Signal detection circuit and charging pile

Abstract

The invention discloses a signal detection circuit and a charging pile. The signal detection circuit comprises a signal input end, an insertion detection module, a limit value detection module and a controller. The insertion detection module comprises a first comparison circuit and a first isolation circuit, and the first comparison circuit and the first isolation circuit are arranged between the signal input end and the controller in series and used for outputting an insertion detection signal to the controller according to the connection state of the signal input end and target equipment; the limit value detection module comprises a second comparison circuit and a second isolation circuit. The insertion detection module and the limit value detection module are arranged in the signal detection circuit, the physical connection condition and the electric connection state can be detected respectively, the detection result is more accurate and clear, the isolation circuit is further arranged in the signal detection circuit for signal isolation, electromagnetic interference can be effectively resisted, and the stability of detection signals is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of charging piles, and in particular to a signal detection circuit and a charging pile. Background Art

[0002] When the target device to be charged is connected to the charging pile for charging, it is first necessary to detect the access signal to determine whether the physical connection and electrical connection between the charging pile and the target device have been established. In the prior art, when detecting the access signal, the access signal is usually input into an operational amplifier for processing, and then the processed analog signal is directly connected to the controller for ADC detection to obtain the physical connection and electrical connection status. However, a single analog signal is easily affected by interference signals, resulting in false detection by the controller and inaccurate detection results. Summary of the invention

[0003] The embodiments of the present invention provide a signal detection circuit and a charging pile to solve the problem that when a controller detects an access signal, false detection is prone to occur and the detection result is not accurate enough.

[0004] An embodiment of the present invention provides a signal detection circuit, including a signal input terminal, an insertion detection module, a limit detection module and a controller; The insertion detection module comprises a first comparison circuit and a first isolation circuit, wherein the first comparison circuit and the first isolation circuit are arranged in series between the signal input terminal and the controller, and are used to output an insertion detection signal to the controller according to the connection state between the signal input terminal and the target device; The limit detection module includes a second comparison circuit and a second isolation circuit, which are arranged in series between the signal input terminal and the controller, and are used to output a limit detection signal to the controller according to the connection state between the signal input terminal and the target device; The controller is used to determine a connection detection result according to the insertion detection signal and the limit detection signal.

[0005] Preferably, the first comparison circuit comprises a first comparator; The first comparator is arranged between the signal input terminal and the first isolation circuit, and is used to control the first isolation circuit to output an insertion detection signal to the controller according to the connection state between the signal input terminal and the target device; The second comparison circuit includes a second comparator and a third comparator; The second comparator and the third comparator are arranged in parallel between the signal input terminal and the second isolation circuit, and are used to output a first comparison signal and a second comparison signal to the second isolation circuit respectively according to the connection state between the signal input terminal and the target device; The second isolation circuit outputs a limit detection signal to the controller according to the first comparison signal and the second comparison signal.

[0006] Preferably, the first comparison circuit further includes a first voltage input unit and a first reference voltage unit; A first end of the first voltage input unit is connected to the signal input end, and a second end of the first voltage input unit is connected to the non-inverting input end of the first comparator, and is used to output a first detection voltage to the first comparator when the signal input end is connected to the target device; The first reference voltage unit is connected to the inverting input terminal of the first comparator, and is used to output a first reference voltage to the first comparator; The output end of the first comparator is connected to the first isolation circuit, and is used to control the first isolation circuit to be turned on when the first detection voltage is less than the first reference voltage, so that the first isolation circuit outputs a first insertion detection signal; and is also used to control the first isolation circuit to be turned off when the first detection voltage is not less than the first reference voltage, so that the first isolation circuit outputs a second insertion detection signal.

[0007] Preferably, the second comparison circuit further includes a second voltage input unit, a third voltage input unit, a second reference voltage unit and a third reference voltage unit; A first end of the second voltage input unit is connected to the signal input end, and a second end of the second voltage input unit is connected to the non-inverting input end of the second comparator, and is used to output a second detection voltage to the second comparator when the signal input end is connected to the target device; The second reference voltage unit is connected to the inverting input terminal of the second comparator, and is used to output a second reference voltage to the second comparator; The second comparator is used to output a first cut-off signal when the second detection voltage is greater than a second reference voltage, and to output a first turn-on signal when the second detection voltage is not greater than the second reference voltage; The first end of the third voltage input unit is connected to the signal input end, and the second end of the third voltage input unit is connected to the inverting input end of the third comparator, and is used to output a third detection voltage to the third comparator when the signal input end is connected to the target device; The third reference voltage unit is connected to the non-inverting input terminal of the third comparator, and is used to output a third reference voltage to the third comparator; The third comparator is used to output a second cut-off signal when the third detection voltage is less than the third reference voltage, and output a second turn-on signal when the third detection voltage is not less than the third reference voltage; The second isolation circuit is connected to the second comparator and the third comparator, and is used to be cut off when receiving the first cutoff signal and the third cutoff signal, and output a first limit detection signal, and to be turned on when receiving any one of the second turn-on signal and the fourth turn-on signal, and output a second limit detection signal.

