Brake control circuit, circuit board assembly and electronic equipment

Abstract

The embodiment of the utility model relates to the technical field of elevators, and discloses a brake control circuit, a circuit board assembly and electronic equipment, the brake control circuit comprises a rectification unit, a PWM output control unit, a follow current unit, a follow current control unit, a first resistor, a first voltage detection unit, a second voltage detection unit and a main control unit; the positive input end and the negative input end of the rectification unit are configured to be connected with the positive output end and the negative output end of a power supply, the positive output end of the rectification unit is connected with the input end of the follow current unit, and the negative output end of the rectification unit is connected with the input end of the PWM output control unit; the output end of the freewheeling unit is connected with the input end of the freewheeling control unit, the output end of the freewheeling control unit is connected with the first end of the first resistor, and the second end of the first resistor is connected with the first end of the brake coil; the output end of the PWM output control unit is connected with the second end of the brake coil; grounding conditions of the positive electrode side and the negative electrode side are detected, and the problem of elevator sliding caused by grounding of the negative electrode side is solved.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of circuit technologies, and in particular, to a brake control circuit, a circuit board assembly, and an electronic device. Background Art

[0002] Currently, during the operation of an elevator system, the brake circuit is used to control the lifting and releasing of the brake. The grounding protection of the brake circuit is crucial for the normal operation of the elevator equipment. The grounding protection of the brake circuit can avoid safety accidents caused by poor grounding. Correct grounding detection can ensure the safe operation of the circuit and prevent damage to the brake or personal injury caused by circuit failures.

[0003] However, the current brake circuit has problems such as the failure to start the release of the brake caused by positive pole grounding and the car slipping problem caused by the continuous lifting of the brake due to negative pole grounding, which affects the normal operation of the elevator system. Summary of the Utility Model

[0004] The purpose of the embodiments of the present application is to provide a brake control circuit, a circuit board assembly, and an electronic device, so as to detect the grounding conditions on the positive pole side and the negative pole side, discover and detect the problem of the elevator not starting caused by positive pole grounding and the car slipping problem caused by the continuous lifting of the brake due to negative pole grounding, and solve the car slipping problem caused by the continuous lifting of the brake due to negative pole grounding.

[0005] To solve the above technical problems, the embodiments of the present application provide a brake control circuit, including: a rectification unit, a PWM output control unit, a freewheeling unit, a freewheeling control unit, a first resistor, a first voltage detection unit, a second voltage detection unit, and a main control unit; the positive input terminal and the negative input terminal of the rectification unit are configured to be connected to the positive output terminal and the negative output terminal of a power supply, the positive output terminal of the rectification unit is connected to the input terminal of the freewheeling unit, and the negative output module of the rectification unit is connected to the input terminal of the PWM output control unit; the output terminal of the freewheeling unit is connected to the input terminal of the freewheeling control unit, the output terminal of the freewheeling control unit is connected to the first end of the first resistor, the second end of the first resistor is connected to the first end of a brake coil; the output terminal of the PWM output control unit is connected to the second end of the brake coil; the first end and the second end of the first voltage detection unit are respectively connected to the first end and the second end of the brake coil; the first end and the second end of the second voltage detection unit are respectively connected to the first end and the second end of the first resistor; the main control unit is connected to the first voltage detection unit and the second voltage detection unit; the main control unit is further connected to the control terminal of the PWM output control unit and the control terminal of the freewheeling control unit.

[0006] Embodiments of the present application further provide a circuit board assembly, including: the brake control circuit as described above.

[0007] Embodiments of the present application further provide an electronic device, including: the circuit board assembly as described above.

[0008] In some embodiments, the first voltage detection unit and the second voltage detection unit both include a second resistor, an optocoupler, and a microcontroller; the first end of the second resistor serves as the first end of the first voltage detection unit or the second voltage detection unit, the second end of the second resistor is connected to the positive input terminal of the optocoupler, the negative input terminal of the optocoupler serves as the second end of the first voltage detection unit or the second voltage detection unit, and the first output terminal and the second output terminal of the optocoupler are connected to the microcontroller.

[0009] In some embodiments, the optocoupler includes a light-emitting diode and a photosensitive triode; the anode of the light-emitting diode serves as the positive input terminal of the optocoupler, and the cathode of the light-emitting diode serves as the negative input terminal of the optocoupler; the light-emitting diode is disposed opposite to the base of the photosensitive triode, and the emitter and collector of the photosensitive triode serve as the first output terminal and the second output terminal of the optocoupler respectively.

