Switch state detection circuit and power supply system

Abstract

The invention provides a switch state detection circuit and a power supply system, the power supply system comprises a power supply end, a load end and a to-be-detected switch arranged between the power supply end and the load end, and the to-be-detected switch is used for connecting / disconnecting a path between the power supply end and the load end. The switch state detection circuit comprises an isolation power supply, a voltage detection circuit and a voltage feedback circuit. The isolation power supply and the to-be-tested switch form a current loop when the to-be-tested switch is closed so as to provide voltage isolated from the power supply end for the to-be-tested switch. The voltage detection circuit outputs a voltage detection signal according to the voltage output by the isolation power supply; the voltage feedback circuit outputs a voltage feedback signal according to the level state of the voltage detection signal. According to the invention, a high-cost auxiliary switch is replaced by a low-cost voltage detection circuit and a low-cost voltage feedback circuit, and the detection of the switch state is realized through the software and hardware combination of the voltage detection circuit and the voltage feedback circuit, so that the space of a circuit board is saved, and the circuit design cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of switch state detection, and in particular to a switch state detection circuit and a power supply system. Background Art

[0002] Reference Figure 3 Auxiliary switches in the prior art, the detection of the opening and closing states of switch devices such as MCB (Micro Circuit Breaker), disconnectors, fuses, etc. are mostly implemented by auxiliary switches. However, the cost of using auxiliary switches is relatively high, which increases the cost of products in other application scenarios. At the same time, the use of auxiliary switches takes up space on the circuit board, which limits the configuration of the system in some compact application scenarios, causing inconvenience to users. ‌‌ Summary of the invention

[0003] The main purpose of the present invention is to provide a switch state detection circuit and a power supply system, aiming to reduce the design cost of the switch state detection circuit.

[0004] The present invention provides a switch state detection circuit, which is applied to a power supply system. The power supply system includes a power supply end, a load end, and a switch to be tested arranged between the power supply end and the load end, wherein the switch to be tested is used to turn on / off a path between the power supply end and the load end. The switch state detection circuit includes: an isolated power supply, wherein the isolated power supply has a power supply end and a ground end, wherein the power supply end of the isolated power supply is connected to the first end of the switch to be tested, and the ground end of the isolated power supply is connected to the second end of the switch to be tested; the isolated power supply is used to form a current loop with the switch to be tested when the switch to be tested is closed, so as to provide the switch to be tested with a voltage that is isolated from the power supply end; a voltage detection circuit, wherein the input end of the voltage detection circuit is connected to the power supply end of the isolated power supply, and the output end of the voltage detection circuit is connected to the ground end of the isolated power supply; the voltage detection circuit is used to output a voltage detection signal according to the voltage output by the isolated power supply; a voltage feedback circuit, wherein the input end of the voltage feedback circuit is connected to the output end of the voltage detection circuit, and the output end of the voltage feedback circuit is connected to the ground end of the isolated power supply; the voltage feedback circuit is used to output a voltage feedback signal according to the level state of the voltage detection signal.

[0005] In one embodiment, the voltage detection circuit includes: a first transistor, wherein an input end of the first transistor is connected to a power supply end of the isolated power supply, a controlled end of the first transistor is connected to a connection point between the input end of the first transistor and a first end of the switch to be tested, and an output end of the first transistor is connected to an input end of the voltage feedback circuit; the first transistor is used to turn on / off a path between the isolated power supply and the voltage feedback circuit according to a voltage output from the isolated power supply to the switch to be tested.

[0006] In one embodiment, the voltage feedback circuit includes: an optocoupler, a first input end of the optocoupler is connected to the output end of the first transistor, a first output end of the optocoupler is connected to the ground end of the isolated power supply, a second input end of the optocoupler is used to access an external power supply end, and a second output end of the optocoupler is used to connect to an external ground end; the optocoupler is used to turn on / off the path between the external power supply end and the external ground end according to the conduction state of the first transistor, and output a corresponding voltage feedback signal.

[0007] In one embodiment, the optical coupler includes a light emitting diode and a phototransistor; the input end of the light emitting diode is the first input end of the optical coupler, the phototransistor is the controlled end of the optical coupler, and the output end of the light emitting diode is the first output end of the optical coupler; the input end of the phototransistor is the second input end of the optical coupler, and the output end of the phototransistor is the second output end of the optical coupler; the light emitting diode is used to emit light / not emit light according to the level state of the voltage detection signal; the phototransistor is used to turn on / off the path between the external power supply end and the external ground end according to the light emitting state of the light emitting diode.

[0008] In one embodiment, the switch state detection circuit also includes: a unidirectional conduction circuit, which is arranged between the power supply end of the isolated power supply and the first end of the switch to be tested; the unidirectional conduction circuit is used to conduct the path between the power supply end of the isolated power supply and the first end of the switch to be tested to prevent the reverse voltage of the main circuit power supply from damaging the isolated power supply, and output the voltage of the isolated power supply to the switch to be tested.

