An isolation circuit to prevent DC from being mistakenly connected to AC

Abstract

An embodiment of the present invention discloses an isolation circuit for preventing DC from being mistakenly connected to AC, comprising: a voltage input terminal for inputting a transmission voltage; an isolation circuit, a first terminal of the isolation circuit connected to the voltage input terminal, the isolation circuit for preventing the transmission voltage from being transmitted when the transmission voltage is AC; and a voltage output terminal connected to a second terminal of the isolation circuit for outputting the transmission voltage when the transmission voltage is DC. The isolation circuit for preventing DC from being mistakenly connected to AC disclosed in an embodiment of the present invention achieves the effect of isolating AC and passing DC through the isolation circuit, reducing circuit costs and improving user experience.

Description

Technical Field

[0001] The embodiments of the present invention relate to electronic technology, and in particular to an isolation circuit for preventing direct current from being mistakenly connected to alternating current. Background Art

[0002] With the rapid development of technology, power electronic devices requiring DC power supply are gaining increasing attention. Existing technologies typically convert AC voltage to DC before powering these devices. However, in practical applications, connecting AC voltage directly to the DC input can easily damage the device.

[0003] Security and fire protection systems often rely on 12V or 24V DC power supplies, which can easily be mixed with indoor AC systems. This can lead to AC power being connected to the DC system, damaging equipment and posing a safety hazard. Existing technologies use NMOS, which is expensive and has limited applicability for negative line control. PMOS, on the other hand, is expensive and dissipates significant power. Summary of the Invention

[0004] The present invention provides an isolation circuit for preventing DC from being mistakenly connected to AC, thereby isolating AC and passing DC, reducing circuit costs and improving user experience.

[0005] An embodiment of the present invention provides an isolation circuit for preventing DC from being mistakenly connected to AC, comprising:

[0006] A voltage input terminal, wherein the voltage input terminal is used to input a transmission voltage;

[0007] an isolation circuit, wherein a first end of the isolation circuit is connected to the voltage input end, and the isolation circuit is used to prevent the transmission voltage from being transmitted when the transmission voltage is alternating current;

[0008] A voltage output terminal is connected to the second end of the isolation circuit and is used to output the transmission voltage when the transmission voltage is direct current.

[0009] Optionally, the isolation circuit includes a thyristor Q and a transient diode TVS, a semiconductor discharge tube TSS and / or a voltage-stabilizing diode Zener, the A pole of the thyristor Q is connected to the voltage input end, the K pole of the thyristor Q is connected to the voltage output end, and the G pole of the thyristor Q is connected to the first end of the transient diode TVS.

[0010] Optionally, the thyristor Q has an anti-reverse connection function.

[0011] Optionally, the isolation circuit further includes a resistor R and a capacitor C, the first end of the resistor R is connected to the voltage input end, the second end of the resistor R is connected to the first end of the capacitor C, and the second end of the capacitor C is connected to the voltage output end.

[0012] Optionally, the resistor R and the capacitor C form an algorithm circuit, and the capacitive reactance of the capacitor C is Rc=1 / 2πFC, where F is the AC frequency 50HZ.

[0013] Optionally, the voltage input terminal includes a voltage terminal DC_in, and the voltage terminal DC_in is connected to the first end of the isolation circuit.

[0014] Optionally, the voltage output end includes a voltage end DC_out, and the voltage end DC_out is connected to the second end of the isolation circuit.

[0015] Optionally, the isolation circuit includes a thyristor Q and a semiconductor discharge tube TSS, the A pole of the thyristor Q is connected to the voltage input end, the K pole of the thyristor Q is connected to the voltage output end, and the G pole of the thyristor Q is connected to the first end of the semiconductor discharge tube TSS.

[0016] Optionally, the first end of the isolation circuit is connected to the voltage input end, and the second end of the isolation circuit is grounded through a diode D.

[0017] Optionally, the first end of the isolation circuit is connected to the voltage input end through a diode D, and the second end of the isolation circuit is grounded.

