阅读说明：本技术 一种电磁铁保护电路 (Electromagnet protection circuit ) 是由 刘冰 华坚 陆叶青 潘一鸣 于 2021-01-25 设计创作，主要内容包括：本发明提供了一种电磁铁保护电路,其可以避免当控制信号发生故障而导致电磁铁持续通电过热毁坏自身的情况发生,从而消除了安全隐患,避免造成人身危险；一种电磁铁保护电路,与控制电路的控制信号输入端相连接,所述电磁铁保护电路包括电磁铁L1,所述电磁铁保护电路还包括MOS管Q1、Q2、电阻R1～R3、电容C1,所述电磁铁L1的一端连接电源VCC,所述电磁铁L1的另一端连接所述MOS管Q1的漏极,所述MOS管Q1的栅极与所述电阻R1、R2的一端、MOS管Q2的漏极均相连接后接于所述控制电路的控制信号输入端,所述MOS管Q2的栅极与所述电阻R2的另一端、电容C1、电阻R3的一端均相连接,所述MOS管Q1、Q2的源极与所述电阻R1、R3、电容C1的另一端均相连接后接地。(The invention provides an electromagnet protection circuit which can avoid the situation that an electromagnet is continuously electrified and thermally destroyed when a control signal fails, thereby eliminating potential safety hazards and avoiding personal danger; the electromagnet protection circuit is connected with a control signal input end of a control circuit, comprises an electromagnet L1, and further comprises MOS (metal oxide semiconductor) tubes Q1 and Q2, resistors R1-R3 and a capacitor C1, wherein one end of the electromagnet L1 is connected with a power supply VCC, the other end of the electromagnet L1 is connected with a drain electrode of the MOS tube Q1, a grid electrode of the MOS tube Q1 is connected with one ends of the resistors R1 and R2 and a drain electrode of the MOS tube Q2 and then connected with the control signal input end of the control circuit, a grid electrode of the MOS tube Q2 is connected with the other end of the resistor R2, one ends of the capacitor C1 and the resistor R3, and source electrodes of the MOS tubes Q1 and Q2 are connected with the other ends of the resistors R1, R3 and the capacitor C1 and then grounded.)

1. An electromagnet protection circuit is connected with a control signal input end of a control circuit, and comprises an electromagnet L1, and is characterized in that: the electromagnet protection circuit further comprises MOS tubes Q1 and Q2, resistors R1-R3 and a capacitor C1, one end of the electromagnet L1 is connected with a power VCC, the other end of the electromagnet L1 is connected with the drain of the MOS tube Q1, the grid of the MOS tube Q1 is connected with one ends of the resistors R1 and R2 and the drain of the MOS tube Q2 and then connected with a control signal input end of the control circuit, the grid of the MOS tube Q2 is connected with the other end of the resistor R2, one ends of the capacitor C1 and the resistor R3, and the sources of the MOS tubes Q1 and Q2 are connected with the other ends of the resistors R1, R3 and the capacitor C1 and then grounded.

2. An electromagnet protection circuit as claimed in claim 1, wherein: the control circuit comprises a controller, the controller adopts an STM32F103RET6 single chip microcomputer, and the grid electrode of the MOS tube Q1 is connected with one end of the resistors R1 and R2 and the drain electrode of the MOS tube Q2 and then connected with a PA6 pin of the controller.

3. An electromagnet protection circuit as claimed in claim 1, wherein: the MOS tubes Q1 and Q2 are NMOS tubes.

4. An electromagnet protection circuit as claimed in claim 1, wherein: the electromagnet L1 is an electromagnet with rated voltage of 12V and electrified current of 3A.

Technical Field

The invention relates to the technical field of electronic circuits, in particular to an electromagnet protection circuit.

Background

The electromagnet is widely applied to various electronic circuit fields, and can be used for switching on and off of circuits, electronic switches of various mechanical structures and the like because the electromagnet generates attraction when being electrified and can convert electric energy into mechanical energy; however, if a proper protection circuit is not added to the commonly used electromagnet with a wound coil, when a control signal fails and a control circuit connected with the electromagnet is continuously conducted, a continuous current can flow through the electromagnet, so that the electromagnet is overheated to damage the electromagnet, and even personal danger is caused.

Disclosure of Invention

In view of the above problems, the present invention provides an electromagnet protection circuit, which can avoid the situation that when a control signal fails, an electromagnet is continuously electrified and thermally destroyed, thereby eliminating potential safety hazards and avoiding personal risks.