[0009] In one embodiment, the switch state detection circuit also includes: a current limiting circuit, which is arranged between the ground terminal of the isolated power supply and the second end of the switch to be tested; the current limiting circuit is used to prevent the current of the main circuit passing through the isolated power supply from damaging the isolated power supply.

[0010] In one embodiment, the voltage feedback circuit includes: a relay, wherein the input end of the relay is connected to the output end of the first transistor, and the output end of the relay is connected to the ground end of the isolated power supply; the relay is used to turn on / off the path between the first transistor and the ground end of the isolated power supply according to the conduction state of the first transistor, and output a corresponding voltage feedback signal.

[0011] The present invention further provides a power supply system, which includes a power supply end, a switch to be tested, a load end and the switch state detection circuit.

[0012] In one embodiment, the switch to be tested includes a multi-pole switch circuit, which includes a first switch and a second switch; the first switch and the second switch are connected in linkage, the first end of the first switch is respectively connected to the power supply end and the power supply end of the isolated power supply, and the second end of the first switch is respectively connected to the load end and the ground end of the isolated power supply; the first end of the second switch is connected to the power supply end, and the second end of the second switch is connected to the load end.

[0013] In one embodiment, the switch to be tested includes a unipolar switch circuit, and the unipolar switch circuit includes a first switch; the first end of the first switch is respectively connected to the power supply end and the power supply end of the isolated power supply, and the second end of the first switch is respectively connected to the load end and the ground end of the isolated power supply.

[0014] The present invention proposes a switch state detection circuit and a power supply system. The power supply system includes a power supply end, a load end, and a switch to be tested arranged between the power supply end and the load end. The switch to be tested is used to turn on / off the path between the power supply end and the load end. The switch state detection circuit includes an isolated power supply, a voltage detection circuit, and a voltage feedback circuit. When the switch to be tested is closed, the isolated power supply forms a current loop with the switch to be tested to provide the switch to be tested with a voltage that is isolated from the power supply end; the voltage detection circuit outputs a voltage detection signal according to the voltage output by the isolated power supply; and the voltage feedback circuit outputs a voltage feedback signal according to the level state of the voltage detection signal. ‌‌The present invention replaces the high-cost auxiliary switch with a low-cost voltage detection circuit and a voltage feedback circuit, and realizes the detection of the switch state by combining the voltage detection circuit and the voltage feedback circuit with software and hardware, which not only saves the space of the circuit board, but also reduces the circuit design cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0016] Figure 1 A circuit flow chart of a switch state detection circuit and a power supply system of the present invention; Figure 2 A circuit flow chart of another embodiment of a switch state detection circuit and a power supply system of the present invention; Figure 3 The auxiliary switch circuit diagram described in the background technology of the present invention; Figure 4 A circuit structure diagram of a switch state detection circuit and a power supply system of the present invention; Figure 5 A circuit structure diagram of another embodiment of a switch state detection circuit and a power supply system of the present invention; Figure 6 The circuit structure diagram of another embodiment of a switch state detection circuit and a power supply system of the present invention.

[0017] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0020] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0021] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0022] It is understandable that the detection of the opening and closing status of switching devices such as MCB (Micro Circuit Breaker), disconnectors, fuses, etc. is mostly implemented by auxiliary switches. The shaft of the auxiliary switch is connected to the action shaft of the switching device. When the switching device is closed, the shaft of the auxiliary switch also moves to the closed position; when the switching device is opened, the auxiliary switch shaft rotates to the open position on the same axis. At the same time, the control circuit of the auxiliary switch sends the status signal corresponding to the switching device according to the direction of the axis, such as fault, alarm, etc., to provide intuitive status information to the operator. However, the cost of using auxiliary switches is high, which increases the product cost in other application scenarios. At the same time, the use of auxiliary switches takes up space on the circuit board, limits the configuration of the system in some compact application scenarios, and brings inconvenience to users.