[0008] Preferably, the signal detection circuit further comprises a first resistor, wherein a first end of the first resistor is used to connect to a first power supply; The first voltage input unit comprises a second resistor, a first end of the second resistor is connected to the second end of the first resistor and the signal input end, and a second end of the second resistor is connected to the non-inverting input end of the first comparator; The second voltage input unit comprises a third resistor, a first end of the third resistor is connected to the second end of the first resistor and the signal input end, and a second end of the third resistor is connected to the non-inverting input end of the second comparator; The third voltage input unit includes a fourth resistor, a first end of the fourth resistor is connected to the second end of the first resistor and the signal input end, and a second end of the fourth resistor is connected to the inverting input end of the third comparator.

[0009] Preferably, the first reference voltage unit includes a fifth resistor and a sixth resistor; The fifth resistor and the sixth resistor are connected in series between the first power supply and the ground, and a connection node between the fifth resistor and the sixth resistor is connected to the inverting input terminal of the first comparator; The second reference voltage unit includes a seventh resistor and an eighth resistor; The seventh resistor and the eighth resistor are connected in series between the first power supply and the ground, and a connection node between the seventh resistor and the eighth resistor is connected to the inverting input terminal of the second comparator; The third reference voltage unit includes a ninth resistor and a tenth resistor; The ninth resistor and the tenth resistor are connected in series between the first power supply and the ground, and a connection node between the ninth resistor and the tenth resistor is connected to the non-inverting input terminal of the third comparator.

[0010] Preferably, the first isolation circuit comprises a first optical coupling unit; The first input end of the first optical coupling unit is used to connect to the first power supply, the second input end of the first optical coupling unit is connected to the first comparison circuit, the first output end of the first optical coupling unit is connected to the second power supply unit, and the second output end of the first optical coupling unit is connected to the controller for outputting an insertion detection signal; The second isolation circuit includes a second optical coupling unit; The first input end of the second optocoupler unit is used to connect to the first power supply, the second input end of the second optocoupler unit is connected to the second comparison circuit, the first output end of the second optocoupler unit is connected to the second power supply unit, the second output end of the first optocoupler unit is grounded, and the first output end of the second optocoupler unit is also connected to the controller for outputting a limit detection signal.

[0011] Preferably, the first isolation circuit further includes a first pull-up resistor and a first current limiting resistor; A first end of the first pull-up resistor is connected to a second power supply, and a second end of the first pull-up resistor is connected to a first output end of the first optical coupling unit; The first end of the first current limiting resistor is connected to the second output end of the first optical coupling unit, and the second end of the first current limiting resistor is grounded; The controller is connected to a connection node between the first current limiting resistor and the first optical coupling unit; The second isolation circuit also includes a second pull-up resistor; A first end of the second pull-up resistor is connected to a second power supply, and a second end of the second pull-up resistor is connected to a first output end of the second optical coupling unit; The controller is connected to a connection node between the second pull-up resistor and the second optical coupling unit.

[0012] Preferably, the first isolation circuit further includes a second current limiting resistor, and the second current limiting resistor is arranged between the first comparison circuit and the first optical coupling unit; The second isolation circuit further includes a third current limiting resistor, and the third current limiting resistor is arranged between the second comparison circuit and the second optical coupling unit.

[0013] An embodiment of the present invention further provides a charging pile, comprising the above-mentioned signal detection circuit.

[0014] The signal detection circuit, system and charging pile provided by the embodiments of the present invention can respectively detect the physical connection status and the electrical connection status by setting an insertion detection module and a limit detection module in the signal detection circuit of the charging pile, so that the detection result is more accurate and clear. In addition, an isolation circuit is also set in the signal detection circuit to isolate the signal, which can effectively resist electromagnetic interference and ensure the stability of the detection signal. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0016] Figure 1 is a block diagram of a signal detection circuit in one embodiment of the present invention; Figure 2 It is a circuit structure diagram of a signal detection circuit in one embodiment of the present invention.

[0017] In the figure: 1. signal input terminal; 2. insertion detection module; 21. first comparison circuit; 211. first voltage input unit; 212. first reference voltage unit; 22. first isolation circuit; 3. limit detection module; 31. second comparison circuit; 311. second voltage input unit; 312. third voltage input unit; 313. second reference voltage unit; 314. third reference voltage unit; 32. second isolation circuit; 4. controller. 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 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 understood that the present invention can be implemented in different forms and should not be construed as being limited to the embodiments set forth herein. On the contrary, providing these embodiments will make the disclosure thorough and complete and fully convey the scope of the present invention to those skilled in the art. In the accompanying drawings, the sizes and relative sizes of layers and regions may be exaggerated for clarity. The same reference numerals throughout represent the same elements.

[0020] It should be understood that when an element or layer is referred to as being "on, adjacent to, connected to or coupled to other elements or layers, it may be directly on, adjacent to, connected to or coupled to other elements or layers, or there may be intervening elements or layers. In contrast, when an element is referred to as being "directly on, directly adjacent to, directly connected to or directly coupled to other elements or layers, there may be no intervening elements or layers. It should be understood that, although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present invention, the first element, component, region, layer or part discussed below may be represented as a second element, component, region, layer or part.

[0021] Spatially relative terms such as "under," "beneath," "below," "under," "above," "above," and the like may be used herein for ease of description to describe the relationship of an element or feature shown in the figures to other elements or features. It should be understood that the spatially relative terms are intended to include different orientations of the device in use and operation in addition to the orientations shown in the figures. For example, if the device in the accompanying drawings is flipped, then the elements or features described as "under other elements" or "under" or "under" will be oriented as "above" the other elements or features. Thus, the exemplary terms "under" and "under" may include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or other orientations) and the spatial descriptors used herein are interpreted accordingly.