The technical scheme is as follows: an electromagnet protection circuit is connected with a control signal input end of a control circuit, and comprises an electromagnet L1, and is characterized in that: the electromagnet protection circuit further comprises MOS tubes Q1 and Q2, resistors R1-R3 and a capacitor C1, one end of the electromagnet L1 is connected with a power VCC, the other end of the electromagnet L1 is connected with the drain of the MOS tube Q1, the grid of the MOS tube Q1 is connected with one ends of the resistors R1 and R2 and the drain of the MOS tube Q2 and then connected with a control signal input end of the control circuit, the grid of the MOS tube Q2 is connected with the other end of the resistor R2, one ends of the capacitor C1 and the resistor R3, and the sources of the MOS tubes Q1 and Q2 are connected with the other ends of the resistors R1, R3 and the capacitor C1 and then grounded.

It is further characterized in that:

the control circuit comprises a controller, the controller adopts an STM32F103RET6 single chip microcomputer, and the grid electrode of the MOS tube Q1 is connected with one end of the resistors R1 and R2 and the drain electrode of the MOS tube Q2 and then connected with a PA6 pin of the controller;

the MOS tubes Q1 and Q2 are NMOS tubes;

the electromagnet L1 is an electromagnet with rated voltage of 12V and electrified current of 3A.

The invention has the advantages that when the input end of the control signal is in fault and continuously outputs a high-level control signal, the RC charging circuit consisting of the resistor R2 and the capacitor C1 can conduct the MOS transistor Q2 after a specific time, so that the grid of the MOS transistor Q1 is pulled down, the MOS transistor Q1 is not conducted, the electromagnet L1 is not electrified, and the function of protecting the electromagnet is achieved, thereby avoiding the situation that the electromagnet is continuously electrified and thermally damages the electromagnet when the control signal is in fault, eliminating the potential safety hazard, avoiding the personal danger and having better economic use value.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic circuit diagram of the present invention.

Detailed Description

The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

As shown in fig. 1, the electromagnet protection circuit of the present invention is connected to a control signal input end en of a control circuit, and includes an electromagnet L1, an MOS transistor Q1, Q2, resistors R1 to R3, and a capacitor C1, wherein an RC charging circuit is formed by the resistor R2 and the capacitor C1; one end of an electromagnet L1 is connected with a power supply VCC, the other end of the electromagnet L1 is connected with a drain electrode of an MOS tube Q1, a grid electrode of the MOS tube Q1 is connected with one ends of resistors R1 and R2 and a drain electrode of the MOS tube Q2, and then connected with a control signal input end en of a control circuit, a grid electrode of the MOS tube Q2 is connected with the other end of the resistor R2, one ends of a capacitor C1 and a resistor R3, and source electrodes of the MOS tubes Q1 and Q2 are connected with the other ends of the resistors R1, R3 and the capacitor C1, and then grounded.

The control circuit comprises a controller, the controller adopts a single chip microcomputer with the model number of STM32F103RET6, the electromagnet is controlled by the single chip microcomputer to output a control signal, the mode selection of the single chip microcomputer can be determined according to the actual situation, various implementation schemes can be used according to the mode selection of the single chip microcomputer, the specific connecting circuit is not the key point of the protection of the invention, the specific connecting circuit is not described in detail, and for technical personnel in the technical field of the invention, on the premise of not departing from the concept of the invention, a plurality of simple replacements and changes can be made, and the invention is considered to belong to the invention protection scope determined by the submitted claims; the gate of the MOS transistor Q1 is connected to one end of the resistors R1, R2 and the drain of the MOS transistor Q2 and then connected to the PA8 pin (i.e., the control signal input end en) of the controller; MOS tubes Q1 and Q2 are NMOS tubes; the electromagnet L1 adopts an electromagnet with rated voltage of 12V and electrified current of 3A; the resistor R2 is a patch resistor with the resistance value of 10K omega, and the capacitor C1 is a patch capacitor with the capacitance value of 0.1 muF.

The electromagnet L1 is composed of an electrified coil, generates magnetic force when electrified, and disappears when power is off, and because the resistance of the coil is very small, if the current is very large when electrified, overheating damage can occur when the coil is electrified for a long time; in the invention, the grid of the MOS tube Q1 is connected to the controller, when the control signal output by the controller is high level, the MOS tube Q1 is conducted, and the electromagnet L1 is electrified; when the control signal is at a low level, the MOS transistor Q1 is controlled to be closed, and the electromagnet L1 is powered off; when the controller breaks down, the control signal is high level all the time, and the RC charging circuit can switch on the MOS transistor Q2 after a certain time (determined by an RC charging constant, different charging time can be obtained by selecting proper resistance and capacitance values, for example, 1 second can be selected), so that the grid of the MOS transistor Q1 is pulled down, the MOS transistor Q1 is not switched on, the electromagnet L1 is not switched on, and the function of protecting the electromagnet is achieved.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.