[0010] In some embodiments, the brake control circuit further includes an overvoltage protection unit; the overvoltage protection unit is disposed between the negative output terminal of the power supply and the negative input terminal of the freewheeling unit.

[0011] In some embodiments, the PWM output control unit includes a first MOS transistor, the control terminal of the first MOS transistor serves as the control terminal of the PWM output control unit, the input terminal of the first MOS transistor serves as the input terminal of the PWM output control unit, and the output terminal of the first MOS transistor serves as the output terminal of the PWM output control unit.

[0012] In some embodiments, the freewheeling control unit includes a second MOS transistor, the control terminal of the second MOS transistor serves as the control terminal of the freewheeling control unit, the input terminal of the second MOS transistor serves as the input terminal of the freewheeling control unit, and the output terminal of the second MOS transistor serves as the output terminal of the freewheeling control unit.

[0013] In some embodiments, the freewheeling unit is a diode, the anode of the diode serves as the input terminal of the freewheeling unit, and the cathode of the diode serves as the output terminal of the freewheeling unit.

[0014] In some embodiments, the rectification unit is a bridge rectifier.

[0015] The technical solutions provided by the embodiments of the present application have at least the following advantages:

[0016] In this embodiment, by providing a rectifying unit, a PWM output control unit, a freewheeling unit 103, a freewheeling control unit, a first resistor, a first voltage detection unit, a second voltage detection unit, and a main control unit in the brake control circuit, the brake control circuit can detect the voltage across the brake coil through the first voltage detection unit to determine whether the negative side is grounded, and can detect the voltage across the first resistor through the second voltage detection unit to determine whether the positive side is grounded, so as to discover and detect the problem that the elevator fails to start caused by the grounding of the positive side and the problem of car slipping caused by the continuous lifting of the brake due to the grounding of the negative side. Thus, it is convenient to turn off the brake control circuit when the positive side or the negative side is grounded, stop the elevator, and solve the problem of car slipping caused by the continuous lifting of the brake due to the grounding of the negative side. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] One or more embodiments are exemplified by the pictures in the corresponding drawings. These exemplary descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements. Unless otherwise stated, the drawings in the drawings do not constitute a scale limitation.

[0018] Figure 1 is a schematic circuit diagram of a brake control circuit according to an embodiment of the present application;

[0019] Figure 2 is a schematic circuit diagram of the first voltage detection unit or the second voltage detection unit according to an embodiment of the present application;

[0020] Figure 3 is a schematic circuit diagram of a brake control circuit according to an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the embodiments of the present application will be described in detail below with reference to the drawings. However, those of ordinary skill in the art can understand that in the embodiments of the present application, many technical details are provided to help the reader better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in the present application can still be implemented. The following division of each embodiment is for convenience of description and should not constitute any limitation on the specific implementation manner of the present application. Each embodiment can be combined and cross-referenced with each other without conflict.

[0022] In the description of the embodiments of the present application, the meaning of "at least one" is one or more, the meaning of "a plurality" is two or more, and the meaning of "at least one group" is one group or more groups, unless otherwise specifically defined.

[0023] In the description of the embodiments of the present application, technical terms such as "first" and "second" are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity, specific order or primary-secondary relationship of the indicated technical features.

[0024] Referring to "embodiment" herein means that a specific feature, structure or characteristic described in connection with the embodiment may be included in at least one embodiment of the present application. The phrase appears in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein may be combined with other embodiments.

[0025] In the description of the embodiments of the present application, when a certain component "includes" another component, unless otherwise stated, other components are not excluded, and other components may further be included.

[0026] An embodiment of the present application relates to a brake control circuit, and the specific circuit structure diagram is as Figure 1 shown. The brake control circuit includes: a rectification unit 101, a PWM (Pulse Width Modulation) output control unit 102, a freewheeling unit 103, a freewheeling control unit 104, a first resistor R1, a first voltage detection unit 105, a second voltage detection unit 106, and a main control unit (not marked in the figure).

