Isolation communication circuit
By combining unidirectional conduction components, switches, and capacitors, the high cost of traditional isolation circuits is solved, achieving isolation and voltage reduction of low-level signals and reducing the cost of communication circuits.
Patent Information
- Application Number
- CN202520183022.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-06
- Publication Date
- 2026-02-24
- Estimated Expiration
- 2035-02-06
AI Technical Summary
Traditional isolation circuits and isolation chips are expensive, increasing the cost of communication circuits. Furthermore, additional step-down circuits are required for low-voltage signal interaction, further increasing costs.
The combination of first and second unidirectional conducting components, first and second switches, capacitors, and disconnect switches is used to achieve signal isolation and voltage reduction by controlling the signal level. The signal isolation and voltage reduction effect is achieved by using components such as optocouplers.
It achieves signal isolation and voltage reduction when the signal is at a low level, reduces circuit cost, and the power supply voltage can be set according to requirements, thus achieving the effects of isolation and voltage reduction.
Smart Images
Figure CN223942691U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of communication technology, and in particular to an isolated communication circuit. Background Technology
[0002] With the development of the economy and society, communication technology is being used more and more widely in various fields. Signals sent by processors or controllers need to be sent to external terminal devices through communication circuits.
[0003] When two motherboards / communication circuit boards exchange signals, they need to be connected by a cable. However, if the cable is too long and a short circuit or interference occurs along the way, it can affect the two motherboards / communication circuit boards that are exchanging signals. To prevent short circuits or interference from affecting the two motherboards / communication circuit boards, an isolation circuit or isolation chip needs to be added between the cable and the motherboard / communication circuit board. However, traditional isolation circuits and isolation chips are relatively expensive, increasing the cost of using the circuit.
[0004] Moreover, since the main control chip and communication chip require low voltage, the interactive electrical signals need to be stepped down. However, adding a step-down circuit or chip on top of the traditional isolation circuit or isolation chip further increases the cost of the communication circuit. Utility Model Content
[0005] The purpose of this invention is to provide an isolated communication circuit. When the input signal is a low-level signal, the first switch is turned on, and the capacitor controls the second switch to turn on through the first switch, which further turns on the isolating switch. The power supply voltage of the controlled end of the isolating switch can be set according to actual needs, thus achieving both isolation and voltage reduction.
[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:
[0007] One aspect of this utility model provides an isolated communication circuit, comprising: a first unidirectional conducting component and a second unidirectional conducting component, wherein the input terminals of the first and second unidirectional conducting components are connected to the positive terminal of an input signal; a first switch and a second switch, wherein the control terminal of the first switch is connected to the positive terminal of the input signal, the input terminal of the first switch is connected to the output terminal of the second unidirectional conducting component, the output terminal of the first switch is connected to the control terminal of the second switch, and the input terminal of the second switch is connected to the output terminal of the first unidirectional conducting component; a capacitor, wherein the positive terminal of the capacitor is connected to the input terminals of the first and second switches, and the negative terminal of the capacitor is connected to the negative terminal of the input signal; and an isolating switch, wherein the output terminal of the second switch is connected to the control terminal of the isolating switch, and the controlled terminal of the isolating switch outputs a stepped-down output signal; the first switch is configured to conduct when the control terminal receives a low-level signal, the second switch is configured to conduct when the control terminal receives a high-level signal, and the isolating switch is configured to output a high-level signal when the control terminal is energized.
[0008] In some embodiments, the disconnecting switch is an optocoupler.
[0009] In some embodiments, the first unidirectional conducting component includes a first diode and a first resistor, the negative terminal of the first diode is connected to one end of the first resistor, and the positive terminal of the first diode is connected to the positive terminal of the input signal; the second unidirectional conducting component uses a second diode, and the positive terminal of the second diode is connected to the positive terminal of the input signal.
