Switch state detection circuit and power supply system

Abstract

The utility model 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 utility model, the auxiliary switch is replaced by the voltage detection circuit and the voltage feedback circuit which are low in cost, 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 utility model relates to the technical field of switch state detection, in particular to a switch state detection circuit and a power supply system. Background Art

[0002] Reference Figure 3 In the prior art, auxiliary switches are often used to detect the open and closed states of switching devices such as MCBs (Micro Circuit Breakers), disconnectors, and fuses. However, the use of auxiliary switches is relatively expensive, increasing product costs in other application scenarios. Furthermore, the use of auxiliary switches occupies space on the circuit board, limiting system configuration in certain compact application scenarios and causing inconvenience for users. Utility Model Content

[0003] The main purpose of the utility model 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 utility model provides a switch state detection circuit for use in a power supply system. The power supply system includes a power supply end, a load end, and a switch to be tested disposed between the power supply end and the load end, the switch to be tested being used to open / close a path between the power supply end and the load end. The switch state detection circuit includes: an isolated power supply having a power supply end and a ground end, the power supply end of the isolated power supply being connected to a first end of the switch to be tested, and the ground end of the isolated power supply being connected to a second end of the switch to be tested; the isolated power supply being 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 having an input end connected to the power supply end of the isolated power supply and an output end connected to the ground end of the isolated power supply; the voltage detection circuit being used to output a voltage detection signal based on a voltage output by the isolated power supply; and a voltage feedback circuit having an input end connected to the output end of the voltage detection circuit and an output end connected to the ground end of the isolated power supply; and the voltage feedback circuit being used to output a voltage feedback signal based on a level 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 the first end of the switch under test, and an output end of the first transistor is connected to an input end of the voltage feedback circuit; the first transistor is configured to open / close a path between the isolated power supply and the voltage feedback circuit based on a voltage output from the isolated power supply to the switch under test.

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

[0007] In one embodiment, the optocoupler includes a light-emitting diode and a phototransistor; the input end of the light-emitting diode is the first input end of the optocoupler, the phototransistor is the controlled end of the optocoupler, and the output end of the light-emitting diode is the first output end of the optocoupler; the input end of the phototransistor is the second input end of the optocoupler, and the output end of the phototransistor is the second output end of the optocoupler; the light-emitting diode is configured to emit light or not emit light according to the level state of the voltage detection signal; and the phototransistor is configured to connect or disconnect the path between the external power supply end and the external ground end according to the light state of the light-emitting diode.

[0008] In one embodiment, the switch state detection circuit further 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, thereby preventing the reverse voltage of the main circuit power supply from damaging the isolated power supply and outputting the voltage of the isolated power supply to the switch to be tested.

[0009] In one embodiment, the switch state detection circuit further includes: a current limiting circuit, which 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.

[0010] In one embodiment, the voltage feedback circuit includes: a relay, wherein an input end of the relay is connected to the output end of the first transistor, and an output end of the relay is connected to the ground end of the isolated power supply; the relay is used to open / close 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 a linkage manner, 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 based on the voltage output by the isolated power supply; and the voltage feedback circuit outputs a voltage feedback signal based on 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 voltage feedback circuit, and realizes the detection of the switch state by combining software and hardware through the voltage detection circuit and the voltage feedback circuit, which not only saves space on 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 following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 any creative work.

[0016] Figure 1 This is a circuit flow chart of a switch state detection circuit and a power supply system of the utility model;

[0017] Figure 2 This is a circuit flow chart of another embodiment of a switch state detection circuit and a power supply system of the present invention;

[0018] Figure 3 This is the auxiliary switch circuit diagram described in the background technology of this utility model;

[0019] Figure 4 This is a circuit structure diagram of a switch state detection circuit and a power supply system of the utility model;

[0020] Figure 5 This is a circuit diagram of another embodiment of a switch state detection circuit and a power supply system of the present invention;

[0021] Figure 6 This is a circuit structure diagram of another embodiment of a switch state detection circuit and a power supply system of the present invention.

[0022] 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

[0023] 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 embodiments described 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 making creative efforts are within the scope of protection of the present invention.

[0024] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), such directional indications are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0025] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only 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 such features. In addition, if the meaning of "and / or" appearing in the full text is to include three parallel schemes, taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which A and B are satisfied at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually 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.

