Switching circuit

Abstract

The utility model provides a switching circuit. The switching circuit comprises a switching unit, a switching signal generating circuit, a driving circuit and a voltage value limiting circuit. The switch unit is turned on in response to a switching signal. The first end of the switch unit receives an input signal. The switching signal generating circuit generates a switching signal according to the control signal. When the switching signal generating circuit generates the switching signal, the driving circuit transmits the switching signal. The voltage value limiting circuit is electrically connected to the driving circuit, the second end of the switch unit and the control end of the switch unit. The voltage value limiting circuit limits the voltage value at the control end of the switch unit.

Description

Technical Field

[0001] The utility model relates to a circuit, and in particular to a switch circuit. Background Art

[0002] A switching circuit includes a switching unit. Existing switching units perform switching operations in response to a switching signal. However, the voltage of the switching signal may vary due to environmental changes. For example, at low temperatures, the voltage of the switching signal may be too high. This excessively high voltage of the switching signal may damage the switching unit. Therefore, limiting the voltage of the switching signal is a key research topic for those skilled in the art. Summary of the Invention

[0003] The utility model provides a switch circuit capable of limiting the voltage value of a switch signal.

[0004] In one embodiment of the present invention, a switching circuit includes a switching unit, a switching signal generating circuit, a driving circuit, and a voltage limiting circuit. The switching unit is turned on in response to a switching signal. A first terminal of the switching unit receives an input signal. The switching signal generating circuit generates a switching signal based on a control signal. The driving circuit is electrically connected to the switching signal generating circuit. When the switching signal generating circuit generates a switching signal, the driving circuit transmits the switching signal. The voltage limiting circuit is electrically connected to the driving circuit, the second terminal of the switching unit, and the control terminal of the switching unit. The voltage limiting circuit limits the voltage at the control terminal of the switching unit.

[0005] In one embodiment of the present invention, the switch unit is implemented by a gallium nitride (GaN) field effect transistor.

[0006] In one embodiment of the present invention, the voltage limiting circuit includes a Zener diode, a cathode of the Zener diode being electrically connected to the control terminal of the switch unit and the drive circuit, and an anode of the Zener diode being electrically connected to the second terminal of the switch unit.

[0007] In one embodiment of the present invention, the voltage limiting circuit includes a voltage divider circuit. The voltage divider circuit is electrically connected to the drive circuit, the second terminal of the switch unit, and the control terminal of the switch unit. The voltage divider circuit divides the switching signal and provides the divided switching signal to the control terminal of the switch unit.

[0008] In one embodiment of the present invention, the voltage divider circuit includes a first voltage divider element and a second voltage divider element. The first voltage divider element is electrically connected between the drive circuit and the control terminal of the switch unit. The second voltage divider element is electrically connected between the control terminal of the switch unit and the second terminal of the switch unit.

[0009] In an embodiment of the present invention, when the switch signal generating circuit stops generating the switch signal, the driving circuit resets the voltage value of the output terminal of the switch signal generating circuit.

[0010] In an embodiment of the present invention, when the switch signal generating circuit stops generating the switch signal, the driving circuit discharges the voltage value at the output terminal of the switch signal generating circuit.

[0011] In one embodiment of the present invention, a switch signal generating circuit includes an input circuit and a coupling circuit. The input circuit generates an operating signal based on a control signal. The coupling circuit is electrically connected to the input circuit and the driving circuit. The coupling circuit generates a switch signal based on the operating signal.

[0012] In one embodiment of the present invention, a coupling circuit includes a light-emitting element and a switching signal generating circuit. The light-emitting element is electrically connected to an input circuit. The light-emitting element generates a light signal in response to a control signal. The switching signal generating circuit is electrically connected to a driving circuit. The switching signal generating circuit generates a switching signal in response to the light signal.

[0013] In one embodiment of the present invention, the switch signal generating circuit includes at least one photodiode.

[0014] Based on the above, when a switching signal is generated, the voltage limiting circuit limits the voltage at the control terminal of the switching unit. Due to environmental changes, fluctuations in the voltage at the control terminal of the switching unit are limited by the voltage limiting circuit. This prevents damage to the switching unit due to excessively high voltages of the switching signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 FIG. 2 is a schematic diagram of a switch circuit according to an embodiment of the present invention.

[0016] Figure 2 It is a schematic diagram of a voltage limiting circuit and a switch unit according to an embodiment of the present invention.

