Solid-state relay circuit
By setting a Darlington tube in the input circuit of the solid-state relay circuit, increasing the current amplification of the isolation circuit, the problem of temperature rise when the traditional solid-state relay circuit is turned on is solved, and faster response speed and longer service life are achieved.
Patent Information
- Application Number
- CN202420566448.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-22
- Publication Date
- 2025-03-25
- Estimated Expiration
- 2034-03-22
AI Technical Summary
Traditional solid-state relay circuits have a problem of temperature rise when they are turned on, especially under high current loads, which affects product performance and service life.
By setting a Darlington tube in the input circuit, the current to open the isolation circuit is increased, thereby shortening the opening time of the isolation circuit and reducing the temperature rise. The Darlington tube consists of a first transistor and a second transistor, and achieves a larger current amplification through their amplification.
It realizes reducing temperature rise when the solid-state relay is turned on, speeding up the response speed, and improving the versatility and service life of the product.
Smart Images
Figure CN222674294U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of relays, in particular to a solid-state relay circuit. Background Art
[0002] At present, with the improvement of people's living standards, the application of intelligent equipment and instruments in the field of industrial control is becoming more and more extensive. Industrial control automation technology is developing towards intelligence, networking and integration. The convenience of module disassembly and assembly is becoming more and more important.
[0003] Traditional solid-state relay circuits usually include input circuits, isolation circuits, and output circuits. The input circuit is used to connect the control end, the output circuit is used to connect the load end, and the isolation circuit is used to isolate the control end from the load end. When a conventional solid-state relay is working normally, the input circuit controls the isolation circuit to open. Affected by the current, it takes a certain amount of time for the isolation circuit to open. During the opening of the isolation circuit, a certain temperature rise will occur, especially under high current loads. According to P=UI, the larger the current, the more obvious the temperature rise, which greatly affects the product performance and service life. Utility Model Content
[0004] The main purpose of the utility model is to overcome the defect of temperature rise when the existing solid-state relay circuit is turned on, and propose a solid-state relay circuit. By setting a Darlington tube, the current of opening the isolation circuit is increased, so that the opening time of the isolation circuit is shortened and the temperature rise generated is lower.
[0005] The utility model adopts the following technical solutions:
[0006] A solid-state relay circuit comprises an input circuit, an isolation circuit and an output circuit, wherein the input end of the isolation circuit is connected to the input circuit, the output end of the isolation circuit is connected to the output circuit, the input circuit is provided with a Darlington tube to amplify the current in the circuit, and the emitter of the Darlington tube is connected to the positive input end of the isolation circuit.
[0007] Furthermore, the Darlington tube is provided with a first triode and a second triode, the first triode and the second triode are connected with the same pole or with different poles, the base of the first triode serves as the base of the Darlington tube, and the emitter of the second triode serves as the emitter of the Darlington tube.
[0008] Furthermore, the gain of the Darlington transistor is the product of the gain of the first transistor and the gain of the second transistor.
[0009] Furthermore, the first transistor is an NPN transistor or a PNP transistor, and the second transistor is an NPN transistor or a PNP transistor; the power of the first transistor is less than the power of the second transistor.
[0010] Furthermore, the input circuit also includes a resistor R1, a resistor R2, a resistor R3, a resistor R4, a diode VD1, a capacitor C1 and a capacitor C2. The positive input end of the input circuit is connected in series with the diode VD1, the resistor R1 and the resistor R2 in sequence. The capacitor C1 is connected in parallel with the resistor R1. One end of the resistor R3 is connected to the connected end of the resistor R2 and the resistor R1. The other end of the resistor R3 is connected to one end of the resistor R4 and one end of the capacitor C2. The other end of the resistor R4 is connected to the base of the Darlington tube. The other end of the capacitor C2 is connected to the negative input end of the isolation circuit.
[0011] Furthermore, the input circuit also includes a resistor R5 and a light emitting diode LED1; the positive electrode of the light emitting diode LED1 is connected to the negative electrode of the diode VD1, the negative electrode of the light emitting diode is connected to one end of the resistor R5, and the other end of the resistor R5 is connected to the other end of the capacitor C2.
[0012] Furthermore, the isolation circuit uses an optical coupler, the input end of the optical coupler is connected to the input circuit, and the output end of the optical coupler is connected to the output circuit.
[0013] Furthermore, the isolation circuit uses a transformer, the input end of the transformer is connected to the input circuit, and the output end of the transformer is connected to the output circuit.
[0014] It can be seen from the above description of the utility model that compared with the prior art, the utility model has the following beneficial effects:
[0015] 1. In the circuit of the utility model, a Darlington tube is arranged in the input circuit to amplify the current in the circuit, that is, a Darlington tube is used at the control electrode to provide a larger current, thereby accelerating the connection speed of the relay, thereby reducing the temperature rise in the connection stage, improving the product response speed, expanding the versatility of the product, increasing the target audience of the product, and better meeting customer needs.
