF below 2.5V, enabling a single circuit to simultaneously achieve both high-voltage regulation and low-voltage small-signal reference functions. This eliminates the need for an additional independent circuit, significantly simplifying the overall circuit structure and reducing cost and space requirements. Moreover, by adjusting the resistance ratio of resistors R2 to R5, the specific regulated voltage value of the regulated output terminal VOUT and the reference voltage value of the small-signal reference source VREF can be flexibly set to adapt to the needs of high and low voltage power supplies in different scenarios, enhancing the versatility and applicability of this invention's circuit.

[0018] Preferably, the transistor Q1 is an NPN transistor.

[0019] This invention uses an NPN transistor Q1, connecting the collector to the input voltage VIN and the emitter to the regulated output VOUT. This allows it to directly respond to the control signal output from the reference voltage source U1 via resistor R1. By precisely adjusting the emitter output current through minute changes in the base current, it achieves rapid dynamic stabilization of the regulated output VOUT. Furthermore, the NPN transistor's low on-state voltage, fast switching speed, and excellent temperature stability reduce losses and delays during voltage adjustment, ensuring high-precision stability of the regulated output VOUT and the small-signal reference source formed by the voltage divider between resistors R4 and R5, regardless of changes in the input voltage VIN or load. Moreover, the NPN transistor is the most widely used transistor type in electronic circuits, offering low procurement costs, a wide selection, and strong process compatibility, which helps reduce the industrialization cost of this invention and improves the reliability and maintainability of the circuit.

[0020] Preferably, the NPN transistor is any one of 9014, BC547, BC548, BC549, 2SC1815, or 2N5551.

[0021] This invention utilizes any one of the following NPN transistors: 9014, BC547, BC548, BC549, 2SC1815, and 2N5551. These NPN transistors are all mature small-signal transistors with suitable current gain to ensure sensitive response to the output control signal of the shunt regulator. Linear control of the collector-emitter path is achieved through precise adjustment of the base current. Together with the resistor network and reference voltage source, they form a stable closed-loop regulation mechanism, ensuring the accuracy and stability of the regulated output and the accuracy of the small-signal reference voltage. Furthermore, these NPN transistors are industry-standard devices that have been proven through long-term practice, exhibiting high consistency in electrical parameters and excellent temperature stability. They maintain stable switching and amplification performance over a wide temperature range of -40℃ to 85℃, adapting to the circuit operating requirements under different environmental conditions. Direct replacement between different models can be achieved without changing the circuit structure, simplifying the production selection process and reducing the cost and technical barriers to industrialization.

[0022] Preferably, the reference voltage source U1 is a shunt regulator.

[0023] The reference voltage source U1 in this invention is a shunt regulator, which integrates a precision reference voltage, an error amplifier, and a shunt adjustment unit. It can accurately compare the difference between two input signals and its own reference through the internal error amplifier, outputting a linearized control signal. Simultaneously, the shunt regulator can achieve signal feedback through dynamic adjustment of its own shunt current, resulting in a fast response speed. It can quickly drive resistor R1 to adjust the base current of transistor Q1, ensuring that the regulated output VOUT stabilizes rapidly when the input voltage VIN fluctuates or the load changes, avoiding voltage drift caused by response lag. Furthermore, the shunt regulator has a compact structure and requires no additional drive module, reducing the number of circuit components, lowering hardware costs and printed circuit board space. The shunt regulator also possesses mature mass production characteristics (such as wide temperature stability and low temperature coefficient), ensuring the long-term accuracy of the small-signal reference source.

[0024] Preferably, the shunt regulator is any one of TL431, LT1431, TS1431, ATL431, ATL431LI, and NCP431.