[0022] The purpose of the terms used herein is only to describe specific embodiments and is not intended to be limiting of the present invention. When used herein, the singular forms "one", "an" and "said / the" are also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "consisting of" and / or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0023] In order to fully understand the present invention, detailed structures and steps will be presented in the following description to illustrate the technical solutions proposed by the present invention. The preferred embodiments of the present invention are described in detail below, but in addition to these detailed descriptions, the present invention may also have other implementations.

[0024] An embodiment of the present invention provides a signal detection circuit, including a signal input terminal 1, an insertion detection module 2, a limit detection module 3 and a controller 4; the insertion detection module 2 includes a first comparison circuit 21 and a first isolation circuit 22, the first comparison circuit 21 and the first isolation circuit 22 are arranged in series between the signal input terminal 1 and the controller 4, and are used to output an insertion detection signal to the controller 4 when the signal input terminal 1 is connected to a target device; the limit detection module 3 includes a second comparison circuit 31 and a second isolation circuit 32, the second comparison circuit 31 and the second isolation circuit 32 are arranged in series between the signal input terminal 1 and the controller 4, and are used to output a limit detection signal to the controller 4 when the signal input terminal 1 is connected to the target device.

[0025] As an example, the signal detection circuit includes a signal input terminal 1, an insertion detection module 2, a limit detection module 3 and a controller 4. The signal input terminal 1 is used to connect the target device to be charged. The insertion detection module 2 includes a first comparison circuit 21 and a first isolation circuit 22, and the first comparison circuit 21 and the first isolation circuit 22 are arranged in series between the signal input terminal 1 and the controller 4. The first comparison circuit 21 is used to perform insertion detection when the target device is connected to the signal input terminal 1 to determine whether the target device is physically connected to the device where the signal detection circuit is located. The first isolation circuit 22 is used to isolate the target device and the controller 4, and can output an insertion detection signal to the controller 4 under the control of the first comparison circuit 21. The limit detection module 3 includes a second comparison circuit 31 and a second isolation circuit 32, and the second comparison circuit 31 and the second isolation circuit 32 are arranged in series between the signal input terminal 1 and the controller 4. The second comparison circuit 31 is used to perform limit detection when the signal input terminal 1 is connected to the target device to determine the electrical connection state between the target device and the device where the signal detection circuit is located. The second isolation circuit 32 is used to isolate the target device and the controller 4, and can output a limit detection signal to the controller 4 under the control of the second comparison circuit 31.

[0026] In this example, by setting up the insertion detection module 2 and the limit detection module 3, the physical connection status and the electrical connection status can be detected separately, making the detection results more accurate and clear, and setting up an isolation circuit for signal isolation can effectively resist electromagnetic interference and ensure the stability of the detection signal.

[0027] In one embodiment, the first comparison circuit 21 includes a first comparator U1A; the first comparator U1A is arranged between the signal input terminal 1 and the first isolation circuit 22, and is used to control the first isolation circuit 22 to output an insertion detection signal to the controller 4 according to the connection status between the signal input terminal 1 and the target device; the second comparison circuit 31 includes a second comparator U2A and a third comparator U2B; the second comparator U2A and the third comparator U2B are arranged in parallel between the signal input terminal 1 and the second isolation circuit 32, and are used to output a first comparison signal and a second comparison signal to the second isolation circuit 32 respectively according to the connection status between the signal input terminal 1 and the target device; the second isolation circuit 32 outputs a limit detection signal to the controller 4 according to the first comparison signal and the second comparison signal.

[0028] As an example, the first comparison circuit 21 includes a first comparator U1A; the first comparator U1A is arranged between the signal input terminal 1 and the first isolation circuit 22, and is used to compare the voltage of the signal input terminal 1 with the first reference voltage when the target device is connected to the signal input terminal 1, and according to the comparison result, control the first isolation circuit 22 to output a corresponding insertion detection signal to the controller 4.

[0029] The second comparison circuit 31 includes a second comparator U2A and a third comparator U2B; the second comparator U2A and the third comparator U2B are arranged in parallel between the signal input terminal 1 and the second isolation circuit 32, the second comparator U2A is used to compare the voltage of the signal input terminal 1 with the second reference voltage, and output a first comparison signal to the second isolation circuit 32, the third comparator U2B is used to compare the voltage of the signal input terminal 1 with the third reference voltage, and output a second comparison signal to the second isolation circuit 32, and the second isolation circuit 32 can output a corresponding limit detection signal to the controller 4 according to the first comparison signal and the second comparison signal.

[0030] In one embodiment, the first comparison circuit 21 further includes a first voltage input unit 211 and a first reference voltage unit 212; the first end of the first voltage input unit 211 is connected to the signal input terminal 1, and the second end of the first voltage input unit 211 is connected to the non-inverting input terminal of the first comparator U1A, and is used to output the first detection voltage to the first comparator U1A when the signal input terminal 1 is connected to the target device; the first reference voltage unit 212 is connected to the inverting input terminal of the first comparator U1A, and is used to output the first reference voltage to the first comparator U1A; the output terminal of the first comparator U1A is connected to the first isolation circuit 22, and is used to control the first isolation circuit 22 to be turned on when the first detection voltage is less than the first reference voltage, so that the first isolation circuit 22 outputs the first insertion detection signal; and is also used to control the first isolation circuit 22 to be turned off when the first detection voltage is not less than the first reference voltage, so that the first isolation circuit 22 outputs the second insertion detection signal. .