[0016] 2. In the circuit of the utility model, the Darlington tube is provided with a first triode and a second triode, the first triode and the second triode are connected with the same pole or with different poles, and the amplification factor of the Darlington tube is the product of the amplification factor of the first triode and the amplification factor of the second triode, thereby achieving a larger current provided by a larger amplification factor to control the solid-state relay to open quickly.
[0017] 3. The circuit of the utility model can be used on various solid-state relays, especially in relays with large current loads, and the use of Darlington tubes to connect them has a significant effect of reducing temperature rise. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 This is the circuit diagram of the solid-state relay;
[0019] Figure 2 This is the input circuit diagram of the solid-state relay of the utility model;
[0020] Figure 3 This is the circuit diagram of the solid-state relay of the utility model. DETAILED DESCRIPTION
[0021] The present invention is further described below through specific implementation methods.
[0022] The terms "first" and "second" appearing in the present invention are only for the convenience of description to distinguish different components with the same name, and do not indicate a sequence or primary and secondary relationship.
[0023] In the description of the present invention, the directions or positional relationships indicated by “up”, “down”, “left”, “right”, “front” and “back” are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention. They do not indicate or imply that the device referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention.
[0024] In addition, in the description of this application, unless otherwise specified, "plurality" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the associated objects are in an "or" relationship.
[0025] See also Figure 1 , Figure 2 A solid-state relay circuit includes an input circuit, an isolation circuit and an output circuit. The input circuit is also a control circuit, which provides a loop for the input control signal so that the control signal becomes the trigger source of the solid-state relay. The isolation circuit is used to achieve isolation and coupling between the input circuit and the output circuit. The input end of the isolation circuit is connected to the input circuit, and the output end of the isolation circuit is connected to the output circuit. The output circuit is controlled by a trigger signal to achieve on / off switching of the load power supply, etc.
[0026] In the utility model, a Darlington tube is arranged in the input circuit to amplify the current in the circuit, and the emitter of the Darlington tube is connected to the positive input end of the isolation circuit, that is, after the control signal is amplified, the large current of the amplified control signal can speed up the connection speed of the relay, thereby reducing the temperature rise in the connection stage.
[0027] Among them, the Darlington tube is provided with two triodes connected in series, namely the first triode and the second triode. The first triode and the second triode are connected in the same polarity or in different polarities. The amplification factor of the Darlington tube is the product of the amplification factor of the first triode and the amplification factor of the second triode. The first triode is an NPN triode or a PNP triode, the second triode is an NPN triode or a PNP triode, and the power of the first triode is set to be less than the power of the second triode. Then the Darlington tube has four connection combinations, namely NPN+NPN, PNP+PNP, NPN+PNP and PNP+NPN, the first two adopt the same polarity connection method, and the latter two adopt the different polarity connection method.
[0028] Figure 2 In the example of connecting the same poles, the base of the first transistor VT1 serves as the base of the Darlington transistor, the collector of the first transistor VT1 is connected to the collector of the second transistor and serves as the collector of the Darlington transistor, the emitter of the first transistor is connected to the base of the second transistor, and the emitter of the second transistor serves as the emitter of the Darlington transistor.
[0029] Furthermore, the input circuit also includes resistor R1, resistor R2, resistor R3, resistor R4, diode VD1, capacitor C1 and capacitor C2. The positive input end of the input circuit is connected in series with diode VD1, resistor R1 and resistor R2 in sequence, capacitor C1 is connected in parallel with resistor R1 to form a parallel RC, one end of resistor R3 is connected to the connected end of resistor R2 and resistor R1, the other end of resistor R3 is connected to one end of resistor R4 and one end of capacitor C2, the other end of resistor R4 is connected to the base of Darlington tube, and the other end of capacitor C2 is connected to the negative input end of the isolation circuit. Setting these resistors, diodes and capacitors in the input circuit can extend the release time and prevent lightning surges from causing malfunctions to the product.
[0030] Specifically, the input circuit also includes a resistor R5 and a light-emitting diode LED1; the positive electrode of the light-emitting diode LED1 is connected to the negative electrode of the diode VD1, the negative electrode of the light-emitting diode is connected to one end of the resistor R5, and the other end of the resistor R5 is connected to the other end of the capacitor C2. The resistor R5 and the light-emitting diode LED1 form an indication circuit, which can be used to indicate the state of the input circuit.
[0031] In the utility model, the isolation circuit adopts an optical coupler, the input end of the optical coupler is connected to the input circuit, and the output end of the optical coupler is connected to the output circuit. Optocouplers usually use photodiode-phototransistor, photodiode-bidirectional photo-controlled thyristor, photovoltaic cell, etc. to achieve isolation control between the control side and the load side. In practical applications, the isolation circuit can also use a high-frequency transformer, that is, the input end of the transformer is connected to the input circuit, and the output end of the transformer is connected to the output circuit. High-frequency transformer coupling is to use the self-excited high-frequency signal generated by the input control signal to couple to the secondary, and after detection and rectification, the drive signal is formed after the logic circuit is processed.
