Multi-winding electromagnetic lock driving circuit

Abstract

The invention provides a multi-winding electromagnetic lock driving circuit, which belongs to the technical field of electromagnetic lock driving, and is characterized in that the input end and the output end of a first electromagnetic lock coil are respectively connected with the positive output end and the ground end of a power supply; the input end and the output end of the second electromagnetic lock coil are respectively connected with the positive output end and the ground end of the power supply; the switching circuit is used for controlling connection and disconnection of the first electromagnetic lock coil, the second electromagnetic lock coil and the power supply connecting circuit; the control module circuit is used for controlling the switching circuit, so that the plurality of first electromagnetic lock coils and the second electromagnetic lock coil are communicated with the power supply connecting circuit in a lock lifting stage of the electromagnetic lock, and the plurality of first electromagnetic lock coils and the second electromagnetic lock coil simultaneously generate suction force to lift the lock pin; and in the keeping stage of the electromagnetic lock, the multiple first electromagnetic lock coils are disconnected from the power supply connecting circuit, and the second electromagnetic lock coils are connected with the power supply connecting circuit to generate suction force to keep the lifting state of the lock pin. The circuit can prolong the service life of the electromagnetic lock.

Description

Technical Field

[0001] The invention belongs to the technical field of electromagnetic lock driving, and in particular relates to a multi-winding electromagnetic lock driving circuit. Background Art

[0002] Electromagnetic locks are widely used in the field of security protection. Their efficient and simple working principle provides reliable locking solutions for many places. When the electromagnetic lock receives a power-on signal, the current will quickly pass through its internal coil, generating a strong electromagnetic suction force, which is enough to easily lift the lock pin and unlock the door or other locked objects, allowing the door or other locked objects to be opened freely. Once the power is disconnected, the electromagnetic force disappears, and the lock pin returns to its original position and falls under the tension of the pre-set spring, firmly locking the door or other locked objects again.

[0003] However, in the prior art, when the electromagnetic lock is working, its coil will generate obvious heat due to the passage of current. This heat will not only affect the working stability of the electromagnetic lock, but also the long-term heat accumulation may cause damage to the materials inside the electromagnetic lock, such as aging of the coil insulation layer, deformation of metal parts, etc., thereby shortening the service life of the electromagnetic lock. Summary of the invention

[0004] In order to overcome the above-mentioned deficiencies in the prior art, the present invention provides a multi-winding electromagnetic lock driving circuit.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A multi-winding electromagnetic lock driving circuit, comprising:

[0007] power supply;

[0008] A plurality of first electromagnetic lock coils, wherein the input end and the output end of the first electromagnetic lock coil are respectively connected to the positive output end of the power supply and the ground end;

[0009] A second electromagnetic lock coil, wherein the input end and the output end of the second electromagnetic lock coil are respectively connected to the positive output end of the power supply and the ground end;

[0010] A switch circuit is provided on the first electromagnetic lock coil, the second electromagnetic lock coil and the power supply connection line; and is used to control the on-off of the first electromagnetic lock coil, the second electromagnetic lock coil and the power supply connection line;

[0011] A control module circuit, whose output end is connected to the input end of the switch circuit, is used to control the switch circuit; so that in the lifting stage of the electromagnetic lock, multiple first electromagnetic lock coils and second electromagnetic lock coils are connected to the power connection circuit, and multiple first electromagnetic lock coils and second electromagnetic lock coils simultaneously generate suction to lift the lock pin; and in the holding stage of the electromagnetic lock, multiple first electromagnetic lock coils are disconnected from the power connection circuit, and the second electromagnetic lock coils are connected to the power connection circuit to generate suction to keep the lock pin in the lifted state.

[0012] Furthermore, it also includes: a third electromagnetic lock coil, whose input end and output end are respectively connected to the positive output end of the power supply and the ground end;

[0013] A switch circuit is provided on the connection line between the third electromagnetic lock coil and the power supply;

[0014] A sampling resistor is provided on the connection line between the first electromagnetic lock coil and the second electromagnetic lock coil and the power supply;

[0015] A sampling circuit, whose input end is connected to both ends of the sampling resistor; used for sampling the voltage at both ends of the resistor and outputting it;

[0016] The input end of the control module circuit is connected to the output end of the sampling circuit, and is used to control the switch circuit to connect the connection line between the third magnetic lock coil and the power supply when the voltage across the sampling resistor of the circuit where the first electromagnetic lock coil and the second electromagnetic lock coil are located is lower than the threshold.

[0017] Further, the sampling circuit comprises:

[0018] The operational amplifier has its positive and negative input terminals connected to the two ends of the sampling resistor; and its output terminal connected to the input terminal of the control module.