[0018] An embodiment of the present invention discloses an isolation circuit for preventing DC from being mistakenly connected to AC, comprising: a voltage input terminal for inputting a transmission voltage; an isolation circuit, a first terminal of the isolation circuit connected to the voltage input terminal, the isolation circuit for preventing the transmission voltage from being transmitted when the transmission voltage is AC; and a voltage output terminal connected to a second terminal of the isolation circuit for outputting the transmission voltage when the transmission voltage is DC. The isolation circuit for preventing DC from being mistakenly connected to AC disclosed in an embodiment of the present invention achieves the effect of isolating AC and passing DC through the isolation circuit, reducing circuit costs and improving user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of a module of an isolation circuit for preventing DC from being misconnected to AC, provided in the first embodiment of the present invention;

[0020] Figure 2 This is a circuit diagram of an isolation circuit for preventing DC from being mistakenly connected to AC in Example 1 of the present invention;

[0021] Figure 3 This is a circuit diagram of an isolation circuit for preventing DC from being mistakenly connected to AC in a second embodiment of the present invention;

[0022] Figure 4 This is a circuit diagram of an isolation circuit for preventing DC from being mistakenly connected to AC in Example 3 of the present invention;

[0023] Figure 5 This is a circuit diagram of an isolation circuit for preventing DC from being mistakenly connected to AC in Example 4 of the present invention. DETAILED DESCRIPTION

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0025] Before discussing the exemplary embodiments in more detail, it should be noted that some exemplary embodiments are described as processes or methods depicted as flow charts. Although the flow charts describe the steps as sequential processes, many of the steps can be implemented in parallel, concurrently, or simultaneously. In addition, the order of the steps can be rearranged. A process can be terminated when its operation is completed, but can also have additional steps not included in the accompanying drawings. A process can correspond to a method, function, procedure, subroutine, subprogram, etc.

[0026] In addition, the terms "first", "second", etc. may be used in this document to describe various directions, actions, steps or elements, but these directions, actions, steps or elements are not limited by these terms. These terms are only used to distinguish a first direction, action, step or element from another direction, action, step or element. For example, without departing from the scope of this application, the first module can be referred to as the second module, and similarly, the second module can be referred to as the first module. Both the first module and the second module are modules, but they are not the same module. The terms "first", "second", etc. should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0027] Example 1

[0028] Figure 1This is a module schematic diagram of an isolation circuit for preventing DC from being mistakenly connected to AC provided in Example 1 of the present invention. The isolation circuit for preventing DC from being mistakenly connected to AC provided in Example 1 of the present invention is suitable for isolating AC from passing DC. Specifically, the isolation circuit for preventing DC from being mistakenly connected to AC provided in Example 1 of the present invention includes: a voltage input terminal 1, an isolation circuit 2 and a voltage output terminal 3.

[0029] The voltage input terminal 1 is used to input a transmission voltage. The voltage input terminal 1 includes a voltage terminal DC_in, and the voltage terminal DC_in is connected to a first terminal of the isolation circuit 2 .

[0030] See Figure 2 , Figure 2 This is a circuit diagram of an isolation circuit 2 for preventing DC from being mistakenly connected to AC in this embodiment. The voltage input terminal 1 is used to input AC voltage or DC voltage.

[0031] A first end of the isolation circuit 2 is connected to the voltage input end 1 , and the isolation circuit 2 is used to prevent the transmission voltage from being transmitted when the transmission voltage is alternating current.

[0032] In this embodiment, the isolation circuit 2 includes a thyristor (SCR) and a transient voltage switching diode (TVS), a semiconductor discharge tube (TSS), and / or a Zener diode. The A terminal of the SCR is connected to the voltage input terminal 1, the K terminal of the SCR is connected to the voltage output terminal 3, and the G terminal of the SCR is connected to the first terminal of the transient voltage switching diode (TVS). A thyristor (Silicon Controlled Rectifier), also known as a thyristor, is a high-power electrical component. It offers advantages such as small size, high efficiency, and long life. In automatic control systems, it can be used as a high-power driver, enabling low-power control of high-power equipment. It is widely used in AC / DC motor speed control systems, power regulation systems, and servo systems. Thyristors are divided into two types: unidirectional SCRs and bidirectional SCRs. A bidirectional SCR is also called a three-terminal bidirectional thyristor (TRIAC). A bidirectional SCR is structurally equivalent to two unidirectional SCRs connected in opposite directions. This type of SCR has bidirectional conduction capabilities. Its on / off state is determined by the control electrode (G). Applying a positive pulse (or negative pulse) to the control electrode G can cause it to conduct in the forward (or reverse) direction. In this embodiment, the unidirectional thyristor is equipped with an anti-reverse connection function, which effectively protects the circuit. The transient voltage sensor (TVS) is a high-efficiency protection device in the form of a diode. When the two poles of the TVS diode are subjected to a reverse transient high-energy impact, it can change the high impedance between the two poles to a low impedance at a speed of 10 to the negative 12th power of seconds, absorbing surge power of up to several kilowatts and clamping the voltage between the two poles to a predetermined value, effectively protecting the precision components in the electronic circuit from damage by various surge pulses. It has the advantages of fast response speed, high transient power, low leakage current, small breakdown voltage deviation, easy to control clamping voltage, no damage limit, and small size.