[0023] In order to realize switch state detection, reduce the design cost of the switch state detection circuit, and improve the use flexibility of the switch state detection circuit, the present invention proposes a switch state detection circuit, which is applied to a power supply system. The power supply system includes a power supply end, a load end, and a switch to be tested arranged between the power supply end and the load end. The switch to be tested is used to turn on / off the path between the power supply end and the load end. Figure 1 , the switch state detection circuit comprises: An isolated power supply 10, wherein the isolated power supply 10 has a power supply terminal VCC and a ground terminal iGND, wherein the power supply terminal VCC of the isolated power supply 10 is connected to a first terminal of the switch to be tested, and the ground terminal iGND of the isolated power supply 10 is connected to a second terminal of the switch to be tested; the isolated power supply 10 is used to form a current loop with the switch to be tested when the switch to be tested is closed, so as to provide the switch to be tested with a voltage that is isolated from the power supply terminal; A voltage detection circuit 20, wherein the input end of the voltage detection circuit 20 is connected to the power supply end VCC of the isolated power supply 10, and the output end of the voltage detection circuit 20 is connected to the ground end iGND of the isolated power supply 10; the voltage detection circuit 20 is used to output a voltage detection signal according to the voltage output by the isolated power supply 10; A voltage feedback circuit 30, wherein the input end of the voltage feedback circuit 30 is connected to the output end of the voltage detection circuit 20, and the output end of the voltage feedback circuit 30 is connected to the ground terminal iGND of the isolated power supply 10; the voltage feedback circuit 30 is used to output a voltage feedback signal according to the level state of the voltage detection signal.

[0024] It is understandable that when the switch state is detected by the auxiliary switch, the shaft of the auxiliary switch is connected to the action shaft of the switch to be tested. When the switch to be tested is disconnected, the shaft of the auxiliary switch also moves to the closed position. The control circuit of the auxiliary switch sends a corresponding closed state signal according to the closed position to prompt the user that the switch to be tested is currently in the disconnected state; when the switch device is turned on, the shaft of the auxiliary switch rotates to the open position on the same axis. The control circuit of the auxiliary switch sends a corresponding open state signal according to the open position to prompt the user that the switch to be tested is currently in the closed state, thereby realizing the detection of the switch state. Since the auxiliary switch requires a fast response, its cost is relatively high, which increases the detection cost when applied to other small power supply equipment. At the same time, the auxiliary switch is composed of multiple sets of simultaneously acting knife switches and multiple porcelain plug-in fuses, which occupies the space of the equipment circuit board. When applied to other compact equipment, it limits the configuration of the equipment, increases the installation volume of the equipment, and brings inconvenience to the user. ‌‌The present invention proposes a switch state detection circuit to replace the high-cost auxiliary switch with a low-cost voltage detection circuit 20 and a voltage feedback circuit 30, so that the switch state detection is realized by combining the voltage detection circuit 20 and the voltage feedback circuit 30 with software and hardware, which not only saves the space of the circuit board, but also reduces the design cost of the switch state detection circuit. Among them, the voltage detection circuit 20 and the voltage feedback circuit 30 can be realized by using low-cost switch tubes such as MOS tubes and triodes.

[0025] In this embodiment, when the switch to be tested is closed, the isolated power supply 10 forms a current loop with the switch to be tested, and the isolated power supply 10 provides the switch to be tested with a voltage that is isolated from the power supply end, that is, there is current passing between the isolated power supply 10 and the switch to be tested, and the voltage output by the isolated power supply 10 to the detection circuit is not zero; when the switch to be tested is disconnected, the isolated power supply 10 and the switch to be tested cannot form a current loop, and the isolated power supply 10 cannot provide voltage to the switch to be tested, that is, there is no current passing between the isolated power supply 10 and the switch to be tested, and the voltage output by the isolated power supply 10 to the detection circuit is zero. The voltage detection circuit 20 detects the connection state between the isolated power supply 10 and the switch to be tested based on whether the voltage output by the isolated power supply 10 is zero, and outputs a corresponding voltage detection signal based on the detection result. Among them, the voltage detection signal can be used to characterize that the voltage is zero, or the voltage is not zero. When the voltage feedback circuit 30 receives a voltage detection signal indicating that the voltage is zero, it outputs a voltage feedback signal with a logic value of 0 to indicate that the switch to be tested is in an open state; when the voltage feedback circuit 30 receives a voltage detection signal indicating that the voltage is not zero, it outputs a voltage feedback signal with a logic value of 1 to indicate that the switch to be tested is in a closed state, thereby achieving the effect of switch state feedback.

[0026] In addition, the power supply system further includes a main control circuit and a prompt circuit. The output end of the voltage feedback circuit 30 can be connected to the main control circuit of the power supply system. The main control circuit controls the prompt circuit to make a prompt according to the voltage feedback signal output by the voltage feedback circuit 30, so as to prompt the user of the switch state of the current switch to be tested. Among them, the main control circuit can be implemented by MCU, single-chip microcomputer, etc., and the prompt circuit can be implemented by LED lamp, LED screen, etc., which are not limited in this embodiment.