[0010] In some embodiments, the first switch includes a PNP transistor, a second resistor, and a third resistor. The emitter of the PNP transistor is connected to the cathode of the second diode. The base of the PNP transistor is connected to the positive terminal of the input signal and one end of the second resistor. The other end of the second resistor is connected to the negative terminal of the input signal. The collector of the PNP transistor is connected to one end of the third resistor. The other end of the third resistor is connected to the negative terminal of the input signal. The second switch includes an NPN transistor and a fourth resistor. The base of the NPN transistor is connected to the collector of the PNP transistor. The collector of the transistor is connected to one end of the fourth resistor, the other end of the fourth resistor is connected to the other end of the first resistor, the emitter of the NPN transistor is connected to the input terminal of the light-emitting terminal of the optocoupler, the output terminal of the light-emitting terminal of the optocoupler is connected to the negative terminal of the input signal, the input terminal of the light-receiving terminal of the optocoupler is connected to the power supply, and the output terminal of the light-receiving terminal of the optocoupler outputs the output signal; the isolation communication circuit also includes a fifth resistor, one end of which is connected to the positive terminal of the capacitor and the other end of the fourth resistor, and the other end of which is connected to the emitter of the PNP transistor.
[0011] In some embodiments, the isolated communication circuit further includes a sixth resistor, one end of which is connected to the emitter of the PNP transistor, and the other end of which is connected to the negative terminal of the input signal.
[0012] In some embodiments, the isolated communication circuit further includes a seventh resistor, one end of which is connected to the emitter of the NPN transistor, and the other end of which is connected to the negative terminal of the input signal.
[0013] In some embodiments, the isolated communication circuit further includes an eighth resistor, one end of which is connected to the output terminal of the light-receiving end of the optocoupler, and the other end of which is grounded.
[0014] An isolated communication circuit according to an embodiment of the present invention has at least the following beneficial effects: when the input signal is a low-level signal, the PNP transistor is turned on, the capacitor controls the NPN transistor to turn on through the PNP transistor, and then the capacitor controls the light-emitting end of the optocoupler to emit light through the NPN transistor, further enabling the light-receiving end of the optocoupler to output a high-level signal. The power supply of the light-emitting end of the optocoupler is provided by the capacitor, and the power supply of the light-receiving end of the optocoupler can be set according to actual needs. Therefore, both isolation and voltage reduction effects are achieved.
[0015] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this disclosure. Attached Figure Description
[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0017] Figure 1 This is a schematic diagram of an isolated communication circuit according to an embodiment. Detailed Implementation
[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0019] The terms "first," "second," and "third" are used 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, a feature defined as "first," "second," or "third" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.
[0020] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" 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 or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0021] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that the description of this disclosure will be more complete and fully convey the concept of the exemplary embodiments to those skilled in the art. The drawings are merely illustrative of this disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted.
[0022] The technical solutions of the embodiments of this application are briefly described below:
[0023] According to some embodiments, such as Figure 1 As shown, this application provides an isolated communication circuit, which includes:
[0024] The first unidirectional conducting component and the second unidirectional conducting component are connected to the positive terminal of the input signal.
[0025] A first switch and a second switch, wherein the control terminal of the first switch is connected to the positive terminal of the input signal, the input terminal of the first switch is connected to the output terminal of the second unidirectional conducting element, the output terminal of the first switch is connected to the control terminal of the second switch, and the input terminal of the second switch is connected to the output terminal of the first unidirectional conducting element.
[0026] Capacitor C, with its positive terminal connected to the input terminals of the first and second switches, and its negative terminal connected to the negative terminal of the input signal;
[0027] The disconnector switch has its output terminal connected to the control terminal of the disconnector switch, and the controlled terminal of the disconnector switch outputs a stepped-down output signal.
[0028] The first switch is configured to conduct when a low-level signal is input to the control terminal, the second switch is configured to conduct when a high-level signal is input to the control terminal, and the isolating switch is configured to output a high-level signal when the control terminal is energized.
[0029] The working principle of the above embodiment is as follows: when the input signal is a high-level signal, capacitor C charges and the first switch is turned off. When the input signal is a low-level signal, the first switch is turned on, and capacitor C outputs a high-level signal to the control terminal of the second switch through the first switch, turning on the second switch and further turning on the isolating switch. The power supply voltage of the controlled terminal of the isolating switch can be set according to actual needs, thus achieving both isolation and voltage reduction effects.
[0030] The following is in conjunction with the appendix to this instruction manual. Figure 1 The preferred embodiments of this disclosure will be further described in detail below.
