Circuit and method for changing output voltage of constant voltage output circuit

Abstract

The invention relates to a circuit and method for changing the output voltage of a constant voltage output circuit, and belongs to the technical field of electronic circuits. The controller is connected with a feedback circuit of the constant voltage output circuit through a resistor; the controller is used for sampling the output voltage of the constant voltage output circuit and generating a PWM signal based on the preset voltage and the output voltage; and the resistor is used for inputting the PWM signal into a feedback circuit of the constant-voltage output circuit and adjusting the constant-voltage output circuit to output a preset voltage. According to the circuit for changing the output voltage of the constant-voltage output circuit, the PWM signal is connected to the feedback network of the constant-voltage output circuit through the resistor, so that the feedback value of the original feedback network is influenced through the PWM signal, the final output value is indirectly influenced, the constant-voltage output circuit outputs the preset voltage, and the output voltage of the constant-voltage output circuit is changed. A constant-voltage output circuit is transformed into an adjustable output circuit, only one resistor is needed for circuit connection, and the cost is low.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic circuits, and in particular to a circuit and method for changing the output voltage of a constant voltage output circuit. Background Art

[0002] In the context of rapid technological development, various intelligent devices are emerging one after another. In terms of internal circuit implementation, many sub-parts include a constant voltage or constant current output circuit, which is implemented according to the negative feedback principle with a voltage or current negative feedback control loop. The intelligent controller can control the negative feedback circuit to achieve the expected function and enable the system to have intelligent functions such as human-computer interaction, data analysis, and remote transmission.

[0003] In response to the above requirements, the general implementation method is to deeply embed the intelligent controller into the negative feedback loop. After the detected voltage and current signals are processed by the controller, the controller outputs the appropriate control signal to control the operation of the negative feedback circuit. The basic structure is as follows: Figure 1 As shown, Figure 1 This diagram illustrates intelligent negative feedback control for existing technologies. This implementation offers the advantages of a unified overall system design and ease of modification. However, the controller hardware typically utilizes a mature embedded system, and the design primarily involves software development. Adjustments often require specialized circuit design tailored to specific needs. This involves knowledge in areas such as digital circuits, analog circuits, spectrum, power consumption, heat dissipation, noise, stability, compatibility, and cost. This can differ significantly from the design methods and knowledge required for the controller, requiring a higher level of expertise. Without extensive and in-depth knowledge, it can be difficult to design a circuit that meets the desired performance.

[0004] On the other hand, many professional companies have launched various chips, modules and even products with negative feedback functions. Each company has conducted in-depth research on various issues that may be involved in feedback adjustment. Users only need to follow the instructions, which greatly reduces the requirements for relevant knowledge level. For example, various DCDC constant voltage output chips, LED constant current driver chips, constant voltage output switching power supplies, etc. Figure 2 The application circuit diagram of the DCDC constant voltage chip provided by the existing technology is as follows: Figure 2 The figure below shows a typical application circuit for the XL6019, a DCDC constant voltage chip launched by Core Dragon Semiconductor. The voltage across capacitor COUT is the output voltage of the circuit. Pin 5 of the chip is the voltage feedback sampling signal input pin, which has a fixed 1.25V comparison voltage set inside. Under the action of the negative feedback loop, the voltage at this pin is equal to the comparison voltage. According to relevant theory, Vout = 1.25·(R1+R2) / R1 = 24.35V. This means that the output of the circuit is a constant voltage. As long as it does not exceed the operating range, this voltage is consistent with the input voltage V INIt does not matter whether the load size is large or small. If a different output voltage is required, different R1 and R2 should be used. Once they are changed, the output remains constant.

[0005] This chip integrates the key components required for a DCDC circuit, including the switching transistors, drivers, and PWM signal generation. This allows users to obtain the required functions without requiring any prior knowledge, and the performance is excellent. However, there is no suitable method for adjusting the output voltage. Typically, DCDC circuits adjust the output by adjusting the duty cycle of the PWM signal, but this chip integrates the PWM signal internally, making it impossible for users to change the PWM signal externally.

