Safety switching device with dual circuit breaking mechanism

Abstract

The invention discloses a safety switch device. The safety switch device comprises a first transistor, a second transistor, a diode, a first resistor and a control loop, the first transistor has a first terminal coupled to a load and a power terminal. The second transistor has a first terminal connected to the first transistor. The diode has an anode coupled to the second transistor. The first resistor has a first end coupled to the second transistor. The control loop includes a first control path and a second control path. One end of the first control path is coupled to the cathode of the diode, one end of the second control path is coupled to the second end of the first resistor, and the first control path and the second control path are respectively used for providing a low voltage level and a high voltage level; when the first control path provides the high voltage level, the second control path provides the low voltage level and causes the power supply terminal to discontinue supplying power to the load.

Description

Technical Field

[0001] The invention relates to a safety switch, in particular to a safety switch device with a double breaking mechanism. Background Art

[0002] Safety switches are usually used to protect equipment or end users from harm in the event of a fault or other dangerous situation. Generally speaking, the safety switch is placed on the power supply path between the power supply end and the load. When the safety switch is triggered due to specific conditions, the power supply path will be disconnected, and the power supply end will stop supplying power to the load. In order to improve the reliability of the safety switch, a redundant design is usually adopted, that is, multiple safety switches are set at the same time to achieve the disconnection of the power supply path, so as to avoid the failure of a single safety switch to disconnect the power supply path. Generally speaking, redundant safety switches include series type and parallel type. The series type redundant safety switch places multiple switch units on the power supply path. As long as one of the switch units is activated, the power supply path will be disconnected. However, the disadvantage of this type is that as long as one of the switch units fails, the power supply path will be disconnected even if the triggering condition is not met, resulting in system failure. The parallel type redundant safety switch disconnects the power supply path by forming different circuits through multiple switch units. In this type, as long as one of the switch units functions normally, the power supply path can be disconnected smoothly and the safety protection mechanism can be exerted. However, its disadvantage is that if all switch units fail, the power supply path can never be disconnected and the safety protection mechanism fails. Therefore, the field to which the present invention belongs needs an innovative safety switch design to overcome the defects of the existing design. Summary of the invention

[0003] The present invention provides a safety switch device with a double circuit breaker mechanism. When a part of the paths or switch units fail, the safety protection mechanism can still operate normally, and the system operation can be shut down when all the paths or switch units are abnormal.

[0004] An embodiment of the present invention provides a safety switch device for selectively stopping the power supply of a power supply end to a load. The safety switch device comprises: a first transistor, a second transistor, a diode, a first resistor and a control loop. The first end of the first transistor is coupled to the load and the power supply end. The first end of the second transistor is coupled to the control end of the first transistor. The anode of the diode is coupled to the first end of the second transistor and the control end of the first transistor. The first end of the first resistor is connected to the control end of the second transistor. The control loop comprises a first control path and a second control path. One end of the first control path is coupled to the cathode of the diode, one end of the second control path is coupled to the second end of the first resistor, and the first control path and the second control path are used to provide a low voltage level and a high voltage level respectively; when the first control path provides the high voltage level, the second control path provides the low voltage level, and causes the power supply end to stop supplying power to the load. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 A structural diagram of a safety switch device according to a first embodiment of the present invention is shown.

[0006] Figure 2 A structural diagram of a safety switch device according to a second embodiment of the present invention is shown.

[0007] The reference numerals are described as follows:

[0008] 100, 400 safety switch device

[0009] 200, 500 control loop

[0010] Q1, Q2 transistors

[0011] E1, E2 emitter

[0012] B1, B2 base

[0013] C1, C2 collector

[0014] VCC power supply terminal

[0015] 210, 220 switch

[0016] 300 load

[0017] RL, R1, R2, RP, RCT resistors

[0018] D1 diode

[0019] CTRPH1, CTRPH2, CTRPH3, CTRPH4 control pathway DETAILED DESCRIPTION

[0020] In the following text, many specific details are described to provide a thorough understanding of embodiments of the present invention to those skilled in the art. However, those skilled in the art will understand how to implement the present invention in the absence of one or more specific details, or using other methods or components, etc. In other cases, well-known structures, materials, or operations will not be shown or described in detail to avoid obscuring the core concepts of the present invention.

