Multipath output power supply circuit for industrial instrument

Abstract

The utility model relates to the technical field of switching power supply circuits, in particular to a multi-output power supply circuit for an industrial instrument. Comprising an input rectification filter circuit used for converting an input AC voltage into a stable DC voltage; the flyback converter comprises a high-frequency transformer U1 and a control chip U3, the high-frequency transformer U1 is provided with a primary winding and a plurality of secondary windings, and the primary winding is connected to the output end of the input rectification filter circuit. The utility model provides a multi-path output power supply circuit for an industrial instrument, which can output four paths of voltages of 24V, 12V, 5V and-12V at the same time, and effectively solves the problems of high cost, large size, low efficiency and insufficient stability in the prior art.

Description

Technical Field

[0001] This utility model relates to the field of switching power supply circuit technology, specifically a multi-output power supply circuit for industrial instruments. Background Technology

[0002] In the field of industrial instrumentation, various DC voltages are typically used to power different functional modules, such as relays, sensors, digital circuits, and DA chips. Traditional power supplies often only provide a single or a few voltage outputs, failing to meet the power supply needs of the diverse components in modern industrial instruments. For example, relays typically require 24V to operate, sensors may require 12V or 5V, digital circuits generally use 5V, while DA chips sometimes require -12V. Using multiple independent power supply modules is not only costly but also bulky, hindering the miniaturization and integration of industrial instruments. Furthermore, some existing power supply circuits are insufficient in terms of stability and load-bearing capacity, making them susceptible to external interference that causes output voltage fluctuations, affecting the normal operation of industrial instruments. Utility Model Content

[0003] This utility model addresses the technical problems existing in the prior art by providing a multi-output power supply circuit for industrial instruments that simultaneously supports multiple stable DC voltage outputs to meet the power supply requirements of different functional modules in industrial instruments. Furthermore, it reduces production costs and circuit size while maintaining high stability and strong load-carrying capacity.

[0004] The technical solution of this utility model to solve the above-mentioned technical problems is as follows:

[0005] A multi-output power supply circuit for industrial instruments is provided, comprising:

[0006] An input rectifier and filter circuit is used to convert the input AC voltage into a stable DC voltage;

[0007] A flyback converter includes a high-frequency transformer U1 and a control chip U3. The high-frequency transformer U1 has a primary winding and multiple secondary windings. The primary winding is connected to the output terminal of the input rectifier filter circuit.

[0008] Multiple output rectifier and filter circuits are respectively connected to the corresponding secondary windings of the high-frequency transformer U1 to convert the high-frequency pulse voltage into a stable DC output voltage.

[0009] A negative feedback control circuit includes sampling resistors R10 and R11, a reference power supply U5, and an optocoupler U4. The negative feedback control circuit samples the output voltage from the secondary winding of the high-frequency transformer U1 and feeds the sampled signal back to the control chip U3. The control chip U3 adjusts the on-time and frequency of the switching transistor according to the feedback signal to stabilize the output voltage.

[0010] Furthermore, the input rectifier and filter circuit includes: a fuse F1 connected between the live wire L and the neutral wire N; a filter YM1 and a capacitor C7 connected in series between the live wire L and the neutral wire N; a common-mode choke U2 connected after the filter YM1 and the capacitor C7; full-bridge rectifier diodes D4-D7 connected to the output terminal of the common-mode choke U2; and a filter capacitor C8 connected to the output terminal of the full-bridge rectifier diodes D4-D7.

[0011] Furthermore, the primary winding of the high-frequency transformer U1 is composed of pins 1 and 3, and the primary winding is connected to the output terminal of the input rectifier and filter circuit; the secondary winding of the high-frequency transformer U1 includes: a 24V output winding composed of pins 10 and 9, a 12V output winding composed of pins 8 and 6, a 5V output winding composed of pins 7 and 6, and a -12V output winding composed of pins 11 and 6, with pin 6 grounded and serving as the common terminal of the secondary winding.

[0012] Furthermore, the output rectifier and filter circuit includes multiple diodes and capacitors, each of which is connected to the corresponding secondary winding of the high-frequency transformer U1. The DC output voltage includes: a 24V voltage for powering the relay, a 12V voltage for powering the sensor, a 5V voltage for powering the digital circuit, and a -12V voltage for powering the DA chip.