[0031] As an example, the first comparison circuit 21 also includes a first voltage input unit 211 and a first reference voltage unit 212. The first end of the first voltage input unit 211 is connected to the signal input terminal 1, and the second end of the first voltage input unit 211 is connected to the non-inverting input terminal of the first comparator U1A. The first voltage input unit 211 is used to output a first detection voltage to the first comparator U1A according to the physical connection state between the target device and the device where the signal detection circuit is located when the signal input terminal 1 is connected to the target device; the first reference voltage unit 212 is connected to the inverting input terminal of the first comparator U1A, and is used to output a first reference voltage to the first comparator U1A; the output terminal of the first comparator U1A is connected to the first isolation circuit 22, and is used to output a low-level signal to control the first isolation circuit 22 to be turned on when the first detection voltage is less than the first reference voltage, and output a high-level signal to control the first isolation circuit 22 to be turned off when the first detection voltage is not less than the first reference voltage.

[0032] In one embodiment, the second comparison circuit 31 also includes a second voltage input unit 311, a third voltage input unit 312, a second reference voltage unit 313 and a third reference voltage unit 314; the first end of the second voltage input unit 311 is connected to the signal input terminal 1, and the second end of the second voltage input unit 311 is connected to the in-phase input terminal of the second comparator U2A, and is used to output a second detection voltage to the second comparator U2A when the signal input terminal 1 is connected to the target device; the second reference voltage unit 313 is connected to the inverting input terminal of the second comparator U2A, and is used to output a second reference voltage to the second comparator U2A; the second comparator U2A is used to output a first cut-off signal when the second detection voltage is greater than the second reference voltage, and output a first conduction signal when the second detection voltage is not greater than the second reference voltage; the first end of the third voltage input unit 312 is connected to the signal input terminal 1, and the second end of the second voltage input unit 311 is connected to the in-phase input terminal of the second comparator U2A, and is used to output a second detection voltage to the second comparator U2A when the signal input terminal 1 is connected to the target device; the second reference voltage unit 313 is connected to the inverting input terminal of the second comparator U2A, and is used to output a second reference voltage to the second comparator U2A; the second comparator U2A is used to output a first cut-off signal when the second detection voltage is greater than the second reference voltage, and output a first conduction signal when the second detection voltage is not greater than the second reference voltage; The third comparator U2B is connected to the input terminal 1, and the second end of the third voltage input unit 312 is connected to the inverting input terminal of the third comparator U2B, and is used to output the third detection voltage to the third comparator U2B when the signal input terminal 1 is connected to the target device; the third reference voltage unit 314 is connected to the non-inverting input terminal of the third comparator U2B, and is used to output the third reference voltage to the third comparator U2B; the third comparator U2B is used to output a second cut-off signal when the third detection voltage is less than the third reference voltage, and output a second turn-on signal when the third detection voltage is not less than the third reference voltage; the second isolation circuit 32 is connected to the second comparator U2A and the third comparator U2B, and is used to cut off when receiving the first cut-off signal and the third cut-off signal, and output the first limit detection signal, and turn on when receiving any one of the second turn-on signal and the fourth turn-on signal, and output the second limit detection signal.

[0033] As an example, the second comparison circuit 31 further includes a second voltage input unit 311, a third voltage input unit 312, a second reference voltage unit 313 and a third reference voltage unit 314. The first end of the second voltage input unit 311 is connected to the signal input terminal 1, and the second end of the second voltage input unit 311 is connected to the non-inverting input terminal of the second comparator U2A, and is used to output the second detection voltage to the third comparator U2B according to the electrical connection state between the target device and the device where the signal detection circuit is located when the signal input terminal 1 is connected to the target device; the second reference voltage unit 313 is connected to the inverting input terminal of the second comparator U2A, and is used to output the second reference voltage to the first comparator U1A. The first end of the third voltage input unit 312 is connected to the signal input terminal 1, and the second end of the third voltage input unit 312 is connected to the inverting input terminal of the third comparator U2B, and is used to output a third detection voltage to the third comparator U2B according to the electrical connection state between the target device and the device where the signal detection circuit is located when the signal input terminal 1 is connected to the target device; the third reference voltage unit 314 is connected to the non-inverting input terminal of the third comparator U2B, and is used to output a third reference voltage to the first comparator U1A, wherein the third reference voltage is greater than the second reference voltage; the output terminal of the second comparator U2A is connected to the second isolation circuit 32, and is used to output a high-level signal, that is, a first cut-off signal, when the second detection voltage is greater than the second reference voltage, and output a low-level signal, that is, a first conduction signal, when the second detection voltage is not greater than the second reference voltage; the output terminal of the third comparator U2B is connected to the second isolation circuit 32, and is used to output a high-level signal, that is, a second cut-off signal, when the third detection voltage is less than the third reference voltage, and output a low-level signal, that is, a second conduction signal, when the third detection voltage is not less than the third reference voltage. The second isolation circuit 32 is used to be turned off and output a first limit detection signal when receiving the first cutoff signal and the third cutoff signal at the same time, and to be turned on and output a second limit detection signal when receiving any one of the second conduction signal and the fourth conduction signal.

