Switching circuit

Abstract

The utility model provides a switching circuit. The switching circuit includes a switching element and a protection circuit. The switching element comprises an input end and an output end. The switching element turns on the connection between the input terminal and the output terminal in response to a control signal. The protection circuit is connected between the input end and the output end. The protection circuit is an element which outputs a working current value under the condition that the voltage difference value between the input end and the output end is higher than or equal to a voltage threshold value. The voltage threshold is higher than or equal to 1000 volts and lower than a breakdown voltage value of the switching element. The working current value is lower than or equal to 1 ampere.

Description

Technical Field

[0001] This disclosure relates to an electronic circuit, and more particularly to a switching circuit. Background Technology

[0002] A switching element (such as a relay) can be turned on to transmit a received input signal and turned off to stop transmitting the input signal. During the period when the switching circuit is off, if the voltage difference between the input and output terminals is too high, the switching element may fail, generating a breakdown current. The voltage value of the input signal and the heat generated by the breakdown current can burn out the switching element.

[0003] It should be noted that the excessively high voltage difference is a prolonged condition. Current surge protection devices used in switching components cannot discharge or absorb the energy of excessively high voltage differences over extended periods. Therefore, providing protection devices with long-term high-voltage protection capabilities is one of the key research focuses for those skilled in the art. Summary of the Invention

[0004] This disclosure provides a switching circuit. The switching circuit includes a protection element with a long-term high-voltage protection function.

[0005] In one embodiment of this disclosure, the switching circuit includes a switching element and a protection circuit. The switching element includes an input terminal and an output terminal. The switching element responds to a control signal to connect the input terminal and the output terminal. The input terminal receives an input signal. The protection circuit is connected between the input terminal and the output terminal. The protection circuit is a component that outputs an operating current value when the voltage difference between the input terminal and the output terminal is higher than or equal to a voltage threshold. The voltage threshold is higher than or equal to 1000 volts and lower than the breakdown voltage of the switching element. The operating current value is lower than or equal to 1 ampere.

[0006] In one embodiment of this disclosure, the protection circuit operates based on the voltage difference during the period when the switching element disconnects the connection between the input and output terminals.

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

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

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

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

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

[0012] In one embodiment of this disclosure, the set time length is greater than or equal to 60 seconds.

[0013] In one embodiment of this disclosure, the switching element is a relay.

[0014] In one embodiment of this disclosure, the switching element is a solid-state relay.

[0015] Based on the above, when the voltage difference between the input and output terminals is higher than or equal to the voltage threshold VT, the protection circuit outputs an operating current value. It should be noted that the operating current value flowing through the protection circuit itself is lower than or equal to the operating current value. In this way, the protection circuit can protect the switching elements from damage caused by excessively high voltage differences over a prolonged period. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a switching circuit illustrated according to an embodiment of the present disclosure.

[0017] Figure 2 This is a schematic diagram of a switching circuit illustrated according to an embodiment of the present disclosure.

[0018] Figure 3 This is a schematic diagram of a switching circuit illustrated according to an embodiment of the present disclosure.

[0019] Explanation of reference numerals in the attached figures

[0020] 100, 200, 300: Switching circuit

[0021] 110, 210: Switching elements

[0022] 120, 220, 320: Protection circuit

[0023] 221: Varistor

[0024] 321: Overcurrent protection element

[0025] IST: Operating current value

[0026] LD: Light-emitting element

[0027] M1, M2: Phototransistors

[0028] SI: Input signal

[0029] SC: Control signal

[0030] SL: Optical signal

[0031] TI: Input terminal

[0032] TC: Control Terminal

[0033] TO: Output terminal

[0034] VD: Voltage Difference

[0035] VL: Reference Low Voltage

[0036] VT: Voltage threshold Detailed Implementation

[0037] The embodiments disclosed herein will now be described in detail with reference to the accompanying drawings. Component symbols used in the following description, when appearing in different drawings, are considered to be the same or similar components. These embodiments are only a part of this disclosure and do not reveal all possible implementations of this disclosure. More precisely, these embodiments are merely examples within the scope of the patent application disclosed herein.

[0038] Please refer to Figure 1 , Figure 1 This is a schematic diagram of a switching circuit according to an embodiment of the present disclosure. In this embodiment, the switching circuit 100 includes a switching element 110 and a protection circuit 120. The switching element 110 includes an input terminal TI and an output terminal TO. The input terminal TI receives an input signal SI. The switching element 110 responds to a control signal SC to connect the input terminal TI and the output terminal TO. For example, the switching element 110 also includes a control terminal TC. The switching element 110 receives the control signal SC via the control terminal TC. When the voltage value of the control signal SC is a first voltage level, the switching element 110 responds to the control signal SC to connect the input terminal TI and the output terminal TO. Therefore, the switching element 110 can transmit the input signal SI.