[0006] For beginners or practitioners in related fields such as machinery and chemical engineering, it is very simple to purchase products from mature professional manufacturers and use them according to the instructions. It only takes a few days or even hours to purchase various types of controllers and generate PWM signals on demand according to the provided routines. However, there are considerable difficulties in combining the two.

[0007] However, they also require this combination for study or work, as they often require adjustable output products with intelligent or remote control capabilities. Specific required parameters vary greatly depending on the individual and the situation, and the fixed output products provided by specialized manufacturers cannot meet everyone's needs. For beginners or practitioners, they may have to conduct in-depth research, or hire others, on the circuits of intelligent controllers deeply embedded in negative feedback loops, solving various problems already addressed by specialized manufacturers in order to achieve their goals. However, this time-consuming, labor-intensive, and costly repetitive research may still not achieve the performance of specialized manufacturers' products.

[0008] If there is a simple way to combine the two, they can achieve their goals at a very low cost, the products of professional manufacturers can be more widely used, and the entire society will not need to invest huge resources in those repetitive research. Summary of the Invention

[0009] In view of this, it is necessary to provide a circuit and method for changing the output voltage of a constant voltage output circuit, so as to achieve the purpose of changing the fixed output of the constant voltage output circuit to an adjustable output, so that anyone can conveniently use the high-performance fixed output products of professional manufacturers to form their own intelligent high-performance adjustable products.

[0010] In order to achieve the above objectives, in a first aspect, the present invention provides a circuit for changing the output voltage of a constant voltage output circuit, comprising: Controller and resistor; The controller is connected to the feedback circuit of the constant voltage output circuit through the resistor; The controller is used to sample the output voltage of the constant voltage output circuit and generate a PWM signal based on a preset voltage and the output voltage; The resistor is used to input the PWM signal into the feedback circuit of the constant voltage output circuit, so as to adjust the constant voltage output circuit to output the preset voltage.

[0011] In a possible implementation, a capacitor is further included; The capacitor and the voltage dividing resistor of the constant voltage output circuit are connected in parallel; The capacitor is used to smooth the PWM signal.

[0012] In a possible implementation, the controller is specifically configured to: When the output voltage is different from the preset voltage, adjusting the duty cycle of the PWM signal; The PWM signal is generated until the output voltage is the same as the preset voltage.

[0013] In a possible implementation, the controller is specifically configured to: When the output voltage is less than the preset voltage, reducing the duty cycle of the PWM signal; When the output voltage is greater than the preset voltage, the duty cycle of the PWM signal is increased.

[0014] In a possible implementation, the output voltage of the constant voltage output circuit is expressed as follows: Vout=V FB (R1+R2) / R1-R2 (V PWM -V FB ) / R Where Vout represents the output voltage of the constant voltage output circuit, V FB Represents the feedback voltage of the constant voltage output circuit, R1 and R2 represent the voltage divider resistors of the constant voltage output circuit, V PWM represents the average voltage of the PWM signal, and R represents the resistance.

[0015] In a possible implementation, the controller is further configured to: A remote control command is received; the control command includes the preset voltage.

[0016] In one possible implementation, the constant voltage output circuit includes any one of the following: DCDC constant voltage output circuit, LED constant current drive circuit or constant voltage output switching power supply circuit.

[0017] In a second aspect, the present invention further provides a method for changing the output voltage of a constant voltage output circuit, which is applied to any of the above-mentioned circuits for changing the output voltage of a constant voltage output circuit, comprising: Using a controller to sample the output voltage of the constant voltage output circuit, and generating a PWM signal based on a preset voltage and the output voltage; The PWM signal is input into a feedback circuit of a constant voltage output circuit by using a resistor, so as to adjust the constant voltage output circuit to output the preset voltage.

[0018] In a possible implementation, generating a PWM signal based on a preset voltage and the output voltage includes: When the output voltage is different from the preset voltage, adjusting the duty cycle of the PWM signal; The PWM signal is generated until the output voltage is the same as the preset voltage.

