Voltage regulation circuit

Abstract

The utility model discloses a voltage regulation circuit, which comprises a voltage detection circuit, a subtracter circuit, an adder circuit and an amplification voltage stabilizing circuit, and is characterized in that the voltage detection circuit is used for acquiring voltage difference between an input end and an output end of a load in real time; the subtracter circuit is used for outputting a compensation voltage according to a difference between a real-time voltage of an input end of a load and a voltage difference, the adder circuit is used for outputting a correction voltage according to a sum of the compensation voltage and a reference voltage, and the amplification voltage stabilizing circuit is used for amplifying and stabilizing the correction voltage and then outputting the correction voltage to the load. According to the voltage regulation circuit, high-precision power supply can be carried out on the load end, the reliability of the power supply voltage of the load end is improved, and the difficulty of later maintenance is reduced; and the circuit is simple and reasonable in structure, low in production cost and wide in application scene.

Description

Technical Field

[0001] The utility model relates to the technical field of power supply, in particular to a voltage regulating circuit. Background Art

[0002] In traditional power supply wiring applications, the inevitable existence of power supply voltage division caused by line resistance (short for line resistance) causes the power supply voltage at the power supply end to be inconsistent with the actual voltage at the load end. This is acceptable for application scenarios with low power supply accuracy requirements, but for application scenarios with extremely high power supply accuracy requirements, it is necessary to manually measure the actual voltage at the load end and then adjust the output voltage of the power supply end to achieve high-precision voltage supply. However, the above voltage adjustment method is too cumbersome and requires recalibration when the intermediate line changes, making subsequent maintenance very difficult.

[0003] In view of this, the present utility model is proposed. Summary of the Invention

[0004] In order to overcome the above-mentioned defects, the utility model provides a voltage regulation circuit, which, on the one hand, can realize high-precision power supply to the load end, greatly improves the reliability of the power supply voltage at the load end, and greatly reduces the difficulty of subsequent maintenance; on the other hand, its circuit structure is simple and reasonable, the production cost is low, and the application scenarios are wide.

[0005] The technical solution adopted by the present invention to solve its technical problems is: a voltage regulation circuit, including a voltage detection circuit, a subtractor circuit, an adder circuit and an amplifying and stabilizing circuit, wherein the voltage detection circuit is used to obtain the voltage difference between the input end and the output end of the load in real time, the subtractor circuit is used to output a compensation voltage according to the difference between the real-time voltage of the input end of the load and the voltage difference, the adder circuit is used to output a correction voltage according to the sum of the compensation voltage and a reference voltage, and the amplifying and stabilizing circuit is used to amplify and stabilize the correction voltage before outputting it to the load.

[0006] As a further improvement of the present invention, the voltage detection circuit includes two first operational amplifiers and a subtractor circuit A, the non-inverting input terminals of the two first operational amplifiers are respectively connected to the input terminal and the output terminal of the load, the inverting input terminals of the two first operational amplifiers are respectively connected to their respective output terminals to lead to a load voltage signal output terminal, and the two load voltage signal output terminals are respectively connected to the input terminals of the subtractor circuit A, and the subtractor circuit A can perform a subtraction operation on the real-time voltages received at the input terminal and the output terminal of the load to obtain the voltage difference.

[0007] As a further improvement of the present invention, the subtractor circuit A includes a second operational amplifier, a first resistor, a second resistor, a third resistor and a fourth resistor, wherein the first ends of the first resistor and the third resistor are respectively connected to the inverting input terminal and the non-inverting input terminal of the second operational amplifier, and the second ends of the first resistor and the third resistor are respectively connected to the two load voltage signal output terminals, that is, the second ends of the first resistor and the third resistor are used as input terminals of the subtractor circuit A; the second resistor is connected between the inverting input terminal and the output terminal of the second operational amplifier, and the first end of the fourth resistor is grounded, and the second end is connected to the first end of the third resistor.

[0008] As a further improvement of the present invention, the load is a resistor;

[0009] The two first operational amplifiers are defined as a first operational amplifier A and a first operational amplifier B, respectively. The non-inverting input terminal of the first operational amplifier A is connected to the input terminal of the load, and the load voltage signal output terminal derived from the connection between the inverting input terminal of the first operational amplifier A and its output terminal is connected to the second terminal of the third resistor; the non-inverting input terminal of the first operational amplifier B is connected to the output terminal of the load, and the load voltage signal output terminal derived from the connection between the inverting input terminal of the first operational amplifier B and its output terminal is connected to the second terminal of the first resistor.

