Signal detection circuit, signal detection method, and electronic device

Abstract

This application discloses a signal detection circuit, a signal detection method, and an electronic device. The signal detection circuit includes a signal modulation circuit comprising a first isolation sub-circuit and a first comparator sub-circuit. The first isolation sub-circuit is coupled to the first comparator sub-circuit and is used to couple with a charging main control circuit. The first comparator sub-circuit is used to couple with a charging load circuit. The first isolation sub-circuit receives a reference detection signal sent by the charging main control circuit. The first comparator sub-circuit compares the reference detection signal with a first reference voltage to obtain a control guidance signal, which is output to the charging load circuit to trigger it to change its connection state to adjust the control guidance signal. The charging main control circuit, in response to the adjusted control guidance signal level, turns the coupling between the charging load circuit and the power supply circuit on or off. Through this method, the signal detection circuit in this application has high detection accuracy for the control guidance signal and can effectively cover more signal detection needs.

Description

Technical Field

[0001] This application relates to the field of circuit signal processing technology, and in particular to a signal detection circuit, a signal detection method, and an electronic device. Background Technology

[0002] Today, with the increasing variety of electronic products on the market, how to meet the safe and reliable charging needs of various electronic products, especially large electronic devices such as new energy vehicles, intelligent robots, and drones, has gradually become a popular research topic. When charging electronic devices, charging facilities generally determine the connection status between the charging plug and the electronic device by sampling and detecting the CP (Control Pilot) signal, such as unplugging, plugging in, charging preparation, charging start, and charging stop. The voltage state of the CP signal is used to determine the charging behavior's status, and according to standard requirements, a response must be made within a limited time when the above state changes are detected.

[0003] However, the detection of the CP signal in related technologies generally adopts the resistor voltage divider method. Since the CP signal usually includes a PWM (Pulse Width Modulation) signal, which has the characteristics of high frequency and small duty cycle, the signal voltage change is small after resistor voltage divider, resulting in poor detection accuracy. It also requires a high software sampling frequency, which greatly increases the computational overhead of the charging main control circuit and affects the system performance. In addition, it cannot monitor the positive and negative level states of the CP signal, and cannot cover the detection of all possible connection states between the charging plug and electronic devices. Summary of the Invention

[0004] The main technical problem addressed by this application is to provide a signal detection circuit, signal detection method, and electronic device that can solve the problems in the prior art, such as poor detection accuracy of control guidance signals, large computational overhead on the charging main control circuit, affecting system performance, and inability to cover the detection of all possible connection states between the charging plug and the electronic device.

[0005] To solve the above-mentioned technical problems, one technical solution adopted in this application is: providing a signal detection circuit, wherein the signal detection circuit includes: a signal modulation circuit, including a first isolation sub-circuit and a first comparison sub-circuit, the first isolation sub-circuit being coupled to the first comparison sub-circuit and used for coupling with a charging main control circuit, and the first comparison sub-circuit being used for coupling with a charging load circuit; wherein the first isolation sub-circuit is configured to receive a reference detection signal sent by the charging main control circuit; the first comparison sub-circuit is configured to receive the reference detection signal sent by the first isolation sub-circuit, and compare the reference detection signal with a first reference voltage to obtain a control guidance signal, which is output to the charging load circuit, thereby triggering the charging load circuit to change its connection state to adjust the control guidance signal; the charging main control circuit is configured to receive the adjusted control guidance signal sent by the first comparison sub-circuit, and to turn on or off the coupling between the charging load circuit and the power supply circuit in response to the level state of the adjusted control guidance signal.

[0006] The signal modulation circuit further includes a voltage regulation sub-circuit and an isolation protection sub-circuit. The voltage regulation sub-circuit is coupled to the isolation protection sub-circuit and is used to couple with the charging main control circuit. The isolation protection sub-circuit is coupled to the first isolation sub-circuit. The voltage regulation sub-circuit is configured to receive a reference detection signal sent by the charging main control circuit and regulate the voltage of the reference detection signal. The isolation protection sub-circuit is configured to receive the voltage-regulated reference detection signal sent by the voltage regulation sub-circuit and send the voltage-regulated reference detection signal to the first isolation sub-circuit.

[0007] The signal modulation circuit further includes a first filtering sub-circuit and a signal protection sub-circuit. The first filtering sub-circuit is coupled to the first comparator sub-circuit and the signal protection sub-circuit, and the signal protection sub-circuit is used to couple with the charging load circuit. The first filtering sub-circuit is configured to receive the control guidance signal sent by the first comparator sub-circuit and perform low-pass filtering on the control guidance signal. The signal protection sub-circuit is configured to receive the low-pass filtered control guidance signal sent by the first filtering sub-circuit and send the low-pass filtered control guidance signal to the charging load circuit.

[0008] The voltage regulation sub-circuit includes a first resistor, a second resistor, and a switching transistor; the isolation protection sub-circuit includes a third resistor, a fourth resistor, and a first capacitor; and the first isolation sub-circuit includes a first optocoupler and a fifth resistor. The first terminal of the first resistor is coupled to the charging main control circuit; the second terminal of the first resistor is coupled to the first terminal of the second resistor and the first terminal of the switching transistor; the second terminal of the second resistor is coupled to the second terminal of the switching transistor and the first ground terminal; the first terminal of the third resistor is coupled to the first level providing terminal; the second terminal of the third resistor is coupled to the first terminal of the fourth resistor, the first terminal of the first capacitor, and the first terminal of the first optocoupler; the third terminal of the switching transistor is coupled to the second terminal of the fourth resistor, the second terminal of the first capacitor, and the second terminal of the first optocoupler; the third terminal of the first optocoupler is coupled to the first terminal of the fifth resistor; the fourth terminal of the first optocoupler is coupled to the first terminal of the first comparator sub-circuit; and the second terminal of the fifth resistor is coupled to the second terminal of the first comparator sub-circuit.

[0009] The first comparator circuit includes a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, and a first comparator. The first terminal of the sixth resistor is coupled to a second level-providing terminal. The second terminal of the sixth resistor is coupled to the first terminal of the first isolation circuit, the first terminal of the seventh resistor, and the inverting input of the first comparator. The second terminal of the seventh resistor is coupled to the second terminal of the first isolation circuit and a second ground terminal. The first terminal of the eighth resistor is coupled to the second level-providing terminal. The second terminal of the eighth resistor is coupled to the first terminal of the ninth resistor and the non-inverting input of the first comparator. The second terminal of the ninth resistor is coupled to a second ground terminal. The positive power supply input terminal of the first comparator is coupled to a third level-providing terminal. The negative power supply input terminal of the first comparator is coupled to a fourth level-providing terminal. The output terminal of the first comparator is coupled to a charging load circuit.

[0010] The signal detection circuit further includes a state detection circuit, which comprises an isolation operational amplifier sub-circuit and a peak detection sub-circuit. The isolation operational amplifier sub-circuit is coupled to the first comparator sub-circuit and the peak detection sub-circuit, and the peak detection sub-circuit is also coupled to the charging main control circuit. The isolation operational amplifier sub-circuit is configured to receive a control guidance signal sent by the first comparator sub-circuit to proportionally adjust the control guidance signal. The peak detection sub-circuit is configured to receive the proportionally adjusted control guidance signal sent by the isolation operational amplifier sub-circuit, and after limiting the proportionally adjusted control guidance signal, output it to the charging main control circuit.

[0011] The state detection circuit further includes a signal conditioning sub-circuit, which is coupled between the first comparator sub-circuit and the isolation operational amplifier sub-circuit. The signal conditioning sub-circuit is configured to receive a control guidance signal sent by the first comparator sub-circuit to adjust the control guidance signal to a set voltage range. The isolation operational amplifier sub-circuit is configured to receive the adjusted control guidance signal sent by the signal conditioning sub-circuit to proportionally adjust the adjusted control guidance signal.

[0012] The state detection circuit also includes a bias sub-circuit, which is coupled to an isolated operational amplifier sub-circuit. The bias sub-circuit is configured to boost the control guidance signal, which has been proportionally adjusted by the isolated operational amplifier sub-circuit, to the positive voltage range.

[0013] The status detection circuit also includes a limiting protection circuit, which is coupled to the peak detection sub-circuit and is used to couple with the charging main control circuit. The limiting protection circuit is configured to receive the limiting-adjusted control guidance signal sent by the peak detection sub-circuit, and output the limiting-adjusted control guidance signal to the charging main control circuit.