[0019] In a possible implementation, when the output voltage is different from the preset voltage, adjusting the duty cycle of the PWM signal includes: When the output voltage is less than the preset voltage, reducing the duty cycle of the PWM signal; When the output voltage is greater than the preset voltage, the duty cycle of the PWM signal is increased.

[0020] The beneficial effects of the present invention are as follows: in the circuit and method for changing the output voltage of a constant-voltage output circuit provided by the present invention, a controller is connected to a feedback circuit of the constant-voltage output circuit via a resistor, the controller samples the output voltage of the constant-voltage output circuit, and generates a PWM signal based on a preset voltage and the output voltage, and inputs the PWM signal into the feedback circuit of the constant-voltage output circuit via a resistor, thereby affecting the feedback value of the original feedback network through the PWM signal, thereby indirectly affecting the final output value, so that the constant-voltage output circuit outputs a preset voltage, thereby realizing the transformation of the constant-voltage output circuit into an adjustable output circuit, and the circuit connection only requires one resistor, which is relatively low in cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 Schematic diagram of intelligent negative feedback control provided by existing technology; Figure 2Schematic diagram of the application circuit of the DCDC constant voltage chip provided by the prior art; Figure 3 A schematic structural diagram of an embodiment of a circuit for changing the output voltage of a constant voltage output circuit provided by the present invention; Figure 4 This is a structural diagram of the fixed output to adjustable output system provided by the present invention; Figure 5 A flow chart of an embodiment of a method for changing the output voltage of a constant voltage output circuit provided by the present invention. DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of the present invention.

[0024] In the description of the embodiments of the present invention, unless otherwise specified, "plurality" means two or more. "And / or" describes the association relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can mean: A exists alone, A and B exist simultaneously, or B exists alone.

[0025] The terms "first," "second," and so on, used in the embodiments of the present invention are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, technical features designated as "first" or "second" may explicitly or implicitly include at least one such feature.

[0026] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute a separate or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0027] The present invention provides a circuit and method for changing the output voltage of a constant voltage output circuit, which are described below.

[0028] Figure 3 A schematic structural diagram of an embodiment of a circuit for changing the output voltage of a constant voltage output circuit provided by the present invention is shown in FIG. Figure 3 As shown, the circuit for changing the output voltage of the constant voltage output circuit includes: Controller and resistor; The controller is connected to the feedback circuit of the constant voltage output circuit through the resistor; The controller is used to sample the output voltage of the constant voltage output circuit and generate a PWM signal based on a preset voltage and the output voltage; The resistor is used to input the PWM signal into the feedback circuit of the constant voltage output circuit, so as to adjust the constant voltage output circuit to output the preset voltage.

[0029] It should be noted that the constant voltage output circuit is a fixed output circuit for outputting a fixed voltage. For example, the constant voltage output circuit can be a DCDC constant voltage output circuit, an LED constant current drive circuit, or a switching power supply circuit with constant voltage output.

[0030] The embodiment of the present invention takes the application of XL6019 chip as an example. Figure 3 The part in the dotted box is the feedback part of the XL6019 fixed output circuit. For details, please refer to Figure 2 .

[0031] The controller is connected to the feedback circuit of the constant voltage output circuit via the resistor R, so that the controller can sample the output voltage of the constant voltage output circuit and generate a PWM signal according to the preset voltage and the output voltage.

[0032] The PWM signal is connected to the feedback network of the constant voltage output circuit through the resistor R, so that the feedback value of the original feedback network is affected by the PWM signal, thereby indirectly affecting the final output value, so that the constant voltage output circuit outputs a preset voltage, transforming the constant voltage output circuit into an adjustable output circuit, and can be smoothly combined with the intelligent control part.

[0033] In the embodiment of the present invention, the circuit connection only requires one resistor. Since the voltage and current of the feedback part are very small, low-voltage and small-capacity devices can be used, the component cost is low, and output sampling and PWM signal generation are easy to achieve.

