Residual voltage discharge circuit of power plug

Abstract

The utility model discloses a power plug residual voltage discharge circuit, comprising an MCU, a rectification filter circuit, a silicon controlled rectifier and a motor coil, the MCU is connected with the rectification filter circuit, the silicon controlled rectifier is controlled by the MCU, and the motor coil is connected with the silicon controlled rectifier; and when the MCU detects a zero-crossing signal of the rectification filter circuit, the silicon controlled rectifier is conducted, so that the residual voltage of the power supply is discharged through the motor coil. Because the voltage is discharged through the motor coil, the circuit is simple, the purpose of rapid discharge can be achieved, a special discharge chip is not needed, and the cost is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of circuits, in particular to a residual voltage discharge circuit for a power plug. Background Art

[0002] According to safety regulations, after the power plug of an appliance is unplugged from the socket, the residual voltage between the plugs needs to be discharged to below 34V after 1S. Currently, the voltage is basically discharged through a discharge resistor in the market. In order to achieve rapid power-off, the resistance value is selected as small as possible, but this will result in a large power consumption during standby, even exceeding 0.5W, so a dedicated discharge chip must be used, and the cost of a dedicated discharge chip is relatively high. Utility Model Content

[0003] The utility model aims to overcome the deficiencies of the prior art and provide a residual voltage discharge circuit for a power plug, so as to achieve rapid pressure relief for the power plug under the premise of reducing costs.

[0004] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0005] The utility model provides a residual voltage discharge circuit of a power plug, comprising an MCU, a rectifier and a filter circuit, a thyristor and a motor coil, wherein the MCU is connected to the rectifier and filter circuit, the thyristor is controlled by the MCU, and the motor coil is connected to the thyristor; when the MCU detects a zero-crossing signal of the rectifier and filter circuit, the thyristor is turned on to discharge the residual voltage of the power supply via the motor coil.

[0006] Furthermore, the internal resistance of the motor coil is less than 100 ohms.

[0007] Furthermore, it also includes a current amplification circuit, which includes a transistor Q1, a base of the transistor Q1 is connected to the MCU, a collector of the transistor Q1 is connected to the thyristor, and an emitter of the transistor Q1 is grounded.

[0008] Furthermore, the rectifying and filtering circuit includes a current limiting unit and a rectifying unit, the current limiting unit is connected to the ACN wire, the rectifying unit is connected to the current limiting unit, the ACL wire is connected to the rectifying unit, and the MCU is connected to the current limiting unit and the rectifying unit.

[0009] Furthermore, the current limiting unit includes a resistor R3, a resistor R5 and a resistor R6, one end of the resistor R3 is connected to the ACN wire, the other end of the resistor R3 is connected to one end of the resistor R5, the other end of the resistor R5 is connected to one end of the resistor R6, and the other end of the resistor R6 is connected to the rectifier unit.

[0010] Furthermore, the rectifier unit includes a first diode and a second diode, the anode of the first diode is grounded, the cathode of the first diode is connected to the anode of the second diode, the cathode of the second diode is connected to the ACL wire, and the MCU is connected to the cathode of the first diode and the anode of the second diode.

[0011] Furthermore, a capacitor C10 is connected in parallel between both ends of the resistor R5.

[0012] Furthermore, the rectification and filtering circuit further includes a capacitor C11, one end of the capacitor C11 is connected to the other end of the resistor R6, and the other end of the capacitor C11 is grounded.

[0013] Furthermore, the rectification and filtering circuit further includes a fuse F1, one end of the fuse F1 is connected to the ACL wire, and the other end of the fuse F1 is connected to the cathode of the second diode.

[0014] Compared with the prior art, the utility model has the following beneficial effects: the residual voltage discharge circuit of the power plug includes an MCU, a rectifier filter circuit, a thyristor and a motor coil, the MCU is connected to the rectifier filter circuit, the thyristor is controlled by the MCU, and the motor coil is connected to the thyristor; when the MCU detects a zero-crossing signal of the rectifier filter circuit, the thyristor is turned on to discharge the residual voltage of the power supply through the motor coil. Since the voltage is discharged through the motor coil, the circuit is simple, and the purpose of rapid discharge can be achieved, and there is no need to set a dedicated discharge chip, which reduces the cost.