[0026] Understandably, the on / off status detection of switching devices such as MCBs (micro circuit breakers), disconnectors, and fuses is often implemented using auxiliary switches. The shaft of the auxiliary switch is connected to the operating shaft of the switching device. When the switching device is closed, the shaft moves to the closed position; when the switching device is opened, the shaft rotates along the same axis to the open position. Simultaneously, the auxiliary switch's control circuit transmits status signals corresponding to the switching device, such as faults and alarms, based on the shaft's direction, providing intuitive status information to the operator. However, the use of auxiliary switches is relatively expensive, increasing product costs in other application scenarios. Furthermore, the use of auxiliary switches occupies circuit board space, limiting system configuration in some compact applications and causing user inconvenience.

[0027] In order to realize switch state detection, reduce the design cost of the switch state detection circuit, and improve the flexibility of the switch state detection circuit, the utility model 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 includes:

[0028] An isolated power supply 10 having a power supply terminal VCC and a ground terminal iGND. The power supply terminal VCC of the isolated power supply 10 is connected to the first terminal of the switch under test, and the ground terminal iGND of the isolated power supply 10 is connected to the second terminal of the switch under test. The isolated power supply 10 is configured to form a current loop with the switch under test when the switch under test is closed, thereby providing the switch under test with a voltage that is isolated from the power supply terminal.

[0029] A voltage detection circuit 20, wherein the input end of the voltage detection circuit 20 is connected to the power supply terminal VCC of the isolated power supply 10, and the output end of the voltage detection circuit 20 is connected to the ground terminal 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;

[0030] 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 end 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.

[0031] It is understood that when using an auxiliary switch to detect switch status, the auxiliary switch's shaft is connected to the operating shaft of the switch under test. When the switch under test is disconnected, the auxiliary switch shaft also moves to the closed position. The auxiliary switch's control circuit transmits a corresponding closed state signal based on the closed position, prompting the user that the switch under test is currently in the open state. When the switch device is opened, the auxiliary switch shaft rotates along the same axis to the open position. The auxiliary switch's control circuit transmits a corresponding open state signal based on the open position, prompting the user that the switch under test is currently in the closed state, thereby achieving switch status detection. Due to the required fast response time of the auxiliary switch, its cost is relatively high, which increases the detection cost when used in other small power supply devices. Furthermore, the auxiliary switch consists of multiple sets of simultaneously operating blades and multiple porcelain plug-in fuses, which consumes space on the device's circuit board. When used in other compact devices, this limits the device's configuration, increases the device's installation volume, and causes inconvenience to the user. This utility model proposes a switch state detection circuit that replaces a high-cost auxiliary switch with a low-cost voltage detection circuit 20 and voltage feedback circuit 30. This circuit combines software and hardware to detect the switch state, saving circuit board space and reducing the design cost of the switch state detection circuit. The voltage detection circuit 20 and voltage feedback circuit 30 can be implemented using relatively low-cost switching transistors, such as MOS transistors and triodes.

[0032] 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, current flows 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, no current flows 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 status 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 indicate 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 of logic 0 to indicate that the switch under test 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 of logic 1 to indicate that the switch under test is in a closed state, thereby achieving the effect of switch state feedback.

[0033] The power supply system also 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 generate a prompt based on the voltage feedback signal output by the voltage feedback circuit 30, thereby notifying the user of the current switch status of the switch under test. The main control circuit can be implemented using an MCU, a single-chip microcomputer, etc., and the prompt circuit can be implemented using an LED light, an LED screen, etc., which are not limited in this embodiment.

[0034] The present invention provides a switch state detection circuit and a power supply system. The power supply system includes a power supply terminal, a load terminal, and a switch to be tested disposed between the power supply terminal and the load terminal. The switch to be tested is used to open / close the path between the power supply terminal and the load terminal. 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 terminal VCC and a ground terminal iGND. The power supply terminal VCC of the isolated power supply 10 is connected to the first terminal of the switch to be tested, and the ground terminal iGND of the isolated power supply 10 is connected to the second terminal of the switch to be tested. The output terminal of the voltage detection circuit 20 is connected to the ground terminal iGND of the isolated power supply 10. The input terminal of the voltage feedback circuit 30 is connected to the output terminal of the voltage detection circuit 20, and the output terminal of the voltage feedback circuit 30 is connected to the ground terminal iGND of the isolated power supply 10. With the above configuration, when the switch under test is on, the isolated power supply 10 and the switch under test form a current loop, providing voltage to the switch under test. 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. Based on the non-zero voltage detection signal, the voltage feedback circuit 30 outputs a voltage feedback signal with a logic of 1, prompting the user that the switch under test is currently in the closed state. When the switch under test is off, the isolated power supply 10 and the switch under test cannot form a current loop, and the isolated power supply 10 stops providing voltage to the switch under test. 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 zero voltage to the voltage feedback circuit 30. Based on the zero voltage detection signal, the voltage feedback circuit 30 outputs a voltage feedback signal with a logic of 0, prompting the user that the switch under test is currently in the off state.