[0027] The present invention proposes a switch state detection circuit and a power supply system. The power supply system includes a power supply end, a load end, and a switch to be tested arranged between the power supply end and the load end. The switch to be tested is used to turn on / off the path between the power supply end and the load end. The switch state detection circuit specifically includes: an isolated power supply 10, a voltage detection circuit 20, and a voltage feedback circuit 30. The isolated power supply 10 has a power supply end VCC and a ground end iGND. The power supply end VCC of the isolated power supply 10 is connected to the first end of the switch to be tested, and the ground end iGND of the isolated power supply 10 is connected to the second end of the switch to be tested; the output end of the voltage detection circuit 20 is connected to the ground end iGND of the isolated power supply 10; the input end of the voltage feedback circuit 30 is connected to the output end of the voltage detection circuit 20, and the output end of the voltage feedback circuit 30 is connected to the ground end iGND of the isolated power supply 10. Through the above settings, when the switch to be tested is turned on, the isolated power supply 10 and the switch to be tested form a current loop, the isolated power supply 10 provides voltage for the switch to be tested, and the voltage detection circuit 20 detects the voltage output by the isolated power supply 10, and outputs a voltage detection signal consistent with the voltage of the isolated power supply 10 to the voltage feedback circuit 30. The voltage feedback circuit 30 outputs a voltage feedback signal with a logic of 1 according to the voltage detection signal whose voltage is not zero, so as to prompt the user that the current switch to be tested is in a closed state; when the switch to be tested is disconnected, the isolated power supply 10 and the switch to be tested cannot form a current loop, and the isolated power supply 10 stops providing voltage to the switch to be tested. The voltage detection circuit 20 detects that the voltage output by the isolated power supply 10 is zero, and outputs a voltage detection signal with a voltage of zero to the voltage feedback circuit 30. The voltage feedback circuit 30 outputs a voltage feedback signal with a logic of 0 according to the voltage detection signal with a voltage of zero, so as to prompt the user that the current switch to be tested is in a disconnected state.

[0028] In one embodiment, referring to Figure 4 and Figure 5 , the voltage detection circuit 20 comprises: a first transistor Q1, wherein an input end of the first transistor Q1 is connected to a power supply end VCC of the isolation power supply 10, a controlled end of the first transistor Q1 is connected to a connection point between the input end of the first transistor Q1 and the first end of the switch to be tested, and an output end of the first transistor Q1 is connected to an input end of the voltage feedback circuit 30; The first transistor Q1 is used to turn on / off the path between the isolated power supply 10 and the voltage feedback circuit 30 according to the voltage output from the isolated power supply 10 to the switch to be tested.

[0029] It can be understood that, in the present embodiment, the voltage detection circuit 20 is implemented by using the first transistor Q1, and the current loop is formed or not formed by controlling the isolated power supply 10 and the switch to be tested to control the on / off of the first transistor Q1 to open the path between the isolated power supply 10 and the voltage feedback circuit 30, so that the voltage feedback circuit 30 sends a corresponding voltage feedback signal according to the on-state of the first transistor Q1.

[0030] In practical applications, when the switch to be tested is closed, the isolated power supply 10 and the switch to be tested form a current loop, the controlled end of the first transistor Q1 is at a low level, the first transistor Q1 is turned on to conduct the path between the isolated power supply 10 and the voltage feedback circuit 30, and the voltage output by the isolated power supply 10 is output to the first end of the switch to be tested after passing through the first transistor Q1 and the voltage feedback circuit 30. The voltage feedback circuit 30 receives the voltage output by the isolated power supply 10, that is, outputs a voltage feedback signal with a logic of 1, to indicate that the switch to be tested is in a closed state; when the switch to be tested is disconnected, the isolated power supply 10 and the switch to be tested cannot form a current loop, the controlled end of the first transistor Q1 is at a high level, the first transistor Q1 is disconnected, to disconnect the path between the isolated power supply 10 and the voltage feedback circuit 30, and the voltage output by the isolated power supply 10 cannot be output to the voltage feedback circuit 30. The voltage feedback circuit 30 cannot receive the voltage output by the isolated power supply 10, that is, outputs a voltage feedback signal with a logic of 0, to indicate that the switch to be tested is in an open state.

[0031] In addition, the first transistor Q1 in this embodiment is connected to the ground terminal iGND of the isolated power supply 10, and the first transistor Q1 plays a role of voltage cutoff, thereby preventing the high voltage at both ends of the switch to be tested from being reversely output to the isolated power supply 10 after the switch is disconnected, thereby preventing the isolated power supply 10 and other electronic components from being damaged.

[0032] In one embodiment, referring to Figure 4 and Figure 5 , the voltage feedback circuit 30 comprises: An optical coupler, wherein a first input end of the optical coupler is connected to an output end of the first transistor Q1, a first output end of the optical coupler is connected to a ground end iGND of the isolated power supply 10, a second input end of the optical coupler is used to access an external power supply end VDD, and a second output end of the optical coupler is used to connect to an external ground end GND; The optical coupler is used to switch on / off the path between the external power supply terminal VDD and the external ground terminal GND according to the conduction state of the first transistor Q1, and output a corresponding voltage feedback signal.