[0033] The isolation circuit 2 also includes a resistor R and a capacitor C. The first end of the resistor R is connected to the voltage input terminal 1, the second end of the resistor R is connected to the first end of the capacitor C, and the second end of the capacitor C is connected to the voltage output terminal 3. The resistor R and the capacitor C form an algorithm circuit. The capacitive reactance of the capacitor C is Rc=1 / 2πFC, where F is the AC frequency of 50 Hz. Specifically, when an AC voltage UAC is applied to DC_in and DC_out:

[0034] The capacitive reactance of capacitor C is Rc = 1 / 2πFC F is the AC frequency 50HZ;

[0035] The voltage divider of capacitor C in AC is UAC (Rc / (R+Rc)). When it is less than the breakdown voltage of TVS, the thyristor does not conduct, achieving the effect of isolating AC. At this time, only a small part of the current flows through the loop of resistors R and C.

[0036] When DC voltage UDC is applied to DC_in and DC_out:

[0037] The capacitive reactance of capacitor C is infinite, and the capacitor will divide all UDC. When UDC is greater than the breakdown voltage of TVS, the thyristor is turned on to pass DC. After conduction, there is no current in the loop formed by resistors R and C.

[0038] The voltage output terminal 3 is connected to the second terminal of the isolation circuit 2 and is used to output the transmission voltage when the transmission voltage is direct current. The voltage output terminal 3 includes a voltage terminal DC_out, which is connected to the second terminal of the isolation circuit 2.

[0039] An embodiment of the present invention discloses an isolation circuit for preventing DC from being mistakenly connected to AC, comprising: a voltage input terminal for inputting a transmission voltage; an isolation circuit, a first terminal of the isolation circuit connected to the voltage input terminal, the isolation circuit for preventing the transmission voltage from being transmitted when the transmission voltage is AC; and a voltage output terminal connected to a second terminal of the isolation circuit for outputting the transmission voltage when the transmission voltage is DC. The isolation circuit for preventing DC from being mistakenly connected to AC disclosed in an embodiment of the present invention achieves the effect of isolating AC and passing DC through the isolation circuit, reducing circuit costs and improving user experience.

[0040] Example 2

[0041] This embodiment is further explained on the basis of the first embodiment. The isolation circuit 2 for preventing DC from being mistakenly connected to AC provided by the embodiment of the present invention is suitable for isolating AC from passing DC. Specifically, the isolation circuit 2 for preventing DC from being mistakenly connected to AC provided by the first embodiment of the present invention includes: a voltage input terminal 1, an isolation circuit 2 and a voltage output terminal 3.

[0042] The voltage input terminal 1 is used to input a transmission voltage. The voltage input terminal 1 includes a voltage terminal DC_in, and the voltage terminal DC_in is connected to a first terminal of the isolation circuit 2 .

[0043] See Figure 3 , Figure 3 This is a circuit diagram of an isolation circuit 2 for preventing DC from being mistakenly connected to AC in this embodiment. The voltage input terminal 1 is used to input AC voltage or DC voltage.

[0044] A first end of the isolation circuit 2 is connected to the voltage input end 1 , and the isolation circuit 2 is used to prevent the transmission voltage from being transmitted when the transmission voltage is alternating current.