[0013] Furthermore, in the negative feedback control circuit, the sampling resistors R10 and R11 are connected between pins 7 and 6 of the high-frequency transformer U1, the input terminal of the reference power supply U5 is connected to the voltage divider point of the sampling resistors R10 and R11, and the output terminal of the reference power supply U5 is connected to pin 4 of the control chip U3 through the optocoupler U4. The control chip U3 adjusts the on-time and frequency of the switching transistor according to the feedback signal transmitted by the optocoupler U4 to stabilize the output voltage.

[0014] Furthermore, pin 3 of the control chip U3 is connected to the secondary winding formed by pins 5 and 4 of the high-frequency transformer U1. The control chip U3 adjusts the on-time and frequency of the switching transistor according to the feedback signal of the negative feedback control circuit. When the switching transistor is on, the primary winding of the high-frequency transformer U1 stores energy. When the switching transistor is off, the energy stored in the primary winding is coupled to the secondary winding through the high-frequency transformer U1, and the secondary winding outputs a high-frequency pulse voltage.

[0015] Furthermore, the power supply circuit also includes an overvoltage protection circuit, which includes a Zener diode ZD1 and a current-limiting resistor R12. The Zener diode ZD1 and the current-limiting resistor R12 are connected in series to the output terminal of the input rectifier and filter circuit. When the input voltage exceeds the set value, the Zener diode ZD1 conducts to shunt the excess voltage, thereby protecting the power supply circuit from overvoltage damage.

[0016] The beneficial effects of this utility model are:

[0017] This invention provides a multi-output power supply circuit for industrial instruments, capable of simultaneously outputting four voltages: 24V, 12V, 5V, and -12V. This effectively solves the problems of high cost, large size, low efficiency, and insufficient stability in existing technologies. By optimizing the turns ratio of the primary and secondary windings of the high-frequency transformer U1, precise output of different voltages is achieved. The high-frequency transformer U1 in the flyback converter has a primary winding and multiple secondary windings. The primary winding is connected to the output terminal of the input rectifier and filter circuit, while the secondary windings output 24V, 12V, 5V, and -12V voltages respectively. Each output rectifier and filter circuit is connected to the corresponding secondary winding of the high-frequency transformer U1, converting the high-frequency pulse voltage into a stable DC output voltage.

[0018] Furthermore, this invention also includes a negative feedback control circuit. This circuit samples the output voltage from the secondary winding of the high-frequency transformer U1 and feeds the sampled signal back to the control chip U3. The control chip U3 adjusts the on-time and frequency of the switching transistor based on the feedback signal to stabilize the output voltage. This negative feedback mechanism effectively resists external interference and ensures the stability of the output voltage. Even under conditions of input voltage fluctuations or load changes, it ensures that the output voltage remains within the specified error range.

[0019] Furthermore, this invention employs a switching transistor and an optimized circuit topology, improving the power supply's load-carrying capacity. It can operate stably over a wide load current range, providing ample power support for various loads in industrial instruments and preventing voltage drops or power supply damage due to excessive load. Simultaneously, by selecting miniaturized electronic components and optimizing the circuit design, the number of unnecessary components is reduced, lowering product size and production costs, making it suitable for large-scale application in industrial instruments. Attached Figure Description

[0020] Figure 1 This is the circuit diagram of this utility model. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model. Furthermore, it should be understood that the specific embodiments described herein are merely for explaining this utility model and are not intended to limit this utility model.

[0022] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0023] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0024] The following disclosure provides numerous different embodiments or examples for implementing various structures of the present invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention; however, those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0025] The present invention provides the following preferred embodiments:

[0026] To address the problems of high cost, large size, low efficiency, and insufficient stability in existing industrial instrument power supply circuits, this embodiment provides a multi-output power supply circuit for industrial instruments, such as... Figure 1 As shown, by cleverly designing the transformer winding turns ratio and rectifier filter circuit, precise output of different voltages is achieved, and the stability of the output voltage is ensured through a negative feedback control circuit.

[0027] Specifically, this switching power supply circuit mainly consists of the following parts:

[0028] The input rectifier and filter circuit converts the input AC voltage into DC voltage and filters it to remove noise and interference, providing a stable DC input for the subsequent flyback converter.

[0029] A flyback converter converts the input DC voltage into a high-frequency pulse voltage by periodically turning the switching transistor on and off, and uses a transformer to achieve voltage transformation and isolation.

[0030] The output rectifier and filter circuit rectifies and filters the high-frequency pulse voltage output from the transformer to obtain stable DC output voltages of 24V, 12V, 5V and -12V.