[0033] It is understandable that the voltage feedback circuit 30 is implemented by an optical coupler, which is a device that assembles a light-emitting device (such as a light-emitting diode D2) and a photosensitive device (such as a phototransistor Q2) together to achieve coupling through light to form an electrical-optical-electrical conversion device. In this embodiment, the optical coupler is used to respond according to the conduction state of the first transistor Q1 to output a voltage feedback signal representing the state of the switch to be tested.

[0034] In practical applications, when the switch to be tested is closed, the isolated power supply 10 and the switch to be tested form a current loop, the controlled end of the first transistor Q1 is at a low level, the first transistor Q1 turns on the path between the isolated power supply 10 and the optocoupler, the light-emitting diode D2 in the optocoupler lights up, so that the photosensitive transistor Q2 in the optocoupler turns on and outputs a voltage feedback signal with a logic of 1 to indicate that the switch to be tested is in a closed state; when the switch to be tested is disconnected, the isolated power supply 10 and the switch to be tested cannot form a current loop, the controlled end of the first transistor Q1 is at a high level, the first transistor Q1 is not turned on, the optocoupler also responds by not turning on, and outputs a voltage feedback signal with a logic of 0 to indicate that the switch to be tested is in an open state, thereby achieving the effect of switch state feedback through the optocoupler.

[0035] In one embodiment, referring to Figure 4 and Figure 5 , the optical coupler includes a light emitting diode D2 and a phototransistor Q2; The input end of the light-emitting diode D2 is the first input end of the optical coupler, the phototransistor Q2 is the controlled end of the optical coupler, and the output end of the light-emitting diode D2 is the first output end of the optical coupler; the input end of the phototransistor Q2 is the second input end of the optical coupler, and the output end of the phototransistor Q2 is the second output end of the optical coupler; The light emitting diode D2 is used to emit light or not emit light according to the level state of the voltage detection signal; The phototransistor Q2 is used to turn on / off the path between the external power supply terminal VDD and the external ground terminal GND according to the light emitting state of the light emitting diode D2.

[0036] It can be understood that, in the present embodiment, the optocoupler is composed of a light-emitting diode D2 and a phototransistor Q2. When an electrical signal is input to the first input terminal of the optocoupler, the light-emitting diode D2 emits light through the electrical signal, and the phototransistor Q2 generates current after being illuminated by light and is in an on state. When no electrical signal is input to the input terminal of the optocoupler, the light-emitting diode D2 does not light up, and the phototransistor Q2 is in an off state.

[0037] In practical applications, when the switch to be tested is closed, the isolated power supply 10 and the switch to be tested form a current loop, the controlled end of the first transistor Q1 is at a low level, and the first transistor Q1 conducts the path between the isolated power supply 10 and the optical coupler. At this time, an electrical signal is input to the first input end of the optical coupler, that is, an electrical signal is input to the input end of the light-emitting diode D2, and the light-emitting diode D2 emits light through the electrical signal. The photosensitive transistor Q2 generates current after being illuminated by light, and the photosensitive transistor Q2 conducts the path between the external power supply terminal VDD and the external ground terminal GND, and outputs a level signal of logic 1 at the same time, to indicate that the switch to be tested is in a closed state; when the switch to be tested is disconnected, the isolated power supply 10 and the switch to be tested cannot form a current loop, the controlled end of the first transistor Q1 is at a high level, and the first transistor Q1 is not conducting. At this time, there is no electrical signal input to the first input end of the optical coupler, that is, there is no electrical signal input to the input end of the light-emitting diode D2, and the light-emitting diode D2 does not emit light. The phototransistor Q2 is not exposed to light and is in an off state by default, that is, it outputs a level signal of logic 0 to indicate that the switch to be tested is in an off state, thereby achieving a switch state feedback effect through the light-emitting diode D2 and the phototransistor Q2.

[0038] In one embodiment, referring to Figure 2 , Figure 4 and Figure 5 , the switch state detection circuit also includes: A unidirectional conduction circuit 40, wherein the unidirectional conduction circuit 40 is arranged between the power supply terminal VCC of the isolated power supply 10 and the first terminal of the switch to be tested; The unidirectional conducting circuit 40 is used to conduct the path between the power supply terminal VCC of the isolated power supply 10 and the first end of the switch to be tested, so as to prevent the reverse voltage of the main circuit power supply from damaging the isolated power supply 10, and output the voltage of the isolated power supply 10 to the switch to be tested.