[0034] In one embodiment, the signal detection circuit also includes a first resistor R1, and a first end of the first resistor R1 is used to connect to a first power supply; the first voltage input unit 211 includes a second resistor R2, and a first end of the second resistor R2 is connected to the second end of the first resistor R1 and the signal input terminal 1, and a second end of the second resistor R2 is connected to the non-inverting input terminal of the first comparator U1A; the second voltage input unit 311 includes a third resistor R3, and a first end of the third resistor R3 is connected to the second end of the first resistor R1 and the signal input terminal 1, and a second end of the third resistor R3 is connected to the non-inverting input terminal of the second comparator U2A; the third voltage input unit 312 includes a fourth resistor R4, and a first end of the fourth resistor R4 is connected to the second end of the first resistor R1 and the signal input terminal 1, and a second end of the fourth resistor R4 is connected to the inverting input terminal of the third comparator U2B.

[0035] As an example, the signal detection circuit further includes a first resistor R1, the first end of the first resistor R1 is used to connect to a first power supply (12V); the first voltage input unit 211 includes a second resistor R2; the first end of the second resistor R2 is connected to the second end of the first resistor R1 and the signal input terminal 1, and the second end of the second resistor R2 is connected to the non-inverting input terminal of the first comparator U1A. When the signal input terminal 1 is connected to the target device, and the target device is physically connected to the device where the signal detection circuit is located, the resistance value between the first power supply and the non-inverting input terminal of the first comparator U1A will change, and the voltage input to the non-inverting input terminal of the first comparator U1A will change. The first comparator U1A compares the voltage of the non-inverting input terminal with the voltage of the inverting input terminal. When the voltage of the non-inverting input terminal is less than the voltage of the inverting input terminal, that is, the first detection voltage is less than the first reference voltage, a low-level signal is output to control the first isolation circuit 22 to be turned on, otherwise, a high-level signal is output to control the first isolation circuit 22 to be turned off.

[0036] The second voltage input unit 311 includes a third resistor R3; the first end of the third resistor R3 is connected to the second end of the first resistor R1 and the signal input terminal 1, and the second end of the third resistor R3 is connected to the non-inverting input terminal of the second comparator U2A. The third voltage input unit 312 includes a fourth resistor R4; the first end of the fourth resistor R4 is connected to the second end of the first resistor R1 and the signal input terminal 1, and the second end of the fourth resistor R4 is connected to the inverting input terminal of the third comparator U2B. Similarly, when the signal input terminal 1 is connected to the target device, and the target device is electrically connected to the device where the signal detection circuit is located, the resistance value between the first power supply and the non-inverting input terminal of the second comparator U2A will change, and the resistance value between the first power supply and the inverting input terminal of the third comparator U2B will change. At this time, the voltage input to the non-inverting input terminal of the second comparator U2A changes, and the voltage input to the inverting input terminal of the third comparator U2B also changes. The second comparator U2A and the third comparator U2B compare the voltage of the non-inverting input terminal and the voltage of the inverting input terminal. When the voltage of the non-inverting input terminal is less than the voltage of the inverting input terminal, that is, the second detection voltage is less than the third reference voltage and greater than the second reference voltage, a high-level signal is output to control the second isolation circuit 32 to be turned off. On the contrary, when the voltage of the non-inverting input terminal of any one of the second comparator U2A and the third comparator U2B is not less than the voltage of the inverting input terminal, a low-level signal is output to control the second isolation circuit 32 to be turned on.

[0037] In one embodiment, the first reference voltage unit 212 includes a fifth resistor R5 and a sixth resistor R6; the fifth resistor R5 and the sixth resistor R6 are connected in series between the first power supply and the ground, and the connection node between the fifth resistor R5 and the sixth resistor R6 is connected to the inverting input terminal of the first comparator U1A; the second reference voltage unit 313 includes a seventh resistor R7 and an eighth resistor R8; the seventh resistor R7 and the eighth resistor R8 are connected in series between the first power supply and the ground, and the connection node between the seventh resistor R7 and the eighth resistor R8 is connected to the inverting input terminal of the second comparator U2A; the third reference voltage unit 314 includes a ninth resistor R9 and a tenth resistor R10; the ninth resistor R9 and the tenth resistor R10 are connected in series between the first power supply and the ground, and the connection node between the ninth resistor R9 and the tenth resistor R10 is connected to the non-inverting input terminal of the third comparator U2B.

[0038] As an example, the first reference voltage unit 212 includes a fifth resistor R5 and a sixth resistor R6; the fifth resistor R5 and the sixth resistor R6 are connected in series between the first power supply (12V) and the ground to form a voltage divider circuit, the connection node between the fifth resistor R5 and the sixth resistor R6 is connected to the inverting input terminal of the first comparator U1A, the voltage input to the inverting terminal of the first comparator U1A is equal to the voltage across the sixth resistor R6, and the first reference voltage can be adjusted by adjusting the resistance values ​​of the fifth resistor R5 and the sixth resistor R6. The second reference voltage unit 313 includes a seventh resistor R7 and an eighth resistor R8; the seventh resistor R7 and the eighth resistor R8 are connected in series between the first power supply (12V) and the ground, and the connection node between the seventh resistor R7 and the eighth resistor R8 is connected to the inverting input terminal of the second comparator U2A. Similarly, the voltage input to the inverting input terminal of the second comparator U2A is equal to the voltage across the eighth resistor R8, and the second reference voltage can be adjusted by adjusting the resistance values ​​of the seventh resistor R7 and the eighth resistor R8. The third reference voltage unit 314 includes a ninth resistor R9 and a tenth resistor R10; the ninth resistor R9 and the tenth resistor R10 are connected in series between the first power supply (12V) and the ground, and the connection node between the ninth resistor R9 and the tenth resistor R10 is connected to the non-inverting input terminal of the third comparator U2B. Similarly, the voltage input to the non-inverting input terminal of the third comparator U2B is equal to the voltage across the tenth resistor R10. By adjusting the resistance values ​​of the ninth resistor R9 and the tenth resistor R10, the size of the third reference voltage can be adjusted.