[0014] The signal conditioning sub-circuit includes an emitter follower, a tenth resistor, an eleventh resistor, and a second capacitor; the isolation operational amplifier sub-circuit includes a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, and an analog isolation operational amplifier; the bias sub-circuit includes a seventh capacitor; and the peak detection sub-circuit includes a first diode, a twelfth resistor, and an eighth capacitor. The non-inverting input of the emitter follower is coupled to the output of the first comparator; the inverting input of the emitter follower is coupled to the output of the emitter follower and the first terminal of the tenth resistor; the second terminal of the tenth resistor is coupled to the first terminal of the eleventh resistor, the first terminal of the second capacitor, and the first terminal of the analog isolation operational amplifier; the second terminal of the eleventh resistor is coupled to the second terminal of the second capacitor and the second ground terminal; and the first terminal of the third capacitor is coupled to the first terminal of the fourth capacitor and the first power supply terminal of the analog isolation operational amplifier, and is used to connect with the fifth level... The circuit provides the following connections: the second terminal of the third capacitor is coupled to the second terminal of the fourth capacitor, the second terminal of the analog isolation operational amplifier, the first ground terminal of the analog isolation operational amplifier, and the second ground terminal; the second power supply terminal of the analog isolation operational amplifier is coupled to the first terminal of the sixth capacitor and is used to couple with the sixth level supply terminal; the third terminal of the analog isolation operational amplifier is coupled to the first terminal of the first diode; the fourth terminal of the analog isolation operational amplifier is coupled to the first terminal of the seventh capacitor and is used to couple with the sixth level supply terminal; the second ground terminal of the analog isolation operational amplifier is coupled to the second terminal of the fifth capacitor, the second terminal of the sixth capacitor, the second terminal of the seventh capacitor, and the first ground terminal; the second terminal of the first diode is coupled to the first terminal of the twelfth resistor and the first terminal of the eighth capacitor and is used to couple with the charging main control circuit; the second terminal of the twelfth resistor is coupled to the second terminal of the eighth capacitor and the first ground terminal.

[0015] The signal detection circuit further includes a signal loss detection circuit, which comprises a second comparator circuit and a second isolation circuit. The second comparator circuit is coupled to the first comparator circuit and the second isolation circuit, and the second isolation circuit is also coupled to the charging main control circuit. The second comparator circuit is configured to receive a control guidance signal sent by the first comparator circuit, and compare the control guidance signal with a second reference voltage to obtain a loss detection signal. The second isolation circuit is configured to receive the loss detection signal sent by the second comparator circuit and output the loss detection signal to the charging main control circuit, so that the charging main control circuit shuts off the coupling between the charging load circuit and the power supply circuit in response to the loss detection signal.

[0016] The signal loss detection circuit further includes a second filtering sub-circuit, which is coupled to the second isolation sub-circuit and used to couple with the charging main control circuit. The second filtering sub-circuit is configured to receive the loss detection signal sent by the second comparison sub-circuit, perform low-pass filtering on the loss detection signal, and then send it to the charging main control circuit.

[0017] The second comparator circuit includes a second diode, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, and a second comparator. The second isolation circuit includes a sixteenth resistor, a seventeenth resistor, a ninth capacitor, and a second optocoupler. The first terminal of the second diode is coupled to the first comparator circuit. The second terminal of the second diode is coupled to the first terminal of the thirteenth resistor. The second terminal of the thirteenth resistor is coupled to the inverting input of the second comparator. The first terminal of the fourteenth resistor is coupled to the non-inverting input of the second comparator and the first terminal of the fifteenth resistor. The second terminal of the fifteenth resistor is coupled to the second ground terminal. The positive power input terminal of the second comparator is coupled to the second ground terminal. The negative power input terminal of the second comparator is coupled to the third level providing terminal. The first terminal of the sixteenth resistor is coupled to the third level providing terminal. The second terminal of the sixteenth resistor is coupled to the first terminal of the seventeenth resistor, the first terminal of the ninth capacitor, and the first terminal of the second optocoupler. The second terminal of the seventeenth resistor is coupled to the output terminal of the second comparator, the second terminal of the ninth capacitor, and the second terminal of the second optocoupler. The third terminal of the second optocoupler is coupled to the charging main control circuit. The fourth terminal of the second optocoupler is coupled to the first ground terminal.

[0018] To solve the above-mentioned technical problems, another technical solution adopted in this application is: providing a signal detection method, applied in the signal detection circuit described above, wherein the signal detection method includes: receiving a reference detection signal sent by an external charging master control circuit; comparing the reference detection signal with a first reference voltage to obtain a control guidance signal; outputting the control guidance signal to an external charging load circuit to trigger the charging load circuit to change its connection state to adjust the control guidance signal; and sending the adjusted control guidance signal to the charging master control circuit so that the charging master control circuit turns on or off the coupling between the charging load circuit and the power supply circuit in response to the level state of the adjusted control guidance signal.

[0019] To solve the above-mentioned technical problems, another technical solution adopted in this application is: to provide an electronic device, wherein the electronic device includes a housing and a signal detection circuit connected to the housing; wherein the signal detection circuit is the signal detection circuit as described in any of the preceding claims.

[0020] The beneficial effects of this application are as follows: Unlike the prior art, the signal detection circuit provided in this application couples the first isolation sub-circuit to the first comparison sub-circuit, and uses the first isolation sub-circuit to couple with the charging main control circuit, and the first comparison sub-circuit to couple with the charging load circuit. The first isolation sub-circuit receives the reference detection signal sent by the charging main control circuit, and the first comparison sub-circuit compares the reference detection signal with the first reference voltage to obtain a control guidance signal, thereby increasing the voltage variation range of the control guidance signal and outputting it to the charging load circuit. This triggers the charging load circuit to change its connection state to adjust the control guidance signal, enabling the charging main control circuit to respond to the adjusted control guidance signal level to achieve charging switch control and state detection of the charging load circuit. This results in higher detection accuracy, lower requirements for the sampling frequency of the charging main control circuit, reduced computational overhead of the charging main control circuit, and improved system performance. Furthermore, the control guidance signal obtained by voltage comparison using the first comparison sub-circuit can effectively monitor positive and negative level states, covering the signal detection requirements for all possible connection states of the charging plug and electronic device. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0022] Figure 1 This is a schematic diagram of the first embodiment of the signal detection circuit of this application; Figure 2This is a schematic diagram of the second embodiment of the signal detection circuit of this application; Figure 3 This application Figure 2 A schematic diagram of a specific embodiment of the signal modulation circuit in the signal detection circuit; Figure 4 This is a schematic diagram of the third embodiment of the signal detection circuit of this application; Figure 5 yes Figure 4 A schematic diagram of a specific embodiment of the state detection circuit in the signal detection circuit; Figure 6 This is a schematic diagram of the fourth embodiment of the signal detection circuit of this application; Figure 7 yes Figure 6 A schematic diagram of a specific embodiment of the signal loss detection circuit in the signal detection circuit; Figure 8 This is a flowchart illustrating one embodiment of the signal detection method of this application; Figure 9 This is a schematic diagram of one embodiment of the electronic device of this application. Detailed Implementation

[0023] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0024] The terms "first," "second," and "third" in this application are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. All directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationships and movements between components in a specific orientation (as shown in the figures). If the specific orientation changes, the directional indications also change accordingly. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices.

[0025] In this document, the term "implementation" means that a specific feature, structure, or characteristic described in connection with an implementation may be included in at least one implementation of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same implementation, nor is it a separate or alternative implementation mutually exclusive with other implementations. It will be explicitly and implicitly understood by those skilled in the art that the implementations described herein can be combined with other implementations.

[0026] The present application will now be described in detail with reference to the accompanying drawings and embodiments.

[0027] Please see Figure 1 , Figure 1 This is a schematic diagram of the structure of the first embodiment of the signal detection circuit of this application. In this embodiment, the signal detection circuit 10 includes a signal modulation circuit 11.

[0028] In this application, a signal detection circuit 10 is specifically applied to the signal detection of the charging main control circuit 101. For example, it can be integrated into a charging facility for any reasonable electronic device such as a new energy vehicle, intelligent robot, or drone. This allows the charging main control circuit 101 to sample and detect the CP signal using the signal detection circuit 10, determining the connection status between the charging plug and the electronic device, such as plugging in, charging preparation, charging start, and charging stop. It also responds to the voltage state of the CP signal to determine the charging behavior's current state. According to standard requirements, upon identifying the aforementioned state changes, it controls the charging load circuit 102 to perform charging switch control and state detection within a limited time. Of course, in other embodiments, the signal detection circuit 10 can also be applied to intelligent fast charging adapters, industrial power management systems, or other reasonable electronic devices used to fulfill charging needs; this embodiment does not limit this application.