[0021] In addition, any examples or explanations given in the specification should not be limited or defined by any words used therein. On the contrary, these examples or explanations should be considered to be described for a specific embodiment and are only used as illustrations. It will be understood by those skilled in the art that any words used in these examples or explanations will cover other embodiments given elsewhere in this specification. Among them, the words used to indicate these non-limiting examples include but are not limited to: "for example", "such as", "for example", "in one embodiment" and "in an example".

[0022] According to an embodiment of the present invention, Figure 1 A structural diagram of a safety switch device is depicted. As shown in the figure, the safety switch device 100 is composed of a first transistor Q1, a second transistor Q2, a diode D1, a resistor RP and a control loop 200. In the present embodiment, the first transistor Q1 and the second transistor Q2 are bipolar transistors (Bipolar Junction Transistor, BJT), but in other embodiments of the present invention, the first transistor Q1 and the second transistor Q2 can also be other types of transistors. Furthermore, the first transistor Q1 has a base B1 (i.e., a control end), a collector C1 (i.e., a first end), and an emitter E1 (i.e., a second end), and the second transistor Q2 has a base B2, an emitter E2 and a collector C2. The collector C1 of the first transistor Q1 is coupled to the power supply end VCC through a resistor RL, and is also connected to the load 300. The collector C2 of the second transistor Q2 is coupled to the power supply end VCC through a resistor R1, and is coupled to the base B1 of the first transistor Q1 through a resistor R2. In addition, an anode of the diode D1 is coupled to the collector C2 of the second transistor, and a first end of the resistor RP is connected to the base B2 of the second transistor.

[0023] The control loop 200 includes a first control path CTRPH1 and a second control path CTRPH2. The first control path CTRPH1 includes a first switch 210, wherein a first end of the first switch 210 is coupled to a collector C2 of a second transistor through a diode D1 (i.e., a cathode of the diode D1 is coupled to a first end of the first switch 210), and a second end of the first switch 210 is coupled to a ground end. The second control path CTRPH2 includes a second switch 220 and a resistor RCT. The first end of the second switch 220 is coupled to a base B2 of a second transistor Q2 through a resistor RP, and a second end of the second switch 220 is coupled to a ground end. The first end of the resistor RCT is coupled to a first end of the second switch 220, and the second end of the resistor RCT is coupled to a power supply end VCC.

[0024] Under normal circumstances, the power supply terminal VCC supplies power to the load 300 through the resistor RL, and the function of the safety switch device 100 is to terminate the power supply operation under certain circumstances. Among them, the first switch 210 and the second switch 220 of the control loop 200 have opposite operating states. Specifically, the first switch 210 and the second switch 220 can be switches with opposite starting mechanisms. For example, the first switch 210 and the second switch 220 can be controlled by the same switch control signal S. When the switch control signal S is at a high voltage level, the first switch 210 is not conducting, while the second switch 220 is conducting; when the switch control signal S is at a low voltage level, the first switch 210 is conducting, while the second switch 220 is not conducting. Alternatively, the first switch 210 and the second switch 220 can be switches with the same starting mechanism, but are respectively controlled by a pair of complementary signals with opposite phases, the switch control signal S and the switch control signal S_inv. When the switch control signal S is at a high voltage level, the switch control signal S_inv is at a low voltage level, so that the first switch 210 is not conducting and the second switch 220 is conducting; and when the switch control signal S is at a low voltage level, when the switch control signal S_inv is at a high voltage level, the first switch 210 is conducting and the second switch 220 is not conducting.

[0025] When the first switch 210 is turned on and the second switch 220 is not turned on, the cathode of the diode D1 is connected to the ground terminal, so that the diode D1 is turned on. At this time, the collector C2 of the second transistor Q2 will have a low voltage, causing the first transistor Q1 to enter the cut-off state. On the other hand, because the second switch 220 is not turned on, the base B2 of the second transistor Q2 has a high voltage provided by the power supply terminal VCC, so the second transistor Q2 will enter the on state. In this way, the power supply terminal VCC can supply power to the load 300 through the resistor RL. Furthermore, when the first switch 210 is not turned on and the second switch 220 is turned on, the cathode of the diode D1 is not connected to the ground terminal, so that the diode D1 is turned off. At this time, the collector C2 of the second transistor Q2 will have a high voltage, causing the first transistor Q1 to enter the on state. On the other hand, because the second switch 220 is turned on, the base B2 of the second transistor Q2 is coupled to the ground terminal, thereby having a low voltage, so the second transistor Q2 enters the cut-off state. As a result, the power terminal VCC cannot supply power to the load 300 through the resistor RL because the first transistor Q1 is turned on.