[0035] In one embodiment, referring to Figure 4 and Figure 5 , the voltage detection circuit 20 includes:

[0036] a first transistor Q1, wherein an input terminal of the first transistor Q1 is connected to the power supply terminal VCC of the isolated power supply 10, a controlled terminal of the first transistor Q1 is connected to a connection point between the input terminal of the first transistor Q1 and the first terminal of the switch to be tested, and an output terminal of the first transistor Q1 is connected to an input terminal of the voltage feedback circuit 30;

[0037] The first transistor Q1 is used to open / close 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.

[0038] It can be understood that in this embodiment, the voltage detection circuit 20 is implemented using the first transistor Q1. By controlling whether a current loop is formed between the isolated power supply 10 and the switch to be tested, the conduction / disconnection of the first transistor Q1 is controlled 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 conduction state of the first transistor Q1.

[0039] In actual applications, when the switch under test is closed, the isolated power supply 10 and the switch under test form a current loop, the controlled terminal of the first transistor Q1 is at a low level, and the first transistor Q1 is turned on, thereby conducting the path between the isolated power supply 10 and the voltage feedback circuit 30. The voltage output by the isolated power supply 10 is output to the first terminal of the switch under test 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, indicating that the switch under test is in the closed state. When the switch under test is open, the isolated power supply 10 and the switch under test cannot form a current loop, the controlled terminal of the first transistor Q1 is at a high level, and the first transistor Q1 is turned off, thereby disconnecting the path between the isolated power supply 10 and the voltage feedback circuit 30. 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, indicating that the switch under test is in the open state.

[0040] In addition, in this embodiment, the first transistor Q1 is connected to the ground terminal iGND of the isolated power supply 10. The first transistor Q1 plays a role of voltage cutoff, thereby preventing the high voltage at both ends of the switch under test from being reversely output to the isolated power supply 10 after the switch under test is disconnected, thereby preventing the isolated power supply 10 and other electronic components from being damaged.

[0041] In one embodiment, referring to Figure 4 and Figure 5 , the voltage feedback circuit 30 includes:

[0042] an optical coupler, wherein a first input end of the optical coupler is connected to the output end of the first transistor Q1, a first output end of the optical coupler is connected to the ground end iGND of the isolated power supply 10, a second input end of the optical coupler is used to access the external power supply end VDD, and a second output end of the optical coupler is used to connect to the external ground end GND;

[0043] The optical coupler is used to open / close 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.

[0044] It will be appreciated that voltage feedback circuit 30 is implemented using an optocoupler. An optocoupler combines a light-emitting device (e.g., light-emitting diode D2) and a photosensitive device (e.g., phototransistor Q2) to create an electrical-to-optical-to-electrical conversion device through light coupling. In this embodiment, the optocoupler responds to the conduction state of the first transistor Q1 to output a voltage feedback signal representing the state of the switch under test.

[0045] In actual 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 conducts the path between the isolated power supply 10 and the optocoupler, the light-emitting diode D2 in the optocoupler lights up, and the photosensitive transistor Q2 in the optocoupler is turned on, and outputs a voltage feedback signal of logic 1, 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, the first transistor Q1 is not turned on, the optocoupler also responds by not conducting, and outputs a voltage feedback signal of logic 0, indicating that the switch to be tested is in an open state, thereby achieving the effect of switch state feedback through the optocoupler.

[0046] In one embodiment, referring to Figure 4 and Figure 5 , the optical coupler includes a light emitting diode D2 and a phototransistor Q2;

[0047] 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;

[0048] The light emitting diode D2 is used to emit light or not emit light according to the level state of the voltage detection signal;

[0049] 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.

[0050] It will be understood that in this 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 due to the electrical signal, and the phototransistor Q2 generates a current when irradiated by the 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.