[0029] It is worth noting that the charging main control circuit 101 includes one or more of any reasonable circuit units with signal processing functions, such as control chip, DSP (Digital Signal Processing) chip, MCU (Micro Controller Unit) circuit, CPU (Central Processing Unit), microcontroller, field-programmable gate array, programmable logic device, discrete gate or transistor logic device, discrete hardware, etc. This application does not limit this.

[0030] Furthermore, the term "coupled" in this document refers to any direct or indirect connection. Therefore, if the document describes a first circuit coupled to a second circuit, it means that the first circuit can be directly connected to the second circuit via electrical connection or signal connection methods such as wireless transmission or optical transmission, or indirectly connected to the second circuit via other circuits or connection methods via electrical connection or signal connection.

[0031] Specifically, the signal modulation circuit 11 further includes a first isolation sub-circuit 111 and a first comparator sub-circuit 112. The first isolation sub-circuit 111 is coupled to the first comparator sub-circuit 112 and is used to be coupled to the charging main control circuit 101. The first comparator sub-circuit 112 is used to be coupled to the charging load circuit 102.

[0032] It is worth noting that the charging load circuit 102 can be understood as a functional circuit in an electronic device that has a charging requirement; the charging main control circuit 101 may also include a switching circuit, or be used to couple with the switching circuit. The switching circuit is used to couple between the power supply circuit 103 and the charging load circuit 102, and may include any reasonable switching element controlled by the charging main control circuit 101, such as a relay or contactor, so that when it receives the corresponding switching control signal sent by the charging main control circuit 101, it can trigger to turn on or off, thereby enabling the power supply circuit 103 to charge or stop charging the charging load circuit 102 through the corresponding switching circuit.

[0033] In some embodiments, the power supply circuit 103 may be any reasonable power supply such as a power grid, a photovoltaic power source, or an independent generator, or a power regulation circuit that is coupled to the power supply to perform one or more of the following reasonable signal regulation functions: power factor regulation, rectification, voltage conversion, filtering, etc. The present application does not limit this.

[0034] The first isolation sub-circuit 111 is used to achieve electrical isolation between the charging main control circuit 101 and the first comparator sub-circuit 112, so as to receive the reference detection signal sent by the charging main control circuit 101, such as one or more of PWM (Pulse Width Modulation) signal, square wave signal, high and low level signal, and send the isolated in-phase signal to the first comparator sub-circuit 112 to prevent noise interference between the load side and the main control side.

[0035] In some embodiments, the first isolation sub-circuit 111 may specifically include one or more of any reasonable circuit elements capable of signal isolation, such as optocoupler isolation, digital isolator, magnetic coupler or capacitive coupler isolation, and this application does not limit this.

[0036] The first comparator circuit 112 is used to receive the isolated reference detection signal sent by the first isolation circuit 111, compare the reference detection signal with the first reference voltage, and output a control guidance signal based on the current comparison result.

[0037] It is worth noting that the first comparator circuit 112 may specifically include a comparator, a core component in analog electronics. This comparator compares the voltage difference between two input terminals and outputs a high or low logic signal. Its core function is to determine whether the input signal exceeds a set threshold voltage. The operating principle is based on the high-gain characteristics of the operational amplifier: when the voltage at the non-inverting input is higher than that at the inverting input, a high level is output; conversely, a low level is output. This high or low level output can respond to different levels of the external power supply input at the positive and negative input terminals, as well as the pull-down and pull-up resistors, and covers both positive and negative levels based on signal detection requirements.

[0038] In addition, the reference detection signal can be understood as an enable reference signal used to realize signal detection, so that after adjustment by the first isolation sub-circuit 111 and the first comparison sub-circuit 112, a control guide signal with a larger voltage change range or closer to the set voltage threshold range can be obtained, so as to realize more accurate detection based on the control guide signal.

[0039] The first comparator circuit 112 is also used to output a control guidance signal to the charging load circuit 102, so as to trigger the charging load circuit 102 to change its connection state under the action of the control guidance signal, such as connecting a pull-down resistor or a switch network according to its own state, and actively adjusting the level or impedance of the control guidance signal.

[0040] The charging master control circuit 101 is used to receive the control guidance signal regulated by the charging load circuit 102 sent by the first comparator circuit 112. When the level of the control guidance signal is valid (e.g., low level indicates "rechargeable"), the power path of the switching circuit (e.g., closing a relay or contactor) is turned on, so that the power supply circuit 103 is connected to the charging load circuit 102 to charge the charging load circuit 102. The charging master control circuit 101 is also connected to the charging load circuit 102 for communication, so as to perform status detection and data communication.

[0041] When the level of the control guidance signal is invalid (such as high impedance, high level), the connection between the power supply circuit 103 and the charging load circuit 102 is disconnected to prevent power supply, thereby preventing dangers such as no-load power-on, reverse connection, and short circuit, and realizing the safety protocol of "handshake first, then power supply".

[0042] The above scheme obtains a control guide signal through voltage comparison, thereby increasing the voltage variation range of the control guide signal or bringing it closer to the set voltage threshold range. This control guide signal is then used to control the charging switch and detect the status of the charging load circuit 102, resulting in higher detection accuracy and lower requirements for the sampling frequency of the charging main control circuit 101, thus reducing the computational overhead of the charging main control circuit 101 and improving system performance. Furthermore, the control guide signal obtained through voltage comparison using the first comparator circuit 112 can effectively monitor positive and negative voltage levels, covering the signal detection requirements for all possible connection states of the charging plug and electronic devices. In addition, the main control is completely isolated from the load side, improving system reliability; the main control maintains detection when there is no load, but the power is not connected, saving energy; the power can be immediately cut off in case of load abnormality to prevent overheating / fire; the circuit is simple, low-cost, highly flexible, and easy to maintain.

[0043] Please see Figure 2 , Figure 2 This is a schematic diagram of the second embodiment of the signal detection circuit of this application. The difference between the signal detection circuit in this embodiment and the first embodiment of the signal detection circuit provided in this application is that the signal modulation circuit 21 in this signal detection circuit 20 specifically includes a voltage regulation sub-circuit 213 and an isolation protection sub-circuit 214.

[0044] The signal modulation circuit 21 further includes a voltage regulation sub-circuit 213 and an isolation protection sub-circuit 214. The voltage regulation sub-circuit 213 is coupled to the isolation protection sub-circuit 214 and is used to be coupled to the charging main control circuit 101. The isolation protection sub-circuit 214 is coupled to the first isolation sub-circuit 211.

[0045] The voltage regulation sub-circuit 213 is used to receive the initial reference detection signal sent by the charging main control circuit 101 and convert it into a standardized reference detection signal with stable amplitude, phase matching, voltage matching, clear edges, and meeting the requirements of the subsequent stage, so as to enhance the subsequent drive through voltage regulation.

[0046] The isolation protection sub-circuit 214 is configured to receive the reference detection signal after voltage regulation sent by the voltage regulation sub-circuit 213, and send the voltage-regulated reference detection signal to the first isolation sub-circuit 211, thereby forming protection and buffer for the first isolation sub-circuit 211, adding a transient and abnormal energy protection barrier before the main isolation, preventing high voltage surges from damaging downstream sensitive devices (especially optocouplers or digital isolators), and ensuring the reliable operation of the first isolation sub-circuit 211.

[0047] In some embodiments, the signal modulation circuit 21 further includes a first filter sub-circuit 215 and a signal protection sub-circuit 216. The first filter sub-circuit 215 is coupled to the first comparator sub-circuit 212 and the signal protection sub-circuit 216. The signal protection sub-circuit 216 is used to couple to the charging load circuit 102.

[0048] The first filter sub-circuit 215 is used to receive the control guidance signal CP output by the first comparator sub-circuit 212 and perform low-pass filtering on the control guidance signal CP to suppress high-frequency oscillations, electromagnetic radiation and ringing caused by transmission line reflections due to rapid switching of the comparator. The parameters are set according to the signal bandwidth to ensure that the effective edge is not distorted and to prevent the signal rise / fall time from being too long, which would affect the load response speed. The output impedance after filtering should match the load input impedance to reduce reflection, thereby improving signal quality, reducing EMI (Electromagnetic Interference) radiation, and preventing false triggering of the load logic.

[0049] The signal protection sub-circuit 216 is used to receive the low-pass filtered control guidance signal CP sent by the first filter sub-circuit 215, and send the low-pass filtered control guidance signal CP to the charging load circuit 102 to achieve anti-static or surge protection for the signal that stops supplying power to the charging load circuit 102, and prevent damage to the internal comparator or filter circuit due to load-side abnormalities (such as hot-plugging, short circuit, static electricity, power reverse flow).