[0031] The negative feedback control circuit samples the output voltage and compares it with a reference voltage to generate an error signal. After amplification and processing, the error signal is fed back to the control chip of the flyback converter to adjust the on-time and frequency of the switching transistors to stabilize the output voltage.

[0032] To address the issues of input voltage fluctuations and interference in existing technologies, this embodiment further optimizes the design of the input rectifier and filter circuit. The input rectifier and filter circuit includes a fuse F1, a filter YM1, a common-mode choke U2, a capacitor C7, full-bridge rectifier diodes D4-D7, and a filter capacitor C8.

[0033] Furthermore, fuse F1 is connected between the live wire L and the neutral wire N to protect the circuit from overcurrent. Filter YM1 and capacitor C7 are connected in series between the live wire L and the neutral wire N to filter out noise and interference in the input AC voltage. Common-mode choke U2 is connected after filter YM1 and capacitor C7 to further filter out power-mode interference. Full-bridge rectifier diodes D4-D7 are connected to the output of common-mode choke U2 to convert AC voltage to DC voltage. Filter capacitor C8 is connected to the output of full-bridge rectifier diodes D4-D7 to smooth the rectified DC voltage and provide a stable DC input to the flyback converter.

[0034] To further improve the efficiency and reliability of the power supply circuit, this embodiment uses a flyback converter as the core component. The flyback converter includes a high-frequency transformer U1 and a control chip U3.

[0035] Furthermore, the high-frequency transformer U1 has a primary winding and multiple secondary windings. The primary winding, consisting of pins 1 and 3, is connected to the output of the input rectifier and filter circuit. The secondary windings of the high-frequency transformer U1 include: a 24V output winding consisting of pins 10 and 9; a 12V output winding consisting of pins 8 and 6; a 5V output winding consisting of pins 7 and 6; and a -12V output winding consisting of pins 11 and 6. Pin 6 is the common terminal of the secondary windings and is grounded. By optimizing the turns ratio of the primary and secondary windings of the high-frequency transformer U1, precise output of different voltages is achieved.

[0036] Furthermore, pin 3 of control chip U3 is connected to the secondary winding formed by pins 5 and 4 of high-frequency transformer U1. Control chip U3 controls the switching transistor to turn on and off according to the feedback signal from the negative feedback control circuit. When the switching transistor is on, the primary winding of the transformer stores energy; when the switching transistor is off, the energy stored in the primary winding is coupled to the secondary winding through the transformer, and the secondary winding outputs a high-frequency pulse voltage.

[0037] To further improve the stability and accuracy of the output voltage, this embodiment includes multiple output rectifier and filter circuits. Each output rectifier and filter circuit is connected to the corresponding secondary winding of the high-frequency transformer U1 to convert the high-frequency pulse voltage into a stable DC output voltage.

[0038] Furthermore, the 24V output rectifier and filter circuit includes diode D8 and capacitor C9, the 12V output rectifier and filter circuit includes diode D9 and capacitor C10, the 5V output rectifier and filter circuit includes diode D10 and capacitor C11, and the -12V output rectifier and filter circuit includes diode D11 and capacitor C12. These rectifier and filter circuits convert the high-frequency pulse voltage output from the high-frequency transformer U1 into stable DC output voltages of 24V, 12V, 5V, and -12V, respectively. The 24V voltage is used to power the relay, the 12V voltage is used to power the sensor, the 5V voltage is used to power the digital circuit, and the -12V voltage is used to power the DA chip.

[0039] To further improve the stability and anti-interference capability of the output voltage, this embodiment introduces a negative feedback control circuit. The negative feedback control circuit includes sampling resistors R10 and R11, a reference power supply U5, and an optocoupler U4.

[0040] Furthermore, sampling resistors R10 and R11 are connected between pins 7 and 6 of the high-frequency transformer U1 to sample the output voltage. The input of the reference power supply U5 is connected to the voltage divider point of sampling resistors R10 and R11, and the output of the reference power supply U5 is connected to pin 4 of the control chip U3 via optocoupler U4. The control chip U3 adjusts the on-time and frequency of the switching transistor according to the feedback signal transmitted by the optocoupler U4 to stabilize the output voltage. This negative feedback mechanism can effectively resist external interference and ensure the stability of the output voltage, ensuring that the output voltage remains within the specified error range even under conditions of input voltage fluctuations or load changes.