[0027] Specifically, the positive input terminal and the negative input terminal of the rectification unit 101 are configured to be connected to the positive output terminal L and the negative output terminal N of the power supply AC. The positive output terminal of the rectification unit 101 is connected to the input terminal of the freewheeling unit 103, and the negative output module of the rectification unit 101 is connected to the input terminal of the PWM output control unit 102. The output terminal of the freewheeling unit 103 is connected to the input terminal of the freewheeling control unit 104, and the output terminal of the freewheeling control unit 104 is connected to the first end a of the first resistor R1. The second end of the first resistor R1 is connected to the first end c of the brake coil L1. The output terminal of the PWM output control unit 102 is connected to the second end d of the brake coil L1. The first end and the second end of the first voltage detection unit 105 are respectively connected to the first end c and the second end d of the brake coil L1. The first end and the second end of the second voltage detection unit 106 are respectively connected to the first end a and the second end b of the first resistor R1. The main control unit is connected to the first voltage detection unit 105 and the second voltage detection unit 106. The main control unit is also connected to the control terminal of the PWM output control unit 102 and the control terminal of the freewheeling control unit 104.

[0028] Specifically, the first voltage detection unit 105 can obtain the first voltage across the two ends cd of the brake coil L1, and the second voltage detection unit 106 can obtain the second voltage across the two ends ab of the first resistor R1. The first voltage detection unit 105 and the second voltage detection unit 106 can send the situations of the obtained first voltage across the two ends cd of the brake coil L1 and the second voltage across the two ends ab of the first resistor R1 to the main control unit, and the main control unit controls the turning on and off of the PWM output control unit 102 and the freewheeling control unit 104 according to the magnitudes of the first voltage and the second voltage.

[0029] In practical applications, when the negative side (such as Figure 1 point A in) of the brake control circuit is grounded, at this time the PWM output control unit 102 is bypassed, and the voltage on the output side of the brake control circuit, that is, the first voltage across the two ends cd of the brake coil L1 (such as Figure 1 both sides of cd), is the bus voltage, and this bus voltage exceeds the normal range. Without detection and protection, during the operation of the elevator, the brake control circuit continuously outputs the bus voltage, the brake is continuously lifted, the brake control circuit controls the brake to fail, which will cause the problem of the elevator running away. Therefore, the first voltage detection unit 105 detects the first voltage across the two ends cd of the brake coil L1 and sends it to the main control unit. The main control unit judges whether the first voltage exceeds the first threshold range. In the case of exceeding the first threshold range, it controls the freewheeling control unit 104 to turn off, so as to cut off the voltage on the positive side, protect the entire brake circuit, make the brake coil L1 lose power, the elevator system is in the braking state, and the elevator stops running, solving the problem of the elevator running away caused by the continuous lifting of the brake due to the grounding of the negative side.

[0030] In practical applications, when the positive side of the brake control circuit (such as Figure 1 point B in

[0031] is grounded, a relatively large voltage will be collected across ab at both ends of the first resistor R1 at the rear end. When the positive side is not grounded, the voltage across ab at both ends of the first resistor R1 is relatively small. After the positive side is grounded, the voltage across ab at both ends of the first resistor R1 is relatively large. At this time, the second voltage detection unit 106 detects the second voltage across ab at both ends of the first resistor R1, and the second voltage detection unit 106 sends the detected second voltage across ab at both ends of the first resistor R1 to the main control unit. The main control unit determines whether the second voltage exceeds the second threshold range. When the second voltage exceeds the second threshold range, the main control unit can control the PWM output control unit 102 to turn off, or control the freewheeling control unit 104 to turn off, so that there is no input voltage across cd at both ends of the brake coil L1, protecting the entire brake circuit, causing the brake coil L1 to lose power, the elevator system to be in the holding brake state, and the elevator to stop running, thereby detecting and detecting the grounding situation of the positive side, and controlling the PWM output control unit 102 or controlling the freewheeling control unit 104 to turn off.

[0032] It should be noted that when the negative side is grounded, the main control unit can control the freewheeling control unit 104 to turn off. When the positive side is grounded, the main control unit can control the PWM output control unit 102 to turn off, or control the freewheeling control unit 104 to turn off. Without adding additional switching devices to the brake control circuit, the brake control loop can be turned off, and the cost is relatively low.

