Switch Circuit

Abstract

To provide a switch circuit having a long-term high voltage protection function. [Solution] A switch circuit 100 includes a switch element 110 and a protection circuit 120. The switch element includes an input terminal TI and an output terminal TO. The switch element conducts a connection between the input terminal and the output terminal in response to a control signal SC. The protection circuit is connected between the input terminal and the output terminal. The protection circuit is an element that outputs an operating current value IST when a voltage difference VD between the input terminal and the output terminal is equal to or greater than a voltage threshold VT. The voltage threshold is equal to or greater than 1000 volts and less than the breakdown voltage value of the switch element. The operating current value is equal to or less than 1 ampere.

Description

[Technical Field]

[0001] The present disclosure relates to electronic circuits, and in particular to switch circuits. [Background technology]

[0002] A switching element (e.g., a relay) is turned on to transmit a received input signal and turned off to stop transmitting the input signal. If the voltage difference between the input and output terminals is excessively high during the time the switching circuit is turned off, the switching element may collapse and generate a collapse current. The thermal energy generated by the voltage value of the input signal and the collapse current may burn out the switching element.

[0003] It should be noted that the excessively high voltage difference refers to a long-term state. The surge protection devices used in current switching devices cannot release or absorb the energy of an excessively high voltage difference for a long period of time. Therefore, how to provide a protection device with long-term high voltage protection function is one of the key research topics for engineers in this field. Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a switch circuit, which includes a protection element having a long-term high-voltage protection function. [Means for solving the problem]

[0005] In one embodiment of the present disclosure, a switch circuit includes a switch element and a protection circuit. The switch element includes an input terminal and an output terminal. The switch element conducts a connection between the input terminal and the output terminal in response to a control signal. The protection circuit is connected between the input terminal and the output terminal. The protection circuit is an element that outputs an operating current value when a voltage difference between the input terminal and the output terminal is equal to or greater than a voltage threshold. The voltage threshold is equal to or greater than 1000 volts and less than a breakdown voltage value of the switch element. The operating current value is equal to or less than 1 ampere.

[0006] In one embodiment of the present disclosure, the protection circuit operates based on the voltage difference during the period when the switch element cuts off the connection between the input terminal and the output terminal.

[0007] In one embodiment of the present disclosure, the protection circuit includes a varistor connected between the input terminal and the output terminal.

[0008] In one embodiment of the present disclosure, the protection circuit includes an overcurrent protection element connected between the input terminal and the output terminal.

[0009] In one embodiment of the present disclosure, the overcurrent protection element is implemented by a surge protection element.

[0010] In one embodiment of the present disclosure, the voltage threshold is greater than or equal to 3300 volts.

[0011] In one embodiment of the present disclosure, when the voltage difference is equal to or greater than the voltage threshold, the protection circuit outputs an operating current value based on a set time period, the set time period being equal to or greater than 5 seconds.

[0012] In one embodiment of the present disclosure, the set time period is 60 seconds or greater.

[0013] In one embodiment of the present disclosure, the switch element is a relay.

[0014] In one embodiment of the present disclosure, the switch element is a solid state relay. [Effects of the Invention]

[0015] Based on the above, when the voltage difference between the input terminal and the output terminal is equal to or greater than the voltage threshold VT, the protection circuit outputs an operating current value. It should be noted that the operating current value of the current flowing through the protection circuit itself is equal to or less than the operating current value. In this way, the protection circuit can protect the switching element from damage caused by an excessively high voltage difference for a long period of time. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 2 is a schematic diagram of a switch circuit illustrated in accordance with one embodiment of the present disclosure. [Figure 2] FIG. 2 is a schematic diagram of a switch circuit illustrated in accordance with one embodiment of the present disclosure. [Figure 3] FIG. 2 is a schematic diagram of a switch circuit illustrated in accordance with one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0017] Some embodiments of the present disclosure will be described in detail below with reference to the drawings, and element reference numerals in the following description are considered to be the same or similar elements when the same element reference numerals appear in different drawings. These embodiments are only a part of the present disclosure and do not disclose all possible embodiments of the present disclosure. More precisely, these embodiments are only examples in the scope of the utility model registration claims of the present disclosure.