[0039] It can be understood that in this embodiment, the unidirectional conduction circuit 40 is implemented by an anti-reverse diode D1. In practical applications, the anti-reverse diode D1 is arranged in series between the power supply terminal VCC of the isolated power supply 10 and the first end of the switch to be tested, and is used to conduct the path between the power supply terminal VCC of the isolated power supply 10 and the first end of the switch to be tested, and output the voltage of the isolated power supply 10 to the switch to be tested in a single direction. It effectively prevents the positive and negative poles of the output voltage of the isolated power supply 10 from being reversed to avoid the reverse voltage from causing damage to the switch to be tested or other electronic components, and can also prevent the high voltage at both ends of the switch to be tested from being reversely output to the isolated power supply 10 at the moment of closing / opening, causing damage to the isolated power supply 10 or other electronic components.

[0040] In one embodiment, referring to Figure 2 , Figure 4 and Figure 5, the switch state detection circuit also includes: A current limiting circuit 50, wherein the current limiting circuit 50 is arranged between the ground terminal iGND of the isolated power supply 10 and the second terminal of the switch to be tested; The current limiting circuit 50 is used to prevent the current of the main circuit passing through the isolated power supply 10 from damaging the isolated power supply.

[0041] It can be understood that, in this embodiment, the current limiting circuit 50 is implemented by using a current limiting resistor with a fixed value, such as Figure 4 The resistance value of the first resistor R1 in the circuit can be selected according to the characteristics of other electronic components in the circuit, and is not limited in this embodiment. In practical applications, the first resistor R1 is arranged in series between the ground terminal iGND of the isolated power supply 10 and the second end of the switch to be tested, and is used to limit the current size of the path between the ground terminal iGND of the isolated power supply 10 and the second end of the switch to be tested, so as to prevent the current from being too large and damaging the isolated power supply 10, the switch to be tested and other electronic components. In addition, the switch state detection circuit also includes other current limiting resistors, such as the second resistor R2, the third resistor R3, the fourth resistor R4, the fifth resistor R5 and the sixth resistor R6, which are used to limit the current size of the loop, so as to prevent the current between the power supply end and the load end from being too large and damaging the isolated power supply 10, the switch to be tested, the first transistor Q1, the phototransistor Q2 and the light-emitting diode D2.

[0042] In one embodiment, referring to Figure 6 , the voltage feedback circuit 30 comprises: A relay K3, wherein an input end of the relay K3 is connected to an output end of the first transistor Q1, and an output end of the relay K3 is connected to a ground end iGND of the isolated power supply 10; The relay K3 is used to open / close the path between the first transistor Q1 and the ground terminal iGND of the isolated power supply 10 according to the conduction state of the first transistor Q1, and output a corresponding voltage feedback signal.

[0043] It can be understood that the voltage feedback circuit 30 is implemented by a relay K3. When the electrical signal at the input end of the relay K3 reaches a certain threshold or condition, the relay K3 will be activated, thereby changing the state of the output circuit. In this embodiment, the relay K3 is used to respond to on / off according to the conduction state of the first transistor Q1 to output a voltage feedback signal representing the state of the switch to be tested. Specifically, the first input end of the relay K3 is connected to the output end of the first transistor Q1, the second input end of the relay K3 is used to access the external power supply end VDD, the first output end of the relay K3 is connected to the ground end iGND of the isolated power supply 10, and the second output end of the relay K3 is used to connect to the external ground end GND. Since the relay K3 is composed of a coil, an iron core, an armature, and a contact, when an electrical signal is input to the first input end of the relay K3, the coil in the relay K3 is energized and generates a magnetic field, so that the iron core is magnetized to attract the armature to move, thereby driving the contacts to close. Conversely, when there is no electrical signal input to the first input end of the relay K3, the contacts are disconnected.

[0044] In practical applications, when the switch to be tested is closed, the isolated power supply 10 and the switch to be tested form a current loop, the controlled end of the first transistor Q1 is at a low level, and the first transistor Q1 conducts the path between the isolated power supply 10 and the relay K3. At this time, an electrical signal is input to the first input end of the relay K3 to form a current loop between the output end of the first transistor Q1, the relay K3, and the ground end iGND of the isolated power supply 10. When a loop is formed between the output end of the first transistor Q1, the relay K3, and the ground end iGND of the isolated power supply 10, the coil in the relay K3 is energized and generates a magnetic field, so that the iron core is magnetized to attract the armature to move, thereby driving the contact to close, and the path between the external power supply end VDD and the external ground end GND is in a conducting state, and the relay K3 outputs a level signal indicating that the switch to be tested is in a closed state. When the switch to be tested is disconnected, the isolated power supply 10 and the switch to be tested cannot form a current loop, the controlled end of the first transistor Q1 is at a high level, and the first transistor Q1 is not conducting. At this time, no electrical signal is input to the first input terminal of the relay K3, and a current loop cannot be formed between the output terminal of the first transistor Q1, the relay K3, and the ground terminal iGND of the isolated power supply 10. When a loop cannot be formed between the output terminal of the first transistor Q1, the relay K3, and the ground terminal iGND of the isolated power supply 10, the coil in the relay K3 is not energized and does not generate a magnetic field, the iron core magnetization does not attract the armature, the electric contact remains disconnected, the path between the external power supply terminal VDD and the external ground terminal GND is in a disconnected state, and the relay K3 outputs a level signal indicating that the switch to be tested is in a disconnected state, thereby achieving the effect of switch state feedback through the relay K3.