[0033] In this embodiment, a rectifying unit 101, a PWM output control unit 102, a freewheeling unit 103, a freewheeling control unit 104, a first resistor R1, a first voltage detection unit 105, a second voltage detection unit 106, and a main control unit are provided in the brake control circuit. The brake control circuit can detect the voltage across the two ends cd of the brake coil L1 through the first voltage detection unit 105 to determine whether the negative side is grounded, and can detect the voltage across the two ends ab of the first resistor R1 through the second voltage detection unit 106 to determine whether the positive side is grounded, so as to discover and detect the problem that the elevator fails to start caused by the grounding of the positive side and the problem of car slipping caused by the continuous lifting of the brake due to the grounding of the negative side, thereby facilitating the shutdown of the brake control circuit when the positive side or the negative side is grounded to stop the elevator from running; and when the negative side of the brake control circuit is grounded, since the brake coil L1 is continuously powered on and lifted, the elevator system is in a car slipping state. At this time, when the grounding of the negative side is detected and the freewheeling control unit 104 is disconnected, the elevator stops running, solving the problem of car slipping caused by the continuous lifting of the control brake due to the grounding of the negative side.

[0034] In one embodiment, the PWM output control unit 102 includes a first MOS transistor MOSA. The control terminal of the first MOS transistor MOSA serves as the control terminal of the PWM output control unit 102, the input terminal of the first MOS transistor MOSA serves as the input terminal of the PWM output control unit 102, and the output terminal of the first MOS transistor MOSA serves as the output terminal of the PWM output control unit 102.

[0035] Specifically, the function of the first MOS transistor MOSA is to control the PWM output. The main control unit controls the conduction and cutoff of the negative output terminal of the rectifying unit 101 by controlling the conduction and cutoff of the first MOS transistor MOSA to control the output of the PWM.

[0036] In one embodiment, the freewheeling control unit 104 includes a second MOS transistor MOSB. The control terminal of the second MOS transistor MOSB serves as the control terminal of the freewheeling control unit 104, the input terminal of the second MOS transistor MOSB serves as the input terminal of the freewheeling control unit 104, and the output terminal of the second MOS transistor MOSB serves as the output terminal of the freewheeling control unit 104.

[0037] Specifically, the function of the second MOS transistor MOSB is to control the output of the brake power supply freewheeling circuit. The main control unit controls the output and cutoff of the brake power supply freewheeling circuit by controlling the conduction and cutoff of the second MOS transistor MOSB, thereby controlling the output of the freewheeling unit 103.

[0038] Among them, the first MOS transistor MOSA and the second MOS transistor MOSB can both be PMOS transistors, or both be NMOS transistors, or the first MOS transistor MOSA be a PMOS transistor and the second MOS transistor MOSB be an NMOS transistor, or the first MOS transistor MOSA be an NMOS transistor and the second MOS transistor MOSB be a PMOS transistor. In one embodiment, the first MOS transistor MOSA and the second MOS transistor MOSB can both be selected as PMOS transistors, thereby reducing the cost of the brake control circuit.

[0039] Specifically, the rectification unit 101 is a bridge rectifier. The power supply AC in this embodiment is alternating current, specifically 220V. The bridge rectifier converts the full wave of the AC signal into a DC signal, thereby realizing the function of AC to DC conversion.

[0040] Due to the characteristics of high frequency, high efficiency, high power density, and high reliability, the bridge rectifier can quickly convert AC into a DC power supply. However, since the diodes in the bridge rectifier work in a high-frequency on-off state, the high-frequency fast transient process itself is an electromagnetic interference source. The electromagnetic interference (EMI, Electromagnetic Interference) signals it generates have a wide frequency range and a certain amplitude. If this DC power supply is directly used in digital devices, the EMI signals generated by the devices will become stronger and more complex.

[0041] Therefore, the brake control circuit further includes a third resistor R3, and the third resistor R3 is connected between the positive output terminal of the rectification unit 101 and the input terminal of the freewheeling unit 103.

[0042] Specifically, the first end of the third resistor R3 is connected to the positive output terminal of the rectification unit 101, and the second end of the third resistor R3 is connected to the input terminal of the freewheeling unit 103. Since an electromagnetic interference source will be generated in the bridge rectifier circuit under the high-frequency on-off state, and the electromagnetic interference source will further generate a spike voltage, by setting the third resistor R3, the spike voltage output by the bridge rectifier can be absorbed, improving the stability of the brake control circuit.