[0018] Referring to FIG. 1, FIG. 1 is a schematic diagram of a switch circuit illustrated according to one embodiment of the present disclosure. In this embodiment, the switch circuit 100 includes a switch element 110 and a protection circuit 120. The switch element 110 includes an input terminal TI and an output terminal TO. The input terminal TI receives an input signal SI. The switch element 110 conducts a connection between the input terminal TI and the output terminal TO in response to a control signal SC. For example, the switch element 210 further includes a control terminal TC. The switch element 110 receives the control signal SC via the control terminal TC. When the voltage value of the control signal SC is at a first voltage level, the switch element 110 conducts a connection between the input terminal TI and the output terminal TO in response to the control signal SC. Therefore, the switch element 110 can transmit the input signal SI.

[0019] On the other hand, when the voltage value of the control signal SC is at a first voltage level, the switch element 110 conducts the connection between the input terminal TI and the output terminal TO. On the other hand, when the voltage value of the control signal SC is at a second voltage level, the switch element 110 cuts off the connection between the input terminal TI and the output terminal TO. Therefore, the switch element 110 does not transmit the input signal SI.

[0020] In this embodiment, the first voltage level may be a high voltage level, but the present disclosure is not limited thereto, and the second voltage level may be a low voltage level, but the present disclosure is not limited thereto.

[0021] In this embodiment, the protection circuit 120 is connected between the input terminal TI and the output terminal TO. The protection circuit 120 is an element that outputs an operating current value IST when the voltage difference VD between the input terminal TI and the output terminal TO is equal to or greater than a voltage threshold value VT. In this embodiment, the voltage threshold value VT is equal to or greater than 1000 volts and less than the breakdown voltage value of the switch element 110 itself. The operating current value IST is equal to or less than 1 ampere.

[0022] It should be noted that current protection devices can only release or absorb energy generated by surges for a few milliseconds. Current protection devices cannot release or absorb energy when the voltage difference VD is excessively high for a long period of time. In this embodiment, when the voltage difference VD between the input terminal TI and the output terminal TO is equal to or greater than the voltage threshold VT, the protection circuit 120 outputs an operating current value IST to provide an energy release path. It should be noted that the operating current value IST of the current flowing through the protection circuit 120 itself is equal to or less than 1 ampere. When the voltage difference VD between the input terminal TI and the output terminal TO is equal to or greater than the voltage threshold VT, the protection circuit 120 can operate based on the limited operating current value IST. In this way, the protection circuit 120 can protect the switch element 110 from damage caused by an excessively high voltage difference VD for a long period of time. Furthermore, the voltage threshold VT is less than the breakdown voltage value of the switch element 110. Therefore, the protection circuit 120 outputs the operating current value IST before the voltage difference VD rises to the breakdown voltage value of the switch element 110.

[0023] In this embodiment, when the voltage difference VD between the input terminal TI and the output terminal TO is equal to or greater than the voltage threshold VT, the protection circuit 120 absorbs or releases energy generated by the voltage difference VD, thereby preventing the energy from flowing through the switch element 110. This reduces the risk that the switch element 110 will be destroyed by the energy, and extends the life of the switch element 110.

[0024] In this embodiment, while the input terminal TI is connected to the output terminal TO, the voltage difference VD drops significantly and approaches zero. Therefore, the protection circuit 120 does not operate. While the switch element 110 cuts off the connection between the input terminal TI and the output terminal TO, the voltage difference VD is approximately equal to the difference between the voltage value of the input signal SI and the voltage value present at the output terminal TO. Therefore, the protection circuit 120 operates based on the voltage difference VD. That is, the protection circuit 120 outputs the operating current value IST based on the voltage value of the input signal SI.

[0025] In this embodiment, the switch element 110 is a relay. In this embodiment, the switch element 110 is a solid state relay (SSR).