[0010] As a further improvement of the present invention, the subtractor circuit includes a third operational amplifier, a fifth resistor, a sixth resistor, a seventh resistor and an eighth resistor, wherein the first ends of the fifth resistor and the seventh resistor are respectively connected to the inverting input terminal and the non-inverting input terminal of the third operational amplifier, and the second end of the fifth resistor is connected to the output terminal of the second operational amplifier, and the second end of the seventh resistor is connected to the input terminal of the load; the sixth resistor is connected between the inverting input terminal and the output terminal of the third operational amplifier, and the first end of the eighth resistor is grounded and the second end is connected to the first end of the seventh resistor.

[0011] As a further improvement of the present invention, the adder circuit includes a fourth operational amplifier, a ninth resistor, a tenth resistor, an eleventh resistor and a twelfth resistor, wherein the eleventh resistor is connected between the output terminal of the third operational amplifier and the non-inverting input terminal of the fourth operational amplifier, the first end of the twelfth resistor is connected to an external reference voltage source, and the second end is connected to the non-inverting input terminal of the fourth operational amplifier, the first end of the ninth resistor is grounded, and the second end is connected to the inverting input terminal of the fourth operational amplifier, and the tenth resistor is connected between the inverting input terminal and the output terminal of the fourth operational amplifier.

[0012] As a further improvement of the present invention, the amplifying and voltage-stabilizing circuit includes a fifth operational amplifier and a transistor, the non-inverting input terminal of the fifth operational amplifier is connected to the output terminal of the four operational amplifiers, the inverting input terminal of the fifth operational amplifier and the emitter of the transistor are respectively connected to the input terminal of the load, the output terminal of the fifth operational amplifier is connected to the base of the transistor, and the collector of the transistor is connected to an external power supply voltage source.

[0013] As a further improvement of the present invention, the base of the transistor is connected to the output end of the fifth operational amplifier through a thirteenth resistor, the collector of the transistor is connected to the power supply voltage source through a fourteenth resistor, and the emitter of the transistor is connected to the input end of the load through a fifteenth resistor.

[0014] As a further improvement of the present invention, the power supply voltage source also supplies power to the first operational amplifier, the second operational amplifier, the third operational amplifier, the fourth operational amplifier and the fifth operational amplifier.

[0015] As a further improvement of the present invention, a sixteenth resistor and a seventeenth resistor are further provided, the second end of the seventh resistor, the inverting input end of the fifth operational amplifier and the emitter of the transistor are connected in parallel to the first end of the sixteenth resistor, the second end of the sixteenth resistor is connected to the input end of the load, the first end of the seventeenth resistor is grounded, and the second end is connected to the output end of the load.

[0016] The beneficial effects of the present invention are as follows: ① The voltage regulating circuit provided by the present invention can automatically and highly accurately adjust the real-time voltage of the load collected and then output it to the load, so as to effectively achieve the consistency of the voltage between the load end and the power supply end, that is, the voltage regulating circuit satisfies the use requirements of high-precision power supply at the load end, and has high regulation efficiency and high precision, which greatly improves the reliability of the power supply voltage at the load end and greatly reduces the difficulty of subsequent maintenance. ② The circuit structure of the voltage regulating circuit of the present invention is simple and reasonable, with low production cost, and by equipping different types of electronic components, the voltage regulating circuit can be well applied in different power supply scenarios. It has been verified by application that the voltage regulating circuit is particularly suitable for all application scenarios of DC power supply of 24V and below, and the application scenarios are very wide. ③ When multiple load ends need to be powered, unlike the existing technology that requires multiple power supply voltage sources to separately power multiple load ends in order to achieve separate calibration of the power supply voltage of each load end, the voltage regulation circuit provided by the utility model only needs to use one reference voltage source and one power supply voltage source to achieve high-precision power supply to multiple load ends in batches, which not only reduces costs and occupancy space, but also facilitates and facilitates subsequent maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a block diagram of the working principle of the voltage regulation circuit of the utility model;

[0018] Figure 2 This is a schematic diagram of the circuit structure of the voltage regulation circuit of the present utility model.