[0043] Specifically, the brake control circuit of this embodiment further includes a first capacitor C1; the first end of the first capacitor C1 is connected to the second end of the third resistor R3, and the second end of the first capacitor C1 is connected to the negative output terminal of the rectification unit 101.

[0044] Specifically, since an electromagnetic interference source will be generated in the bridge rectifier circuit under the high-frequency on-off state, and the generated EMI signals have a wide frequency range and a certain amplitude, the first filtering unit can filter the electrical signals output by the rectification unit 101 to reduce noise and improve the stability of the brake control circuit.

[0045] Specifically, the brake control circuit of this embodiment further includes a second capacitor C2; the first end of the second capacitor C2 is connected to the output end of the freewheeling unit 103, and the second end of the second capacitor C2 is connected to the output end of the PWM output control unit 102.

[0046] Specifically, the second capacitor C2 filters the electrical signal output by the freewheeling unit 103 to reduce noise, thereby improving the stability of the brake control circuit.

[0047] Specifically, the freewheeling unit 103 is a diode, the anode of the diode is used as the input end of the freewheeling unit 103, and the cathode of the diode is used as the output end of the freewheeling unit 103.

[0048] In one embodiment, the first voltage detection unit 105 and the second voltage detection unit 106 have the same structure, as Figure 2 shown, which is the circuit structure schematic diagram of the first voltage detection unit 105 or the second voltage detection unit 106 of this embodiment.

[0049] Specifically, both the first voltage detection unit 105 and the second voltage detection unit 106 include a second resistor R2, an optocoupler 201, and a microcontroller 202; the first end of the second resistor R2 is used as the first end of the first voltage detection unit 105 or the second voltage detection unit 106, the second end of the second resistor R2 is connected to the positive input end of the optocoupler 201, the negative input end of the optocoupler 201 is used as the second end of the first voltage detection unit 105 or the second voltage detection unit 106, and the first output end and the second output end of the optocoupler 201 are connected to the microcontroller 202.

[0050] Specifically, taking the first voltage detection unit 105 as an example, the first voltage detection unit 105 includes a second resistor R2, an optocoupler 201, and a microcontroller 202; the first end of the second resistor R2 is used as the first end e of the first voltage detection unit 105 and is connected to the first end c of the brake coil L1, the second end of the second resistor R2 is connected to the positive input end of the optocoupler 201, the negative input end of the optocoupler 201 is used as the second end f of the first voltage detection unit 105 and is connected to the second end d of the brake coil L1, and the first output end and the second output end of the optocoupler 201 are connected to the microcontroller 202.

[0051] Specifically, taking the second voltage detection unit 106 as an example, the second voltage detection unit 106 includes a second resistor R2, an optocoupler 201, and a microcontroller 202; the first end of the second resistor R2 serves as the first end e of the second voltage detection unit 106 and is connected to the first end a of the first resistor R1, the second end of the second resistor R2 is connected to the positive input terminal of the optocoupler 201, the negative input terminal of the optocoupler 201 serves as the second end f of the second voltage detection unit 106 and is connected to the second end b of the first resistor R1, and the first output terminal and the second output terminal of the optocoupler 201 are connected to the microcontroller 202.

[0052] In this embodiment, by providing the second resistor R2, the optocoupler 201, and the microcontroller 202 in the first voltage detection unit 105 and the second voltage detection unit 106, the first voltage across the cd terminals of the brake coil L1 and the second voltage across the ab terminals of the first resistor R1 are obtained. The main control unit can control the working states of the PWM output control unit 102 and the freewheeling control unit 104 according to the conditions of the first voltage across the cd terminals of the electric brake coil L1 and the second voltage across the ab terminals of the first resistor R1.

[0053] Specifically, the optocoupler 201 includes a light-emitting diode D1 and a photosensitive triode Q; the anode of the light-emitting diode D1 serves as the positive input terminal of the optocoupler 201, and the cathode of the light-emitting diode D1 serves as the negative input terminal of the optocoupler 201; the light-emitting diode D1 is disposed opposite to the base B of the photosensitive triode Q, and the emitter and collector of the photosensitive triode Q serve as the first output terminal and the second output terminal of the optocoupler 201, respectively.