[0026] In this embodiment, when the voltage difference VD is equal to or greater than the voltage threshold Vt, the protection circuit 120 outputs the operating current value Ist for a set period of time. The set period of time is equal to or greater than 5 seconds. In some embodiments, the set period of time is equal to or greater than 60 seconds.

[0027] The operating current value IST is designed to have a positive correlation with the voltage difference VD. For example, when the voltage difference VD is 1000 volts or more, the operating current value IST is 1 milliampere or less (however, the present disclosure is not limited to this). For example, when the voltage difference VD is 3300 volts or more, the operating current value IST is limited to between several tens and several hundred milliamperes (however, the present disclosure is not limited to this). For example, when the voltage difference VD is 6600 volts or more, the operating current value IST is 1 ampere or less (however, the present disclosure is not limited to this).

[0028] In this embodiment, the switch circuit 100 is applicable to the automotive field (although the present disclosure is not limited thereto) or other high power applications.

[0029] Referring to FIG. 2, FIG. 2 is a schematic diagram of a switch circuit illustrated according to one embodiment of the present disclosure. In this embodiment, the switch circuit 200 includes a switch element 210 and a protection circuit 220. The switch element 210 includes an input terminal TI, an output terminal TO, and a control terminal TC. The input terminal TI receives an input signal SI. In this embodiment, the switch element 210 is implemented by a solid-state relay (although the present disclosure is not limited thereto). The switch element 210 further includes phototransistors M1 and M2 and a light-emitting element LD. A first terminal of the phototransistor M1 is connected to the input terminal TI. A second terminal of the phototransistor M1 is connected to the first terminal of the phototransistor M1. A second terminal of the phototransistor M2 is connected to the output terminal TO. The phototransistors M1 and M2 perform a switching operation based on a light signal SL. A first terminal (e.g., an anode) of the light-emitting element LD is connected to the control terminal TC to receive a control signal SC. A second terminal (e.g., a cathode) of the light-emitting element LD is connected to a reference low voltage VL (e.g., ground).

[0030] For example, the switch circuit 200 can be designed as a normally open relay. When the voltage value of the control signal SC is at a first voltage level, the light-emitting element LD outputs the optical signal SL. The phototransistors M1 and M2 are conductive in response to the optical signal SL. Therefore, the input terminal TI is connected to the output terminal TO via the phototransistors M1 and M2. On the other hand, when the voltage value of the control signal SC is at a second voltage level, the light-emitting element LD does not output the optical signal SL. The phototransistors M1 and M2 are cut off. Therefore, the connection between the input terminal TI and the output terminal TO is cut off.

[0031] As another example, the switch circuit 200 can be designed as a normally closed relay. When the voltage value of the control signal SC is at a first voltage level, the light-emitting element LD outputs the optical signal SL. The phototransistors M1 and M2 are cut off in response to the optical signal SL. Therefore, the connection between the input terminal TI and the output terminal TO is cut off. On the other hand, when the voltage value of the control signal SC is at a second voltage level, the light-emitting element LD does not output the optical signal SL. The phototransistors M1 and M2 are conductive. Therefore, the input terminal TI is connected to the output terminal TO via the phototransistors M1 and M2.

[0032] In this embodiment, the protection circuit 220 includes a varistor 221. The varistor 221 is connected between the input terminal TI and the output terminal TO. What differs from current varistors is that the maximum value of the operating current value IST of the varistor 221 is limited. The varistor 221 is designed to output the operating current value IST when the voltage difference VD is equal to or greater than the voltage threshold value VT. The operating current value IST is equal to or less than 1 ampere.

[0033] In this embodiment, the operating current value IST is designed to have a positive correlation with the voltage difference VD. For example, when the voltage difference VD is 1000 volts or more, the operating current value IST is 1 milliampere or less (however, the present disclosure is not limited to this). For example, when the voltage difference VD is 3300 volts or more, the operating current value IST is limited to between several tens and several hundred milliamperes (however, the present disclosure is not limited to this). For example, when the voltage difference VD is 6600 volts or more, the operating current value IST is 1 ampere or less (however, the present disclosure is not limited to this).