[0017] Figure 3 It is a schematic diagram of a voltage limiting circuit and a switch unit according to an embodiment of the present invention.

[0018] Figure 4 FIG. 2 is a schematic diagram of a switch circuit according to an embodiment of the present invention.

[0019] Description of Reference Numerals

[0020] 100, 200: Switching circuit

[0021] 110: Switch unit

[0022] 120, 220: Switching signal generating circuit

[0023] 130: Driving circuit

[0024] 140, 140_1, 140_2: Voltage limit circuit

[0025] 141: Voltage divider circuit

[0026] 221: Input circuit

[0027] 222: Coupling Circuit

[0028] 2221: Switch signal output circuit

[0029] L: optical signal

[0030] LD: light-emitting element

[0031] SC: control signal

[0032] SD: Input signal

[0033] SO: Operation Signal

[0034] SSW: switch signal

[0035] VC: clamping voltage value

[0036] VGS: voltage difference

[0037] Z1, Z2: voltage divider elements

[0038] ZD: Zener diode DETAILED DESCRIPTION

[0039] Some embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Reference numbers will be used to identify identical or similar elements in different figures. These embodiments constitute only a portion of the present invention and do not disclose all possible implementations of the present invention. Rather, these embodiments are merely examples within the scope of the present invention's patent application.

[0040] Please refer to Figure 1 , Figure 1is a schematic diagram of a switching circuit according to an embodiment of the present invention. In this embodiment, the switching circuit 100 includes a switching unit 110, a switching signal generating circuit 120, a driving circuit 130, and a voltage limiting circuit 140. The switching unit 110 is turned on in response to a switching signal SSW. A first end of the switching unit 110 receives an input signal SD. In other words, when the switching signal SSW is received, the switching unit 110 is turned on to output the input signal SD through the second end of the switching unit 110. When the switching signal SSW is not received, the switching unit 110 is turned off to stop transmitting the input signal SD. In this embodiment, the switching circuit 100 may be, for example, a solid-state relay (SSR) circuit, but the present invention is not limited thereto.

[0041] In this embodiment, the switching signal generating circuit 120 generates the switching signal SSW according to the control signal SC. The driving circuit 130 is electrically connected to the switching signal generating circuit 120. When the switching signal generating circuit 120 generates the switching signal SSW, the driving circuit 130 transmits the switching signal SSW.

[0042] In this embodiment, the voltage limiting circuit 140 is electrically connected to the driving circuit 130, the second terminal of the switch unit 110, and the control terminal of the switch unit 110. The voltage limiting circuit 140 limits the voltage at the control terminal of the switch unit 110.

[0043] Generally speaking, the voltage value of the switching signal SSW may vary due to environmental changes. For example, at low temperatures, the voltage value of the switching signal SSW may be too high, thereby damaging the switch unit 110. It is worth noting that in this embodiment, when the switching signal SSW is generated, the voltage limiting circuit 140 limits the voltage value at the control terminal of the switch unit 110. Due to environmental changes, the voltage value at the control terminal of the switch unit 110 is limited by the voltage limiting circuit 140. As a result, the switch unit 110 is not damaged by excessively high voltage values ​​of the switching signal SSW.

[0044] In this embodiment, the switch unit 110 is implemented using a gallium nitride (GaN) field-effect transistor. Specifically, the switch unit 110 can be implemented using an enhancement-mode GaN field-effect transistor. Therefore, the switch circuit 100 can be, for example, a solid-state relay (SSR) circuit capable of transmitting an input signal SD having a high voltage (e.g., greater than 600 volts) or a high frequency, but the present invention is not limited thereto. It should be noted that the voltage difference VGS between the gate of the GaN field-effect transistor (i.e., the control terminal of the switch unit 110) and the source of the GaN field-effect transistor (i.e., the second terminal of the switch unit 110) cannot exceed a set voltage value. The set voltage value is, for example, 6 volts. However, the voltage value of the switching signal SSW may vary. At low temperatures, the voltage value of the switching signal SSW may rise to 10 volts. Excessively high voltage values ​​of the switching signal SSW may damage the GaN field-effect transistor.

[0045] In this embodiment, the voltage difference VGS between the control terminal of the switch unit 110 and the second terminal of the switch unit 110 can be limited by the voltage limiting circuit 140. In this way, the switch unit 110 will not be damaged by the excessively high voltage of the switch signal SSW.