[0025] This invention utilizes a shunt regulator from any one of the following models: TL431, LT1431, TS1431, ATL431, ATL431LI, or NCP431. These shunt regulators all employ a mature shunt regulation structure, integrating a high-precision voltage reference unit and a precise shunt control module. They can quickly respond to and suppress interference from input voltage fluctuations, dynamic load changes, and environmental factors (such as temperature drift) on core circuit parameters, significantly improving the overall circuit power supply stability and output accuracy. Furthermore, these shunt regulators are standardized devices that have undergone long-term application verification, possessing excellent electrical performance such as low quiescent current and high output impedance, making them suitable for various circuit systems ranging from low-voltage, low-power to medium-voltage, conventional power. In addition, the peripheral circuit interfaces of these shunt regulators have good compatibility, allowing for integration without significant adjustments to the hardware structure of the application system (such as power modules, detection circuits, and control units), making them convenient to use.

[0026] Preferably, the resistors R2, R3, R4, and R5 can be resistors with fixed resistance values ​​or resistors with adjustable resistance values.

[0027] In this invention, resistors R2, R3, R4, and R5 can be either fixed-value or adjustable-value resistors. When fixed-value resistors are used, mature fixed-resistor technology enables low-cost, high-stability voltage division, meeting the needs of scenarios with fixed voltage parameter requirements (such as standardized power supplies for specific equipment). This avoids the additional costs and potential contact failure risks associated with adjustable components, ensuring the consistency and reliability of the circuit in mass production. When adjustable-value resistors are used, the feedback voltage at the second signal input terminal and the sampling voltage at the first signal input terminal of the reference voltage source U1 can be flexibly changed by adjusting the voltage division ratio of each resistor in real time. This allows for precise adjustment of the high voltage value of the regulated output terminal VOUT and the low voltage value of the small-signal reference source VREF. This enables the same circuit to adapt to the diverse high and low voltage power supply requirements of different electronic devices (such as reference voltages for different sensor models and regulated power supplies for different modules) without redesigning the hardware structure, significantly expanding the circuit's applicability and effectively reducing the cost and time required to develop dedicated circuits for different application scenarios.

[0028] Preferably, the ratio of the total resistance of resistors R2 and R3 to the total resistance of resistors R4 and R5 is adjusted according to the magnitude of the input voltage VIN, so that the magnitude of the regulated output voltage at the regulated output terminal VOUT meets the requirements.

[0029] This invention dynamically adjusts the ratio of the total resistance of resistors R2 and R3 and the total resistance of resistors R4 and R5 according to the magnitude of the input voltage VIN. This allows for real-time matching of the reference voltage source U1's requirements for acquiring high-voltage feedback signals (voltage divider at the regulated output terminal VOUT via resistors R2 and R3) and low-voltage reference signals (voltage divider at the regulated output terminal VOUT via resistors R4 and R5). Under the new ratio, the reference voltage source U1 can still accurately compare the differences between the two signals and the internal reference, and stably output control signals to adjust the base current of transistor Q1, thereby achieving flexible adjustment and stable output of the regulated output terminal VOUT. Furthermore, this adjustment method does not require replacing core components such as the reference voltage source U1 and transistor Q1, nor does it require introducing additional active components or control modules. It can be completed simply by adjusting the passive resistor parameters, simplifying the circuit structure and reducing costs. During the adjustment process, the dual-input collaborative comparison mechanism of the reference voltage U1 is not affected by changes in the resistance ratio. It can still accurately capture voltage deviations and output control signals to adjust the base current of transistor Q1. This ensures that the voltage regulation accuracy of the regulated output VOUT at the new set value and the proportional synchronization of the small-signal reference source remain stable. This effectively broadens the input voltage adaptation range, optimizes circuit energy efficiency, avoids the impact of output fluctuations on downstream loads, and improves the overall system reliability.

[0030] Preferably, the resistance ratio of resistor R4 to resistor R5 is adjusted according to the magnitude of the input voltage VIN so that the output voltage of the small signal reference source meets the requirements.