[0050] For ease of understanding, taking the specific application of the signal detection circuit 20 in a European standard charging pile as an example, the reference detection signal ref provided by the main charging control circuit 101 can specifically include a 3.3V (volt) PWM signal, a 3.3V DC signal, and a 0V DC signal, so as to control the primary side of the first isolation sub-circuit 211 to work through the voltage regulation sub-circuit 213. The secondary output of the first isolation sub-circuit 211 is connected to the inverting terminal of the first comparator sub-circuit 212 to be compared with the reference voltage provided by the non-inverting terminal of the first comparator sub-circuit 212. The ±12V PWM signal and the ±12V DC signal are obtained at the output terminal of the first comparator sub-circuit 212.

[0051] When the control guide signal CP is a PWM signal, after being protected by the first filter sub-circuit 215 and the signal protection sub-circuit 216, it charges the charging load circuit 102 through the charging interface; when the control guide signal CP is a ±12V DC signal, the charging main control circuit 101 and the charging load circuit 102 are electrically isolated by the first isolation sub-circuit 211, and the reference ground of the first comparison sub-circuit 212 and the signal protection sub-circuit 216 is the casing ground.

[0052] Understandably, the signal detection circuit 20 can effectively meet the charging interface guidance standards of European standard charging piles, achieve reliable monitoring and protection, and can be widely used in new energy fields such as European standard charging piles and integrated energy storage and charging piles; moreover, the circuit is simple, low in cost, highly flexible, and easy to maintain.

[0053] Please continue to refer to the following: Figure 3 , Figure 3 This application Figure 2 A schematic diagram of a specific embodiment of the signal modulation circuit 21 in the signal detection circuit 20.

[0054] In some embodiments, the voltage regulation sub-circuit 213 further includes a first resistor R1, a second resistor R2, and a switching transistor Q1; the isolation protection sub-circuit 214 includes a third resistor R3, a fourth resistor R4, and a first capacitor C1; and the first isolation sub-circuit 211 includes a first optocoupler U1 and a fifth resistor R5.

[0055] Specifically, the first end of the first resistor R1 is coupled to the charging main control circuit 101, the second end of the first resistor R1 is coupled to the first end of the second resistor R2 and the first end of the switching transistor Q1, the second end of the second resistor R2 is coupled to the second end of the switching transistor Q1 and the first ground terminal GND, the first end of the third resistor R3 is coupled to the first level providing terminal VCC1, the second end of the third resistor R3 is coupled to the first end of the fourth resistor R4, the first end of the first capacitor C1 and the first end of the first optocoupler U1, the third end of the switching transistor Q1 is coupled to the second end of the fourth resistor R4, the second end of the first capacitor C1 and the second end of the first optocoupler U1, the third end of the first optocoupler U1 is coupled to the first end of the fifth resistor R5, the fourth end of the first optocoupler U1 is coupled to the first end of the first comparator circuit 212, and the second end of the fifth resistor R5 is coupled to the second end of the first comparator circuit 212.

[0056] In some embodiments, the first comparator circuit 212 includes a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, and a first comparator U2; wherein, the first end of the sixth resistor R6 is coupled to the second level providing terminal VCC2, the second end of the sixth resistor R6 is coupled to the first end of the first isolation circuit 211, the first end of the seventh resistor R7, and the inverting terminal of the first comparator U2, the second end of the seventh resistor R7 is coupled to the second end of the first isolation circuit 211 and the second ground terminal PE, the first end of the eighth resistor R8 is coupled to the second level providing terminal VCC2, the second end of the eighth resistor R8 is coupled to the first end of the ninth resistor R9 and the non-inverting terminal of the first comparator U2, the second end of the ninth resistor R9 is coupled to the second ground terminal PE, the positive power supply input terminal of the first comparator U2 is coupled to the third level providing terminal, the negative power supply input terminal of the first comparator U2 is coupled to the fourth level providing terminal, and the output terminal of the first comparator U2 is coupled to the charging load circuit 102.

[0057] In some embodiments, the switch Q1 may be a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), a transistor, a thin film transistor, a field effect transistor, or any other reasonable switch Q1, and this application does not limit it.

[0058] It is worth noting that, to distinguish the two ends of each switching transistor Q1 except for the control terminal, one terminal is referred to as the second terminal and the other as the third terminal. When each switching transistor Q1 is a bipolar transistor, the control terminal, i.e., the first terminal, can specifically be the base, the second terminal as the collector, and the third terminal as the emitter; or, the first terminal can also specifically be the base, the second terminal as the emitter, and the third terminal as the collector.

[0059] When the switching transistors Q1 mentioned above are MOSFETs, thin-film transistors, or field-effect transistors, the first terminal can be the gate, the second terminal can be the drain, and the third terminal can be the source; or, the first terminal can be the gate, the second terminal can be the source, and the third terminal can be the drain.

[0060] In particular, when each switch Q1 is a MOSFET, a thin film transistor or a field-effect transistor, it can also be a composite transistor or a single transistor, which is not limited in this application.

[0061] In some embodiments, the level inputs corresponding to the first level providing terminal VCC1, the second level providing terminal VCC2, the third level providing terminal, and the fourth level providing terminal may be the same or different, and may specifically correspond to different power output terminals of an external power supply circuit or different power output terminals in the charging main control circuit 101. The level inputs corresponding to the first level providing terminal VCC1, the second level providing terminal VCC2, the third level providing terminal, and the fourth level providing terminal may specifically be 3.3V, 5V, +12V, -12V, or any reasonable combination of large voltages such as 3V, 6V, +10V, and -10V. This application does not limit this.

[0062] Furthermore, in some embodiments, the first filter sub-circuit 215 specifically includes an eighteenth resistor R18 and a twelfth capacitor C12. The signal protection sub-circuit 216 includes a transient voltage suppression diode (TVS). The first end of the eighteenth resistor R18 is coupled to the output terminal of the first comparator U2. The second end of the eighteenth resistor R18 is coupled to the first end of the twelfth capacitor C12 and the first end of the transient voltage suppression diode TVS, and is used to couple with the charging load circuit 102. The second end of the twelfth capacitor C12 is coupled to the second end of the transient voltage suppression diode TVS and the second ground terminal PE.

[0063] In some embodiments, the first comparator circuit 212 further includes a tenth capacitor C10 and an eleventh capacitor C11. The first end of the tenth capacitor C10 is coupled to the positive power supply input terminal of the first comparator U2, and the second end of the tenth capacitor C10 is coupled to the second ground terminal PE. The first end of the eleventh capacitor C11 is coupled to the negative power supply input terminal of the first comparator U2, and the second end of the eleventh capacitor C11 is coupled to the second ground terminal PE.

[0064] In some embodiments, the signal protection sub-circuit 216 further includes a ferrite bead L and a nineteenth resistor R19. The first end of the ferrite bead L is coupled to the second end of the eighteenth resistor R18, the first end of the twelfth capacitor C12, the first end of the transient voltage suppression diode TVS, and the first end of the nineteenth resistor R19. The second end of the ferrite bead L is coupled to the second end of the nineteenth resistor R19 and is used to couple with the charging load circuit 102.

[0065] Understandably, the charging main control circuit 101 outputs a PWM signal through its internal IO port (input / output port), which is connected in series with the first resistor R1 to the first terminal of the switching transistor Q1. The second terminal of the switching transistor Q1 is connected to the cathode of the light-emitting diode inside the first optocoupler U1. The anode of the light-emitting diode of the first optocoupler U1 is connected to the first level providing terminal VCC1 through the third resistor R3. The fourth resistor R4 and the first capacitor C1 are connected in parallel across the light-emitting diode of the first optocoupler U1 to ensure reliable operation of the first optocoupler U1. The collector of the secondary transistor of the first optocoupler U1 is connected in series with the fifth resistor R5 and sent to the inverting terminal of the first comparator U2. The input power of the second level providing terminal VCC2 is connected to the inverting terminal of the first comparator U2 after being divided by the sixth resistor R6 and the seventh resistor R7.

[0066] Furthermore, the input power supply of the second level providing terminal VCC2 is divided by the eighth resistor R8 and the ninth resistor R9 to provide a reference voltage, which is connected to the non-inverting input terminal of the first comparator U2. The output terminal of the first comparator U2 is connected to a low-pass filter composed of the eighteenth resistor R18 and the second capacitor. After filtering, the control guidance signal CP is obtained. The ferrite bead L and the nineteenth resistor R19 are connected in parallel and then in series between the low-pass filter and the charging interface. The transient voltage suppression diode TVS is used for electrostatic discharge or surge protection.