[0045] In this embodiment, the isolation circuit 2 includes a thyristor (SCR) and a semiconductor discharge tube (TSS). The A terminal of the SCR is connected to the voltage input terminal 1, the K terminal of the SCR is connected to the voltage output terminal 3, and the G terminal of the SCR is connected to the first terminal of the semiconductor discharge tube (TSS). A thyristor (Silicon Controlled Rectifier), also known as a thyristor, is a high-power electrical component. It has advantages such as small size, high efficiency, and long life. In automatic control systems, it can be used as a high-power driver, enabling low-power controls to control high-power equipment. It is widely used in AC and DC motor speed control systems, power regulation systems, and servo systems. Thyristors are divided into two types: unidirectional SCRs and bidirectional SCRs. A bidirectional SCR is also called a three-terminal bidirectional thyristor (TRIAC). A bidirectional SCR is structurally equivalent to two unidirectional SCRs connected in reverse order. This type of SCR has bidirectional conduction capabilities. Its on / off state is determined by the control terminal (G). Applying a positive pulse (or negative pulse) to the control electrode G causes it to conduct in the forward (or reverse) direction. In this embodiment, the thyristor is equipped with a reverse polarity protection function, effectively protecting the circuit. A semiconductor discharge tube, also known as a solid-state discharge tube, is a PNP element. When the applied voltage is lower than the off-state voltage, the device is in the off-state. When the voltage exceeds its off-state peak voltage, the semiconductor discharge tube clamps the transient voltage to within the component's transition voltage. As the voltage continues to increase, the semiconductor discharge tube enters the on-state due to the negative resistance effect, which is almost a short circuit. When the applied voltage returns to normal, the current quickly decreases and falls below the holding current, causing the element to automatically reset and return to a high-impedance state.

[0046] The isolation circuit 2 also includes a resistor R and a capacitor C. The first end of the resistor R is connected to the voltage input terminal 1, the second end of the resistor R is connected to the first end of the capacitor C, and the second end of the capacitor C is connected to the voltage output terminal 3. The resistor R and the capacitor C form an algorithm circuit. The capacitive reactance of the capacitor C is Rc=1 / 2πFC, where F is the AC frequency of 50 Hz. Specifically, when an AC voltage UAC is applied to DC_in and DC_out:

[0047] The capacitive reactance of capacitor C is Rc = 1 / 2πFC F is the AC frequency 50HZ;

[0048] The voltage divider of capacitor C in AC is UAC (Rc / (R+Rc)). When it is less than the breakdown voltage of TVS, the thyristor does not conduct, achieving the effect of isolating AC. At this time, only a small part of the current flows through the loop of resistors R and C.

[0049] When DC voltage UDC is applied to DC_in and DC_out:

[0050] The capacitive reactance of capacitor C is infinite, and the capacitor will divide all UDC. When UDC is greater than the breakdown voltage of TVS, the thyristor is turned on to pass DC. After conduction, there is no current in the loop formed by resistors R and C.

[0051] The voltage output terminal 3 is connected to the second terminal of the isolation circuit 2 and is used to output the transmission voltage when the transmission voltage is direct current. The voltage output terminal 3 includes a voltage terminal DC_out, which is connected to the second terminal of the isolation circuit 2.

[0052] An embodiment of the present invention discloses an isolation circuit for preventing DC from being mistakenly connected to AC, comprising: a voltage input terminal for inputting a transmission voltage; an isolation circuit, a first terminal of the isolation circuit connected to the voltage input terminal, the isolation circuit for preventing the transmission voltage from being transmitted when the transmission voltage is AC; and a voltage output terminal connected to a second terminal of the isolation circuit for outputting the transmission voltage when the transmission voltage is DC. The isolation circuit for preventing DC from being mistakenly connected to AC disclosed in an embodiment of the present invention achieves the effect of isolating AC and passing DC through the isolation circuit, reducing circuit costs and improving user experience.

[0053] Example 3

[0054] This embodiment is further explained on the basis of the first embodiment. The isolation circuit 2 for preventing DC from being mistakenly connected to AC provided by the embodiment of the present invention is suitable for isolating AC from passing DC. Specifically, the isolation circuit 2 for preventing DC from being mistakenly connected to AC provided by the first embodiment of the present invention includes: a voltage input terminal 1, an isolation circuit 2 and a voltage output terminal 3.