[0019] The following description is made with reference to the accompanying drawings:

[0020] 1. Voltage detection circuit; 2. Subtractor circuit; 3. Adder circuit; 4. Amplifier and voltage regulator circuit; 5. Load; 6. Reference voltage source; 7. Power supply voltage source. DETAILED DESCRIPTION

[0021] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0022] Example 1:

[0023] Please see the attached Figure 1 and attached Figure 2As shown, this embodiment provides a voltage regulation circuit, which includes a voltage detection circuit 1, a subtractor circuit 2, an adder circuit 3 and an amplifying and stabilizing circuit 4. The voltage detection circuit 1 is used to obtain a voltage difference VCC between an input terminal and an output terminal of a load 5 in real time, that is, the voltage difference VCC = the real-time voltage V01 of the input terminal of the load 5 - the real-time voltage V02 of the output terminal of the load 5; the subtractor circuit 2 is used to output a compensation voltage V1 according to the difference between the real-time voltage V01 of the input terminal of the load 5 and the voltage difference VCC, that is, the compensation voltage V1 = the real-time voltage V01 of the input terminal of the load 5 - the voltage difference VCC; the adder circuit 3 is used to output a correction voltage Vout according to the sum of the compensation voltage V1 and a reference voltage VREF, that is, the correction voltage Vout = the compensation voltage V1 + the reference voltage VREF; the amplifying and stabilizing circuit 4 is used to amplify and stabilize the correction voltage Vout and then output it to the load 5. As can be understood, the voltage regulation circuit provided in this embodiment can automatically and highly precisely regulate the real-time voltage of the load before outputting it to the load, effectively achieving voltage consistency between the load and power supply terminals. Specifically, the voltage regulation circuit effectively meets the requirements for high-precision power supply to the load terminal, and offers high regulation efficiency and precision, significantly improving the reliability of the load-side power supply voltage and significantly reducing the difficulty of subsequent maintenance. Supplementary Note: Load 5 does not constitute the voltage regulation circuit described in this embodiment.

[0024] The specific circuit structure of the voltage regulating circuit described in this embodiment is described in detail below.

[0025] Please continue to refer to the attached Figure 2 As shown, in this embodiment, the voltage detection circuit 1 preferably adopts a circuit structure as follows: the voltage detection circuit 1 includes two first operational amplifiers and a subtractor circuit A. The non-inverting input terminals of the two first operational amplifiers are respectively connected to the input terminal (such as point A) and the output terminal (such as point B) of the load 5. The inverting input terminals of the two first operational amplifiers are respectively connected to their respective output terminals to lead to a load voltage signal output terminal. The two load voltage signal output terminals are respectively connected to the input terminals of the subtractor circuit A. The subtractor circuit A is capable of subtracting the received real-time voltages of the input and output terminals of the load 5 to obtain the voltage difference VCC. It can be understood that in this embodiment, the real-time voltages of the input and output terminals of the load 5 (i.e., V01 and V02 mentioned above) are first acquired by the two first operational amplifiers in an op amp manner, and then the subtractor circuit A subtracts the received real-time voltages of the input and output terminals of the load 5 to obtain the voltage difference VCC.

[0026] Furthermore, the subtractor circuit A preferably employs a specific circuit structure as follows: the subtractor circuit A includes a second operational amplifier U2, a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4. The first ends of the first resistor R1 and the third resistor R3 are respectively connected to the inverting input and the non-inverting input of the second operational amplifier U2, and the second ends of the first resistor R1 and the third resistor R3 are respectively connected to the two load voltage signal output terminals. In other words, the second ends of the first resistor R1 and the third resistor R3 serve as input terminals of the subtractor circuit A. The second resistor R2 is connected between the inverting input and the output of the second operational amplifier U2. The first end of the fourth resistor R4 is grounded, and the second end is connected to the first end of the third resistor R3. It is understood that the subtractor circuit A employs a general subtractor circuit structure capable of achieving non-inverting output, and therefore its circuit principle will not be described in detail herein.

[0027] Based on the specific circuit structure of the above-mentioned subtractor circuit A, and taking the load 5 as an example using a resistor (i.e., using a resistor to simulate the load end), the two first operational amplifiers in this embodiment preferably adopt a circuit layout method as follows: the two first operational amplifiers are respectively defined as a first operational amplifier AU11 and a first operational amplifier BU12, wherein the non-inverting input terminal of the first operational amplifier AU11 is connected to the input end of the load 5 (such as point A), and the load voltage signal output end (such as point C1) derived from the connection between the inverting input terminal of the first operational amplifier AU11 and its output end is connected to the second end of the third resistor R3; the non-inverting input terminal of the first operational amplifier BU12 is connected to the output end of the load 5 (such as point B), and the load voltage signal output end (such as point C2) derived from the connection between the inverting input terminal of the first operational amplifier BU12 and its output end is connected to the second end of the first resistor R1.