[0026] The safety switch device 100 of the present application forms a dual disconnection mechanism through the first control path CTRPH1 and the second control path CTRPH2, which can ensure that even if one of the first switch 210 and the second switch 220 fails, the other control path can still effectively stop the power supply terminal VCC from supplying power to the load 300. For example, when the first switch 210 or the first control path CTRPH1 is abnormal and disconnected, the second switch 220 can be turned on to make the second transistor Q2 enter the off state, so that the first transistor Q1 enters the on state, thereby stopping the power supply terminal VCC from supplying power to the load 300. On the other hand, when the second switch 220 or the second control path CTRPH2 is abnormal and disconnected, the first switch 210 can be set to be non-conductive to make the first transistor Q1 enter the on state, thereby stopping the power supply terminal VCC from supplying power to the load 300. Furthermore, if the first switch 210 and the first control path CTRPH1, as well as the second switch 220 and the second control path CTRPH2, are abnormal and open, the diode D1 will be turned off because it is not connected to the ground terminal, and the transistor Q2 will also be turned off because there is no power supply. Therefore, the collector of the transistor Q2 will have a high voltage provided by the power supply terminal VCC, so that the transistor Q1 is turned on, so that the power supply terminal VCC cannot supply power to the load 300 through the resistor RL. In other words, in extreme fault conditions, the safety switch device 100 can still play a protective role and stop supplying power.

[0027] Figure 2FIG. 4 is a schematic diagram of a safety switch device according to another embodiment of the present invention. As shown in the figure, the safety switch device 400 is composed of a first transistor Q1, a second transistor Q2, a diode D1, a resistor RP, and a control loop 500. Similar to the previous embodiment, the collector C1 of the first transistor Q1 is coupled to the power supply terminal VCC through a resistor RL, and is also connected to the load 300. The collector C2 of the second transistor Q2 is coupled to the power supply terminal VCC through a resistor R1, and is coupled to the base B1 of the first transistor Q1 through a resistor R2. In addition, the anode of the diode D1 is coupled to the collector C2 of the second transistor, and the first end of the resistor RP is coupled to the base B2 of the second transistor.

[0028] The control loop 500 includes a third control path CTRPH3 and a third control path CTRPH4. One end of the third control path CTRPH3 is coupled to the cathode of the diode D1, and the other end is coupled to the first loop control signal LS1; one end of the fourth control path CTRPH4 is coupled to the second end of the resistor RP, and the other end is coupled to the second loop control signal LS2, wherein the first loop control signal LS1 and the second loop control signal LS2 are a set of complementary signals with opposite phases.

[0029] When the first loop control signal LS1 is at a low voltage level and the second loop control signal LS2 is at a high voltage level, the cathode of the diode D1 has a low voltage, so that the diode D1 is turned on. At this time, the collector C2 of the second transistor Q2 will have a low voltage, causing the first transistor Q1 to enter a cut-off state. On the other hand, because the high voltage level of the second loop control signal LS2 causes the base B2 of the second transistor Q2 to have a high voltage, the second transistor Q2 will enter a conduction state. In this way, the power supply terminal VCC can supply power to the load 600 through the resistor RL. Furthermore, when the first loop control signal LS1 is at a high voltage level and the second loop control signal LS2 is at a low voltage level, the cathode of the diode D1 has a high voltage, so that the diode D1 is turned off. At this time, the collector C2 of the second transistor Q2 will have a high voltage, causing the first transistor Q1 to enter a conduction state. On the other hand, because the low voltage level of the second loop control signal LS2 causes the base B2 of the second transistor Q2 to have a low voltage, causing the second transistor Q2 to enter a cut-off state. As a result, the power terminal VCC cannot supply power to the load 600 through the resistor RL because the first transistor Q1 is turned on.

[0030] Similar to the previous embodiment, the third control path CTRPH3 and the fourth control path CTRPH2 form a dual disconnection mechanism to ensure that even if one of the control paths is disconnected due to an abnormality, the other control path can still effectively stop the power supply terminal VCC from supplying power to the load 300. For example, when the third control path CTRPH3 is disconnected due to an abnormality, the second loop control signal LS2 can be set to a low voltage level to implement a safety protection mechanism (disconnecting power to the load 300). On the other hand, when the fourth control path CTRPH4 is disconnected due to an abnormality, the first loop control signal LS1 can be set to a high voltage level to implement a safety protection mechanism (disconnecting power to the load 300). Furthermore, if both the third control path CTRPH3 and the fourth control path CTRPH4 are disconnected due to an abnormality, the diode D1 will be turned off because it is not connected to the ground terminal, and the transistor Q2 will also be turned off because there is no power supply. Therefore, in extreme fault conditions, the safety switch device 400 can still play a protective role and stop power supply.