[0031] This invention utilizes a dynamic adjustment mechanism—specifically, dynamically adjusting the resistance ratio of resistors R4 and R5 based on the input voltage VIN—to respond in real-time to changes in VIN. By precisely adjusting the ratio of R4 and R5, the voltage divider effect is controlled, ensuring that the voltage input to the small-signal reference source always matches its operating characteristics, thus enabling the small-signal reference source to stably output a voltage signal that meets the requirements. Specifically, the voltage divider node of resistors R4 and R5 serves as both the small-signal reference source and is directly connected to the second signal input terminal of the reference voltage source U1. Based on the voltage divider principle, the reference source voltage can be flexibly set by adjusting the resistance ratio of resistors R4 and R5. Simultaneously, by presetting the resistance range of resistors R4 and R5, it is ensured that the adjusted voltage signal output by the small-signal reference source meets the requirements, precisely matching the voltage threshold requirements of the reference voltage source U1 for the second signal input terminal. Furthermore, this adjustment method does not require replacing core components such as the reference voltage source U1 and transistor Q1, nor does it require introducing additional voltage regulation or isolation modules. It can be achieved simply by adjusting the parameters of the passive resistor, which greatly simplifies the circuit structure and reduces the implementation cost. At the same time, during the adjustment process, the dual-input comparison mechanism of the reference voltage source U1 is not affected. It can still stably output control signals by comparing the voltage difference between the first and second signal input terminals, and regulate the base current of transistor Q1 to maintain the stability of the regulated output terminal VOUT. This ensures that the small-signal reference source maintains high precision consistent with the internal reference of the reference voltage source U1 under different set values.

[0032] Preferably, when the input voltage VIN is 12V, the resistance of resistor R2 is 22KΩ, the resistance of resistor R3 is 3KΩ, the resistance of resistor R4 is 22KΩ, the resistance of resistor R5 is 3KΩ, the regulated output terminal VOUT is stable at 5V, and the voltage of the small signal reference source is 0.3V.

[0033] In this invention, by configuring the resistor parameters of the input voltage VIN (12V) as R2=22KΩ, R3=3KΩ, R4=22KΩ, and R5=3KΩ, the regulated output VOUT can be stabilized at 5V, and the small-signal reference source voltage can be stabilized at 0.3V. This ensures high accuracy and consistency of the voltage output and solves the output deviation problem caused by improper parameter matching. Furthermore, by using the same resistance values ​​for R2 and R4, and for R3 and R5, this invention significantly reduces the types of resistors required in the circuit, simplifies material procurement, warehousing management, and production assembly processes, and lowers the production error rate caused by a wide variety of materials. Simultaneously, the use of resistors of the same specification on a large scale reduces procurement costs and improves industrialization efficiency. While ensuring voltage regulation accuracy, it enhances the circuit's adaptability to input fluctuations and environmental interference, further improving the stability of the entire circuit system.

[0034] The advantages of this utility model are as follows: ① The entire circuit of this utility model has no complex redundant structure, the circuit structure is simplified, there are few components, the cost is low, and no additional independent modules are required. The step-down regulated output and small signal reference source output can be realized simultaneously through the reference voltage source U1. There is less signal interference, which meets the requirements of high precision, high stability and diverse application scenarios for constant current control voltage and small signal reference source.

[0035] ② The output voltage of this utility model circuit is flexible. The output voltage value can be adjusted simply by adjusting the resistance parameters in the circuit. It is very convenient to use and greatly improves debugging efficiency. It can be adapted to various scenarios such as vehicle, small household appliances, sensor calibration, and solar charging power supply systems, and can meet diverse voltage requirements, thus having great versatility.

[0036] ③ The small-signal reference source in this circuit is achieved by comparing the voltage with the reference voltage source U1 through a resistor voltage divider, resulting in high voltage accuracy. Combined with the output drive function and load regulation function, it ensures the stability of the regulated output and the consistency of the output performance, significantly improving the overall reliability of the circuit. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the overall structure of the small-signal reference source and voltage regulator circuit of this utility model; Figure 2 This is a functional block diagram of the reference voltage source U1 in this utility model; Figure 3 This is a circuit diagram of this embodiment. Detailed Implementation