[0031] According to some embodiments, such as Figure 1 As shown, the disconnecting switch uses an optocoupler U, but it can also use a relay or other electronic components with isolation functions. This application does not limit the application.
[0032] According to some embodiments, such as Figure 1 As shown, the first unidirectional conducting component includes a first diode D1 and a first resistor R1. The cathode of the first diode D1 is connected to one end of the first resistor R1, and the anode of the first diode D1 is connected to the positive terminal of the input signal.
[0033] The second unidirectional conducting component uses a second diode D2, with the positive terminal of the second diode D2 connected to the positive terminal of the input signal.
[0034] In other embodiments, the first and second unidirectional conducting components may also be NPN transistors and resistors, with the two ends of the resistor connected to the base and collector of the NPN transistor, respectively. Other components with unidirectional conducting function may also be used, and this application is not limited thereto.
[0035] Furthermore, such as Figure 1 As shown, the first switch includes a PNP transistor Q1, a second resistor R2, and a third resistor R3. The emitter of the PNP transistor Q1 is connected to the negative terminal of the second diode D2, the base of the PNP transistor Q1 is connected to the positive terminal of the input signal, one end of the second resistor R2, the other end of the second resistor R2 is connected to the negative terminal of the input signal, and the collector of the PNP transistor Q1 is connected to one end of the third resistor R3, the other end of the third resistor R3 is connected to the negative terminal of the input signal.
[0036] like Figure 1 As shown, the second switch includes an NPN transistor Q2 and a fourth resistor R4. The base of the NPN transistor Q2 is connected to the collector of the PNP transistor Q1. The collector of the NPN transistor Q2 is connected to one end of the fourth resistor R4. The other end of the fourth resistor R4 is connected to the other end of the first resistor R1. The emitter of the NPN transistor Q2 is connected to the input terminal of the light-emitting end of the optocoupler U. The output terminal of the light-emitting end of the optocoupler U is connected to the negative terminal of the input signal. The input terminal of the light-receiving end of the optocoupler U is connected to the power supply. The output terminal of the light-receiving end of the optocoupler U outputs the output signal.
[0037] like Figure 1 As shown, the isolation communication circuit also includes a fifth resistor R5. One end of the fifth resistor R5 is connected to the positive terminal of the capacitor C and the other end of the fourth resistor R4. The other end of the fifth resistor R5 is connected to the emitter of the PNP transistor Q1.
[0038] In other embodiments, the transistor may be replaced by other electronic components with switching functions, such as MOSFETs. This application does not limit the scope of the application.
[0039] The working principle of the above embodiment is as follows: when the input signal is a high-level signal, capacitor C charges, and PNP transistor Q1 is cut off. When the input signal is a low-level signal, PNP transistor Q1 is turned on, and capacitor C outputs a high-level signal to the base of NPN transistor Q2 through PNP transistor Q1, turning on NPN transistor Q2, which in turn turns on the light-emitting end of optocoupler U. The power supply for the light-emitting end of optocoupler U is provided by capacitor C through the fourth resistor R4 and NPN transistor Q2. The power supply voltage for the light-receiving end of optocoupler U can be set according to actual needs, achieving both isolation and voltage reduction.
[0040] Specifically, the optocoupler U outputs an output signal that is out of phase with the input signal.
[0041] According to some embodiments, such as Figure 1 As shown, the isolation communication circuit also includes a sixth resistor R6. One end of the sixth resistor R6 is connected to the emitter of the PNP transistor Q1, and the other end of the sixth resistor R6 is connected to the negative terminal of the input signal.
[0042] Among them, the sixth resistor R6 and the fifth resistor R5 form a voltage divider circuit.
[0043] According to some embodiments, such as Figure 1 As shown, the isolation communication circuit also includes a seventh resistor R7. One end of the seventh resistor R7 is connected to the emitter of the NPN transistor Q2, and the other end of the seventh resistor R7 is connected to the negative terminal of the input signal.
[0044] Among them, the seventh resistor R7 is used to quickly turn off the optocoupler U when the NPN transistor Q2 is turned off.