[0028] From the above, it can be seen that the voltage detection circuit 1 used in this embodiment has high signal acquisition and calculation accuracy, which provides very good technical support and guarantee for the voltage regulation circuit of this embodiment to achieve high-precision voltage regulation / power supply.

[0029] Please continue to refer to the attached Figure 2As shown, in this embodiment, the subtractor circuit 2 preferably adopts a circuit structure as follows: the subtractor circuit 2 includes a third operational amplifier U3, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7 and an eighth resistor R8, wherein the first ends of the fifth resistor R5 and the seventh resistor R7 are respectively connected to the inverting input terminal and the non-inverting input terminal of the third operational amplifier U3, and the second end of the fifth resistor R5 is connected to the output terminal of the second operational amplifier U2, and the second end of the seventh resistor R7 is connected to the input terminal of the load 5 (such as point A); the sixth resistor R6 is connected between the inverting input terminal and the output terminal of the third operational amplifier U3, and the first end of the eighth resistor R8 is grounded, and the second end is connected to the first end of the seventh resistor R7. It is understandable that the subtractor circuit 2 described in this embodiment also adopts a universal subtractor circuit structure that can achieve in-phase output, which can obtain the real-time voltage V01 at the input end of the load 5 and the voltage difference VCC output by the voltage detection circuit 1, and then subtract the two to obtain the compensation voltage V1.

[0030] Please continue to refer to the attached Figure 2 As shown, in this embodiment, the adder circuit 3 preferably adopts a circuit structure as follows: the adder circuit 3 includes a fourth operational amplifier U4, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11 and a twelfth resistor R12, wherein the eleventh resistor R11 is connected between the output terminal of the third operational amplifier U3 and the non-inverting input terminal of the fourth operational amplifier U4, and the first end of the twelfth resistor R12 is connected to an external reference voltage source ( Figure 2 , the reference voltage VREF is 5V), the second end is connected to the non-inverting input terminal of the fourth operational amplifier U4, the first end of the ninth resistor R9 is grounded, and the second end is connected to the inverting input terminal of the fourth operational amplifier U4, and the tenth resistor R10 is connected between the inverting input terminal of the fourth operational amplifier U4 and the output terminal of the fourth operational amplifier U4. It will be appreciated that the adder circuit 3 described in this embodiment employs a general non-inverting adder circuit structure (so its circuit principle is not described in detail here), which can add the obtained reference voltage VREF and the compensation voltage V1 to obtain the corrected voltage Vout.

[0031] Please continue to refer to the attached Figure 2As shown, in this embodiment, the amplifying and voltage-stabilizing circuit 4 preferably adopts a circuit structure as follows: the amplifying and voltage-stabilizing circuit 4 includes a fifth operational amplifier U5, a transistor Q1, a thirteenth resistor R13, a fourteenth resistor R14 and a fifteenth resistor R15, wherein the non-inverting input terminal of the fifth operational amplifier U5 is connected to the output terminal of the four operational amplifiers U4, the inverting input terminal of the fifth operational amplifier U5 is connected to the input terminal of the load 5 (such as point A), the base of the transistor Q1 is connected to the output terminal of the fifth operational amplifier U5 through the thirteenth resistor R13, and the collector of the transistor Q1 is connected to the external power supply voltage source through the fourteenth resistor R14 ( Figure 2 (The power supply voltage source is shown as 15V in FIG. 1 ), and the emitter of the transistor Q1 is connected to the input terminal of the load 5 (e.g., point A) via the fifteenth resistor R15. It will be appreciated that this embodiment utilizes the fifth operational amplifier U5 in combination with the transistor Q1 to amplify and stabilize the correction voltage Vout, thereby providing a highly stable and accurate correction voltage to the load 5.

[0032] Supplementary explanation: The current passing through the two ends of the fifteenth resistor R15 can be approximately regarded as the current passing through the two ends of the load 5. In situations where current measurement is insensitive, the current passing through the fifteenth resistor R15 can be calculated by measuring the voltage difference across the fifteenth resistor R15, and thus approximately regarded as the current passing through the two ends of the load 5.