[0055] The voltage input terminal 1 is used to input a transmission voltage. The voltage input terminal 1 includes a voltage terminal DC_in, and the voltage terminal DC_in is connected to a first terminal of the isolation circuit 2 .

[0056] See Figure 4 , Figure 4 This is a circuit diagram of an isolation circuit 2 for preventing DC from being mistakenly connected to AC in this embodiment. The voltage input terminal 1 is used to input AC voltage or DC voltage.

[0057] A first end of the isolation circuit 2 is connected to the voltage input end 1 , and the isolation circuit 2 is used to prevent the transmission voltage from being transmitted when the transmission voltage is alternating current.

[0058] In this embodiment, the first end of the isolation circuit 2 is connected to the voltage input terminal 1, and the second end of the isolation circuit 2 is grounded via a diode D. This circuit forms a functional module, connected in series with the positive line, and is suitable for various situations. The isolation circuit 2 includes a thyristor (SCR) and a semiconductor discharge tube (TSS). The A terminal of the SCR is connected to the voltage input terminal 1, the K terminal of the SCR is connected to the voltage output terminal 3, and the G terminal of the SCR is connected to the first end of the semiconductor discharge tube (TSS). A thyristor (Silicon Controlled Rectifier), also known as a thyristor, is a high-power electrical component. It has advantages such as small size, high efficiency, and long life. In automatic control systems, it can be used as a high-power driver, enabling low-power control devices to control high-power equipment. It is widely used in AC and DC motor speed control systems, power regulation systems, and servo systems. Thyristors are divided into two types: unidirectional SCRs and bidirectional SCRs. Bidirectional SCRs are also called triacs, or TRIACs. A bidirectional thyristor (TRIAC) is structurally equivalent to two unidirectional thyristors connected in reverse order. This type of thyristor has bidirectional conduction capabilities. Its on / off state is determined by the control electrode G. Applying a positive (or negative) pulse to the control electrode G turns it on in the forward (or reverse) direction. In this embodiment, the unidirectional thyristor has a reverse polarity protection feature, effectively protecting the circuit. A semiconductor discharge tube, also known as a solid-state discharge tube, is a PNP element. When the applied voltage is lower than the off-state voltage, the device is in the off-state. When the voltage exceeds its off-state peak voltage, the semiconductor discharge tube clamps the transient voltage to within the component's breakover voltage. As the voltage continues to increase, the semiconductor discharge tube enters the on-state due to the negative resistance effect, effectively short-circuiting. When the applied voltage returns to normal, the current quickly decreases and falls below the holding current, causing the element to automatically reset and return to a high-impedance state.

[0059] The isolation circuit 2 also includes a resistor R and a capacitor C. The first end of the resistor R is connected to the voltage input terminal 1, the second end of the resistor R is connected to the first end of the capacitor C, and the second end of the capacitor C is connected to the voltage output terminal 3. The resistor R and the capacitor C form an algorithm circuit. The capacitive reactance of the capacitor C is Rc=1 / 2πFC, where F is the AC frequency of 50 Hz. Specifically, when an AC voltage UAC is applied to DC_in and DC_out:

[0060] The capacitive reactance of capacitor C is Rc = 1 / 2πFC F is the AC frequency 50HZ;

[0061] The voltage divider of capacitor C in AC is UAC (Rc / (R+Rc)). When it is less than the breakdown voltage of TVS, the thyristor does not conduct, achieving the effect of isolating AC. At this time, only a small part of the current flows through the loop of resistors R and C.

[0062] When DC voltage UDC is applied to DC_in and DC_out:

[0063] The capacitive reactance of capacitor C is infinite, and the capacitor will divide all UDC. When UDC is greater than the breakdown voltage of TVS, the thyristor is turned on to pass DC. After conduction, there is no current in the loop formed by resistors R and C.

[0064] The voltage output terminal 3 is connected to the second terminal of the isolation circuit 2 and is used to output the transmission voltage when the transmission voltage is direct current. The voltage output terminal 3 includes a voltage terminal DC_out, which is connected to the second terminal of the isolation circuit 2.