[0031] In addition, it is worth mentioning that the diode D1 in the aforementioned embodiment can also be replaced by a resistor with a low resistance value.

[0032] In summary, the present invention provides a safety switch device with a double circuit-breaking mechanism. When part of the circuit or the switch unit fails, the safety protection mechanism can still operate normally, and shut down the system operation when both switch units are disconnected. The present invention can be further applied to the brake circuit of an electric vehicle, driving the safety protection mechanism through a high voltage level drive or a low voltage level, and shutting down the system when all circuits are disconnected.

[0033] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A safety switch device for selectively stopping the power supply from a power source to a load, comprising: A first transistor, a first terminal of the first transistor is coupled to the load and the power terminal; a second transistor, a first terminal of the second transistor being coupled to a control terminal of the first transistor; a diode, an anode of the diode being coupled to the first end of the second transistor and the control end of the first transistor; a first resistor, wherein a first end of the first resistor is connected to a control end of the second transistor; as well as a control loop, comprising a first control path and a second control path, wherein one end of the first control path is coupled to the cathode of the diode, one end of the second control path is coupled to the second end of the first resistor, and the first control path is used to provide a signal transmission path between a low voltage level or a high voltage level and the first transistor, and the second control path is used to provide a signal transmission path between the low voltage level or the high voltage level and the second transistor; When the first control path does not provide a signal transmission path between the low voltage level and the first transistor or does not provide a signal transmission path between the high voltage level and the first transistor, the second control path provides a signal transmission path between the low voltage level and the second transistor, so that the power supply end stops supplying power to the load.

2. The safety switch device according to claim 1, characterized in that: The first control path includes a first switch, and the second control path includes a second switch and a second resistor, wherein the cathode of the diode is coupled to the first end of the first switch, and the second end of the first switch is coupled to the ground end; the second end of the first resistor is coupled to the first end of the second switch and the second resistor, the second end of the second switch is coupled to the ground end, the first end of the second resistor is coupled to the first end of the second switch, and the second end of the second resistor is coupled to the power supply end.

3. The safety switch device according to claim 2, characterized in that: The first switch and the second switch are respectively controlled by a switch control signal. When the switch control signal has a first level, the first switch is turned on and the second switch is not turned on, so that the first control path provides the low voltage level and the second control path provides the high voltage level, so that the first transistor is not turned on and the second transistor is turned on, so that the power supply terminal can supply power to the load; When the switch control signal has a second level, the first switch is off and the second switch is on, so that the second control path provides the low voltage level, the first transistor is on and the second transistor is off, so that the power supply terminal stops supplying power to the load.

4. The safety switch device according to claim 3, characterized in that: When both the first control path and the second control path are disconnected due to an abnormality, the first transistor will be turned on and the second transistor will not be turned on, so that the power supply end stops supplying power to the load.

5. The safety switch device according to claim 1, characterized in that: The other end of the first control path is coupled to a first loop control signal, and the other end of the second control path is coupled to a second loop control signal. The first loop control signal and the second loop control signal are signals with opposite phases, and the first loop control signal has a high voltage level and a low voltage level, and the second loop control signal also has a high voltage level and a low voltage level.

6. The safety switch device according to claim 5, characterized in that: When the first loop control signal has the low voltage level and the second loop control signal has the high voltage level, the first transistor is turned off and the second transistor is turned on, so that the power supply end can supply power to the load; when the first loop control signal has the high voltage level and the second loop control signal has the low voltage level, the first transistor is turned on and the second transistor is turned off, so that the power supply end can supply power to the load.

7. The safety switch device according to claim 5, characterized in that: When both the first control path and the second control path are disconnected due to an abnormality, the first transistor will be turned on and the second transistor will not be turned on, so that the power supply end stops supplying power to the load.

8. The safety switch device according to claim 1, characterized in that: The second terminal of the first transistor and the second terminal of the second transistor are coupled to the ground.

9. The safety switch device according to claim 1, characterized in that: The first end of the first transistor is coupled to the power supply end through a load resistor, and the first end of the second transistor is coupled to the power supply end through a resistor.

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