[0033] Please continue to refer to the attached Figure 2 As shown, in this embodiment, the two first operational amplifiers, the second operational amplifier U2, the third operational amplifier U3, the fourth operational amplifier U4, the fifth operational amplifier U5 and the transistor Q1 are respectively powered by an external power supply voltage source ( Figure 2 The power supply voltage source is shown to be 15V) to provide electrical energy.

[0034] From the specific circuit structure of the voltage regulation circuit provided by the present invention, it can be seen that the voltage accuracy difference between the power supply end and the load end only depends on the accuracy error of the operational amplifier in the above circuit structure. Therefore, in practical applications, it is only necessary to select a high-precision operational amplifier to achieve high voltage consistency between the power supply end and the load end. It can be understood that the voltage regulation circuit provided by the present invention can achieve the purpose of high-precision voltage regulation.

[0035] In addition, please refer to the attached Figure 2As shown, in this embodiment, a sixteenth resistor R16 and a seventeenth resistor R17 are further provided. The second end of the seventh resistor R7, the inverting input end of the fifth operational amplifier U5, and the emitter of the transistor Q1 are connected in parallel to the first end of the sixteenth resistor R16. If the fifteenth resistor R15 is provided, then: the second end of the seventh resistor R7, the inverting input end of the fifth operational amplifier U5, and the end of the fifteenth resistor R15 away from the emitter of the transistor Q1 are connected in parallel to the first end of the sixteenth resistor R16; the second end of the sixteenth resistor R16 is connected to the input end of the load 5 (such as point A), and the first end of the seventeenth resistor R17 is grounded, and the second end is connected to the output end of the load 5 (such as point B). As can be seen from the above, the sixteenth resistor R16 and the seventeenth resistor R17 can be understood as being used to simulate the line resistance of the entire power supply line.

[0036] Note: In this specification, the prefixes "first", "second", etc. of component names (such as the first operational amplifier, the second operational amplifier, etc.), and the suffixes "A", "B", etc. of component names (such as the first operational amplifier A, the first operational amplifier B, etc.) are only for the convenience of description and are not intended to limit the scope of implementation of this utility model patent.

[0037] In summary, the voltage regulation circuit of the present invention can achieve high-precision power supply to the load end, greatly improving the reliability of the load end power supply voltage and significantly reducing the difficulty of subsequent maintenance. Furthermore, the voltage regulation circuit has the characteristics of simple and rational structure, low production cost, and wide application scenarios, which well meet market demand.

[0038] In the above description, many specific details are set forth in order to fully understand the present invention. However, the above description is only a preferred embodiment of the present invention. The present invention can be implemented in many other ways different from those described herein, so the present invention is not limited by the specific implementation disclosed above. At the same time, any person skilled in the art can use the above-disclosed methods and technical contents to make many possible changes and modifications to the technical solution of the present invention without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

Claims

1. A voltage regulating circuit, characterized in that: The invention comprises a voltage detection circuit (1), a subtractor circuit (2), an adder circuit (3) and an amplifying and stabilizing circuit (4), wherein the voltage detection circuit (1) is used to obtain the voltage difference between the input end and the output end of the load (5) in real time, the subtractor circuit (2) is used to output a compensation voltage according to the difference between the real-time voltage of the input end of the load (5) and the voltage difference, the adder circuit (3) is used to output a correction voltage according to the sum of the compensation voltage and a reference voltage, and the amplifying and stabilizing circuit (4) is used to amplify and stabilize the correction voltage and then output it to the load (5).

2. The voltage regulating circuit according to claim 1, wherein: The voltage detection circuit (1) includes two first operational amplifiers and a subtractor circuit A, wherein the non-inverting input terminals of the two first operational amplifiers are respectively connected to the input terminal and the output terminal of the load (5), and the inverting input terminals of the two first operational amplifiers are respectively connected to their respective output terminals to lead to a load voltage signal output terminal, and the two load voltage signal output terminals are respectively connected to the input terminals of the subtractor circuit A. The subtractor circuit A can perform a subtraction operation on the received real-time voltages of the input terminal and the output terminal of the load (5) to obtain the voltage difference.

3. The voltage regulating circuit according to claim 2, wherein: The subtractor circuit A comprises a second operational amplifier (U2), a first resistor (R1), a second resistor (R2), a third resistor (R3) and a fourth resistor (R4), wherein the first ends of the first resistor (R1) and the third resistor (R3) are respectively connected to the inverting input terminal and the non-inverting input terminal of the second operational amplifier (U2), and the second ends of the first resistor (R1) and the third resistor (R3) are respectively connected to the two load voltage signal output terminals, that is, the second ends of the first resistor (R1) and the third resistor (R3) are used as the input terminals of the subtractor circuit A; the second resistor (R2) is connected between the inverting input terminal and the output terminal of the second operational amplifier (U2), and the first end of the fourth resistor (R4) is grounded and the second end is connected to the first end of the third resistor (R3).