[0034] To summarize, in the circuit for changing the output voltage of a constant-voltage output circuit provided by an embodiment of the present invention, a controller is connected to the feedback circuit of the constant-voltage output circuit through a resistor. The controller samples the output voltage of the constant-voltage output circuit and generates a PWM signal based on a preset voltage and the output voltage. The PWM signal is input into the feedback circuit of the constant-voltage output circuit through a resistor, thereby affecting the feedback value of the original feedback network through the PWM signal, thereby indirectly affecting the final output value, so that the constant-voltage output circuit outputs a preset voltage, thereby realizing the transformation of the constant-voltage output circuit into an adjustable output circuit. The circuit connection only requires one resistor, and the cost is relatively low.

[0035] In some embodiments of the present invention, further comprising a capacitor; The capacitor and the voltage dividing resistor of the constant voltage output circuit are connected in parallel; The capacitor is used to smooth the PWM signal.

[0036] like Figure 3 As shown, C is a smoothing capacitor, the voltage divider resistor R1 of the constant voltage output circuit is connected in parallel, one end of the capacitor C is connected to the resistor R, and the other end is grounded.

[0037] The PWM signal is a square wave signal with varying high and low levels. The capacitor C acts as a smoothing function, eliminating the fluctuation of the square wave signal. The average voltage V of the PWM signal can be used to calculate the average voltage of the PWM signal. PWM Describes the voltage output by the controller.

[0038] In some embodiments of the present invention, the controller is further configured to: A remote control command is received; the control command includes the preset voltage.

[0039] The controller may receive a remote control command via a network, wireless, or other means. The control command includes a preset voltage Vo, and the control command is used to instruct the output voltage Vout of the constant voltage output circuit to be the preset voltage Vo.

[0040] In a possible implementation, the controller is specifically configured to: When the output voltage is different from the preset voltage, adjusting the duty cycle of the PWM signal; The PWM signal is generated until the output voltage is the same as the preset voltage.

[0041] In some embodiments of the present invention, the controller is specifically configured to: When the output voltage is less than the preset voltage, reducing the duty cycle of the PWM signal; When the output voltage is greater than the preset voltage, the duty cycle of the PWM signal is increased.

[0042] In some embodiments of the present invention, the output voltage of the constant voltage output circuit is expressed as follows: Vout=V FB (R1+R2) / R1-R2 (V PWM -V FB ) / R Where Vout represents the output voltage of the constant voltage output circuit, V FB Represents the feedback voltage of the constant voltage output circuit, R1 and R2 represent the voltage divider resistors of the constant voltage output circuit, V PWM represents the average voltage of the PWM signal, and R represents the resistance.

[0043] like Figure 3As shown, V FB =1.25V, R3, R4 and the controller are designed according to the needs of the actual intelligent system. R is the resistor connecting the fixed output product and the controller in this solution.

[0044] from Figure 3 It can be seen that when V PWM =1.25V, the current in resistor R is 0, and the entire right part has no effect on the left. At this time, Vout maintains the original product output voltage unchanged.

[0045] When V PWM When V > 1.25V, there is a leftward current in the resistor R, and when V PWM When <1.25V, there is a rightward current in the resistor R, which will affect the final output of the circuit through the feedback network. The relationship is: Vout = V FB (R1+R2) / R1-R2 (V PWM -V FB ) / R(1) Assuming that R1 = 2.7kΩ, R2 = 49.9kΩ, the PWM signal high level is 3.3V, the low level is 0V, the PWM signal duty cycle is D, and assuming R = 10kΩ, substituting into the above formula we can get: Vout = 30.6 - 16.47·D (2) When D=40%, the output Vout=24V; in the extreme state, when D=100%, Vout=14.13V; when D=0%, Vout=30.6V.

[0046] That is, after modification, the output voltage of the fixed output circuit can be varied between 14.13V and 30.6V according to the needs of the controller. If other ranges are required, the resistance value can be adjusted accordingly without exceeding the operating range of the component.