[0054] Specifically, when the first end and the second end of the first voltage detection unit 105 are connected to the cd terminals of the brake coil L1, when the electrical signals across the cd terminals of the brake coil L1 are sent to the positive input terminal and the negative input terminal of the optocoupler 201 through the second resistor R2, the light-emitting diode D1 emits light by passing through current, the photosensitive triode Q generates current after being illuminated, and the collector C and the emitter E of the photosensitive triode Q are turned on; the microcontroller 202 can determine the first voltage across the cd terminals of the brake coil L1 according to the conduction condition of the CE of the photosensitive triode Q and then send it to the main control unit. The main control unit determines whether the first voltage across the cd terminals of the brake coil L1 exceeds a preset range. If it exceeds, it is determined that the negative side is grounded. The main control unit can control the freewheeling control unit 104 to turn off, so that the voltage on the positive side is cut off, protecting the entire brake circuit, preventing the brake from being powered on, making the elevator system in the brake state, and the elevator stops running, solving the problem of car slipping caused by the continuous lifting of the brake due to the grounding of the negative side.

[0055] Specifically, when the first end and the second end of the second voltage detection unit 106 are connected to the two ends ab of the first resistor R1, when the electrical signal at the two ends ab of the first resistor R1 is sent to the positive input terminal and the negative input terminal of the optocoupler 201 through the second resistor R2, the light-emitting diode D1 emits light due to the passing of current. When the photosensitive triode Q is illuminated, a current is generated, and the CE of the photosensitive triode Q conducts; the microcontroller 202 can determine the second voltage at the two ends ab of the first resistor R1 according to the conduction condition of the CE of the photosensitive triode Q, and then send it to the main control unit. The main control unit determines whether the second voltage at the two ends ab of the first resistor R1 exceeds the preset range. If it exceeds, it is determined that the positive electrode side is grounded. The main control unit can control the turn-on or turn-off of the freewheeling control unit 104. The main control unit can control the PWM output control unit 102 to turn off, or control the freewheeling control unit 104 to turn off, so that the brake loses power, the elevator system is in the brake state, and the elevator stops running, thereby discovering and detecting the problem that the brake release does not start due to the positive electrode grounding.

[0056] Specifically, the input impedance of the optocoupler 201 is very small, only a few hundred ohms. Even if the amplitude of the interference voltage is large, the noise voltage fed to the input terminal of the optocoupler 201 will be very small, and only a very weak current can be formed. Since there is not enough energy to make the diode emit light, it is suppressed; there is no electrical connection between the input circuit and the output circuit of the optocoupler 201, nor is there a common ground. The distributed capacitance between them is extremely small, and the insulation resistance is very large. Therefore, various interference signals on one side of the circuit are difficult to be fed to the other side through the optocoupler 201, avoiding the generation of interference signals of common impedance coupling; therefore, the optocoupler 201 can effectively suppress sharp pulses and various noise interferences while transmitting signals, greatly improving the signal-to-noise ratio of the signals on the channel, and improving the accuracy of the first voltage detection unit 105 and the second voltage detection unit 106 in obtaining voltage information. In addition, the response speed of the optocoupler 201 is extremely fast, and its response delay time is only about 10 us, improving the response speed of the brake control circuit.

[0057] In one embodiment, as Figure 3 shown, the brake control circuit further includes an overvoltage protection unit 107; the overvoltage protection unit 107 is arranged between the negative output terminal N of the power supply AC and the negative input terminal of the freewheeling unit 103.

[0058] Specifically, the overvoltage protection unit 107 is a fuse. In other embodiments, the overvoltage protection unit 107 can also be a relay, etc. In this embodiment, by setting the overvoltage protection unit 107, when the voltage of the AC power supply AC is too large, the power supply can be cut off in time to avoid damage to each device in the brake control circuit and the brake coil L1 caused by too high voltage, and improve the stability of the brake control circuit.

[0059] Another aspect of the embodiments of the present application further provides a circuit board assembly, including: the brake control circuit of any one of the above embodiments.

[0060] It is not difficult to find that this embodiment is a circuit board assembly embodiment corresponding to the circuit embodiment, and this embodiment can be implemented in cooperation with the circuit embodiment. The relevant technical details mentioned in the circuit embodiment are still valid in this embodiment. To avoid repetition, they will not be elaborated here. Correspondingly, the relevant technical details mentioned in this embodiment can also be applied to the circuit embodiment.