[0038] like Figures 1 to 2 As shown, a small-signal reference source and voltage regulator circuit are characterized by comprising an output drive circuit composed of a transistor Q1 and a resistor R1, and a reference voltage source U1. The transistor Q1 is an NPN transistor, and the NPN transistor model is any one of 9014, BC547, BC548, BC549, 2SC1815, and 2N5551. The reference voltage source U1 is a shunt regulator, and the shunt regulator model is any one of TL431, LT1431, TS1431, ATL431, ATL431LI, and NCP431. The output terminal of the reference voltage source U1 is connected to the base of the transistor Q1 in the output drive circuit, and a resistor R1 is provided between the base and the collector of the transistor Q1. The collector of the transistor Q1 is connected to the input voltage VIN. The emitter of transistor Q1 serves as the regulated output terminal VOUT, used to output a regulated voltage higher than 2.5V. A voltage divider circuit is provided between the second signal input terminal and the regulated output terminal VOUT of the reference voltage source U1. The voltage divider circuit includes resistors R2, R3, R4, and R5. Resistors R2, R3, R4, and R5 can be resistors with fixed resistance values ​​or resistors with adjustable resistance values. Resistor R5 is connected to the second signal input terminal of the reference voltage source U1 and grounded. The connection node of resistors R3 and R4 is connected to the first signal input terminal of the reference voltage source U1, and the connection node of resistors R4 and R5 serves as a small signal reference source VREF, used to output a reference voltage lower than 2.5V.

[0039] The reference voltage source U1 compares the voltages at the first signal input terminal and the second signal input terminal, and outputs a control signal that adjusts the base current of the transistor Q1 via resistor R1, thereby stabilizing the regulated output terminal VOUT.

[0040] Based on the input voltage VIN, adjust the ratio of the total resistance of resistors R2 and R3 to the total resistance of resistors R4 and R5 so that the regulated output voltage at the regulated output terminal VOUT meets the requirements.

[0041] Adjust the resistance ratio of resistor R4 to resistor R5 according to the magnitude of the input voltage VIN to make the output voltage of the small signal reference source meet the requirements.

[0042] When the input voltage VIN is 12V, the resistance of resistor R2 is 22KΩ, the resistance of resistor R3 is 3KΩ, the resistance of resistor R4 is 22KΩ, the resistance of resistor R5 is 3KΩ, the regulated output VOUT is stable at 5V, and the voltage of the small signal reference source is 0.3V.

[0043] The following is an example using the above-mentioned small-signal reference source and voltage regulator circuit: like Figure 3 As shown, a small-signal reference source and voltage regulator circuit consists of a reference voltage source U1, an output drive circuit, and a voltage divider circuit. Through standardized component selection and precise parameter configuration, it achieves a 5V regulated output and a 0.3V small-signal reference source output under a 12V input. The connection relationship, component parameters, and working principle of each module are as follows: I. Internal Connections of Each Module in the Circuit (1) Output drive circuit: including NPN transistor Q1 and resistor R1 The input voltage VIN is connected to the collector of transistor Q1, and the emitter of transistor Q1 serves as the regulated output terminal VOUT, used to output a regulated voltage higher than 2.5V. A resistor R1 is placed between the base and collector of transistor Q1. The output terminal of the reference voltage source U1 is connected to the base of transistor Q1, used to transmit the control signal of the reference voltage source U1 to adjust the conduction level of transistor Q1.

[0044] (2) Voltage divider circuit: including resistors R2, R3, R4, and R5 1. Voltage Divider Branch for Voltage Regulation Feedback: A voltage divider circuit is provided between the regulated output terminal VOUT and the second signal input terminal of the reference voltage source U1. The voltage divider circuit includes resistors R2, R3, R4, and R5. Resistor R5 is connected to the second signal input terminal of the reference voltage source U1 (i.e., the ANODE terminal of the reference voltage source U1) and grounded. The connection node of resistors R3 and R4 (i.e., the voltage divider node) is connected to the first signal input terminal of the reference voltage source U1 (i.e., the REF terminal of the reference voltage source U1), which is used to divide the voltage signal of the regulated output terminal VOUT and feed it back to the reference voltage source U1 to realize voltage regulation closed-loop control.