[0047] When the controller receives a remote control command, when the control command requires the circuit output voltage Vout to be Vo, when the output voltage Vout is different from the preset voltage Vo, the duty cycle of the PWM signal needs to be adjusted.

[0048] When the output voltage is less than the preset voltage, the duty cycle of the PWM signal is reduced. When the output voltage is greater than the preset voltage, the duty cycle of the PWM signal is increased until the output voltage is the same as the preset voltage, and a corresponding PWM signal is generated according to the duty cycle.

[0049] Exemplarily, the control algorithm is as follows: S1, the controller outputs PWM signal according to the initial D=40%; S2. Detect the voltage division result of R3 and R4 on the circuit output voltage Vout in real time, denoted as Vf; S3. Calculate the circuit output voltage Vout = Vf·(R3 + R4) / R3 according to the voltage division principle; S4. Compare the magnitudes of Vout and Vo. If Vout < Vo, then D is decreased by a fixed unit; if Vout > Vo, then D is increased by a fixed unit; if Vout = Vo, then D remains unchanged; S5. Loop and execute the above S2, S3, and S4.

[0050] The fixed unit size by which the duty cycle D increases or decreases, as well as the values of R3 and R4, should be specifically determined according to actual needs.

[0051] According to the above method, a product with a fixed output can be transformed into a product with an adjustable output through this simple modification, and it can be successfully combined with the intelligent control part.

[0052] The circuit for changing the output voltage of a constant voltage output circuit provided by an embodiment of the present invention retains all the circuits of the existing product with a fixed output. In the intelligent control part, the output of the circuit is detected by the output sampling part, and after the controller performs operations through an appropriate algorithm, an adjustment signal is output in the form of a PWM pulse. This PWM signal is connected to the feedback network of the existing product with a fixed output through a resistor, and the feedback value of the original feedback network is affected through this PWM signal, thereby indirectly affecting the final output value.

[0053] Figure 4 It is a schematic structural diagram of the fixed output to adjustable output system provided by the present invention. As Figure 4 shown, the present invention can quickly combine various existing products with fixed outputs with a controller and transform them into an adjustable output form, so as to adapt to a wider range of applications. The advantages of the present invention are easy to implement and low cost. First, only one resistor is required for circuit connection, and a capacitor can be added for smoothing when necessary. Since the voltage and current of the feedback part are very small, low-voltage and small-capacity devices can be used, and the total cost of the two components is less than 1 cent. All other parts are essential for any solution and cannot be included in the cost of this solution. Second, both output sampling and PWM signal generation are easy to implement, and beginners can achieve them in a short time. As for the adjustment algorithm, it is essential for any solution and only needs to be slightly modified for this solution.

[0054] Figure 5 It is a schematic flowchart of an embodiment of the method for changing the output voltage of a constant voltage output circuit provided by the present invention. As Figure 5 shown, the method for changing the output voltage of a constant voltage output circuit includes: S501 : Utilize a controller to sample an output voltage of a constant voltage output circuit, and generate a PWM signal based on a preset voltage and the output voltage.

[0055] S502 : Input the PWM signal into a feedback circuit of a constant voltage output circuit using a resistor, and adjust the constant voltage output circuit to output the preset voltage.

[0056] The method for changing the output voltage of a constant voltage output circuit provided by the present invention may be implemented by the circuit for changing the output voltage of a constant voltage output circuit described in any of the above embodiments.

[0057] The constant voltage output circuit can be a DCDC constant voltage output circuit, an LED constant current drive circuit or a switching power supply circuit with constant voltage output, etc., which is used to output a fixed voltage.

[0058] The controller is connected to the feedback circuit of the constant voltage output circuit via the resistor R, so that the controller can sample the output voltage of the constant voltage output circuit and generate a PWM signal according to the preset voltage and the output voltage.

[0059] The PWM signal is connected to the feedback network of the constant voltage output circuit through the resistor R, so that the feedback value of the original feedback network is affected by the PWM signal, thereby indirectly affecting the final output value, so that the constant voltage output circuit outputs a preset voltage, transforming the constant voltage output circuit into an adjustable output circuit, and can be smoothly combined with the intelligent control part.