[0015] The above description is only an overview of the technical solution of the utility model. In order to more clearly understand the technical means of the utility model, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the utility model more obvious and easy to understand, the following preferred embodiments are specifically cited and described in detail as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 A circuit schematic diagram of a residual voltage discharge circuit for a power plug provided in a specific embodiment of the utility model. DETAILED DESCRIPTION

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

[0019] It should be understood that when used in this specification and claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or collections thereof.

[0020] It should also be understood that the terms used in the utility model specification are only for the purpose of describing specific embodiments and are not intended to limit the utility model. As used in the utility model specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0021] It should be further understood that the term “and / or” used in the present specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0022] The embodiment of the utility model provides a power plug residual voltage discharge circuit, which is mainly used in electrical equipment with motors, such as vacuum cleaners, blenders, etc., to achieve rapid discharge of residual voltage in the power plugs of these electrical equipment. The utility model is introduced below through specific embodiments.

[0023] like Figure 1 As shown, the residual voltage discharge circuit of the power plug includes an MCU, a rectifier filter circuit, a thyristor and a motor coil. The MCU is connected to the rectifier filter circuit, the thyristor is controlled by the MCU, and the motor coil is connected to the thyristor. When the MCU detects a zero-crossing signal of the rectifier filter circuit, the thyristor is turned on to discharge the residual voltage of the power supply through the motor coil. Since the voltage is discharged through the motor coil, the circuit is simple and can achieve the purpose of rapid discharge, and there is no need to set up a dedicated discharge chip, which reduces the cost.

[0024] In this embodiment, if Figure 1 As shown, Figure 1U1 in the figure is MCU, and the model used is CMS79F111, which has low cost. Of course, in other embodiments, MCUs with the same functions and effects as CMS79F111 can also be used, for example, CMS79F112, CMS79F113, CMS79F116, etc.

[0025] Furthermore, the internal resistance of the motor coil is less than 100 ohms. Figure 1 In the figure, M1 indicates the motor. This design can help the energy transmitted to the motor coil by the thyristor to be converted into heat energy and released more quickly, so as to achieve faster pressure relief.

[0026] Furthermore, if Figure 1 As shown, the residual voltage discharge circuit of the power plug also includes a current amplification circuit, which includes a transistor Q1, the base of which is connected to the MCU, the collector of which is connected to the thyristor, and the emitter of which is grounded. Since the driving current of the thyristor is generally not large, in order to enable the thyristor to have sufficient driving current to meet the requirements of the motor coil for piezoelectric discharge, a current amplification circuit is designed, which amplifies the current and then conducts it to the thyristor.

[0027] Furthermore, if Figure 1 As shown, the rectifier filter circuit includes a current limiting unit and a rectifier unit, the current limiting unit is connected to the ACN wire, the rectifier unit is connected to the current limiting unit, the ACL wire is connected to the rectifier unit, and the MCU is connected to the current limiting unit and the rectifier unit. The function of the current limiting unit is to limit the amount of current passing through the circuit to protect the circuit from damage by excessive current. The function of the rectifier unit is to convert the positive half-wave of the alternating current into direct current.

[0028] Specifically, the current limiting unit includes a resistor R3, a resistor R5, and a resistor R6, one end of the resistor R3 is connected to the ACN wire, the other end of the resistor R3 is connected to one end of the resistor R5, the other end of the resistor R5 is connected to one end of the resistor R6, and the other end of the resistor R6 is connected to the rectifying unit. The rectifying unit includes a first diode and a second diode, the anode of the first diode is grounded, the cathode of the first diode is connected to the anode of the second diode, the cathode of the second diode is connected to the ACL wire, and the MCU is connected to the cathode of the first diode and the anode of the second diode.