[0045] 2. Small-signal reference source voltage divider branch: The connection node between resistors R4 and R5 serves as the small-signal reference source VREF, used to output a reference voltage lower than 2.5V.

[0046] (3) Reference voltage source U1 Its function is based on Figure 2 The structure shown (including CATHODE, REF, Vref, and ANODE terminals) compares the voltage difference between the "first signal input terminal (voltage divider signal of resistors R2 and R3)" and the "second signal input terminal (voltage divider signal of resistors R4 and R5)" and outputs a corresponding control signal. This control signal adjusts the base current of transistor Q1 via resistor R1, thereby controlling the emitter output voltage of transistor Q1 to stabilize the output voltage at a set regulated value higher than 2.5V.

[0047] II. Component models and parameter configurations used in the circuit Transistor Q1: NPN type small signal transistor, model number 9014; Resistor R1: 10KΩ; Resistor R2: 22KΩ; Resistor R3: 3KΩ; Resistor R4: 22KΩ; Resistor R5: 3KΩ; Reference voltage source U1: Shunt type voltage regulator, model TL431; Input voltage VIN: 12V DC voltage; Target regulated output: 5V; Target small-signal reference source voltage: 0.3V.

[0048] The transistor Q1 used in this embodiment is a 9014. As a general-purpose, high-gain NPN transistor, the 9014 has a typical current amplification factor (β value) of 100-1000, which is highly compatible with the signal regulation requirements of the circuit in this invention. It can efficiently convert the weak control signal output from the reference voltage source U1 into a regulation capability sufficient to drive changes in the emitter current, effectively improving the response speed and stability accuracy of the regulated output VOUT when the input voltage VIN fluctuates or the load changes. This solves the problem of regulation lag or insufficient voltage regulation accuracy that may be caused by low-gain transistors. Simultaneously, the low-noise characteristics of the 9014 reduce interference during signal transmission, ensuring that the small-signal reference source formed by the voltage divider through resistors R4 and R5 is unaffected by transistor noise, guaranteeing the voltage purity and accuracy of the small-signal reference source, and overcoming the reference signal distortion problem that may be introduced by high-noise devices. Moreover, the 9014 has good temperature stability. Its reverse saturation current is small at room temperature and changes slowly with temperature. It can maintain the stability of its electrical characteristics when the ambient temperature fluctuates, avoiding the deviation of the regulated output VOUT and small signal reference source voltage caused by temperature drift. This solves the problem of unstable performance of temperature-sensitive devices in wide temperature scenarios.

[0049] Furthermore, the reference voltage source U1 used in this embodiment is a TL431. The TL431 integrates a 2.5V high-precision reference voltage, a high-gain error amplifier, and a controllable shunt transistor. It can accurately acquire and compare the differences between the two input signals and the internal reference through the TL431's reference terminal, and output a linearization control signal to adjust the base current of transistor Q1 via resistor R1, significantly improving the voltage regulation accuracy of the regulated output VOUT and the voltage accuracy of the small-signal reference source. Simultaneously, the TL431 possesses excellent temperature stability, maintaining a stable reference voltage over a wide temperature range and avoiding the impact of temperature drift on circuit performance.

[0050] III. Connection Relationships of the Entire Circuit The components are electrically connected according to the following logic, and the parameter matching is verified by the voltage divider principle: (1) Power supply circuit connection The positive terminal of the input voltage VIN (12V) is connected to the collector of transistor Q1, and the negative terminal of the input voltage VIN is directly grounded to provide the main power supply for the circuit.

[0051] (2) Connection of regulated output terminal The emitter of transistor Q1 is directly used as the regulated output terminal VOUT to output a 5V regulated voltage. The emitter of transistor Q1 is also connected to resistor R2 in the voltage divider circuit. In the voltage divider circuit, resistors R2, R3, R4, and R5 are connected in series (the other end of resistor R2 is connected to resistor R3, the other end of resistor R3 is connected to resistor R4, the other end of resistor R4 is connected to resistor R5, and the other end of resistor R5 is grounded). Through this series voltage divider structure, on the one hand, the connection node of resistor R3 and resistor R4 can transmit the sampling signal to the first signal input terminal of the reference voltage source U1, and the connection node of resistor R4 and resistor R5 forms a small signal reference source VREF. On the other hand, in conjunction with the comparison of the voltages of the first and second signal input terminals by the reference voltage source U1, feedback adjustment of the regulated output terminal VOUT is realized, realizing signal splitting and feedback.