[0019] Furthermore, the power supply outputs 36V direct current to the first electromagnetic lock coil, the second electromagnetic lock coil, the third electromagnetic lock coil and the input end of the operational amplifier.

[0020] Furthermore, the power supply outputs 1.65V direct current to the input end of the current sampling circuit; and outputs 3.3V direct current to the input end of the control module circuit.

[0021] Further, the switch circuit comprises:

[0022] An N-channel MOSFET transistor, whose source is connected to the output ends of the first electromagnetic lock coil and the second electromagnetic lock coil; and whose drain is grounded;

[0023] NPN transistor; its collector is connected to the gate of N-channel MOSFET transistor; the emitter is grounded; the base is connected to the control signal;

[0024] The Schottky diode has an input end connected to the output ends of the first electromagnetic lock coil and the second electromagnetic lock coil, and an output end connected to the input ends of the first electromagnetic lock coil and the second electromagnetic lock coil.

[0025] Furthermore, it also includes: an NTC temperature measurement circuit, whose output end is connected to the input end of the control module; and the NTC temperature measurement circuit includes: an NTC thermistor, sampling its voltage to obtain the internal temperature of the electromagnetic lock, when the temperature is too high, the control module controls the LED light to emit a prompt.

[0026] Furthermore, it also includes: a feedback detection circuit, whose input end is connected to the auxiliary contact of the electromagnetic lock, and whose output end is connected to the input end of the control module.

[0027] Furthermore, it also includes: an alarm prompt circuit, whose input end is connected to the output end of the control module; and the alarm prompt circuit includes: an LED light, whose input end is connected to the output end of the control module and whose output end is grounded; when the first electromagnetic lock coil and the second electromagnetic lock coil fail, the internal temperature of the electromagnetic lock is too high, and the auxiliary contact fails, the control module controls the LED light to emit light and issue a prompt.

[0028] Furthermore, the CPU control module is a single chip microcomputer or ARM or DSP.

[0029] The multi-winding electromagnetic lock driving circuit provided by the present invention has the following beneficial effects:

[0030] Since the electromagnetic lock requires a large power to lift the lock pin during the lock lifting stage, only a small power is required to maintain the lifted state after the lock lifting is completed. If the electromagnetic lock has the same power during the lock lifting stage and the holding stage, the coil of the electromagnetic lock will have obvious heat generation, high energy consumption, and will increase the service life of the electromagnetic lock. Therefore, the present invention uses multiple first electromagnetic lock coils and second electromagnetic lock coils to simultaneously generate suction to lift the lock pin during the lock lifting stage of the electromagnetic lock, and uses the second electromagnetic lock coil to generate suction to maintain the lifted state of the lock pin during the holding stage of the electromagnetic lock; since the first electromagnetic lock coil is disconnected during the holding stage of the electromagnetic lock, only the second electromagnetic lock coil operates with lower energy consumption, thereby fully reducing the heating of the electromagnetic lock coil and increasing the service life of the electromagnetic lock. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiment of the present invention and its design scheme, the following briefly introduces the drawings required for this embodiment. The drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 It is a circuit module diagram of the present invention;

[0033] Figure 2 A multi-winding electromagnetic lock driving circuit diagram of the present invention;

[0034] Figure 3 The CPU output drive signal Channel1-4 waveform diagram of the present invention;

[0035] Figure 4 It is the voltage difference between the two ends of electromagnetic lock coil 1-4. DETAILED DESCRIPTION

[0036] In order to enable those skilled in the art to better understand the technical solution of the present invention and implement it, the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the scope of protection of the present invention.

[0037] In addition, the terms "first", "second", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance. In the description of the present invention, it should be noted that, unless otherwise clearly specified or limited, the terms "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. In the description of the present invention, unless otherwise specified, "plurality" means two or more, which will not be described in detail here.

[0038] The present invention provides a multi-winding electromagnetic lock driving circuit, specifically Figure 1-Figure 4 As shown, it includes: a voltage conversion circuit, a current sampling circuit, a MOS drive circuit, a safety margin circuit, an NTC temperature measurement circuit, a feedback detection circuit, an alarm prompt circuit, and a CPU control circuit.

[0039] The voltage conversion circuit includes input DC voltage D36V, GND, Schottky diode D1, resistor R1, capacitors C1-C12, and power chips U1-U3. 36V DC acts on the electromagnetic lock coil and operational amplifier; the power chip U2 generates 1.65V DC to act on the current sampling circuit; the power chip U3 generates 3.3V DC to power the CPU and protect the IO port at the same time.

[0040] The current sampling circuit includes the first electromagnetic lock coil and the second electromagnetic lock coil 1-3, sampling resistors 1-3, resistors R14-R25, operational amplifiers U4-U6, and diodes D2-D7. The current on the sampling resistor is converted into a 0-3V voltage value ADC1-3 by the operational amplifier, and after being processed by the CPU, it can be determined whether the electromagnetic lock coil 1-3 is open.