[0039] In one embodiment, the first isolation circuit 22 includes a first optocoupler unit U1; the first input end of the first optocoupler unit U1 is used to connect to the first power supply, the second input end of the first optocoupler unit U1 is connected to the first comparison circuit 21, the first output end of the first optocoupler unit U1 is connected to the second power supply unit, and the second output end of the first optocoupler unit U1 is connected to the controller 4 for outputting an insertion detection signal; the second isolation circuit 32 includes a second optocoupler unit U2; the first input end of the second optocoupler unit U2 is used to connect to the first power supply, the second input end of the second optocoupler unit U2 is connected to the second comparison circuit 31, the first output end of the second optocoupler unit U2 is connected to the second power supply unit, the second output end of the first optocoupler unit U1 is grounded, and the first output end of the second optocoupler unit is also connected to the controller 4 for outputting a limit detection signal.

[0040] As an example, the first isolation circuit 22 includes a first optocoupler unit U1. The first input end of the first optocoupler unit U1 is used to connect to the first power supply, the second input end of the first optocoupler unit U1 is connected to the first comparison circuit 21, the first output end of the first optocoupler unit U1 is connected to the second power supply unit, and the second output end of the first optocoupler unit U1 is connected to the controller 4. When the first comparator U1A outputs a low level, the first output end and the second output end of the second optocoupler unit U2 are turned on, and the controller 4 can receive a high level signal, that is, a first insertion detection signal, indicating that a physical connection has been established between the target device and the device where the signal detection circuit is located. When the first comparator U1A outputs a high level, the first output end and the second output end of the second optocoupler unit U2 are cut off, and the controller 4 can receive a low level signal, that is, a second insertion detection signal, indicating that a physical connection has not been established between the target device and the device where the signal detection circuit is located.

[0041] The second isolation circuit 32 includes a second optical coupling unit U2. The first input end of the second optical coupling unit U2 is used to connect to the first power supply, the second input end of the second optical coupling unit U2 is connected to the second comparison circuit 31, the first output end of the second optical coupling unit U2 is connected to the second power supply unit, the second output end of the first optical coupling unit U1 is grounded, and the first output end of the second optical coupling unit is also connected to the controller 4. When the second comparator U2A and the third comparator U2B in the second comparison circuit 31 both output a high level, the first output end and the second output end of the second optical coupling unit U2 are cut off, and the controller 4 can receive a high level signal, that is, output a first limit detection signal, indicating that the target device and the device where the signal detection circuit is located have been normally electrically connected; and when any one of the second comparator U2A and the third comparator U2B in the second comparison circuit 31 outputs a low level, so that the first output end and the second output end of the second optical coupling unit U2 are connected to the ground, the controller 4 can receive a low level signal, that is, output a second limit detection signal, indicating that the target device and the device where the signal detection circuit is located have not been normally electrically connected.

[0042] In one embodiment, the first isolation circuit also includes a first pull-up resistor R11 and a first current limiting resistor R12; the first end of the first pull-up resistor R11 is connected to the second power supply, and the second end of the first pull-up resistor R11 is connected to the first output end of the first optocoupler unit U1; the first end of the first current limiting resistor R12 is connected to the second output end of the first optocoupler unit U1, and the second end of the first current limiting resistor R12 is grounded; the controller 4 is connected to the connection node between the first current limiting resistor R12 and the first optocoupler unit U1; the second isolation circuit also includes a second pull-up resistor R13; the first end of the second pull-up resistor R13 is connected to the second power supply, and the second end of the second pull-up resistor R13 is connected to the first output end of the second optocoupler unit U2; the controller 4 is connected to the connection node between the second pull-up resistor R13 and the second optocoupler unit.

[0043] As an example, the first isolation circuit also includes a first pull-up resistor R11 and a first current limiting resistor R12; the first end of the first pull-up resistor R11 is connected to the second power supply, and the second end of the first pull-up resistor R11 is connected to the first output end of the first optical coupling unit U1; the first end of the first current limiting resistor R12 is connected to the second output end of the first optical coupling unit U1, the second end of the first current limiting resistor R12 is grounded, and the controller 4 is connected to the connection node between the first current limiting resistor R12 and the first optical coupling unit U1. When the first optical coupling unit U1 is turned on, the voltage input to the controller 4 is the same as the voltage across the first current limiting resistor. The second isolation circuit also includes a second pull-up resistor R13; the first end of the second pull-up resistor R13 is connected to the second power supply, and the second end of the second pull-up resistor R13 is connected to the first output end of the second optical coupling unit U2; the controller 4 is connected to the connection node between the second pull-up resistor R13 and the second optical coupling unit.