[0029] like Figure 1 As shown, in this embodiment, a capacitor C10 is connected in parallel between both ends of the resistor R5.

[0030] like Figure 1 As shown, in this embodiment, the rectification and filtering circuit further includes a capacitor C11, one end of the capacitor C11 is connected to the other end of the resistor R6, and the other end of the capacitor C11 is grounded.

[0031] Furthermore, the rectifier filter circuit also includes a fuse F1, one end of the fuse F1 is connected to the ACL wire, and the other end of the fuse F1 is connected to the cathode of the second diode. The fuse F1 serves as a safety device. When the current is too large, the fuse will melt and disconnect the circuit to prevent the circuit from being damaged.

[0032] The working principle of the whole circuit is as follows: Figure 1 As shown, the AC power supply passes through U1, L1 / L2 inductors, R3 resistor current limiting, C7 / C8 / C9 filtering, and finally provides a stable 5V voltage for the entire circuit. When ACN is a positive half-wave, the current flows from ACN through R3->R5->R6->D1->5V->F1->ACL. The MCU detects the ZERO signal (zero point signal) to determine whether the power line is disconnected. When the power line is disconnected, the OUT output signal is controlled, and the thyristor TR1 is turned on. At this time, the plug voltage is discharged through the coil internal resistance of the AC Motor, and finally the purpose of rapid voltage discharge is achieved.

[0033] The above is only a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the utility model, and these modifications or replacements should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. The power plug residual voltage discharge circuit is characterized by: It includes an MCU, a rectifier and a filter circuit, a thyristor and a motor coil, wherein the MCU is connected to the rectifier and filter circuit, the thyristor is controlled by the MCU, and the motor coil is connected to the thyristor; When the MCU detects the zero-crossing signal of the rectifier and filter circuit, the thyristor is turned on to discharge the residual voltage of the power supply through the motor coil.

2. The power plug residual voltage discharge circuit according to claim 1, characterized in that: The internal resistance of the motor coil is less than 100 ohms.

3. The power plug residual voltage discharge circuit according to claim 1, characterized in that: It also includes a current amplifying circuit, which includes a transistor Q1, a base of the transistor Q1 is connected to the MCU, a collector of the transistor Q1 is connected to the thyristor, and an emitter of the transistor Q1 is grounded.

4. The power plug residual voltage discharge circuit according to claim 1, characterized in that: The rectifying and filtering circuit comprises a current limiting unit and a rectifying unit, the current limiting unit is connected to the ACN wire, the rectifying unit is connected to the current limiting unit, the ACL wire is connected to the rectifying unit, and the MCU is connected to the current limiting unit and the rectifying unit.

5. The power plug residual voltage discharge circuit according to claim 4, characterized in that: The current limiting unit includes a resistor R3, a resistor R5 and a resistor R6, one end of the resistor R3 is connected to the ACN wire, the other end of the resistor R3 is connected to one end of the resistor R5, the other end of the resistor R5 is connected to one end of the resistor R6, and the other end of the resistor R6 is connected to the rectifying unit.

6. The power plug residual voltage discharge circuit according to claim 4, characterized in that: The rectifier unit includes a first diode and a second diode, the anode of the first diode is grounded, the cathode of the first diode is connected to the anode of the second diode, the cathode of the second diode is connected to the ACL wire, and the MCU is connected to the cathode of the first diode and the anode of the second diode.

7. The power plug residual voltage discharge circuit according to claim 5, characterized in that: The two ends of the resistor R5 are connected in parallel with a capacitor C10.

8. The power plug residual voltage discharge circuit according to claim 5, characterized in that: The rectification and filtering circuit further includes a capacitor C11, one end of the capacitor C11 is connected to the other end of the resistor R6, and the other end of the capacitor C11 is grounded.

9. The power plug residual voltage discharge circuit according to claim 6, characterized in that: The rectification and filtering circuit further includes a fuse F1 , one end of the fuse F1 is connected to the ACL wire, and the other end of the fuse F1 is connected to the cathode of the second diode.

Images