[0065] An embodiment of the present invention discloses an isolation circuit for preventing DC from being mistakenly connected to AC, comprising: a voltage input terminal for inputting a transmission voltage; an isolation circuit, a first terminal of the isolation circuit connected to the voltage input terminal, the isolation circuit for preventing the transmission voltage from being transmitted when the transmission voltage is AC; and a voltage output terminal connected to a second terminal of the isolation circuit for outputting the transmission voltage when the transmission voltage is DC. The isolation circuit for preventing DC from being mistakenly connected to AC disclosed in an embodiment of the present invention achieves the effect of isolating AC and passing DC through the isolation circuit, reducing circuit costs and improving user experience.

[0066] Example 4

[0067] This embodiment is further explained on the basis of the first embodiment. The isolation circuit 2 for preventing DC from being mistakenly connected to AC provided by the embodiment of the present invention is suitable for isolating AC from passing DC. Specifically, the isolation circuit 2 for preventing DC from being mistakenly connected to AC provided by the first embodiment of the present invention includes: a voltage input terminal 1, an isolation circuit 2 and a voltage output terminal 3.

[0068] The voltage input terminal 1 is used to input a transmission voltage. The voltage input terminal 1 includes a voltage terminal DC_in, and the voltage terminal DC_in is connected to a first terminal of the isolation circuit 2 .

[0069] See Figure 5 , Figure 5 This is a circuit diagram of an isolation circuit 2 for preventing DC from being mistakenly connected to AC in this embodiment. The voltage input terminal 1 is used to input AC voltage or DC voltage.

[0070] A first end of the isolation circuit 2 is connected to the voltage input end 1 , and the isolation circuit 2 is used to prevent the transmission voltage from being transmitted when the transmission voltage is alternating current.

[0071] In this embodiment, the first terminal of the isolation circuit 2 is connected to the voltage input terminal 1 via a diode D, and the second terminal of the isolation circuit 2 is grounded. This circuit constitutes a functional module that can be connected in series to GND and is applicable to various situations. The isolation circuit 2 includes a thyristor (SCR) and a semiconductor discharge tube (TSS). The A terminal of the thyristor (SCR) is connected to the voltage input terminal 1, the K terminal of the SCR is connected to the voltage output terminal 3, and the G terminal of the SCR is connected to the first terminal of the semiconductor discharge tube (TSS). A thyristor (Silicon Controlled Rectifier), also known as a thyristor, is a high-power electrical component. It has advantages such as small size, high efficiency, and long life. In automatic control systems, it can be used as a high-power driver, enabling low-power control devices to control high-power equipment. It is widely used in AC and DC motor speed control systems, power regulation systems, and servo systems. Thyristors are divided into two types: unidirectional SCRs and bidirectional SCRs. Bidirectional SCRs are also called triacs, or TRIACs. A bidirectional thyristor (TRIAC) is structurally equivalent to two unidirectional thyristors connected in reverse order. This type of thyristor has bidirectional conduction capabilities. Its on / off state is determined by the control electrode G. Applying a positive (or negative) pulse to the control electrode G turns it on in the forward (or reverse) direction. In this embodiment, the unidirectional thyristor has a reverse polarity protection feature, effectively protecting the circuit. A semiconductor discharge tube, also known as a solid-state discharge tube, is a PNP element. When the applied voltage is lower than the off-state voltage, the device is in the off-state. When the voltage exceeds its off-state peak voltage, the semiconductor discharge tube clamps the transient voltage to within the component's breakover voltage. As the voltage continues to increase, the semiconductor discharge tube enters the on-state due to the negative resistance effect, effectively short-circuiting. When the applied voltage returns to normal, the current quickly decreases and falls below the holding current, causing the element to automatically reset and return to a high-impedance state.

[0072] The isolation circuit 2 also includes a resistor R and a capacitor C. The first end of the resistor R is connected to the voltage input terminal 1, the second end of the resistor R is connected to the first end of the capacitor C, and the second end of the capacitor C is connected to the voltage output terminal 3. The resistor R and the capacitor C form an algorithm circuit. The capacitive reactance of the capacitor C is Rc=1 / 2πFC, where F is the AC frequency of 50 Hz. Specifically, when an AC voltage UAC is applied to DC_in and DC_out:

[0073] The capacitive reactance of capacitor C is Rc = 1 / 2πFC F is the AC frequency 50HZ;

[0074] The voltage divider of capacitor C in AC is UAC (Rc / (R+Rc)). When it is less than the breakdown voltage of TVS, the thyristor does not conduct, achieving the effect of isolating AC. At this time, only a small part of the current flows through the loop of resistors R and C.