[0051] In actual applications, when the switch under test is closed, the isolated power supply 10 and the switch under test form a current loop, the controlled terminal 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 optocoupler. At this time, an electrical signal is input to the first input terminal of the optocoupler, that is, an electrical signal is input to the input terminal of the light-emitting diode D2, and the light-emitting diode D2 emits light due to the electrical signal. When the phototransistor Q2 is exposed to light, a current is generated, and the phototransistor Q2 conducts the path between the external power supply terminal VDD and the external ground terminal GND, while outputting a logic 1 level signal to indicate that the switch under test is in the closed state. When the switch under test is open, the isolated power supply 10 and the switch under test cannot form a current loop, the controlled terminal 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 optocoupler, that is, no electrical signal is input to the input terminal 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 the off state by default, that is, it outputs a logic level signal of 0 to indicate that the switch under test is in the off state, thereby achieving the effect of switch state feedback through the light-emitting diode D2 and the phototransistor Q2.

[0052] In one embodiment, referring to Figure 2 、 Figure 4 and Figure 5 , the switch state detection circuit further includes:

[0053] A unidirectional conducting circuit 40, wherein the unidirectional conducting circuit 40 is provided between the power supply terminal VCC of the isolated power supply 10 and the first terminal of the switch to be tested;

[0054] The unidirectional conducting circuit 40 is used to conduct a path between the power supply terminal VCC of the isolated power supply 10 and the first terminal of the switch under test, thereby preventing the reverse voltage of the main circuit power supply from damaging the isolated power supply 10 and outputting the voltage of the isolated power supply 10 to the switch under test.

[0055] It will be appreciated that, in this embodiment, the unidirectional conduction circuit 40 is implemented using 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 under test. It 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 under test, and output the voltage of the isolated power supply 10 in a single direction to the switch under test. This effectively prevents the positive and negative poles of the output voltage of the isolated power supply 10 from being connected in reverse, thereby preventing the reverse voltage from damaging the switch under test or other electronic components. It also prevents the high voltage at both ends of the switch under test from being reversely output to the isolated power supply 10 at the moment of closing / opening, thereby damaging the isolated power supply 10 or other electronic components.

[0056] In one embodiment, referring to Figure 2 、 Figure 4 and Figure 5 , the switch state detection circuit further includes:

[0057] A current limiting circuit 50, wherein the current limiting circuit 50 is provided between the ground terminal iGND of the isolated power supply 10 and the second terminal of the switch to be tested;

[0058] 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.

[0059] 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 actual applications, the first resistor R1 is set 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 in 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 of the loop 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.

[0060] In one embodiment, referring to Figure 6 , the voltage feedback circuit 30 includes:

[0061] 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 ;

[0062] 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.

[0063] It will be appreciated that the voltage feedback circuit 30 is implemented using a relay K3. When the electrical signal at the input terminal of relay K3 reaches a certain threshold or condition, relay K3 will activate, thereby changing the state of the output circuit. In this embodiment, relay K3 is used to respond to the conduction state of the first transistor Q1 by switching on / off, thereby outputting a voltage feedback signal representing the state of the switch under test. Specifically, the first input terminal of relay K3 is connected to the output terminal of the first transistor Q1, the second input terminal of relay K3 is connected to the external power supply terminal VDD, the first output terminal of relay K3 is connected to the ground terminal iGND of the isolated power supply 10, and the second output terminal of relay K3 is connected to the external ground terminal GND. Since relay K3 is composed of a coil, an iron core, an armature, and contacts, when an electrical signal is input to the first input terminal of relay K3, the coil within relay K3 is energized and generates a magnetic field, magnetizing the iron core and attracting the armature, thereby driving the contacts to close. Conversely, when no electrical signal is input to the first input terminal of relay K3, the contacts are open.

[0064] In actual application, when the switch under test is closed, a current loop is formed between the isolated power supply 10 and the switch under test. The controlled terminal of the first transistor Q1 is at a low level, and the first transistor Q1 conducts electricity between the isolated power supply 10 and the relay K3. At this time, an electrical signal is input to the first input terminal of the relay K3, forming a current loop between the output terminal of the first transistor Q1, the relay K3, and the ground terminal iGND of the isolated power supply 10. When the loop is 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 within the relay K3 is energized and generates a magnetic field, magnetizing the iron core and attracting the armature, thereby driving the contacts to close. The path between the external power supply terminal VDD and the external ground terminal GND is in a conductive state, and the relay K3 outputs a level signal indicating that the switch under test is in the closed state. When the switch under test is open, the isolated power supply 10 and the switch under test cannot form a current loop, the controlled terminal of the first transistor Q1 is at a high level, and the first transistor Q1 is non-conductive. At this time, no electrical signal is input to the first input terminal of relay K3, and a current loop cannot be formed between the output terminal of the first transistor Q1, 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, relay K3, and the ground terminal iGND of the isolated power supply 10, the coil within relay K3 is not energized and no magnetic field is generated. The magnetized core does not attract the armature, the contact remains disconnected, and the path between the external power supply terminal VDD and the external ground terminal GND is disconnected. Relay K3 outputs a level signal indicating that the switch under test is in the off state, thereby achieving switch state feedback through relay K3.