[0045] The present invention also provides a power supply system, referring to Figure 1 , Figure 4 and Figure 5 The power supply system includes a power supply end, a switch to be tested, a load end and a switch state detection circuit as described in the above embodiments. Since the power supply system adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be repeated here one by one.

[0046] In one embodiment, referring to Figure 4 , the switch to be tested includes a multi-pole switch circuit, and the multi-pole switch circuit includes a first switch K1 and a second switch K2; The first switch K1 and the second switch K2 are connected in linkage, the first end of the first switch K1 is respectively connected to the power supply end and the power supply end VCC of the isolated power supply 10, the second end of the first switch K1 is respectively connected to the load end and the ground end iGND of the isolated power supply 10; the first end of the second switch K2 is connected to the power supply end, and the second end of the second switch K2 is connected to the load end.

[0047] It can be understood that, in this embodiment, the switch to be tested is implemented by a multi-pole switch circuit, so that the power supply end, the multi-pole switch circuit and the load end constitute a power supply system of the multi-pole switch.

[0048] In practical applications, the multi-pole switch circuit includes a first switch K1 and a second switch K2, which are connected in a linkage manner, and are both implemented by relays. Specifically, when the first switch K1 is closed, the second switch K2 is linked to be closed, the isolation power supply 10 and the switch to be tested form a current loop, the controlled end of the first transistor Q1 is at a low level, and the optical coupler outputs a voltage feedback signal with a logic of 1, to indicate that the first switch K1 and the second switch K2 are in a closed state; when the first switch K1 is disconnected, the second switch K2 is linked to be disconnected, the isolation power supply 10 and the switch to be tested cannot form a current loop, the controlled end of the first transistor Q1 is at a high level, and the optical coupler outputs a voltage feedback signal with a logic of 0, to indicate that the first switch K1 and the second switch K2 are in a disconnected state.

[0049] In one embodiment, referring to Figure 5 , the switch to be tested includes a unipolar switch circuit, and the unipolar switch circuit includes a first switch K1; The first end of the first switch K1 is connected to the power end and the power supply end VCC of the isolated power supply 10 respectively, and the second end of the first switch K1 is connected to the load end and the ground end iGND of the isolated power supply 10 respectively.

[0050] It can be understood that in this embodiment, the switch to be tested is implemented using a unipolar switching circuit. At this time, the power supply end in the power supply system is used to output DC power, the power supply end is a DC power supply end, and the DC power supply end, the unipolar switching circuit and the load end constitute a DC power supply system of a unipolar switch.

[0051] In practical applications, the unipolar switch circuit includes a first switch K1, and the first switch K1 is implemented by a relay. Specifically, when the first switch K1 is closed, the DC power supply at the DC power supply end is output to the load end through the first switch K1 to supply power to the load end. At this time, the isolated power supply 10 forms a current loop with the switch to be tested, the controlled end of the first transistor Q1 is at a low level, and the optocoupler outputs a voltage feedback signal with a logic of 1 to indicate that the first switch K1 is in a closed state; when the first switch K1 is disconnected, the DC power supply at the DC power supply end cannot be output to the load end, the isolated power supply 10 and the switch to be tested cannot form a current loop, the controlled end of the first transistor Q1 is at a high level, and the optocoupler outputs a voltage feedback signal with a logic of 0 to indicate that the first switch K1 is in a disconnected state.

[0052] It should be understood that for a DC power supply system with a single-pole switch, there is a potential path for conducting from the power supply end to the load end after the first switch K1 is turned off. Figure 5 The DC power supply system of the single-pole switch has two connection paths. The first switch K1 is set in one connection path. After the first switch K1 is turned off, the DC power supply at the DC power supply end can still be output to the load end through the other connection path, resulting in a current loop between the DC power supply end and the load end. At this time, the positive and negative pole connection mode of the isolated power supply can be adjusted so that the current loop of the isolated power supply is prevented from forming this potential path by the diode in the load end or the load power supply connected to the load end.