[0067] Similarly, taking the signal detection circuit 20 as an example of its specific application in a European standard charging pile, the IO port of the main charging control circuit 101 outputs a PWM pulse with an amplitude of 3.3V, a frequency of 1KHz, and a duty cycle of 5%, which controls the first optocoupler U1 to work. The secondary side of the first optocoupler U1 outputs a PWM pulse signal with an amplitude of 5V. This PWM pulse signal is compared with the reference voltage composed of the eighth resistor R8 and the ninth resistor R9. A ±12V PWM pulse signal is generated at the output of the first comparator U2. After passing through a low-pass filter and a transient voltage suppression diode TVS for protection, the PWM pulse signal is output to the charging interface after being connected in parallel with the ferrite bead L and the nineteenth resistor R19. This charging interface is the interface used for charging electronic devices.

[0068] Therefore, the signal modulation circuit 21 can obtain a PWM interface pulse signal with ±12V, a frequency of 1KHz, a duty cycle of 5%, and a reference ground of PE. This PWM interface pulse signal is the interface level signal required by the charging system standard.

[0069] Please see Figure 4 , Figure 4 This is a schematic diagram of the third embodiment of the signal detection circuit of this application. The difference between the signal detection circuit in this embodiment and the first embodiment of the signal detection circuit provided in this application is that the signal detection circuit 30 specifically includes a state detection circuit 32.

[0070] The state detection circuit 32 further includes an isolation operational amplifier sub-circuit 321 and a peak detection sub-circuit 322. The isolation operational amplifier sub-circuit 321 is coupled to the first comparator sub-circuit 312 and the peak detection sub-circuit 322. The peak detection sub-circuit 322 is also used to couple to the charging main control circuit 101.

[0071] The isolated operational amplifier sub-circuit 321 is used to receive the control guidance signal CP sent by the first comparator sub-circuit 312, so as to proportionally adjust the control guidance signal CP, such as linearly scaling the control guidance signal CP to the range acceptable to the main control or the range that is convenient for voltage detection and reading, and cutting off the common-mode interference path between the main power ground and the main control ground.

[0072] The peak detection sub-circuit 322 is used to receive the proportionally regulated control guide signal CP sent by the isolation operational amplifier sub-circuit 321, and to limit the amplitude of the proportionally regulated control guide signal CP, such as filtering out signals outside the set level range and retaining signals within the set level range, and outputting them to the charging main control circuit 101 for reading and detection, so that the charging main control circuit 101 can accurately measure the peak value of the PWM wave with a small duty cycle.

[0073] In some embodiments, the state detection circuit 32 further includes a signal conditioning sub-circuit 323, which is coupled between the first comparator sub-circuit 312 and the isolation operational amplifier sub-circuit 321. The signal conditioning sub-circuit 323 receives a control guidance signal CP sent by the first comparator sub-circuit 312 and performs voltage division and / or scaling adjustment on the control guidance signal CP to adjust it to a set voltage range suitable for subsequent processing.

[0074] The isolated operational amplifier sub-circuit 321 is used to receive the regulated control pilot signal CP sent by the signal conditioning sub-circuit 323, and to further proportionally adjust it based on the regulated control pilot signal CP.

[0075] In some embodiments, the state detection circuit 32 further includes a bias sub-circuit 324, which is coupled to the isolation operational amplifier sub-circuit 321. The bias sub-circuit 324 is used to adjust the voltage bias of the control guidance signal CP after proportional adjustment by the isolation operational amplifier sub-circuit 321. For example, an adaptation voltage is superimposed on the proportionally adjusted control guidance signal CP to raise it to the positive voltage range and eliminate the negative voltage part, so as to facilitate subsequent detection and reading.

[0076] In some embodiments, the state detection circuit 32 further includes a limiting protection circuit 325, which is coupled to the peak detection sub-circuit 322 and is used to be coupled to the charging main control circuit 101. The limiting protection circuit 325 is used to receive the control guidance signal CP sent by the peak detection sub-circuit 322 after being limited by it, so as to output the limited control guidance signal CP to the charging main control circuit 101 and to protect the peak detection sub-circuit 322 from the impact of the negative current on the load side on the peak detection sub-circuit 322.

[0077] Understandably, the peak detection sub-circuit 322 can accurately and reliably detect the control guide signal CP. After impedance matching, resistor voltage division and filtering by the signal conditioning sub-circuit 323, the control guide signal CP is connected to the non-inverting input of the isolation operational amplifier sub-circuit 321. Specifically, the isolation operational amplifier sub-circuit 321 can be an analog isolation operational amplifier to amplify positive and negative signal inputs. The output of the isolation operational amplifier sub-circuit 321 is detected by the peak detection sub-circuit 322 and the amplitude limiting protection circuit 325, and then output to the charging main control circuit 101 for analog quantity detection. This can effectively monitor the positive and negative level states to cover the signal detection requirements of all possible connection states of the charging plug and electronic devices. Moreover, through the peak detection method, even for PWM waves with a very small duty cycle, the peak value can be accurately measured.

[0078] Please continue to refer to the following: Figure 5 , Figure 5 yes Figure 4 A schematic diagram of a specific embodiment of the state detection circuit 32 in the signal detection circuit 30.

[0079] In some embodiments, the signal conditioning sub-circuit 323 further includes an emitter follower U3, a tenth resistor R10, an eleventh resistor R11, and a second capacitor C2; the isolation operational amplifier sub-circuit 321 includes a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, and an analog isolation operational amplifier U4; the bias sub-circuit 324 includes a seventh capacitor C7; and the peak detection sub-circuit 322 includes a first diode D1, a twelfth resistor R12, and an eighth capacitor C8.

[0080] In this circuit, the non-inverting input of emitter follower U3 is coupled to the output of the first comparator U2; the inverting input of emitter follower U3 is coupled to the output of emitter follower U3 and the first terminal of the tenth resistor R10; the second terminal of the tenth resistor R10 is coupled to the first terminal of the eleventh resistor R11, the first terminal of the second capacitor C2, and the first terminal INP of the analog isolation operational amplifier U4; the second terminal of the eleventh resistor R11 is coupled to the second terminal of the second capacitor C2 and the second ground terminal PE; the first terminal of the third capacitor C3 is coupled to the first terminal of the fourth capacitor C4 and the first power supply terminal VDD1 of the analog isolation operational amplifier U4, and is used to couple with the fifth level providing terminal VCC5; the second terminal of the third capacitor C3 is coupled to the second terminal of the fourth capacitor C4, the second terminal SNSN of the analog isolation operational amplifier U4, the first ground terminal GND1 of the analog isolation operational amplifier U4, and the second ground terminal PE. The second power supply terminal VDD2 of the analog isolation operational amplifier U4 is coupled to the first terminal of the sixth capacitor C6 and is used to couple with the sixth level supply terminal VCC6. The third terminal OUT of the analog isolation operational amplifier U4 is coupled to the first terminal of the first diode D1. The fourth terminal REFIN of the analog isolation operational amplifier U4 is coupled to the first terminal of the seventh capacitor C7 and is used to couple with the sixth level supply terminal VCC6. The second ground terminal GND2 of the analog isolation operational amplifier U4 is coupled to the second terminal of the fifth capacitor C5, the second terminal of the sixth capacitor C6, the second terminal of the seventh capacitor C7, and the first ground terminal GND. The second terminal of the first diode D1 is coupled to the first terminal of the twelfth resistor R12 and the first terminal of the eighth capacitor C8 and is used to couple with the charging main control circuit 101. The second terminal of the twelfth resistor R12 is coupled to the second terminal of the eighth capacitor C8 and the first ground terminal GND.

[0081] In some embodiments, the limiting protection circuit 325 further includes a third diode D3 and a fourth diode D4. The second end of the third diode D3 is coupled to the first level providing terminal VCC1, and the first end of the third diode D3 is coupled to the second end of the fourth diode D4, the second end of the first diode D1, the first end of the twelfth resistor R12, and the first end of the eighth capacitor C8. The first end of the fourth diode D4 is coupled to the first ground terminal GND.

[0082] Understandably, the control guidance signal CP is coupled to the non-inverting input of the emitter follower U3. The output of the emitter follower U3 is divided by the tenth resistor R10 and the eleventh resistor R11 to obtain a voltage signal with a suitable range, which is then sent to the non-inverting input of the analog isolation operational amplifier U4. The output of the analog isolation operational amplifier U4 is connected to the anode of the first diode D1. The cathode of the first diode D1 is connected to the charging main control circuit 101. The twelfth resistor R12 and the eighth capacitor C8 are connected in parallel between the cathode of the first diode D1 and the first ground terminal GND. The first diode D1, the twelfth resistor R12, and the eighth capacitor C8 form a peak detection sub-circuit 322. The third diode D3 and the fourth diode D4 are connected to the charging main control circuit 101 and are used for positive and negative limiting protection.