[0044] In one embodiment, the first isolation circuit 22 also includes a second current limiting resistor R14; the second current limiting resistor R14 is arranged between the first comparison circuit 21 and the first optical coupling unit U1; the second isolation circuit 32 also includes a third current limiting resistor R15, and the third current limiting resistor R15 is arranged between the second comparison circuit 31 and the second optical coupling unit U2.

[0045] As an example, the first isolation circuit 22 also includes a second current limiting resistor R14; the two ends of the second current limiting resistor R14 are respectively connected to the first comparison circuit 21 and the first optocoupler unit U1; the second isolation circuit 32 also includes a third current limiting resistor R15; the two ends of the third current limiting resistor R15 are respectively connected to the second comparison circuit 31 and the second optocoupler unit U2, and the second current limiting resistor R14 and the third current limiting resistor R15 are used to play a current limiting role.

[0046] An embodiment of the present invention further provides a charging pile, comprising the signal detection circuit in the above embodiment.

[0047] As an example, the charging pile includes a controller 4 and a signal detection circuit in the above-mentioned embodiment; the controller 4 is used to determine the connection status between the signal input terminal 1 and the target device according to the insertion detection signal and the limit detection signal. Specifically, when a physical connection has been established between the target device and the device where the signal detection circuit is located, the first comparator U1A in the first comparison circuit 21 outputs a low-level signal to turn on the first optical coupling unit U1, and the controller 4 can receive a high-level signal, that is, the first insertion detection signal; when a physical connection is not established between the target device and the device where the signal detection circuit is located, the first comparator U1A in the first comparison circuit 21 outputs a high-level signal to turn off the first optical coupling unit U1 , the controller 4 can receive a low-level signal, that is, the second insertion detection signal; when the electrical connection between the target device and the device where the signal detection circuit is located is normally established, the second comparator U2A and the third comparator U2B in the second comparison circuit 31 both output a high level, the second optical coupling unit U2 is cut off, and the controller 4 can receive a high-level signal, that is, output the first limit detection signal; when the electrical connection between the target device and the device where the signal detection circuit is located is not normally established, in the second comparison circuit 31, any one of the second comparator U2A and the third comparator U2B outputs a low level, the second optical coupling unit U2 is turned on, and the controller 4 can receive a low-level signal, that is, output the second limit detection signal. When the controller 4 detects the first insertion detection signal and the first limit detection signal, it can be determined that the current signal input terminal 1 has established a physical connection and an electrical connection with the target device, and the connection between the target device and the device where the signal detection circuit is located is completed; when the controller 4 detects the first insertion detection signal and the second limit detection signal, it can be determined that the current signal input terminal 1 has established a physical connection with the target device but has not been electrically connected normally, and the connection voltage between the target device and the device where the signal detection circuit is located is in an abnormal state; when the controller 4 detects the second insertion detection signal and the first limit detection signal, it can be determined that the current signal input terminal 1 has not established a physical connection with the target device but has been electrically connected normally, and the target device and the device where the signal detection circuit is located are in a semi-connected state; when the controller 4 detects the second insertion detection signal and the second limit detection signal, it can be determined that the current signal input terminal 1 has not established a physical connection with the target device and has not been electrically connected normally, and the target device and the device where the signal detection circuit is located are in a disconnected state.

[0048] In this example, by setting the insertion detection module 2 and the limit detection module 3 in the signal detection circuit of the charging pile, the physical connection status and the electrical connection status can be detected separately, making the detection result more accurate and clear. In this example, an isolation circuit is also set for signal isolation, which can effectively resist electromagnetic interference and ensure the stability of the detection signal.

[0049] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A signal detection circuit, characterized in that: It includes a signal input terminal, an insertion detection module, a limit detection module and a controller; The insertion detection module comprises a first comparison circuit and a first isolation circuit, wherein the first comparison circuit and the first isolation circuit are arranged in series between the signal input terminal and the controller, and are used to output an insertion detection signal to the controller according to the connection state between the signal input terminal and the target device; The limit detection module includes a second comparison circuit and a second isolation circuit, which are arranged in series between the signal input terminal and the controller, and are used to output a limit detection signal to the controller according to the connection state between the signal input terminal and the target device; The controller is used to determine a connection detection result according to the insertion detection signal and the limit detection signal.

2. The signal detection circuit according to claim 1, characterized in that: The first comparison circuit includes a first comparator; The first comparator is arranged between the signal input terminal and the first isolation circuit, and is used to control the first isolation circuit to output an insertion detection signal to the controller according to the connection state between the signal input terminal and the target device; The second comparison circuit includes a second comparator and a third comparator; The second comparator and the third comparator are arranged in parallel between the signal input terminal and the second isolation circuit, and are used to output a first comparison signal and a second comparison signal to the second isolation circuit respectively according to the connection state between the signal input terminal and the target device; The second isolation circuit outputs a limit detection signal to the controller according to the first comparison signal and the second comparison signal.

3. The signal detection circuit according to claim 2, characterized in that: The first comparison circuit also includes a first voltage input unit and a first reference voltage unit; A first end of the first voltage input unit is connected to the signal input end, and a second end of the first voltage input unit is connected to the non-inverting input end of the first comparator, and is used to output a first detection voltage to the first comparator when the signal input end is connected to the target device; The first reference voltage unit is connected to the inverting input terminal of the first comparator, and is used to output a first reference voltage to the first comparator; The output end of the first comparator is connected to the first isolation circuit, and is used to control the first isolation circuit to be turned on when the first detection voltage is less than the first reference voltage, so that the first isolation circuit outputs a first insertion detection signal; It is also used to control the first isolation circuit to be cut off when the first detection voltage is not less than a first reference voltage, so that the first isolation circuit outputs a second insertion detection signal.