[0039] On the other hand, when the voltage value of the control signal SC is at the first voltage level, the switching element 110 connects the input terminal TI and the output terminal TO. On the other hand, when the voltage value of the control signal SC is at the second voltage level, the switching element 110 disconnects the connection between the input terminal TI and the output terminal TO. Therefore, the switching element 110 does not transmit the input signal SI.

[0040] In this embodiment, the first voltage level can be a high voltage level, but this disclosure is not limited thereto. The second voltage level can be a low voltage level, but this disclosure is not limited thereto.

[0041] In this embodiment, protection circuit 120 is connected between input terminal TI and output terminal TO. Protection circuit 120 is a component that outputs operating current value IST when the voltage difference VD between input terminal TI and output terminal TO is higher than or equal to a voltage threshold VT. In this embodiment, the voltage threshold VT is higher than or equal to 1000 volts and lower than the breakdown voltage of the switching element 110 itself. The operating current value IST is lower than or equal to 1 ampere.

[0042] It is worth mentioning that current protection elements can only discharge or absorb energy generated by surges within milliseconds. Current protection elements cannot discharge or absorb energy from excessively high voltage differences VD over extended periods. In this embodiment, when the voltage difference VD between the input terminal TI and the output terminal TO is higher than or equal to 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 flowing through the protection circuit 120 itself is less than or equal to 1 ampere. When the voltage difference VD between the input terminal TI and the output terminal TO is higher than or equal to 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 switching element 110 from damage caused by excessively high voltage differences VD over extended periods. Furthermore, the voltage threshold VT is lower than the breakdown voltage of the switching element 110. Therefore, the protection circuit 120 provides the output operating current value IST before the voltage difference VD rises to the breakdown voltage of the switching element 110.

[0043] In this embodiment, when the voltage difference VD between the input terminal TI and the output terminal TO is higher than or equal to the voltage threshold VT, the protection circuit 120 can absorb or release the energy generated by the voltage difference VD, thereby preventing the energy from flowing through the switching element 110. Therefore, the risk of damage to the switching element 110 from the aforementioned energy can be reduced, and the lifespan of the switching element 110 can be extended.

[0044] In this embodiment, during the period when the input terminal TI is connected to the output terminal TO, the voltage difference VD is significantly reduced to near zero. Therefore, the protection circuit 120 does not operate. During the period when the switching element 110 disconnects 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 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.

[0045] In this embodiment, the switching element 110 is a relay. In this embodiment, the switching element 110 is a solid-state relay (SSR).

[0046] In this embodiment, when the voltage difference VD is higher than or equal to the voltage threshold VT, the protection circuit 120 outputs an operating current value IST based on a set time length. The set time length is higher than or equal to 5 seconds. In some embodiments, the set time length is higher than or equal to 60 seconds.

[0047] The operating current value IST is designed to be positively correlated with the voltage difference VD. For example, when the voltage difference VD is greater than or equal to 1000 volts, the operating current value IST is less than or equal to 1 mA (however, this disclosure is not limited thereto). For example, when the voltage difference VD is greater than or equal to 3300 volts, the operating current value IST is limited to tens to hundreds of mA (however, this disclosure is not limited thereto). For example, when the voltage difference VD is greater than or equal to 6600 volts, the operating current value IST is less than or equal to 1 ampere (however, this disclosure is not limited thereto).

[0048] In this embodiment, the switching circuit 100 may be applicable to the automotive field (however, this disclosure is not limited thereto) or other high-power application fields.

[0049] Please refer to Figure 2 , Figure 2 This is a schematic diagram of a switching circuit according to an embodiment of the present disclosure. In this embodiment, the switching circuit 200 includes a switching element 210 and a protection circuit 220. The switching 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 switching element 210 is implemented by a solid-state relay (however, the present disclosure is not limited thereto). The switching element 210 also includes phototransistors M1 and M2 and a light-emitting element LD. The first terminal of phototransistor M1 is connected to the input terminal TI. The second terminal of phototransistor M1 is connected to the first terminal of phototransistor M1. The second terminal of phototransistor M2 is connected to the output terminal TO. Phototransistors M1 and M2 perform switching operations based on the light signal SL. The first terminal (e.g., anode) of the light-emitting element LD is connected to the control terminal TC to receive a control signal SC. The second terminal (e.g., cathode) of the light-emitting element LD is connected to a reference low voltage VL (e.g., ground).