[0060] In the embodiment of the present invention, the circuit connection only requires one resistor. Since the voltage and current of the feedback part are very small, low-voltage and small-capacity devices can be used, the component cost is low, and output sampling and PWM signal generation are easy to achieve.

[0061] To sum up, the method for changing the output voltage of a constant-voltage output circuit provided by an embodiment of the present invention samples the output voltage of the constant-voltage output circuit through a controller, and generates a PWM signal based on a preset voltage and the output voltage, and inputs the PWM signal into the feedback circuit of the constant-voltage output circuit through a resistor, thereby affecting the feedback value of the original feedback network through the PWM signal, thereby indirectly affecting the final output value, so that the constant-voltage output circuit outputs a preset voltage, thereby realizing the transformation of the constant-voltage output circuit into an adjustable output circuit, and the circuit connection only requires one resistor, which is relatively low in cost.

[0062] In some embodiments of the present invention, generating a PWM signal based on a preset voltage and the output voltage includes: When the output voltage is different from the preset voltage, adjusting the duty cycle of the PWM signal; The PWM signal is generated until the output voltage is the same as the preset voltage.

[0063] In some embodiments of the present invention, when the output voltage is different from the preset voltage, adjusting the duty cycle of the PWM signal includes: When the output voltage is less than the preset voltage, reducing the duty cycle of the PWM signal; When the output voltage is greater than the preset voltage, increasing the duty cycle of the PWM signal.

[0064] The controller can receive remote control commands through networks, wirelessly, etc. The control command includes a preset voltage Vo, and the control command is used to instruct the output voltage Vout of the constant voltage output circuit to be the preset voltage Vo.

[0065] When the controller receives a remote control command, when the control command requires the circuit output voltage Vout to be Vo, and when the output voltage Vout is different from the preset voltage Vo, it is necessary to adjust the duty cycle of the PWM signal.

[0066] When the output voltage is less than the preset voltage, reduce the duty cycle of the PWM signal. When the output voltage is greater than the preset voltage, increase the duty cycle of the PWM signal. Until the output voltage is the same as the preset voltage, generate a corresponding PWM signal according to this duty cycle.

[0067] Exemplarily, the control algorithm is as follows: S1. The controller outputs a PWM signal according to an initial D = 40%; S2. Detect in real time the voltage division result of R3 and R4 on the circuit output voltage Vout, and assume it is denoted as Vf; S3. Calculate the circuit output voltage Vout = Vf·(R3 + R4) / R3 according to the voltage division principle; S4. Compare the magnitudes of Vout and Vo. If Vout < Vo, then D decreases by a fixed unit. If Vout > Vo, then D increases by a fixed unit. If Vout = Vo, then D remains unchanged; S5. Loop and execute the above S2, S3, and S4.

[0068] The method for changing the output voltage of the constant voltage output circuit provided by the embodiments of the present invention retains all the circuits of the existing fixed-output products. In the intelligent control part, the output of the circuit is detected by the output sampling part. After the controller completes the operation with an appropriate algorithm, it outputs an adjustment signal in the form of a PWM pulse. This PWM signal is connected to the feedback network of the existing fixed-output product through a resistor, and affects the feedback value of the original feedback network through this PWM signal, thereby indirectly affecting the final output value.

[0069] Furthermore, the same circuit processing can be used for other constant-voltage output circuits, and similar approaches can be used for other types of circuits, such as constant-current output and constant-power output. By sampling the circuit output current and then inputting it into the constant-voltage output circuit according to the method of the present invention, the constant-voltage output circuit can be transformed into a constant-current output circuit. In other words, the solution provided by the present invention can be combined with intelligent control to change the operating characteristics of the circuit, thereby expanding the scope of application of this solution.