[0075] When DC voltage UDC is applied to DC_in and DC_out:

[0076] The capacitive reactance of capacitor C is infinite, and the capacitor will divide all UDC. When UDC is greater than the breakdown voltage of TVS, the thyristor is turned on to pass DC. After conduction, there is no current in the loop formed by resistors R and C.

[0077] The voltage output terminal 3 is connected to the second terminal of the isolation circuit 2 and is used to output the transmission voltage when the transmission voltage is direct current. The voltage output terminal 3 includes a voltage terminal DC_out, which is connected to the second terminal of the isolation circuit 2.

[0078] An embodiment of the present invention discloses an isolation circuit for preventing DC from being mistakenly connected to AC, comprising: a voltage input terminal for inputting a transmission voltage; an isolation circuit, a first terminal of the isolation circuit connected to the voltage input terminal, the isolation circuit for preventing the transmission voltage from being transmitted when the transmission voltage is AC; and a voltage output terminal connected to a second terminal of the isolation circuit for outputting the transmission voltage when the transmission voltage is DC. The isolation circuit for preventing DC from being mistakenly connected to AC disclosed in an embodiment of the present invention achieves the effect of isolating AC and passing DC through the isolation circuit, reducing circuit costs and improving user experience.

[0079] Note that the above are only preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments and may include many other equivalent embodiments without departing from the concept of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. An isolation circuit for preventing DC from being mistakenly connected to AC, characterized in that: include: A voltage input terminal, wherein the voltage input terminal is used to input a transmission voltage; an isolation circuit, wherein a first end of the isolation circuit is connected to the voltage input end, and the isolation circuit is used to prevent the transmission voltage from being transmitted when the transmission voltage is alternating current; a voltage output terminal connected to the second terminal of the isolation circuit, and configured to output the transmission voltage when the transmission voltage is direct current; The isolation circuit includes a thyristor Q and a transient diode TVS or a semiconductor discharge tube TSS and / or a voltage-stabilizing diode Zener, wherein the A pole of the thyristor Q is connected to the voltage input terminal, the K pole of the thyristor Q is connected to the voltage output terminal, and the G pole of the thyristor Q is connected to the first terminal of the transient diode TVS; The thyristor is a unidirectional thyristor; The isolation circuit further includes a resistor R and a capacitor C, wherein a first end of the resistor R is connected to the voltage input end, a second end of the resistor R is connected to a first end of the capacitor C, and a second end of the capacitor C is connected to the voltage output end.

2. The isolation circuit for preventing DC from being mistakenly connected to AC according to claim 1, characterized in that: The thyristor Q has a reverse connection protection function.

3. The isolation circuit for preventing DC from being mistakenly connected to AC according to claim 1, characterized in that: The resistor R and the capacitor C form an algorithm circuit, and the capacitive reactance of the capacitor C is Rc=1 / 2πFC, where F is the AC frequency of 50 Hz.

4. The isolation circuit for preventing DC from being mistakenly connected to AC according to claim 1, characterized in that: The voltage input end includes a voltage end DC_in, and the voltage end DC_in is connected to the first end of the isolation circuit.

5. The isolation circuit for preventing DC from being mistakenly connected to AC according to claim 1, characterized in that: The voltage output end includes a voltage end DC_out, and the voltage end DC_out is connected to the second end of the isolation circuit.

6. The isolation circuit for preventing DC from being mistakenly connected to AC according to claim 1, characterized in that: A first terminal of the isolation circuit is connected to the voltage input terminal, and a second terminal of the isolation circuit is grounded via a diode D.

7. The isolation circuit for preventing DC from being mistakenly connected to AC according to claim 1, characterized in that: A first end of the isolation circuit is connected to the voltage input end through a diode D, and a second end of the isolation circuit is grounded.

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