[0041] Further, the working process of this utility model is as follows: 220V AC power is input through the live wire L and neutral wire N in the circuit diagram. F1 is a fuse. The input AC voltage is filtered and common-mode interference is removed by YM1, C7, and U2. D4-D7 are used for full-bridge rectification, and C8 is used for filtering after rectification. The rectified and filtered voltage is input from pin 1 of the U1 high-frequency transformer. Pins 1 and 3 of U1 are the primary windings of the high-frequency transformer. U1 also has 5 secondary windings. The secondary winding formed by pins 10 and 9 outputs 24V; the secondary winding formed by pins 8 and 6 outputs 12V; the secondary winding formed by pins 7 and 6 outputs 5V; and the secondary winding formed by pins 11 and 6 outputs -12V. Pin 6 is the common terminal of the above three secondary windings and is grounded. The high-frequency pulse voltage output from the secondary winding passes through its respective output rectifier and filter circuits to obtain DC output voltages of 24V, 12V, 5V and -12V, which power relays, sensors, digital circuits and DA chips.

[0042] Furthermore, the secondary winding output voltage formed by pins 5 and 4 of U1 is supplied to pin 3 of the control chip U3 of the flyback converter. The control chip controls the switching transistor to turn on and off based on the feedback signal. When the switching transistor is on, the primary winding of the transformer stores energy; when the switching transistor is off, the energy stored in the primary winding is coupled to the secondary winding through the transformer, and the secondary winding outputs a high-frequency pulse voltage.

[0043] Furthermore, the negative feedback control circuit samples the output voltage of the secondary winding formed by pins 7 and 6 of U1 in real time. The sampled 5V voltage is divided by R10 and R11 and then input to the reference power supply U5 as its reference voltage. The output voltage of U5 is output through its pin 2, and then through the optocoupler U4 to the pin 4 of the control chip U4. The control chip compares the sampled signal with the reference voltage and adjusts the conduction time and frequency of the switching transistor according to the error signal, thereby ensuring the stability of the output voltage.

[0044] To further optimize circuit performance, this embodiment also considers other possible additional features. For example, an overvoltage protection circuit can be added to the circuit to protect it from overvoltage damage. The overvoltage protection circuit may include a Zener diode ZD1 and a current-limiting resistor R12. When the input voltage exceeds a set value, the Zener diode ZD1 conducts, diverting the excess voltage and protecting the circuit from damage.

[0045] Furthermore, a temperature compensation circuit can be added to the circuit to compensate for the impact of temperature changes on the output voltage. The temperature compensation circuit can include a thermistor RT1 and an operational amplifier U6, which detects the ambient temperature and adjusts the output voltage to ensure its stability and accuracy.

[0046] The advantage of this embodiment is that the multi-output power supply circuit for industrial instruments provided in this embodiment can simultaneously provide multiple stable DC voltage outputs in a single power supply circuit, meeting the power supply requirements of different functional modules in industrial instruments. By optimizing the turns ratio of the primary and secondary windings of the high-frequency transformer U1, precise output of different voltages is achieved. The input rectifier and filter circuit includes a fuse F1, a filter YM1, a common-mode choke U2, a capacitor C7, full-bridge rectifier diodes D4-D7, and a filter capacitor C8, converting the input AC voltage into a stable DC voltage. The high-frequency transformer U1 in the flyback converter has a primary winding and multiple secondary windings. The primary winding is connected to the output terminal of the input rectifier and filter circuit, and the secondary windings output 24V, 12V, 5V, and -12V voltages respectively. Each output rectifier and filter circuit is connected to the corresponding secondary winding of the high-frequency transformer U1, converting the high-frequency pulse voltage into a stable DC output voltage.

[0047] Furthermore, the negative feedback control circuit samples the output voltage and compares it with a reference voltage to generate an error signal. This error signal, after amplification and processing, is fed back to the flyback converter's control chip to adjust the on-time and frequency of the switching transistors, thereby stabilizing the output voltage. This negative feedback mechanism effectively resists external interference and ensures the stability of the output voltage, maintaining it within a specified error range even under conditions of input voltage fluctuations or load changes.

[0048] Furthermore, by employing high-performance switching transistors and an optimized circuit topology, the power supply's load-carrying capacity is improved, enabling stable operation over a wider load current range. This provides ample power support for various loads in industrial instruments, preventing voltage drops or power supply damage due to excessive load. Simultaneously, the selection of miniaturized electronic components and optimized circuit design reduces the number of unnecessary components, lowering production costs and resulting in excellent cost-effectiveness, making it more suitable for large-scale application in industrial instruments.