[0070] The circuit and method for changing the output voltage of a constant voltage output circuit provided in embodiments of the present invention are low-cost, requiring only one resistor and one capacitor, and eliminating the need to modify the original circuit. They are highly compatible and applicable to any fixed-output product (such as a DC-DC chip or a constant-current module). Furthermore, they are intelligent and support remote control, load adaptation, and characteristic conversion (such as constant voltage to constant current).

[0071] Those skilled in the art will appreciate that all or part of the process flow of the above-described method embodiment can be implemented by instructing related hardware (such as a processor, controller, etc.) through a computer program, and the computer program can be stored in a computer-readable storage medium. The computer-readable storage medium may be a magnetic disk, an optical disk, a read-only memory, or a random access memory.

[0072] The above is a detailed introduction to the circuit and method for changing the output voltage of a constant voltage output circuit provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A circuit for changing the output voltage of a constant voltage output circuit, characterized in that: include: Controller and resistor; The controller is connected to the feedback circuit of the constant voltage output circuit through the resistor; The controller is used to sample the output voltage of the constant voltage output circuit and generate a PWM signal based on a preset voltage and the output voltage; The resistor is used to input the PWM signal into the feedback circuit of the constant voltage output circuit, so as to adjust the constant voltage output circuit to output the preset voltage.

2. The circuit for changing the output voltage of a constant voltage output circuit according to claim 1, wherein: Also includes capacitors; The capacitor and the voltage dividing resistor of the constant voltage output circuit are connected in parallel; The capacitor is used to smooth the PWM signal.

3. The circuit for changing the output voltage of a constant voltage output circuit according to claim 1, wherein: The controller is specifically used for: When the output voltage is different from the preset voltage, adjusting the duty cycle of the PWM signal; The PWM signal is generated until the output voltage is the same as the preset voltage.

4. The circuit for changing the output voltage of a constant voltage output circuit according to claim 3, wherein: The controller is specifically used for: When the output voltage is less than the preset voltage, reducing the duty cycle of the PWM signal; When the output voltage is greater than the preset voltage, the duty cycle of the PWM signal is increased.

5. The circuit for changing the output voltage of a constant voltage output circuit according to claim 1, wherein: The output voltage of the constant voltage output circuit is expressed as follows: Vout=V FB ·(R1+R2) / R1-R2·(V PWM -IN FB ) / R Where Vout represents the output voltage of the constant voltage output circuit, V FB Represents the feedback voltage of the constant voltage output circuit, R1 and R2 represent the voltage divider resistors of the constant voltage output circuit, V PWM represents the average voltage of the PWM signal, and R represents the resistance.

6. The circuit for changing the output voltage of a constant voltage output circuit according to claim 1, wherein: The controller is further configured to: A remote control command is received; the control command includes the preset voltage.

7. The circuit for changing the output voltage of a constant voltage output circuit according to claim 1, wherein: The constant voltage output circuit includes any one of the following: DCDC constant voltage output circuit, LED constant current drive circuit or constant voltage output switching power supply circuit.

8. A method for changing the output voltage of a constant voltage output circuit, characterized in that: The circuit for changing the output voltage of a constant voltage output circuit as claimed in any one of claims 1 to 7, comprising: Using a controller to sample the output voltage of the constant voltage output circuit, and generating a PWM signal based on a preset voltage and the output voltage; The PWM signal is input into a feedback circuit of a constant voltage output circuit by using a resistor, so as to adjust the constant voltage output circuit to output the preset voltage.

9. The method for changing the output voltage of a constant voltage output circuit according to claim 8, wherein: The generating of the PWM signal based on the preset voltage and the output voltage includes: When the output voltage is different from the preset voltage, adjusting the duty cycle of the PWM signal; The PWM signal is generated until the output voltage is the same as the preset voltage.

10. The method for changing the output voltage of a constant voltage output circuit according to claim 9, wherein: When the output voltage is different from the preset voltage, adjusting the duty cycle of the PWM signal includes: When the output voltage is less than the preset voltage, reducing the duty cycle of the PWM signal; When the output voltage is greater than the preset voltage, the duty cycle of the PWM signal is increased.

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