[0032] The output circuit is mainly used to realize the switching of the load power supply. It is mainly realized by high-power transistors (switching transistors), unidirectional thyristors (thyristors or SCRs), bidirectional thyristors (silicon controlled rectifiers), power field effect transistors (MOSFETs) or insulated gate bipolar transistors (IGBTs).
[0033] by Figure 3 Taking the output circuit in as an example, it includes resistor R6, resistor R7, transistor VT3, transistor VT4, resistor R8, diode D1, diode D2, field effect transistor Q1, field effect transistor Q2, capacitor C4 and TVS diode DR1, etc. Resistor R6 is connected in series to the output end of the isolation circuit, the base of transistor VT3 is connected to the base of transistor VT4, the collector of transistor VT3 is connected to one end of resistor R8, and the emitter of transistor VT3 is connected to the emitter of transistor VT4. The emitter is connected, the resistor R7 is connected between the base of the transistor VT3 and the emitter of the transistor VT3, the other end of the resistor R8 is connected to one end of the capacitor C3 and the cathode of the diode D1, the anode of the diode D1 is connected to the drain of the field effect transistor Q1 and the drain of the field effect transistor Q2, the gates of the field effect transistor Q1 and the field effect transistor Q2 are connected, the cathode of the diode D2 is connected to the gate of the field effect transistor Q1, one end of the TVS diode DR1 and one end of the capacitor C4 are connected to the drain of the field effect transistor Q2. The collector of the transistor VT4, the other end of the capacitor C3, the source of the field effect transistor Q1, the source of the field effect transistor Q2, the anode of the diode D2, the other end of the TVS diode DR1 and the other end of the capacitor C4 are connected. Among them, the TVS diode DR1 is a transient voltage suppression diode, which can prevent the impact on the product under the inductive load and protect the product.
[0034] The circuit of the utility model uses the first transistor VT1 and the second transistor VT2 to form a Darlington tube, which amplifies the circuit current at the control pole and improves the opening speed of the optocoupler in the isolation circuit. According to Joule's law: Q = UIt, the conduction current converts electrical energy into thermal energy, and the heat generated by the current passing through the conductor is proportional to the square of the current, proportional to the resistance of the conductor, and proportional to the power-on time. Therefore, the shorter the optocoupler opening time, the smaller the internal resistance, and the lower the power consumption generated by the product during the optocoupler opening process, which improves the temperature rise.
[0035] The above is only a specific implementation method of the utility model, but the design concept of the utility model is not limited to this. Any non-substantial changes to the utility model using this concept shall be deemed as an infringement of the protection scope of the utility model.
Claims
1. A solid-state relay circuit, comprising an input circuit, an isolation circuit and an output circuit, wherein the input end of the isolation circuit is connected to the input circuit, and the output end of the isolation circuit is connected to the output circuit, characterized in that: The input circuit is provided with a Darlington tube to amplify the current in the circuit, and the emitter of the Darlington tube is connected to the positive input end of the isolation circuit.
2. A solid-state relay circuit as claimed in claim 1, characterized in that: The Darlington tube is provided with a first triode and a second triode, the first triode and the second triode are connected with the same pole or with different poles, the base of the first triode serves as the base of the Darlington tube, and the emitter of the second triode serves as the emitter of the Darlington tube.
3. A solid-state relay circuit as claimed in claim 2, characterized in that: The amplification factor of the Darlington tube is the product of the amplification factor of the first triode and the amplification factor of the second triode.
4. A solid-state relay circuit as claimed in claim 2, characterized in that: The first transistor is an NPN transistor or a PNP transistor, and the second transistor is an NPN transistor or a PNP transistor; the power of the first transistor is less than the power of the second transistor.
5. A solid-state relay circuit as claimed in claim 1, characterized in that: The input circuit also includes a resistor R1, a resistor R2, a resistor R3, a resistor R4, a diode VD1, a capacitor C1 and a capacitor C2. The positive input end of the input circuit is connected in series with the diode VD1, the resistor R1 and the resistor R2 in sequence. The capacitor C1 is connected in parallel with the resistor R1. One end of the resistor R3 is connected to the connected end of the resistor R2 and the resistor R1. The other end of the resistor R3 is connected to one end of the resistor R4 and one end of the capacitor C2. The other end of the resistor R4 is connected to the base of the Darlington tube. The other end of the capacitor C2 is connected to the negative input end of the isolation circuit.
6. A solid-state relay circuit as claimed in claim 5, characterized in that: The input circuit also includes a resistor R5 and a light emitting diode LED1; the positive electrode of the light emitting diode LED1 is connected to the negative electrode of the diode VD1, the negative electrode of the light emitting diode is connected to one end of the resistor R5, and the other end of the resistor R5 is connected to the other end of the capacitor C2.
7. A solid-state relay circuit as claimed in claim 1, characterized in that: The isolation circuit adopts an optical coupler, the input end of the optical coupler is connected to the input circuit, and the output end of the optical coupler is connected to the output circuit.
8. A solid-state relay circuit as claimed in claim 1, characterized in that: The isolation circuit uses a transformer, the input end of the transformer is connected to the input circuit, and the output end of the transformer is connected to the output circuit.