[0046] In this embodiment, the switching signal SSW may be a signal having a first voltage level. The driver circuit 130 is coupled to the output terminal of the switching signal generating circuit 120. Therefore, upon receiving a signal having the first voltage level, the driver circuit 130 can detect the generation of the switching signal SSW based on the first voltage level and transmit the switching signal SSW. Upon receiving a signal not having the first voltage level, the driver circuit 130 detects that the switching signal SSW is not being generated. Therefore, when the switching signal generating circuit 120 stops generating the switching signal SSW, the driver circuit 130 resets the voltage value at the control terminal of the switch unit 110.

[0047] For example, the first voltage level is a high voltage level. When the switching signal generating circuit 120 stops generating the switching signal SSW, the driving circuit 130 discharges the voltage at the output terminal of the switching signal generating circuit 120. Therefore, when the switching signal generating circuit 120 stops generating the switching signal SSW, the switching unit 110 is quickly turned off and will not be abnormally turned on due to external interference.

[0048] Please refer to Figure 1 as well as Figure 2 , Figure 2 1 is a schematic diagram of a voltage limiting circuit and a switch unit according to an embodiment of the present invention. In this embodiment, the voltage limiting circuit 140_1 is used to implement Figure 1 The voltage limiting circuit 140 shown in FIG. 1 includes a Zener diode ZD. The cathode of the Zener diode ZD is electrically connected to the control terminal of the switch unit 110 and the drive circuit 130 . The anode of the Zener diode ZD is electrically connected to the second terminal of the switch unit 110 .

[0049] In this embodiment, the Zener diode ZD has a clamping voltage VC. Therefore, the voltage of the switching signal SSW at the control terminal of the switch unit 110 is limited based on the clamping voltage VC. For example, the clamping voltage VC is 6 volts. Therefore, when the switching signal generating circuit 120 generates the switching signal SSW, the voltage difference VGS between the control terminal of the switch unit 110 and the second terminal of the switch unit 110 is limited to 6 volts.

[0050] Please refer to Figure 1 as well as Figure 3 , Figure 3 1 is a schematic diagram of a voltage limiting circuit and a switch unit according to an embodiment of the present invention. In this embodiment, the voltage limiting circuit 140_2 is used to implement Figure 1 The voltage limiting circuit 140 shown in FIG. 1 includes a voltage dividing circuit 141. The voltage dividing circuit 141 is electrically connected to the driving circuit 130, the second terminal of the switch unit 110, and the control terminal of the switch unit 110. The voltage dividing circuit 141 divides the switching signal SSW and provides the divided switching signal SSW to the control terminal of the switch unit 110.

[0051] In this embodiment, the voltage divider circuit 141 includes voltage divider elements Z1 and Z2. The voltage divider element Z1 is electrically connected between the drive circuit 130 and the control terminal of the switch unit 110. The voltage divider element Z2 is electrically connected between the control terminal of the switch unit 110 and the second terminal of the switch unit 110. In this embodiment, the voltage divider elements Z1 and Z2 are resistors.

[0052] In some embodiments, the voltage divider Z2 may be implemented by a Zener diode, wherein the cathode of the voltage divider Z2 is electrically connected to the control terminal of the switch unit 110 , and the anode of the voltage divider Z2 is electrically connected to the second terminal of the switch unit 110 .

[0053] In some embodiments, the voltage divider Z1 may be implemented by a diode. The anode of the voltage divider Z1 is electrically connected to the driving circuit 130 , and the cathode of the voltage divider Z1 is electrically connected to the control terminal of the switch unit 110 .

[0054] The voltage value of the divided switching signal SSW is lower than the voltage value of the switching signal SSW received by the driving circuit 130. Therefore, the voltage difference VGS between the control terminal of the switching unit 110 and the second terminal of the switching unit 110 is limited.

[0055] Please refer to Figure 4 , Figure 4 1 is a schematic diagram of a switch circuit according to an embodiment of the present invention. In this embodiment, the switch circuit 200 includes a switch unit 110, a switch signal generating circuit 220, a drive circuit 130, and a voltage limiting circuit 140. The implementation details of the switch unit 110, the drive circuit 130, and the voltage limiting circuit 140 have been described in detail. Figures 1 to 3 The above is clearly described in the embodiments, so it will not be repeated here.

[0056] In this embodiment, the switching signal generating circuit 220 includes an input circuit 221 and a coupling circuit 222. The input circuit 221 generates the operating signal SO according to the control signal SC. The coupling circuit 222 is electrically connected to the input circuit 221 and the driving circuit 130. The coupling circuit 222 generates the switching signal SSW according to the operating signal SO.