[0049] The circuit design provided in this embodiment not only solves the problems of high cost, large size, low efficiency and insufficient stability in the prior art, but also provides an efficient, reliable and economical solution that meets the diverse needs of industrial instruments in practical applications.

[0050] The beneficial effects of this utility model are specifically reflected in the fact that the above description is only a preferred embodiment of this utility model and is not intended to limit this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A multi-output power supply circuit for industrial instruments, characterized by, The utility model relates to a kind of power supply, including: An input rectifier filter circuit is used to convert input AC voltage into stable DC voltage; A flyback converter, the flyback converter includes high-frequency transformer U1 and control chip U3, the high-frequency transformer U1 has primary winding and multiple secondary windings, the primary winding is connected to the output terminal of the input rectifier filter circuit; Multiple output rectifier filter circuits are respectively connected to the corresponding secondary windings of the high-frequency transformer U1 to convert high-frequency pulse voltage into stable DC output voltage; A negative feedback control circuit, the negative feedback control circuit includes sampling resistors R10 and R11, reference power supply U5, optocoupler U4, the negative feedback control circuit samples output voltage from the secondary winding of the high-frequency transformer U1, and feeds back the sampling signal to the control chip U3, the control chip U3 adjusts the on-time and frequency of the switching tube according to the feedback signal to stabilize the output voltage.

2. The multiple output power supply circuit for an industrial meter as claimed in claim 1, wherein, The input rectifier filter circuit includes: a fuse F1 connected between the live wire L and the neutral wire N, a filter YM1 and a capacitor C7 connected in series and then connected between the live wire L and the neutral wire N, a common-mode choke U2 connected after the filter YM1 and the capacitor C7, full-bridge rectifier diodes D4-D7 connected at the output terminal of the common-mode choke U2, and a filter capacitor C8 connected at the output terminal of the full-bridge rectifier diodes D4-D7.

3. The multiple output power supply circuit for an industrial meter as claimed in claim 1, wherein, The primary winding of the high-frequency transformer U1 is composed of pin 1 and pin 3, and the primary winding is connected to the output terminal of the input rectifier filter circuit; the secondary windings of the high-frequency transformer U1 include: a 24V output winding composed of pin 10 and pin 9, a 12V output winding composed of pin 8 and pin 6, a 5V output winding composed of pin 7 and pin 6, and a -12V output winding composed of pin 11 and pin 6, with pin 6 grounded and serving as the common terminal of the secondary windings.

4. The multiple output power supply circuit for an industrial meter as claimed in claim 1, wherein, The output rectifier filter circuits include multiple diodes and capacitors, and each output rectifier filter circuit is connected to the corresponding secondary winding of the high-frequency transformer U1, and the DC output voltage includes: 24V voltage for powering the relay, 12V voltage for powering the sensor, 5V voltage for powering the digital circuit, and -12V voltage for powering the DA chip.

5. The multiple output power supply circuit for an industrial meter as claimed in claim 1, wherein, In the negative feedback control circuit, the sampling resistors R10 and R11 are connected between pin 7 and pin 6 of the high-frequency transformer U1, the input terminal of the reference power supply U5 is connected to the voltage-dividing point of the sampling resistors R10 and R11, the output terminal of the reference power supply U5 is connected to pin 4 of the control chip U3 through the optocoupler U4, and the control chip U3 adjusts the on-time and frequency of the switching tube according to the feedback signal transmitted by the optocoupler U4 to stabilize the output voltage.

6. The multiple output power supply circuit for an industrial meter as claimed in claim 1, wherein, The No. 3 pin of the control chip U3 is connected to the secondary winding composed of No. 5 pin and No. 4 pin of the high-frequency transformer U1, and the control chip U3 adjusts the on-time and frequency of the switch tube according to the feedback signal of the negative feedback control circuit; when the switch tube is on, the primary winding of the high-frequency transformer U1 stores energy, and when the switch tube is off, the energy stored in the primary winding is coupled to the secondary winding through the high-frequency transformer U1, and the secondary winding outputs high-frequency pulse voltage.

7. The multiple output power supply circuit for an industrial meter as claimed in claim 1, wherein, The power supply circuit further comprises an overvoltage protection circuit, which comprises a voltage stabilizing diode ZD1 and a current limiting resistor R12, which are connected in series at the output end of the input rectification and filtering circuit; when the input voltage exceeds the set value, the voltage stabilizing diode ZD1 is turned on to shunt the excess voltage, so as to protect the power supply circuit from overvoltage damage.

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