[0053] The above descriptions are only optional embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the contents or ideas of the present invention's specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A switch state detection circuit, applied to a power supply system, It is characterized in that The power supply system includes a power supply end, a load end, and a switch to be tested arranged between the power supply end and the load end, the switch to be tested is used to turn on / off the path between the power supply end and the load end, and the switch state detection circuit includes: An isolated power supply, the isolated power supply having a power supply end and a ground end, the power supply end of the isolated power supply being connected to the first end of the switch to be tested, and the ground end of the isolated power supply being connected to the second end of the switch to be tested; the isolated power supply is used to form a current loop with the switch to be tested when the switch to be tested is closed, so as to provide the switch to be tested with a voltage that is isolated from the power supply end; A voltage detection circuit, wherein the input end of the voltage detection circuit is connected to the power supply end of the isolated power supply, and the output end of the voltage detection circuit is connected to the ground end of the isolated power supply; the voltage detection circuit is used to output a voltage detection signal according to the voltage output by the isolated power supply; A voltage feedback circuit, wherein the input end of the voltage feedback circuit is connected to the output end of the voltage detection circuit, and the output end of the voltage feedback circuit is connected to the ground end of the isolated power supply; the voltage feedback circuit is used to output a voltage feedback signal according to the level state of the voltage detection signal.

2. The switch state detection circuit according to claim 1, It is characterized in that The voltage detection circuit comprises: a first transistor, wherein an input end of the first transistor is connected to a power supply end of the isolation power supply, a controlled end of the first transistor is connected to a connection point between the input end of the first transistor and a first end of the switch to be tested, and an output end of the first transistor is connected to an input end of the voltage feedback circuit; The first transistor is used to turn on / off the path between the isolated power supply and the voltage feedback circuit according to the voltage output from the isolated power supply to the switch to be tested.

3. The switch state detection circuit according to claim 2, It is characterized in that The voltage feedback circuit comprises: an optical coupler, wherein a first input end of the optical coupler is connected to an output end of the first transistor, a first output end of the optical coupler is connected to a ground end of the isolated power supply, a second input end of the optical coupler is used to access an external power supply end, and a second output end of the optical coupler is used to connect to an external ground end; The optical coupler is used to turn on / off the path between the external power supply terminal and the external ground terminal according to the conduction state of the first transistor, and output a corresponding voltage feedback signal.

4. The switch state detection circuit according to claim 3, It is characterized in that The optical coupler includes a light emitting diode and a phototransistor; The input end of the light emitting diode is the first input end of the optical coupler, the phototransistor is the controlled end of the optical coupler, and the output end of the light emitting diode is the first output end of the optical coupler; the input end of the phototransistor is the second input end of the optical coupler, and the output end of the phototransistor is the second output end of the optical coupler; The light emitting diode is used to emit light or not emit light according to the level state of the voltage detection signal; The phototransistor is used to turn on / off the path between the external power supply terminal and the external ground terminal according to the light emitting state of the light emitting diode.

5. The switch state detection circuit according to claim 1, It is characterized in that The switch state detection circuit also includes: A unidirectional conducting circuit, wherein the unidirectional conducting circuit is arranged between the power supply end of the isolated power supply and the first end of the switch to be tested; The unidirectional conducting circuit is used to conduct the path between the power supply end of the isolated power supply and the first end of the switch to be tested, so as to prevent the reverse voltage of the main circuit power supply from damaging the isolated power supply, and output the voltage of the isolated power supply to the switch to be tested.

6. The switch state detection circuit according to claim 1, It is characterized in that The switch state detection circuit also includes: A current limiting circuit, wherein the current limiting circuit is arranged between the ground terminal of the isolated power supply and the second terminal of the switch to be tested; The current limiting circuit is used to prevent the current of the main circuit passing through the isolated power supply from damaging the isolated power supply.

7. The switch state detection circuit according to claim 2, It is characterized in that The voltage feedback circuit comprises: A relay, wherein an input end of the relay is connected to an output end of the first transistor, and an output end of the relay is connected to a ground end of the isolated power supply; The relay is used to open / close the path between the first transistor and the ground terminal of the isolated power supply according to the conduction state of the first transistor, and output a corresponding voltage feedback signal.

8. A power supply system, It is characterized in that The power supply system comprises a power supply end, a switch to be tested, a load end and a switch state detection circuit as described in any one of claims 1 to 7.

9. The power supply system according to claim 8, It is characterized in that The switch to be tested includes a multi-pole switch circuit, and the multi-pole switch circuit includes a first switch and a second switch; The first switch and the second switch are connected in linkage, the first end of the first switch is respectively connected to the power supply end and the power supply end of the isolated power supply, and the second end of the first switch is respectively connected to the load end and the ground end of the isolated power supply; the first end of the second switch is connected to the power supply end, and the second end of the second switch is connected to the load end.

10. The power supply system according to claim 8, It is characterized in that The switch to be tested includes a unipolar switch circuit, and the unipolar switch circuit includes a first switch; The first end of the first switch is connected to the power supply end and the power supply end of the isolated power supply respectively, and the second end of the first switch is connected to the load end and the ground end of the isolated power supply respectively.

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