[0041] The MOS driving circuit includes R2-R13, NPN transistors Q1-Q3, N-channel MOSFET transistors Q4-Q6, and Schottky diodes D8-D10. The driving signal Channel1-3 output by the CPU controls the working state of the electromagnetic lock coil 1-3 through the MOS driving circuit.

[0042] The safety margin circuit includes the third electromagnetic lock coil 4, resistors R26-R29, NPN transistor Q7, N-channel MOSFET transistor Q8, and Schottky diode D11. When a fault occurs in one of the electromagnetic lock coils 1-3, the electromagnetic lock coil 4 is driven to work, thereby maintaining the normal function of the electromagnetic lock.

[0043] The present invention utilizes the third electromagnetic lock coil as a safety margin circuit. When the sampling circuit detects that the voltage across the sampling resistor of the circuit where the first electromagnetic lock coil and the second electromagnetic lock coil are located is lower than a threshold value, the control module is used to control the third electromagnetic lock coil to be turned on, so as to prevent the electromagnetic lock drive circuit from malfunctioning, ensure the normal function of the electromagnetic lock, and improve the reliability of the electromagnetic lock.

[0044] The NTC temperature measurement circuit includes resistor R31, thermistor NTC and capacitor C13. Resistor R31 is used for voltage division and current limiting; sampling the voltage of thermistor NTC can obtain the internal temperature of the electromagnetic lock; capacitor C13 is used for filtering. When the internal temperature of the electromagnetic lock is too high, the control module controls the LED light to emit a prompt.

[0045] The feedback detection circuit includes resistors R32, R33 and R34, which are used for voltage division. When the current sampling circuit detects the current, but the feedback detection circuit outputs a low level, it indicates that the auxiliary contact has a fault.

[0046] The alarm prompt circuit includes a resistor R30 and an LED, which is used to issue a prompt when a fault occurs in the electromagnetic lock coils 1-3, when the internal temperature of the electromagnetic lock is too high, or when a fault occurs in the auxiliary contact.

[0047] The CPU control circuit includes the main control chip U7, which is used to process the sampling current signal, feedback detection circuit signal, NTC temperature data, alarm signal and output the driving signal of the electromagnetic lock coil. The CPU can be a single-chip microcomputer, ARM, DSP, etc.

[0048] The working principle of the circuit of the present invention is:

[0049] When the electromagnetic lock needs to be lifted, the control module sends a lock-lifting signal, and the electromagnetic lock inputs a DC 36V voltage, and obtains a DC 3.3V voltage through the power chip U2 for CPU power supply and IO port protection, and obtains a DC 1.65V voltage through the power chip U3 for the DC bias of the operational amplifier; after the CPU is started, Channel1-3 outputs a low level, the NPN transistor is cut off, and the gate voltage of the N-channel MOSFET transistor Q4-Q6 is the voltage after the DC 36V is divided, so that the MOSFET Q4-Q6 is turned on, at this time, the voltage difference between the two ends of the electromagnetic lock coil 1-3 is approximately 36V, and the electromagnetic lock is in the lock-lifting state. At the same time, the current of the sampling resistor 1-3 is converted into a 0-3.3V voltage value ADC1-3 through the sampling circuit and transmitted to the CPU. After processing by the CPU, the current value of the electromagnetic lock coil 1-3 is obtained; if valid current is detected in all three channels, Channel1 maintains a low level after time t, and Channel2 and Channel3 output a high level. At this time, the voltage difference between the two ends of the electromagnetic lock coil 1 is approximately 36V, and the voltage difference between the two ends of the electromagnetic lock coil 2 and 3 is approximately 0V, and the electromagnetic lock is in the holding state, which reduces the electromagnetic lock holding stage power; if no effective current is detected in a certain circuit, the safety margin circuit starts to work, Channel4 outputs a low level, the corresponding electromagnetic lock coil 4 works, and keeps Channel1-3 outputting a low level, so that all the coils that are not faulty work, and at the same time the CPU outputs an Error signal, the corresponding alarm circuit works, so that the electromagnetic lock can still work normally when a certain circuit of the electromagnetic lock coil fails; at the same time, the NTC temperature measurement circuit detects the internal temperature of the electromagnetic lock in real time, and the feedback detection circuit detects the state of the auxiliary contacts. When the internal temperature of the electromagnetic lock is too high or the auxiliary contacts fail, the alarm circuit works, thereby improving the reliability of the electromagnetic lock.

[0050] The embodiments described above are only preferred specific implementation modes of the present invention, and the protection scope of the present invention is not limited thereto. Any simple changes or equivalent replacements of the technical solutions that can be obviously obtained by any technician familiar with the field within the technical scope disclosed in the present invention belong to the protection scope of the present invention.