[0050] For example, the switching circuit 200 can be designed as a normally open relay. When the voltage value of the control signal SC is at the first voltage level, the light-emitting element LD outputs a light signal SL. Phototransistors M1 and M2 are turned on in response to the light signal SL. Therefore, the input terminal TI is connected to the output terminal TO via phototransistors M1 and M2. On the other hand, when the voltage value of the control signal SC is at the second voltage level, the light-emitting element LD does not output a light signal SL. Phototransistors M1 and M2 are turned off. Therefore, the connection between the input terminal TI and the output terminal TO is broken.

[0051] For another example, the switching circuit 200 can be designed as a normally open (normally closed) relay. When the voltage value of the control signal SC is at the first voltage level, the light-emitting element LD outputs a light signal SL. Phototransistors M1 and M2 are turned off in response to the light signal SL. Therefore, the connection between the input terminal TI and the output terminal TO is broken. On the other hand, when the voltage value of the control signal SC is at the second voltage level, the light-emitting element LD does not output a light signal SL. Phototransistors M1 and M2 are turned on. Therefore, the input terminal TI is connected to the output terminal TO via phototransistors M1 and M2.

[0052] 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. Unlike conventional varistors, the maximum value of the operating current IST of the varistor 221 is limited. The varistor 221 is designed to output the operating current IST when the voltage difference VD is higher than or equal to the voltage threshold VT. The operating current IST is lower than or equal to 1 ampere.

[0053] In this embodiment, the operating current value IST is designed to be positively correlated with the voltage difference VD. For example, when the voltage difference VD is greater than or equal to 1000 volts, the operating current value IST is less than or equal to 1 mA (however, this disclosure is not limited thereto). For example, when the voltage difference VD is greater than or equal to 3300 volts, the operating current value IST is limited to tens to hundreds of mA (however, this disclosure is not limited thereto). For example, when the voltage difference VD is greater than or equal to 6600 volts, the operating current value IST is less than or equal to 1 ampere (however, this disclosure is not limited thereto).

[0054] Please refer to Figure 3 , Figure 3 This is a schematic diagram of a switching circuit according to an embodiment of the present disclosure. In this embodiment, the switching circuit 300 includes a switching element 210 and a protection circuit 320. The implementation of the switching element 210 has already been described. Figure 2 The embodiments are clearly illustrated and will not be repeated here.

[0055] 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 by a surge protection element. Unlike conventional surge protection elements, the maximum value of the operating current 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 higher than or equal to a voltage threshold VT. The operating current value IST is lower than or equal to 1 ampere. The surge protection element is implemented, for example, by a circuit including at least one TVS diode.

[0056] In some embodiments, the protection circuit 320 may include an overcurrent protection element 321 and, as well as... Figure 2 The varistor 221 shown. The overcurrent protection element 321 and the varistor 221 are connected in series between the input terminal TI and the output terminal TO.

[0057] In summary, when the voltage difference between the input and output terminals is higher than or equal to the voltage threshold, the protection circuit outputs an operating current value. It should be noted that the operating current flowing through the protection circuit itself is lower than or equal to the operating current value. In this way, the protection circuit can protect the switching elements from damage caused by excessively high voltage differences over a prolonged period, thus extending the lifespan of the switching elements.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A switching circuit, characterized in that, The switching circuit includes: A switching element includes an input terminal and an output terminal, wherein the switching element responds to a control signal to connect the input terminal and the output terminal, wherein the input terminal receives an input signal; and A protection circuit is connected between the input terminal and the output terminal. The protection circuit mentioned above is a component that outputs a working current value when the voltage difference between the input terminal and the output terminal is higher than or equal to a voltage threshold. The voltage threshold is higher than or equal to 1000 volts and lower than the breakdown voltage value of the switching element, and The operating current value is less than or equal to 1 ampere.

2. The switching circuit according to claim 1, characterized in that, The protection circuit operates based on the voltage difference while the switching element disconnects the connection between the input and output terminals.

3. The switching circuit according to claim 1, characterized in that, The protection circuit includes: A varistor is connected between the input terminal and the output terminal.

4. The switching circuit according to claim 1, characterized in that, The protection circuit includes: An overcurrent protection element is connected between the input terminal and the output terminal.

5. The switching circuit according to claim 4, characterized in that, The overcurrent protection element is implemented by the surge protection element.

6. The switching circuit according to claim 1, characterized in that, The voltage threshold is higher than or equal to 3300 volts.

7. The switching circuit according to claim 1, characterized in that: When the voltage difference is higher than or equal to a voltage threshold, the protection circuit outputs a working current value based on a set time period, and The set time length is greater than or equal to 5 seconds.

8. The switching circuit according to claim 7, characterized in that, The set time length is greater than or equal to 60 seconds.

9. The switching circuit according to claim 1, characterized in that, The switching element is a relay.

10. The switching circuit according to claim 1, characterized in that, The switching element is a solid-state relay.

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