[0065] The utility model also proposes 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 described one by one here.

[0066] 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;

[0067] The first switch K1 and the second switch K2 are connected in linkage, wherein a first end of the first switch K1 is connected to the power supply end and the power supply end VCC of the isolated power supply 10, respectively, and a 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; a first end of the second switch K2 is connected to the power supply end, and a second end of the second switch K2 is connected to the load end.

[0068] It can be understood that, in this embodiment, the switch to be tested is implemented using 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.

[0069] 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 using relays. Specifically, when the first switch K1 is closed, the second switch K2 is simultaneously closed, forming a current loop between the isolated power supply 10 and the switch under test. The controlled terminal of the first transistor Q1 is at a low level, and the optocoupler outputs a voltage feedback signal of logic 1, indicating that the first switch K1 and the second switch K2 are in a closed state. When the first switch K1 is opened, the second switch K2 is simultaneously opened, preventing the isolated power supply 10 from forming a current loop with the switch under test. The controlled terminal of the first transistor Q1 is at a high level, and the optocoupler outputs a voltage feedback signal of logic 0, indicating that the first switch K1 and the second switch K2 are in an open state.

[0070] 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;

[0071] A first end of the first switch K1 is connected to the power supply end and the power supply end VCC of the isolated power supply 10 , respectively. A 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.

[0072] 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 the unipolar switch.

[0073] In practical applications, the unipolar switch circuit includes a first switch K1, which is implemented using 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 an open state.

[0074] It should be understood that for a DC power supply system with a single-pole switch, there is a potential path from the power supply end to the load end after the first switch K1 is turned off. Figure 5 A single-pole switching DC power supply system has two connection paths. The first switch K1 is located in one connection path. Even after the first switch K1 is turned off, the DC power supply can still be output to the load through the other connection path, forming a current loop between the DC power supply and the load. In this case, the positive and negative pole connections of the isolated power supply can be adjusted so that the diode at the load end or in the load's own power supply connected to the load end prevents the formation of this potential path.

[0075] The above embodiments are only preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A switch state detection circuit, applied to a power supply system, characterized in that: The power supply system includes a power supply end, a load end, and a switch to be tested provided between the power supply end and the load end. The switch to be tested is used to open / close the path between the power supply end and the load end. The switch state detection circuit includes: an isolated power supply, the isolated power supply having a power supply terminal and a ground terminal, the power supply terminal of the isolated power supply being connected to the first terminal of the switch under test, and the ground terminal of the isolated power supply being connected to the second terminal of the switch under test; the isolated power supply being configured to form a current loop with the switch under test when the switch under test is closed, thereby providing the switch under test with a voltage that is isolated from the power supply terminal; 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, wherein: 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 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 the 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 open / close 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, wherein: The voltage feedback circuit includes: an optical coupler, wherein a first input end of the optical coupler is connected to the output end of the first transistor, a first output end of the optical coupler is connected to the ground end of the isolated power supply, a second input end of the optical coupler is used to connect to 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 open / close 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, wherein: 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 configured to emit light or not emit light according to the level 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 lighting state of the light emitting diode.

5. The switch state detection circuit according to claim 1, wherein: The switch state detection circuit further includes: A unidirectional conducting circuit, wherein the unidirectional conducting circuit is provided 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 a path between the power supply end of the isolated power supply and the first end of the switch to be tested, thereby preventing the reverse voltage of the main circuit power supply from damaging the isolated power supply and outputting the voltage of the isolated power supply to the switch to be tested.

6. The switch state detection circuit according to claim 1, wherein: The switch state detection circuit further includes: a current limiting circuit, the current limiting circuit being 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, wherein: The voltage feedback circuit includes: a relay, wherein an input end of the relay is connected to the output end of the first transistor, and an output end of the relay is connected to the 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, characterized in that: The power supply system includes a power supply end, a switch to be tested, a load end, and a switch state detection circuit according to any one of claims 1 to 7.

9. The power supply system according to claim 8, wherein: 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 a linkage manner, wherein a 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 a second end of the first switch is respectively connected to the load end and the ground end of the isolated power supply; a first end of the second switch is connected to the power supply end, and a second end of the second switch is connected to the load end.

10. The power supply system according to claim 8, wherein: 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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