[0083] The emitter follower U3 is used to achieve impedance matching for the control guidance signal CP. The tenth resistor R10, the eleventh resistor R11, and the second capacitor C2 form a voltage divider and low-pass filter sub-circuit to condition the control guidance signal CP to a suitable range. The analog isolation operational amplifier U4 has positive and negative input signal amplification and primary and secondary electrical isolation functions. The output signal of the analog isolation operational amplifier U4 is passed through the peak detection sub-circuit 322 to obtain a suitable ratio value, namely the limiting detection signal CP-AD, which is output to the charging main control circuit 101 for reading and detection.

[0084] It is understood that the signal modulation circuit 31, the first isolation sub-circuit 311 and the first comparator sub-circuit 312, the voltage regulation sub-circuit 313 and the isolation protection sub-circuit 314, the first filter sub-circuit 315 and the signal protection sub-circuit 316 in this embodiment are the same as those in the signal modulation circuit 21, the first isolation sub-circuit 211 and the first comparator sub-circuit 212, the voltage regulation sub-circuit 213 and the isolation protection sub-circuit 214, the first filter sub-circuit 215 and the signal protection sub-circuit 216, respectively. Please refer to [link / reference] for details. Figure 2 The relevant textual content will not be repeated here.

[0085] Please see Figure 6 , Figure 6 This is a schematic diagram of the fourth embodiment of the signal detection circuit of this application. The difference between the signal detection circuit in this embodiment and the first embodiment of the signal detection circuit provided in this application is that the signal detection circuit 40 specifically includes a signal loss detection circuit 43.

[0086] The signal detection circuit 40 further includes a signal loss detection circuit 43, which includes a second comparator circuit 431 and a second isolation circuit 432. The second comparator circuit 431 is coupled to the first comparator circuit 412 and the second isolation circuit 432. The second isolation circuit 432 is also used to couple to the charging main control circuit 101.

[0087] The second comparator circuit 431 is used to receive the control guidance signal CP sent by the first comparator circuit 412, compare the control guidance signal CP with the second reference voltage, and output the loss detection signal CP1_LT based on the current comparison result.

[0088] The second isolation sub-circuit 432 is used to achieve electrical isolation between the charging main control circuit 101 and the second comparison sub-circuit 431, so as to receive the loss detection signal CP1_LT sent by the second comparison sub-circuit 431, and output the isolated loss detection signal CP1_LT to the charging main control circuit 101 to prevent noise interference between the signal detection side and the main control side.

[0089] The charging main control circuit 101 is also used to shut off the coupling between the charging load circuit 102 and the power supply circuit 103 in response to receiving the loss detection signal CP1_LT, so as to prevent power supply and thus prevent dangers such as no-load power-on, reverse connection, and short circuit.

[0090] In some embodiments, the signal loss detection circuit 43 further includes a second filter sub-circuit 433, which is coupled to the second isolation sub-circuit 432 and is used to couple with the charging main control circuit 101.

[0091] The second filter sub-circuit 433 is used to receive the loss detection signal CP1_LT sent by the second comparator sub-circuit 431, and perform low-pass filtering on the loss detection signal CP1_LT to suppress high-frequency oscillations, electromagnetic radiation and ringing caused by transmission line reflections caused by rapid switching of the comparator, and send it to the charging main control circuit 101, thereby improving signal quality, reducing EMI radiation and preventing false triggering of shutdown logic.

[0092] Understandably, when the control guide signal CP is abnormally lost, it is detected by the signal loss detection circuit 43 and sent to the external interrupt port of the charging main control circuit 101. At the same time, the circuit protection is triggered, and the charging contactor is directly disconnected to disconnect the connection between the charging load circuit 102 and the power supply circuit 103. This can quickly realize the detection of connection signal loss and disconnect the charging circuit.

[0093] In the signal loss detection circuit 43, the control guide signal CP is compared with the second reference voltage through the second comparator sub-circuit 431, and then isolated and output as a protection signal, namely the loss detection signal CP1_LT, through the second isolation sub-circuit 432. This loss detection signal CP1_LT can be directly output to the corresponding charging contactor to trigger its shutdown, or it can be sent to the external interrupt port of the charging main control circuit 101 to trigger an interrupt, and the charging contactor can be opened via software control. When the control guide signal CP is lost, the signal loss detection circuit 43 can quickly control the charging contactor to open.

[0094] The aforementioned signal modulation circuit 21, state detection circuit 32, and signal loss detection circuit 43 realize the modulation generation of the control guidance signal CP. The measurement state detection and connection loss protection are all isolation schemes, which provide a guarantee for improving the system's anti-interference and reliability. They have certain promotional value and economic benefits in practical applications.

[0095] Please continue to refer to the following: Figure 7 , Figure 7 yes Figure 6 A schematic diagram of a specific embodiment of the signal loss detection circuit 43 in the signal detection circuit 40.

[0096] In some embodiments, the second comparator circuit 431 further includes a second diode D2, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, and a second comparator U5; the second isolation circuit 432 includes a sixteenth resistor R16, a seventeenth resistor R17, a ninth capacitor C9, and a second optocoupler U6.

[0097] In this circuit, the first terminal of the second diode D2 is coupled to the first comparator circuit 412; the second terminal of the second diode D2 is coupled to the first terminal of the thirteenth resistor R13; the second terminal of the thirteenth resistor R13 is coupled to the inverting input of the second comparator U5; the first terminal of the fourteenth resistor R14 is coupled to the third level providing terminal; the second terminal of the fourteenth resistor R14 is coupled to the non-inverting input of the second comparator U5; the first terminal of the fifteenth resistor R15 is coupled to the second ground terminal PE; and the positive power supply input terminal of the second comparator U5 is coupled to the second ground terminal PE. The negative power input terminal of device U5 is coupled to the third level providing terminal. The first terminal of the sixteenth resistor R16 is used to couple to the third level providing terminal. The second terminal of the sixteenth resistor R16 is coupled to the first terminal of the seventeenth resistor R17, the first terminal of the ninth capacitor C9, and the first terminal of the second optocoupler U6. The second terminal of the seventeenth resistor R17 is coupled to the output terminal of the second comparator U5, the second terminal of the ninth capacitor C9, and the second terminal of the second optocoupler U6. The third terminal of the second optocoupler U6 is used to couple to the charging main control circuit 101. The fourth terminal of the second optocoupler U6 is coupled to the first ground terminal GND.

[0098] In some embodiments, the second comparator sub-circuit 431 further includes a thirteenth capacitor C13, the first end of which is coupled to the negative power supply input terminal of the second comparator U5, and the second end of which is coupled to the second ground terminal PE. The second isolation sub-circuit 432 further includes a fourteenth capacitor C14, the first end of which is coupled to the second end of the seventeenth resistor R17, the output terminal of the second comparator U5, the second end of the ninth capacitor C9, and the second end of the second optocoupler U6, and the second end of which is coupled to the second ground terminal PE.

[0099] In some embodiments, the second filter sub-circuit 433 specifically includes a twentieth resistor R20, a twenty-first resistor R21, and a fifteenth capacitor C15. The first end of the twentieth resistor R20 is coupled to the first level providing terminal VCC1, the second end of the twentieth resistor R20 is coupled to the first end of the twenty-first resistor R21 and the third end of the second optocoupler U6, the second end of the twenty-first resistor R21 is coupled to the first end of the fifteenth capacitor C15 and is used to couple with the charging main control circuit 101, and the second end of the fifteenth capacitor C15 is coupled to the fourth end of the second optocoupler U6 and the first ground terminal GND.

[0100] Understandably, the control guidance signal CP is clipped by the second diode D2 and input to the inverting input of the second comparator U5. The second reference voltage obtained by the voltage divider circuit composed of the fourteenth resistor R14 and the fifteenth resistor R15 is input to the non-inverting input of the second comparator U5. The output of the second comparator U5 is connected to the cathode of the primary-side light-emitting diode of the second optocoupler U6. The anode of the primary-side light-emitting diode of the second optocoupler U6 is connected to the third level providing terminal through the sixteenth resistor R16. The seventeenth resistor R17 and the ninth capacitor C9 are connected in parallel across the light-emitting diode of the second optocoupler U6. The collector of the secondary-side transistor of the second optocoupler U6 is connected in series with the twentieth resistor R20 and connected to the first level providing terminal VCC1. At the same time, the loss detection signal CP1_LT is obtained through the low-pass filter composed of the twenty-first resistor R21 and the fifteenth capacitor C15. The loss detection signal CP1_LT can be used to directly disconnect the charging contactor. At the same time, the loss detection signal CP1_LT can be output to the external interrupt input of the charging main control circuit 101, or the charging contactor can be disconnected by software logic control.