[0061] In addition, in order to highlight the innovative part of the present application, units that are not closely related to solving the technical problems proposed by the present application are not introduced in this embodiment, but this does not mean that there are no other units in this embodiment.

[0062] Another aspect of the embodiments of the present application further provides an electronic device, including: the circuit board assembly of the above embodiment.

[0063] The above division of various components is only for clear description. When implemented, they can be combined into one component or some components can be split into multiple components. As long as the same logical relationship is included, they are all within the protection scope of this patent.

[0064] Those of ordinary skill in the art can understand that the above embodiments are specific embodiments for implementing the present application. In actual applications, various changes can be made to them in form and details without departing from the spirit and scope of the present application.

Claims

1. A brake control circuit, characterized in that, Comprising: A rectification unit, a PWM output control unit, a freewheeling unit, a freewheeling control unit, a first resistor, a first voltage detection unit, a second voltage detection unit, and a main control unit; The positive input terminal and the negative input terminal of the rectification unit are configured to be connected to the positive output terminal and the negative output terminal of a power supply. The positive output terminal of the rectification unit is connected to the input terminal of the freewheeling unit, and the negative output module of the rectification unit is connected to the input terminal of the PWM output control unit; The output terminal of the freewheeling unit is connected to the input terminal of the freewheeling control unit. The output terminal of the freewheeling control unit is connected to the first end of the first resistor, and the second end of the first resistor is connected to the first end of a brake coil. The output terminal of the PWM output control unit is connected to the second end of the brake coil; The first end and the second end of the first voltage detection unit are respectively connected to the first end and the second end of the brake coil. The first end and the second end of the second voltage detection unit are respectively connected to the first end and the second end of the first resistor; The main control unit is connected to the first voltage detection unit and the second voltage detection unit. The main control unit is further connected to the control terminal of the PWM output control unit and the control terminal of the freewheeling control unit.

2. The brake control circuit according to claim 1, wherein Both the first voltage detection unit and the second voltage detection unit include a second resistor, an optocoupler, and a microcontroller. The first end of the second resistor serves as the first end of the first voltage detection unit or the second voltage detection unit. The second end of the second resistor is connected to the positive input terminal of the optocoupler. The negative input terminal of the optocoupler serves as the second end of the first voltage detection unit or the second voltage detection unit. The first output terminal and the second output terminal of the optocoupler are connected to the microcontroller.

3. The brake control circuit according to claim 2, wherein The optocoupler includes a light-emitting diode and a photosensitive triode; The anode of the light-emitting diode serves as the positive input terminal of the optocoupler, and the cathode of the light-emitting diode serves as the negative input terminal of the optocoupler. The light-emitting diode is disposed opposite to the base of the photosensitive triode. The emitter and the collector of the photosensitive triode respectively serve as the first output terminal and the second output terminal of the optocoupler.

4. The brake control circuit according to claim 1, wherein The brake control circuit further includes an overvoltage protection unit; the overvoltage protection unit is disposed between the negative output terminal of the power supply and the negative input terminal of the freewheeling unit.

5. The brake control circuit according to any one of claims 1 to 4, characterized in that The PWM output control unit includes a first MOS transistor. The control terminal of the first MOS transistor serves as the control terminal of the PWM output control unit. The input terminal of the first MOS transistor serves as the input terminal of the PWM output control unit. The output terminal of the first MOS transistor serves as the output terminal of the PWM output control unit.

6. The brake control circuit according to any one of claims 1 to 4, characterized in that, The freewheeling control unit includes a second MOS transistor. The control terminal of the second MOS transistor serves as the control terminal of the freewheeling control unit. The input terminal of the second MOS transistor serves as the input terminal of the freewheeling control unit. The output terminal of the second MOS transistor serves as the output terminal of the freewheeling control unit.

7. The brake control circuit according to claim 1, wherein The freewheeling unit is a diode, the anode of the diode serves as the input end of the freewheeling unit, and the cathode of the diode serves as the output end of the freewheeling unit.

8. The brake control circuit according to claim 1, wherein, The rectifying unit is a bridge rectifier.

9. A circuit board assembly, characterized in that, Comprising: The brake control circuit according to any one of claims 1-8.

10. An electronic device, characterized in that, Comprising: The circuit board assembly according to claim 9.

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