4. The voltage regulating circuit according to claim 3, wherein: The load (5) is a resistor; The two first operational amplifiers are respectively defined as a first operational amplifier A (U11) and a first operational amplifier B (U12), wherein the non-inverting input terminal of the first operational amplifier A (U11) is connected to the input terminal of the load (5), and the load voltage signal output terminal derived from the connection between the inverting input terminal of the first operational amplifier A (U11) and its output terminal is connected to the second terminal of the third resistor (R3); the non-inverting input terminal of the first operational amplifier B (U12) is connected to the output terminal of the load (5), and the load voltage signal output terminal derived from the connection between the inverting input terminal of the first operational amplifier B (U12) and its output terminal is connected to the second terminal of the first resistor (R1).

5. The voltage regulating circuit according to claim 3, wherein: The subtractor circuit (2) comprises a third operational amplifier (U3), a fifth resistor (R5), a sixth resistor (R6), a seventh resistor (R7) and an eighth resistor (R8), wherein the first ends of the fifth resistor (R5) and the seventh resistor (R7) are respectively connected to the inverting input terminal and the non-inverting input terminal of the third operational amplifier (U3), and the second end of the fifth resistor (R5) is connected to the output terminal of the second operational amplifier (U2), and the second end of the seventh resistor (R7) is connected to the input terminal of the load (5); the sixth resistor (R6) is connected between the inverting input terminal and the output terminal of the third operational amplifier (U3), and the first end of the eighth resistor (R8) is grounded and the second end is connected to the first end of the seventh resistor (R7).

6. The voltage regulating circuit according to claim 5, wherein: The adder circuit (3) comprises a fourth operational amplifier (U4), a ninth resistor (R9), a tenth resistor (R10), an eleventh resistor (R11) and a twelfth resistor (R12), wherein the eleventh resistor (R11) is connected between the output terminal of the third operational amplifier (U3) and the non-inverting input terminal of the fourth operational amplifier (U4), a first end of the twelfth resistor (R12) is connected to an external reference voltage source, and a second end is connected to the non-inverting input terminal of the fourth operational amplifier (U4), a first end of the ninth resistor (R9) is grounded, and a second end is connected to the inverting input terminal of the fourth operational amplifier (U4), and the tenth resistor (R10) is connected between the inverting input terminal and the output terminal of the fourth operational amplifier (U4).

7. The voltage regulating circuit according to claim 6, wherein: The amplifying and voltage-stabilizing circuit (4) comprises a fifth operational amplifier (U5) and a transistor (Q1); the non-inverting input terminal of the fifth operational amplifier (U5) is connected to the output terminal of the four operational amplifiers (U4); the inverting input terminal of the fifth operational amplifier (U5) and the emitter of the transistor (Q1) are respectively connected to the input terminal of the load (5); the output terminal of the fifth operational amplifier (U5) is connected to the base of the transistor (Q1); and the collector of the transistor (Q1) is connected to an external power supply voltage source.

8. The voltage regulating circuit according to claim 7, wherein: The base of the transistor (Q1) is connected to the output end of the fifth operational amplifier (U5) via a thirteenth resistor (R13), the collector of the transistor (Q1) is connected to the power supply voltage source via a fourteenth resistor (R14), and the emitter of the transistor (Q1) is connected to the input end of the load (5) via a fifteenth resistor (R15).

9. The voltage regulating circuit according to claim 7, wherein: The power supply voltage source also supplies power to the first operational amplifier, the second operational amplifier (U2), the third operational amplifier (U3), the fourth operational amplifier (U4) and the fifth operational amplifier (U5).

10. The voltage regulating circuit according to claim 7, wherein: A sixteenth resistor (R16) and a seventeenth resistor (R17) are also provided. The second end of the seventh resistor (R7), the inverting input end of the fifth operational amplifier (U5) and the emitter of the transistor (Q1) are connected in parallel to the first end of the sixteenth resistor (R16). The second end of the sixteenth resistor (R16) is connected to the input end of the load (5). The first end of the seventeenth resistor (R17) is grounded and the second end is connected to the output end of the load (5).

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