[0101] Therefore, when the charging interface is connected normally, the control guidance signal CP is a 9V or 6V PWM pulse. After passing through the second comparator U5, the output high level is connected to the cathode of the LED on the primary side of the second optocoupler U6. The LED is not conducting, and the output of the second optocoupler U6 is high, that is, the loss detection signal CP1_LT is high. When the charging interface is abnormally connected, the control guidance signal CP is 12V. The second comparator U5 outputs 0V to the cathode of the LED on the primary side of the second optocoupler U6. The LED is conducting, and the output of the second optocoupler U6 is low, that is, the loss detection signal CP1_LT is high. The low level triggers the charging contactor protection action. The signal loss detection circuit 43 achieves electrical isolation detection through the second optocoupler U6, which improves the detection reliability.

[0102] It is understood that the signal modulation circuit 41, the first isolation sub-circuit 411, the first comparator sub-circuit 412, the voltage regulation sub-circuit 413, the isolation protection sub-circuit 414, the first filter sub-circuit 415, and the signal protection sub-circuit 416 in this embodiment are the same as those in the signal modulation circuit 21, the first isolation sub-circuit 211, the first comparator sub-circuit 212, the voltage regulation sub-circuit 213, the isolation protection sub-circuit 214, the first filter sub-circuit 215, and the signal protection sub-circuit 216, respectively. Please refer to [link / reference] for details. Figure 2 The relevant textual content will not be repeated here.

[0103] This application also employs a signal detection method; please refer to [link / reference needed]. Figure 8 , Figure 8 This is a flowchart illustrating one embodiment of the signal detection method of this application. Specifically, it may include the following steps: S51: Receives the reference detection signal sent by the external charging main control circuit.

[0104] It is understood that the signal detection method in this embodiment is specifically applied to the signal detection circuit 10, signal detection circuit 20, signal detection circuit 20 or signal detection circuit 40 described in any of the above embodiments.

[0105] For ease of understanding, the application of the signal detection method to the signal detection circuit 10 is used as an example. The first isolation sub-circuit 111 is used to realize the electrical isolation between the charging main control circuit 101 and the first comparison sub-circuit 112, so as to receive the reference detection signal sent by the charging main control circuit 101, such as one or more of PWM signal, square wave signal, high and low level signal, and send the isolated in-phase signal to the first comparison sub-circuit 112 to prevent noise interference between the load side and the main control side.

[0106] S52: The control guidance signal is obtained by comparing the reference detection signal with the first reference voltage.

[0107] The first comparator circuit 112 is used to receive the isolated reference detection signal sent by the first isolation circuit 111, compare the reference detection signal with the first reference voltage, and output a control guidance signal CP based on the current comparison result.

[0108] S53: Outputs a control guidance signal to an external charging load circuit to trigger the charging load circuit to change its connection state to adjust the control guidance signal.

[0109] The first comparator circuit 112 is also used to output the control guide signal CP to the charging load circuit 102, so as to trigger the charging load circuit 102 to change its connection state under the action of the control guide signal CP, such as connecting a pull-down resistor or a switch network according to its own state, and actively adjusting the level or impedance of the control guide signal CP.

[0110] S54: Send the adjusted control guidance signal to the charging main control circuit so that the charging main control circuit turns on or off the coupling between the charging load circuit and the power supply circuit in response to the level state of the adjusted control guidance signal.

[0111] Furthermore, the first comparator circuit 112 is also used to send the adjusted control guidance signal CP to the charging master control circuit 101, so that when the level of the control guidance signal CP is at an effective level (such as a low level indicating "rechargeable"), the charging master control circuit 101 turns on the power path of the switching circuit (such as closing a relay or contactor), thereby connecting the power supply circuit 103 with the charging load circuit 102 to charge the charging load circuit 102, and making the charging master control circuit 101 correspondingly communicatively connected with the charging load circuit 102 to perform status detection and data communication.

[0112] When the level of the control guidance signal CP is invalid (such as high impedance, high level), the connection between the power supply circuit 103 and the charging load circuit 102 is disconnected to prevent power supply, thereby preventing dangers such as no-load power-on, reverse connection, and short circuit, and realizing the safety protocol of "handshake first, then power supply".

[0113] It is worth noting that when the signal detection method is applied to signal detection circuit 20, signal detection circuit 30, or signal detection circuit 40, the signal detection method may also include some other specific implementation steps. Please refer to [link / reference needed] for details. Figures 1-7 The relevant textual content will not be elaborated upon here.

[0114] This application also employs an electronic device; please refer to [link / reference needed]. Figure 9 , Figure 9This is a schematic diagram of one embodiment of the electronic device of this application. In this embodiment, the electronic device 60 includes a housing 61 and a signal detection circuit 62 connected to the housing 61.

[0115] It should be noted that the signal detection circuit 62 described in this embodiment is any of the signal detection circuits 10, 20, 30, or 40 described in the above embodiments. Please refer to [link / reference] for details. Figures 1-8 The relevant textual content will not be elaborated upon here.

[0116] The beneficial effects of this application are as follows: Unlike the prior art, the signal detection circuit provided in this application couples the first isolation sub-circuit to the first comparison sub-circuit, and uses the first isolation sub-circuit to couple with the charging main control circuit, and the first comparison sub-circuit to couple with the charging load circuit. The first isolation sub-circuit receives the reference detection signal sent by the charging main control circuit, and the first comparison sub-circuit compares the reference detection signal with the first reference voltage to obtain a control guidance signal, thereby increasing the voltage variation range of the control guidance signal and outputting it to the charging load circuit. This triggers the charging load circuit to change its connection state to adjust the control guidance signal, enabling the charging main control circuit to respond to the adjusted control guidance signal level to achieve charging switch control and state detection of the charging load circuit. This results in higher detection accuracy, lower requirements for the sampling frequency of the charging main control circuit, reduced computational overhead of the charging main control circuit, and improved system performance. Furthermore, the control guidance signal obtained by voltage comparison using the first comparison sub-circuit can effectively monitor positive and negative level states, covering the signal detection requirements for all possible connection states of the charging plug and electronic device.

[0117] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A signal detection circuit, used for signal detection in a charging main control circuit, characterized in that, The signal detection circuit includes: The signal modulation circuit includes a first isolation sub-circuit and a first comparator sub-circuit. The first isolation sub-circuit is coupled to the first comparator sub-circuit and is used to be coupled to the charging main control circuit. The first comparator sub-circuit is used to be coupled to the charging load circuit. The first isolation sub-circuit is configured to receive a reference detection signal sent by the charging main control circuit; the first comparison sub-circuit is configured to receive the reference detection signal sent by the first isolation sub-circuit, and compare the reference detection signal with a first reference voltage to obtain a control guidance signal, which is then output to the charging load circuit to trigger the charging load circuit to change its connection state to adjust the control guidance signal; the charging main control circuit is configured to receive the adjusted control guidance signal sent by the first comparison sub-circuit, and to turn on or off the coupling between the charging load circuit and the power supply circuit in response to the level state of the adjusted control guidance signal.

2. The signal detection circuit according to claim 1, characterized in that, The signal modulation circuit further includes a voltage regulation sub-circuit and an isolation protection sub-circuit. The voltage regulation sub-circuit is coupled to the isolation protection sub-circuit and is used to be coupled to the charging main control circuit. The isolation protection sub-circuit is coupled to the first isolation sub-circuit. The voltage regulation sub-circuit is configured to receive the reference detection signal sent by the charging main control circuit and regulate the voltage of the reference detection signal; the isolation protection sub-circuit is configured to receive the voltage-regulated reference detection signal sent by the voltage regulation sub-circuit and send the voltage-regulated reference detection signal to the first isolation sub-circuit.

3. The signal detection circuit according to claim 2, characterized in that, The signal modulation circuit further includes a first filter sub-circuit and a signal protection sub-circuit. The first filter sub-circuit is coupled to the first comparator sub-circuit and the signal protection sub-circuit. The signal protection sub-circuit is used to couple with the charging load circuit. The first filtering sub-circuit is configured to receive the control guidance signal sent by the first comparison sub-circuit and perform low-pass filtering on the control guidance signal; the signal protection sub-circuit is configured to receive the low-pass filtered control guidance signal sent by the first filtering sub-circuit and send the low-pass filtered control guidance signal to the charging load circuit.

4. The signal detection circuit according to claim 2, characterized in that, The voltage regulation sub-circuit includes a first resistor, a second resistor, and a switching transistor; the isolation protection sub-circuit includes a third resistor, a fourth resistor, and a first capacitor; the first isolation sub-circuit includes a first optocoupler and a fifth resistor. Wherein, the first end of the first resistor is used to couple to the charging main control circuit, the second end of the first resistor is coupled to the first end of the second resistor and the first end of the switching transistor, the second end of the second resistor is coupled to the second end of the switching transistor and the first ground terminal, the first end of the third resistor is used to couple to the first level providing terminal, the second end of the third resistor is coupled to the first end of the fourth resistor, the first end of the first capacitor and the first end of the first optocoupler, the third end of the switching transistor is coupled to the second end of the fourth resistor, the second end of the first capacitor and the second end of the first optocoupler, the third end of the first optocoupler is coupled to the first end of the fifth resistor, the fourth end of the first optocoupler is coupled to the first end of the first comparator circuit, and the second end of the fifth resistor is coupled to the second end of the first comparator circuit.