[0052] (3) Connection of voltage divider branch for voltage regulation feedback The regulated output terminal VOUT is connected in series with resistors R2 (22KΩ) and R3 (3KΩ) and then grounded to form a voltage divider circuit. The connection point of resistors R3 and R4 is connected to the REF terminal 1 (first signal input terminal) of the reference voltage source U1 (TL431) to feed back the voltage status of the regulated output terminal VOUT to the reference voltage source U1.

[0053] (4) Connection of small signal reference source voltage divider branch: After the regulated output terminal VOUT is connected in series with resistor R4 (22KΩ), it is connected to one end of resistor R5 (3KΩ). The other end of resistor R5 is grounded and connected to the ANODE terminal 2 (second signal input terminal) of the reference voltage source U1 (TL431). It serves as both a low potential reference for the reference voltage source U1 and a small signal reference source output terminal, outputting a 0.3V accurate signal to the outside.

[0054] (5) Connection between reference source and drive circuit: The CATHODE terminal 3 (output terminal) of the reference voltage source U1 (TL431) is connected to the base of the transistor Q1 through the resistor R1 (1KΩ) to transmit the control signal output by the reference voltage source U1; the ANODE terminal of the reference voltage source U1 directly participates in the small signal voltage divider branch, and its internal 2.5V precision reference does not require external additional reference power supply.

[0055] IV. Working Principle and Process This circuit achieves synchronous stability between the regulated output and the small-signal reference source based on closed-loop feedback control. The specific workflow is as follows: (1) Power-on initialization The circuit is connected to a 12V DC voltage. The input voltage VIN provides the working voltage for the collector of transistor Q1. Transistor Q1 is driven to conduct by the initial weak current at the base, and the emitter initially outputs voltage VOUT (the initial value is close to the input voltage VIN, and gradually stabilizes with feedback adjustment).

[0056] (2) Dual signal acquisition The regulated output terminal VOUT simultaneously enters two voltage divider branches: First, after being divided by resistors R2 and R3, a 2.5V feedback signal is generated and input to the REF terminal of the reference voltage source U1, reflecting the voltage state of the regulated output terminal VOUT in real time; Second, after being divided by resistors R4 and R5, a small signal voltage of 0.3V is generated and input to the ANODE terminal of the reference voltage source U1. This 0.3V small signal voltage serves as both a low potential reference for the reference voltage source U1 and an externally usable small signal reference source.

[0057] (3) Benchmark comparison and control signal output The core function of the reference voltage source U1 (TL431) is to compare the 2.5V feedback signal input at the REF terminal with the internal 2.5V precision reference (the 0.3V signal at the ANODE terminal provides a stable low-potential reference for the circuit, ensuring the consistency of the comparison reference), and output corresponding control signals based on the comparison result. If the regulated output VOUT is too high: the voltage divider signal of resistors R2 and R3 is >2.5V. The reference voltage source U1 determines that the regulated output VOUT exceeds the set value. The control signal output from its CATHODE terminal reduces the current in resistor R1, which reduces the base current of transistor Q1. The conduction of transistor Q1 weakens (the equivalent resistance between collector and emitter increases), and the regulated output VOUT decreases accordingly. If the regulated output VOUT is too low: the voltage divider signal of resistors R2 and R3 is <2.5V. The reference voltage source U1 determines that the regulated output VOUT is lower than the set value. The control signal output from its CATHODE terminal increases the current in resistor R1, the base current of transistor Q1 increases, the conduction of transistor Q1 is enhanced (the equivalent resistance between collector and emitter decreases), and the regulated output VOUT increases accordingly.