[0045] According to some embodiments, such as Figure 1 As shown, the isolated communication circuit also includes an eighth resistor R8. One end of the eighth resistor R8 is connected to the output terminal of the light-receiving end of the optocoupler U, and the other end of the eighth resistor R8 is grounded.
[0046] The eighth resistor R8 is used to pull down the output low-level signal when the optocoupler U is turned off.
[0047] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.
[0048] Although this disclosure has been described with reference to several typical embodiments, it should be understood that the terminology used is descriptive and exemplary, and not restrictive. Because this disclosure can be embodied in many forms without departing from the spirit or substance of this application, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope defined by the appended claims. Therefore, all variations and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.
Claims
1. An isolated communication circuit, characterized in that, The isolated communication circuit includes: A first unidirectional conducting component and a second unidirectional conducting component, wherein the input terminals of the first unidirectional conducting component and the second unidirectional conducting component are connected to the positive terminal of the input signal; A first switch and a second switch, wherein the control terminal of the first switch is connected to the positive terminal of the input signal, the input terminal of the first switch is connected to the output terminal of the second unidirectional conducting element, the output terminal of the first switch is connected to the control terminal of the second switch, and the input terminal of the second switch is connected to the output terminal of the first unidirectional conducting element. A capacitor, wherein the positive terminal of the capacitor is connected to the input terminal of the first switch and the input terminal of the second switch, and the negative terminal of the capacitor is connected to the negative terminal of the input signal; A disconnecting switch, wherein the output terminal of the second switch is connected to the control terminal of the disconnecting switch, and the controlled terminal of the disconnecting switch outputs a stepped-down output signal; The first switch is configured to turn on when a low-level signal is input to the control terminal, the second switch is configured to turn on when a high-level signal is input to the control terminal, and the isolating switch is configured to output a high-level signal when the control terminal is energized.
2. The isolated communication circuit according to claim 1, characterized in that, The disconnecting switch uses an optocoupler.
3. The isolated communication circuit according to claim 2, characterized in that, The first unidirectional conducting component includes a first diode and a first resistor. The negative terminal of the first diode is connected to one end of the first resistor, and the positive terminal of the first diode is connected to the positive terminal of the input signal. The second unidirectional conducting component uses a second diode, with the positive terminal of the second diode connected to the positive terminal of the input signal.
4. The isolated communication circuit according to claim 3, characterized in that, The first switch includes a PNP transistor, a second resistor, and a third resistor. The emitter of the PNP transistor is connected to the negative terminal of the second diode. The base of the PNP transistor is connected to the positive terminal of the input signal and one end of the second resistor. The other end of the second resistor is connected to the negative terminal of the input signal. The collector of the PNP transistor is connected to one end of the third resistor. The other end of the third resistor is connected to the negative terminal of the input signal. The second switch includes an NPN transistor and a fourth resistor. The base of the NPN transistor is connected to the collector of the PNP transistor. The collector of the NPN transistor is connected to one end of the fourth resistor. The other end of the fourth resistor is connected to the other end of the first resistor. The emitter of the NPN transistor is connected to the input terminal of the light-emitting end of the optocoupler. The output terminal of the light-emitting end of the optocoupler is connected to the negative terminal of the input signal. The input terminal of the light-receiving end of the optocoupler is connected to the power supply. The output terminal of the light-receiving end of the optocoupler outputs the output signal. The isolated communication circuit also includes a fifth resistor, one end of which is connected to the positive terminal of the capacitor and the other end of the fourth resistor, and the other end of which is connected to the emitter of the PNP transistor.
5. The isolated communication circuit according to claim 4, characterized in that, The isolated communication circuit also includes a sixth resistor, one end of which is connected to the emitter of the PNP transistor, and the other end of which is connected to the negative terminal of the input signal.
6. The isolated communication circuit according to claim 4, characterized in that, The isolated communication circuit also includes a seventh resistor, one end of which is connected to the emitter of the NPN transistor, and the other end of which is connected to the negative terminal of the input signal.
7. The isolated communication circuit according to claim 4, characterized in that, The isolated communication circuit also includes an eighth resistor, one end of which is connected to the output terminal of the light-receiving end of the optocoupler, and the other end of which is grounded.