[0034] 3, which is a schematic diagram of a switch circuit illustrated according to one embodiment of the present disclosure. In this embodiment, the switch circuit 300 includes a switch element 210 and a protection circuit 320. The implementation of the switch element 210 has already been clearly described in the embodiment of FIG. 2, so it will not be repeated here.

[0035] In this embodiment, the protection circuit 320 includes an overcurrent protection element 321. The overcurrent protection element 321 is connected between the input terminal TI and the output terminal TO. For example, the overcurrent protection element 321 is implemented as a surge protection element. What distinguishes it from current surge protection elements is that the maximum value of the operating current value IST of the surge protection element is limited. The surge protection element is designed to output the operating current value IST when the voltage difference VD is equal to or greater than the voltage threshold value VT. The operating current value IST is equal to or less than 1 ampere. The surge protection element is implemented as a circuit including at least one TVS diode, for example.

[0036] In some embodiments, the protection circuit 320 may include an overcurrent protection element 321 and the varistor 221 shown in Figure 2. The overcurrent protection element 321 and the varistor 221 are connected in series between the input terminal TI and the output terminal TO.

[0037] In summary, when the voltage difference between the input terminal and the output terminal is equal to or greater than the voltage threshold, the protection circuit outputs an operating current value. It is important to note that the operating current value of the current flowing through the protection circuit itself must be equal to or less than the operating current value. In this way, the protection circuit can protect the switching element from damage caused by an excessively high voltage difference for a long period of time, thereby extending the life of the switching element.

[0038] Although the present disclosure has been disclosed by the above-described embodiments, this does not limit the present disclosure, and those skilled in the art may make some changes and modifications without departing from the spirit and scope of the present disclosure, and therefore, the scope of protection of the present disclosure shall be determined based on the scope of the attached utility model registration claims. [Industrial Applicability]

[0039] The present disclosure provides a switch circuit that can provide long-term high voltage protection. [Explanation of symbols]

[0040] 100, 200, 300 switch circuit 110, 210 Switch element 120, 220, 320 protection circuit 221 Barista 321 Overcurrent protection element IST operating current value LD light emitting element M1, M2 phototransistors SI input signal SC control signal SL optical signal TI input terminal TC control terminal TO output terminal VD voltage difference VL Reference low voltage VT Voltage Threshold

Claims

1. a switch element including an input terminal and an output terminal, the switch element being responsive to a control signal to conduct a connection between the input terminal and the output terminal, the input terminal receiving an input signal; a protection circuit connected between the input terminal and the output terminal, the protection circuit is an element that outputs an operating current value when a voltage difference between the input terminal and the output terminal is equal to or greater than a voltage threshold; the voltage threshold is greater than or equal to 1000 volts and less than a breakdown voltage of the switch element; The operating current value of the switch circuit is 1 ampere or less. One type of open circuit, comprehensive:

2. 2. The switch circuit according to claim 1, wherein the protection circuit operates based on the voltage difference during a period in which the switch element cuts off the connection between the input terminal and the output terminal.

3. 2. The switch circuit according to claim 1, wherein the protection circuit includes a varistor connected between the input terminal and the output terminal.

4. 2. The switch circuit according to claim 1, wherein the protection circuit includes an overcurrent protection element connected between the input terminal and the output terminal.

5. 5. The switch circuit of claim 4, wherein the overcurrent protection element is implemented by a surge protection element.

6. 2. The switch circuit of claim 1, wherein the voltage threshold is greater than or equal to 3300 volts.

7. When the voltage difference is equal to or greater than a voltage threshold, the protection circuit outputs an operating current value based on a set time length; 2. The switch circuit according to claim 1, wherein the set time period is 5 seconds or more.

8. 8. The switch circuit according to claim 7, wherein the set time period is 60 seconds or more.

9. 2. The switch circuit according to claim 1, wherein the switch element is a relay.

10. 2. The switch circuit of claim 1, wherein the switch element is a solid-state relay.

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