[0057] In this embodiment, the coupling circuit 222 may be, for example, an optical coupling circuit. The coupling circuit 222 includes a light-emitting element LD and a switching signal output circuit 2221. The light-emitting element LD is electrically connected to the input circuit 221. The light-emitting element LD generates a light signal L based on a control signal SC. The switching signal output circuit 2221 is electrically connected to the driving circuit 130. The switching signal output circuit 2221 generates a switching signal SSW based on the light signal L. The switching signal output circuit 2221 includes at least one photodiode. In this embodiment, the switching signal output circuit 2221 includes a plurality of photodiodes connected in series.

[0058] In this embodiment, upon receiving a control signal SC, the input circuit 221 converts the control signal SC into an operating signal SO and uses the operating signal SO to drive the light-emitting element LD. The light-emitting element LD responds to the operating signal SO by providing a light signal L. Upon receiving the light signal L, the switch signal output circuit 2221 generates a switch signal SSW. The driver circuit 130 transmits the switch signal SSW to the voltage limit circuit 140 or the switch unit 110.

[0059] On the other hand, when the control signal SC is not received, the input circuit 221 does not generate the operation signal SO. Therefore, the light-emitting element LD does not provide the light signal L. The switching signal output circuit 2221 does not generate the switching signal SSW. Therefore, the driving circuit 130 discharges the voltage value at the output terminal of the switching signal generating circuit 220.

[0060] In this embodiment, the light emitting element LD may be implemented by a light emitting diode or a laser diode.

[0061] In summary, when a switching signal is generated, the voltage limiting circuit limits the voltage at the control terminal of the switching unit. Due to environmental changes, fluctuations in the voltage at the control terminal of the switching unit are limited by the voltage limiting circuit. Furthermore, the voltage difference between the control terminal of the switching unit and the second terminal of the switching unit is limited. This prevents damage to the switching unit due to excessively high voltages of the switching signal.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A switching circuit, characterized in that: The switching circuit comprises: a switch unit configured to be turned on in response to a switch signal, wherein a first terminal of the switch unit receives an input signal; a switch signal generating circuit configured to generate the switch signal according to a control signal; a driving circuit electrically connected to the switching signal generating circuit and configured to transmit the switching signal when the switching signal generating circuit generates the switching signal; and The voltage limiting circuit is electrically connected to the driving circuit, the second end of the switch unit and the control end of the switch unit, and is configured to limit the voltage at the control end of the switch unit.

2. The switching circuit according to claim 1, wherein: The switch unit is implemented by a gallium nitride field effect transistor.

3. The switching circuit according to claim 1, wherein: The voltage value limiting circuit includes: A Zener diode, wherein a cathode of the Zener diode is electrically connected to the control terminal of the switch unit and the drive circuit, and an anode of the Zener diode is electrically connected to the second terminal of the switch unit.

4. The switching circuit according to claim 1, wherein: The voltage value limiting circuit includes: The voltage divider circuit is electrically connected to the driving circuit, the second end of the switch unit and the control end of the switch unit, and is configured to divide the switch signal and provide the divided switch signal to the control end of the switch unit.

5. The switching circuit according to claim 4, characterized in that: The voltage divider circuit comprises: a first voltage dividing element electrically connected between the driving circuit and the control terminal of the switch unit; and The second voltage dividing element is electrically connected between the control terminal of the switch unit and the second terminal of the switch unit.

6. The switching circuit according to claim 1, wherein: When the switch signal generating circuit stops generating the switch signal, the driving circuit resets the voltage value at the output terminal of the switch signal generating circuit.

7. The switching circuit according to claim 1, wherein: When the switching signal generating circuit stops generating the switching signal, the driving circuit discharges the voltage value at the output end of the switching signal generating circuit.

8. The switching circuit according to claim 1, wherein: The switch signal generating circuit includes: an input circuit configured to generate an operation signal according to the control signal; and The coupling circuit is electrically connected to the input circuit and the driving circuit, and is configured to generate the switching signal according to the operation signal.

9. The switching circuit according to claim 8, wherein: The coupling circuit comprises: a light emitting element electrically connected to the input circuit and configured to generate a light signal according to the control signal; and The switch signal output circuit is electrically connected to the driving circuit and is configured to generate the switch signal according to the optical signal.

10. The switching circuit according to claim 9, wherein: The switch signal output circuit includes at least one photodiode.

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