4. The signal detection circuit according to claim 2, characterized in that: The second comparison circuit further includes a second voltage input unit, a third voltage input unit, a second reference voltage unit and a third reference voltage unit; A first end of the second voltage input unit is connected to the signal input end, and a second end of the second voltage input unit is connected to the non-inverting input end of the second comparator, and is used to output a second detection voltage to the second comparator when the signal input end is connected to the target device; The second reference voltage unit is connected to the inverting input terminal of the second comparator, and is used to output a second reference voltage to the second comparator; The second comparator is used to output a first cut-off signal when the second detection voltage is greater than a second reference voltage, and to output a first turn-on signal when the second detection voltage is not greater than the second reference voltage; The first end of the third voltage input unit is connected to the signal input end, and the second end of the third voltage input unit is connected to the inverting input end of the third comparator, and is used to output a third detection voltage to the third comparator when the signal input end is connected to the target device; The third reference voltage unit is connected to the non-inverting input terminal of the third comparator, and is used to output a third reference voltage to the third comparator; The third comparator is used to output a second cut-off signal when the third detection voltage is less than the third reference voltage, and output a second turn-on signal when the third detection voltage is not less than the third reference voltage; The second isolation circuit is connected to the second comparator and the third comparator, and is used to be cut off when receiving the first cutoff signal and the third cutoff signal, and output a first limit detection signal, and to be turned on when receiving any one of the second turn-on signal and the fourth turn-on signal, and output a second limit detection signal.

5. The signal detection circuit according to claim 3 or 4, characterized in that: The signal detection circuit further includes a first resistor, wherein a first end of the first resistor is used to connect to a first power supply; The first voltage input unit comprises a second resistor, a first end of the second resistor is connected to the second end of the first resistor and the signal input end, and a second end of the second resistor is connected to the non-inverting input end of the first comparator; The second voltage input unit comprises a third resistor, a first end of the third resistor is connected to the second end of the first resistor and the signal input end, and a second end of the third resistor is connected to the non-inverting input end of the second comparator; The third voltage input unit includes a fourth resistor, a first end of the fourth resistor is connected to the second end of the first resistor and the signal input end, and a second end of the fourth resistor is connected to the inverting input end of the third comparator.

6. The signal detection circuit according to claim 3 or 4, characterized in that: The first reference voltage unit includes a fifth resistor and a sixth resistor; The fifth resistor and the sixth resistor are connected in series between the first power supply and the ground, and a connection node between the fifth resistor and the sixth resistor is connected to the inverting input terminal of the first comparator; The second reference voltage unit includes a seventh resistor and an eighth resistor; The seventh resistor and the eighth resistor are connected in series between the first power supply and the ground, and a connection node between the seventh resistor and the eighth resistor is connected to the inverting input terminal of the second comparator; The third reference voltage unit includes a ninth resistor and a tenth resistor; The ninth resistor and the tenth resistor are connected in series between the first power supply and the ground, and a connection node between the ninth resistor and the tenth resistor is connected to the non-inverting input terminal of the third comparator.

7. The signal detection circuit according to claim 1, characterized in that: The first isolation circuit includes a first optical coupling unit; The first input end of the first optical coupling unit is used to connect to the first power supply, the second input end of the first optical coupling unit is connected to the first comparison circuit, the first output end of the first optical coupling unit is connected to the second power supply unit, and the second output end of the first optical coupling unit is connected to the controller for outputting an insertion detection signal; The second isolation circuit includes a second optical coupling unit; The first input end of the second optocoupler unit is used to connect to the first power supply, the second input end of the second optocoupler unit is connected to the second comparison circuit, the first output end of the second optocoupler unit is connected to the second power supply unit, the second output end of the first optocoupler unit is grounded, and the first output end of the second optocoupler unit is also connected to the controller for outputting a limit detection signal.

8. The signal detection circuit according to claim 7, characterized in that: The first isolation circuit also includes a first pull-up resistor and a first current limiting resistor; A first end of the first pull-up resistor is connected to a second power supply, and a second end of the first pull-up resistor is connected to a first output end of the first optical coupling unit; The first end of the first current limiting resistor is connected to the second output end of the first optical coupling unit, and the second end of the first current limiting resistor is grounded; The controller is connected to a connection node between the first current limiting resistor and the first optical coupling unit; The second isolation circuit also includes a second pull-up resistor; A first end of the second pull-up resistor is connected to a second power supply, and a second end of the second pull-up resistor is connected to a first output end of the second optical coupling unit; The controller is connected to a connection node between the second pull-up resistor and the second optical coupling unit.

9. The signal detection circuit according to claim 7, characterized in that: The first isolation circuit further includes a second current limiting resistor, and the second current limiting resistor is arranged between the first comparison circuit and the first optical coupling unit; The second isolation circuit further includes a third current limiting resistor, and the third current limiting resistor is arranged between the second comparison circuit and the second optical coupling unit.

10. A charging pile, characterized in that: The invention comprises the signal detection circuit described in claims 1 to 9.

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