Claims

1. A multi-winding electromagnetic lock drive circuit, characterized in that: include: A plurality of first electromagnetic lock coils, wherein the input end and the output end of the first electromagnetic lock coil are respectively connected to the output end of an external power supply and a ground end; A second electromagnetic lock coil, wherein an input end and an output end of the second electromagnetic lock coil are respectively connected to an output end of an external power supply and a ground end; A switch circuit is provided on a connection line between the first electromagnetic lock coil, the second electromagnetic lock coil and an external power supply; Used to control the on / off of the first electromagnetic lock coil, the second electromagnetic lock coil and the power supply connection line; A control module circuit, whose output end is connected to the input end of the switch circuit, is used to control the switch circuit so that in the lock lifting stage of the electromagnetic lock, the plurality of first electromagnetic lock coils and the second electromagnetic lock coils are connected to the external power supply connection line, and the plurality of first electromagnetic lock coils and the second electromagnetic lock coils simultaneously generate suction to lift the lock pin; And in the holding stage of the electromagnetic lock, the plurality of first electromagnetic lock coils are disconnected from the external power connection circuit, and the second electromagnetic lock coils are connected to the external power connection circuit to generate suction to keep the lock pin in the lifted state.

2. A multi-winding electromagnetic lock driving circuit according to claim 1, characterized in that: Also includes: The third electromagnetic lock coil has an input end and an output end thereof connected to the output end of the power supply and the ground end respectively; A switch circuit is provided on the connection line between the third electromagnetic lock coil and the power supply; A sampling resistor is provided on the connection line between the first electromagnetic lock coil and the second electromagnetic lock coil and the power supply; A sampling circuit, whose input end is connected to both ends of the sampling resistor; used for sampling the voltage at both ends of the resistor and outputting it; The input end of the control module circuit is connected to the output end of the sampling circuit, and is used to control the switch circuit to connect the connection line between the third magnetic lock coil and the power supply when the voltage across the sampling resistor of the circuit where the first electromagnetic lock coil and the second electromagnetic lock coil are located is lower than the threshold.

3. A multi-winding electromagnetic lock driving circuit according to claim 2, characterized in that: The sampling circuit comprises: The operational amplifier has its positive and negative input terminals connected to the two ends of the sampling resistor; and its output terminal connected to the input terminal of the control module.

4. A multi-winding electromagnetic lock driving circuit according to claim 3, characterized in that: The power supply outputs 36V direct current to the first electromagnetic lock coil, the second electromagnetic lock coil, the third electromagnetic lock coil and the input end of the operational amplifier.

5. A multi-winding electromagnetic lock driving circuit according to claim 3, characterized in that: The power supply outputs 1.65V direct current to the input end of the current sampling circuit; and outputs 3.3V direct current to the input end of the control module circuit.

6. A multi-winding electromagnetic lock driving circuit according to claim 1, characterized in that: The switch circuit comprises: An N-channel MOSFET transistor, whose source is connected to the output ends of the first electromagnetic lock coil and the second electromagnetic lock coil; and whose drain is grounded; NPN transistor; its collector is connected to the gate of N-channel MOSFET transistor; the emitter is grounded; the base is connected to the control signal; The Schottky diode has an input end connected to the output ends of the first electromagnetic lock coil and the second electromagnetic lock coil, and an output end connected to the input ends of the first electromagnetic lock coil and the second electromagnetic lock coil.

7. A multi-winding electromagnetic lock driving circuit according to claim 1, characterized in that: Also includes: The NTC temperature measurement circuit has an output end connected to the input end of the control module; and the NTC temperature measurement circuit includes: an NTC thermistor, which obtains the internal temperature of the electromagnetic lock by sampling the voltage of the NTC thermistor. When the temperature is abnormal, the control module controls the LED light to emit a prompt.

8. The multi-winding electromagnetic lock driving circuit according to claim 1, characterized in that: Also includes: The feedback detection circuit has an input end connected to the auxiliary contact of the electromagnetic lock, and an output end connected to the input end of the control module.

9. A multi-winding electromagnetic lock driving circuit according to claim 1, characterized in that: Also includes: An alarm prompt circuit, whose input end is connected to the output end of the control module; And the alarm prompt circuit includes: an LED lamp, whose input end is connected to the output end of the control module, and whose output end is grounded; When the first electromagnetic lock coil and the second electromagnetic lock coil fail, the internal temperature of the electromagnetic lock is abnormal, or the auxiliary contact fails, the control module controls the LED light to emit a prompt.

10. A multi-winding electromagnetic lock driving circuit according to claim 1, characterized in that: The CPU control module is a single chip microcomputer.

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