5. The signal detection circuit according to claim 1, characterized in that, The first comparator circuit includes a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, and a first comparator; Wherein, the first end of the sixth resistor is coupled to the second level providing terminal; the second end of the sixth resistor is coupled to the first end of the first isolation sub-circuit, the first end of the seventh resistor, and the inverting terminal of the first comparator; the second end of the seventh resistor is coupled to the second end of the first isolation sub-circuit and the second ground terminal; the first end of the eighth resistor is coupled to the second level providing terminal; the second end of the eighth resistor is coupled to the first end of the ninth resistor and the non-inverting terminal of the first comparator; the second end of the ninth resistor is coupled to the second ground terminal; the positive power supply input terminal of the first comparator is coupled to the third level providing terminal; the negative power supply input terminal of the first comparator is coupled to the fourth level providing terminal; and the output terminal of the first comparator is coupled to the charging load circuit.

6. The signal detection circuit according to any one of claims 1-5, characterized in that, The signal detection circuit further includes a state detection circuit, which includes an isolation operational amplifier sub-circuit and a peak detection sub-circuit. The isolation operational amplifier sub-circuit is coupled to the first comparator sub-circuit and the peak detection sub-circuit. The peak detection sub-circuit is also used to couple with the charging main control circuit. The isolated operational amplifier sub-circuit is configured to receive the control guidance signal sent by the first comparator sub-circuit, and to proportionally adjust the control guidance signal; the peak detection sub-circuit is configured to receive the proportionally adjusted control guidance signal sent by the isolated operational amplifier sub-circuit, and to limit the proportionally adjusted control guidance signal before outputting it to the charging main control circuit.

7. The signal detection circuit according to claim 6, characterized in that, The state detection circuit further includes a signal conditioning sub-circuit, which is coupled between the first comparator sub-circuit and the isolation operational amplifier sub-circuit. The signal conditioning sub-circuit is configured to receive the control guidance signal sent by the first comparator sub-circuit to adjust the control guidance signal to a set voltage range; the isolation operational amplifier sub-circuit is configured to receive the adjusted control guidance signal sent by the signal conditioning sub-circuit to proportionally adjust the adjusted control guidance signal.

8. The signal detection circuit according to claim 7, characterized in that, The state detection circuit further includes a bias sub-circuit coupled to the isolation operational amplifier sub-circuit; wherein the bias sub-circuit is configured to boost the control guidance signal, after proportional adjustment by the isolation operational amplifier sub-circuit, to a positive voltage range.

9. The signal detection circuit according to claim 8, characterized in that, The state detection circuit further includes a limiting protection circuit, which is coupled to the peak detection sub-circuit and is used to couple with the charging main control circuit. The limiting protection circuit is configured to receive the limiting-adjusted control guidance signal sent by the peak detection sub-circuit, and output the limiting-adjusted control guidance signal to the charging main control circuit.

10. The signal detection circuit according to claim 8, characterized in that, The signal conditioning sub-circuit includes an emitter follower, a tenth resistor, an eleventh resistor, and a second capacitor; the isolation operational amplifier sub-circuit includes a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, and an analog isolation operational amplifier; the bias sub-circuit includes a seventh capacitor; and the peak detection sub-circuit includes a first diode, a twelfth resistor, and an eighth capacitor. In this configuration, the non-inverting input of the emitter follower is coupled to the output of the first comparator; the inverting input of the emitter follower is coupled to the output of the emitter follower and the first terminal of the tenth resistor; the second terminal of the tenth resistor is coupled to the first terminal of the eleventh resistor, the first terminal of the second capacitor, and the first terminal of the analog isolated operational amplifier; the second terminal of the eleventh resistor is coupled to the second terminal of the second capacitor and the second ground terminal; the first terminal of the third capacitor is coupled to the first terminal of the fourth capacitor and the first power supply terminal of the analog isolated operational amplifier, and is used to couple with the fifth level providing terminal; the second terminal of the third capacitor is coupled to the second terminal of the fourth capacitor, the second terminal of the analog isolated operational amplifier, the first ground terminal of the analog isolated operational amplifier, and the second ground terminal. At ground, the second power supply terminal of the analog isolated operational amplifier is coupled to the first terminal of the sixth capacitor and is used to couple with the sixth level supply terminal; the third terminal of the analog isolated operational amplifier is coupled to the first terminal of the first diode; the fourth terminal of the analog isolated operational amplifier is coupled to the first terminal of the seventh capacitor and is used to couple with the sixth level supply terminal; the second ground terminal of the analog isolated operational amplifier is coupled to the second terminal of the fifth capacitor, the second terminal of the sixth capacitor, the second terminal of the seventh capacitor, and the first ground terminal; the second terminal of the first diode is coupled to the first terminal of the twelfth resistor and the first terminal of the eighth capacitor and is used to couple with the charging main control circuit; the second terminal of the twelfth resistor is coupled to the second terminal of the eighth capacitor and the first ground terminal.

11. The signal detection circuit according to any one of claims 1-5, characterized in that, The signal detection circuit further includes a signal loss detection circuit, which includes a second comparator circuit and a second isolation circuit. The second comparator circuit is coupled to the first comparator circuit and the second isolation circuit. The second isolation circuit is also used to couple with the charging main control circuit. The second comparator sub-circuit is configured to receive the control guidance signal sent by the first comparator sub-circuit, and compare the control guidance signal with the second reference voltage to obtain a loss detection signal; the second isolation sub-circuit is configured to receive the loss detection signal sent by the second comparator sub-circuit, and output the loss detection signal to the charging master control circuit, so that the charging master control circuit shuts off the coupling between the charging load circuit and the power supply circuit in response to the loss detection signal.

12. The signal detection circuit according to claim 11, characterized in that, The signal loss detection circuit further includes a second filtering sub-circuit, which is coupled to the second isolation sub-circuit and is used to couple with the charging main control circuit. The second filtering sub-circuit is configured to receive the loss detection signal sent by the second comparison sub-circuit, perform low-pass filtering on the loss detection signal, and then send it to the charging main control circuit.

13. The signal detection circuit according to claim 11, characterized in that, The second comparator circuit includes a second diode, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, and a second comparator; the second isolation circuit includes a sixteenth resistor, a seventeenth resistor, a ninth capacitor, and a second optocoupler. In this circuit, the first terminal of the second diode is coupled to the first comparator circuit; the second terminal of the second diode is coupled to the first terminal of the thirteenth resistor; the second terminal of the thirteenth resistor is coupled to the inverting input of the second comparator; the first terminal of the fourteenth resistor is coupled to the third level providing terminal; the second terminal of the fourteenth resistor is coupled to the non-inverting input of the second comparator and the first terminal of the fifteenth resistor; the second terminal of the fifteenth resistor is coupled to the second ground terminal; the positive power supply input terminal of the second comparator is coupled to the second ground terminal; the negative power supply input terminal of the second comparator is coupled to the third level providing terminal; the first terminal of the sixteenth resistor is coupled to the third level providing terminal; the second terminal of the sixteenth resistor is coupled to the first terminal of the seventeenth resistor, the first terminal of the ninth capacitor, and the first terminal of the second optocoupler; the second terminal of the seventeenth resistor is coupled to the output terminal of the second comparator, the second terminal of the ninth capacitor, and the second terminal of the second optocoupler; the third terminal of the second optocoupler is coupled to the charging main control circuit; and the fourth terminal of the second optocoupler is coupled to the first ground terminal.

14. A signal detection method, applied in the signal detection circuit as described in any one of claims 1-13, characterized in that, The signal detection method includes: Receives reference detection signals sent by the external charging main control circuit; The control guidance signal is obtained by comparing the reference detection signal with the first reference voltage. The control guidance signal is output to an external charging load circuit to trigger the charging load circuit to change the connection state to adjust the control guidance signal. The adjusted control guidance signal is sent to the charging master control circuit so that the charging master control circuit turns on or off the coupling between the charging load circuit and the power supply circuit in response to the level state of the adjusted control guidance signal.

15. An electronic device, characterized in that, The electronic device includes a housing and a signal detection circuit connected to the housing; The signal detection circuit is the signal detection circuit as described in any one of claims 1-13.

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