[0058] (4) Closed-loop stable output Through the closed-loop cycle of "signal acquisition - reference comparison - current adjustment" described above, the regulated output terminal VOUT finally stabilizes at 5V; at the same time, because the voltage division ratio of resistors R4 and R5 is bound to the regulated output terminal VOUT, the small signal reference source synchronously and stably outputs 0.3V, thus achieving the design goal of "coordinated stability of regulated output and small signal reference source".

[0059] (5) Adjust VOUT The above workflow steps (1) to (4) are typical configurations for a 12V input voltage, a 5V output voltage, and a 0.3V small signal reference source.

[0060] In fact, this invention can also adjust the component parameters to adjust the value of VOUT according to the actual scenario requirements, without changing the circuit topology and core component models. For example, if the input voltage VIN is set to 24V, the target regulated output VOUT is 12V, and the target small-signal reference source is 1.0V, then resistors R2=59KΩ, R3=36KΩ, R4=15KΩ, and R5=10KΩ can be adjusted. That is, the regulated output VOUT=[(R2+R3+R4+R5) / (R4+R5)]×2.5V=12V, and the small-signal reference source=[R5 / (R4+R5)]×2.5V=1V.

[0061] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications made to the present utility model by those skilled in the art without departing from the spirit of the present utility model shall fall within the protection scope of the present utility model.

Claims

1. A small-signal reference source and voltage regulator circuit, characterized in that, It includes an output drive circuit consisting of a transistor Q1 and a resistor R1, and a reference voltage source U1. The output terminal of the reference voltage source U1 is connected to the base of the transistor Q1, and a resistor R1 is provided between the base and the collector of the transistor Q1. The collector of the transistor Q1 is connected to the input voltage VIN. The emitter of transistor Q1 serves as the regulated output terminal VOUT, used to output a regulated voltage higher than 2.5V. A voltage divider circuit is provided between the second signal input terminal and the regulated output terminal VOUT of the reference voltage source U1. The voltage divider circuit includes resistors R2, R3, R4, and R5. Resistor R5 is connected to the second signal input terminal of the reference voltage source U1 and grounded. The connection node of resistors R3 and R4 is connected to the first signal input terminal of the reference voltage source U1, and the connection node of resistors R4 and R5 serves as a small signal reference source VREF, used to output a reference voltage lower than 2.5V.

2. The small-signal reference source and voltage regulator circuit according to claim 1, characterized in that, The transistor Q1 is an NPN transistor.

3. The small-signal reference source and voltage regulator circuit according to claim 2, characterized in that, The NPN transistor is any one of the following: 9014, BC547, BC548, BC549, 2SC1815, or 2N5551.

4. The small-signal reference source and voltage regulator circuit according to claim 1, characterized in that, The reference voltage source U1 is a shunt regulator.

5. The small-signal reference source and voltage regulator circuit according to claim 4, characterized in that, The shunt voltage regulator is any one of TL431, LT1431, TS1431, ATL431, ATL431LI, or NCP431.

6. The small-signal reference source and voltage regulator circuit according to claim 1, characterized in that, The resistors R2, R3, R4, and R5 can be resistors with fixed resistance values ​​or resistors with adjustable resistance values.

7. The small-signal reference source and voltage regulator circuit according to claim 1, characterized in that, Based on the input voltage VIN, adjust the ratio of the total resistance of resistors R2 and R3 to the total resistance of resistors R4 and R5 so that the regulated output voltage at the regulated output terminal VOUT meets the requirements.

8. The small-signal reference source and voltage regulator circuit according to claim 1, characterized in that, Adjust the resistance ratio of resistor R4 to resistor R5 according to the magnitude of the input voltage VIN to make the output voltage of the small signal reference source meet the requirements.

9. The small-signal reference source and voltage regulator circuit according to claim 1, characterized in that, When the input voltage VIN is 12V, the resistance of resistor R2 is 22KΩ, the resistance of resistor R3 is 3KΩ, the resistance of resistor R4 is 22KΩ, the resistance of resistor R5 is 3KΩ, the regulated output VOUT is stable at 5V, and the voltage of the small signal reference source is 0.3V.

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