Elevator external calling board driving circuit

Abstract

The utility model relates to an elevator external call board driving circuit, which comprises an MCU (Microprogrammed Control Unit), an anode driving circuit, a cathode driving circuit and a nixie tube, the MCU sends out a control signal for controlling the anode driving circuit and the cathode driving circuit; the MCU adopts serial communication, uses four chip pins, and outputs four control signals. And the anode driving circuit receives four control signals from the MCU, outputs three paths of signals, respectively drives three triodes, supplies power to the nixie tube through the triodes, and drives the anode of the nixie tube. And the cathode driving circuit receives four control signals from the MCU, controls and outputs 24 paths of signals through three digital chips, and the 24 paths of signals are connected to the cathode of the nixie tube through a driving resistor. The elevator external call board driving circuit provided by the utility model can provide large driving current, and is strong in circuit stability and high in cost performance.

Description

Technical Field

[0001] The utility model relates to the technical field of elevator control, in particular to a driving circuit for an elevator external call board. Background Art

[0002] The elevator external call is a calling system outside the elevator hall. It allows passengers to send calling instructions to the elevator by operating the specified buttons or panels outside the elevator, requesting the elevator to stop at the current floor. This system is an important means of interaction between the elevator and passengers. Through the elevator external call system, passengers can instruct the elevator to go up or down to meet their travel needs.

[0003] The operation of the elevator external call system depends on the real-time communication between the elevator main control board and the external call board on each floor. This communication usually uses a serial bus to ensure that the elevator can promptly respond to the call inputs from each floor and display corresponding information on the floor output. Each external call device has an independent address on the bus, so that devices can interact with each other according to their respective addresses, thereby realizing the elevator's response to the external call instructions.

[0004] The display panel of the elevator external call usually only shows the up or down arrow and the digital information of the current floor where the elevator is located. When it is necessary to display more content and increase the number of digital tubes, or when it is necessary to increase the display brightness of the digital tubes in special places, it is necessary to increase the driving current of the digital tubes. However, the traditional elevator external call driving circuit directly uses a digital chip for driving, and the driving current provided by the digital chip is relatively small, which is likely to cause the chip to be damaged due to overcurrent. Content of the Utility Model

[0005] The utility model aims to solve the deficiencies of the prior art and provides a driving circuit for an elevator external call board, which can provide a relatively large driving current, has strong circuit stability and high cost performance.

[0006] The utility model adopts the following technical solutions to achieve the above object:

[0007] A driving circuit for an elevator external call board includes an MCU, an anode driving circuit, a cathode driving circuit and a digital tube; the anode driving circuit and the cathode driving circuit are connected between the MCU and the digital tube.

[0008] The MCU issues control signals for controlling the anode driving circuit and the cathode driving circuit; the MCU uses serial communication and outputs four control signals with four chip pins.

[0009] The anode driving circuit receives the four control signals from the MCU, outputs three signals, respectively drives three triodes, and then supplies power to the digital tube through the triodes to drive the anode of the digital tube.

[0010] The cathode drive circuit receives four control signals from the MCU, passes through three digital chips, and controls the output of a total of twenty-four signals. The twenty-four signals are then connected to the cathodes of the digital tubes through drive resistors.

[0011] The digital tubes used are common-anode digital tubes. The digital tubes have three common anodes, and each common anode is respectively combined with the cathodes of twenty-four light-emitting diodes.

[0012] The anode drive circuit includes 595 chip U1, filter capacitor C1, drive resistors R2, R4, R6, zener diodes D1, D2, D3, resistors R1, R3, R5, transistors Q1, Q2, and Q3;

[0013] The 595 chip U1 is controlled to output through four control signals. The SQ1 signal at pin 9 is used for cascading with the 595 chip U2 of the cathode drive circuit; the 595 chip U1 outputs digital signals Ano1, Ano2, Ano3, which are respectively used to drive the bases of transistors Q1, Q2, Q3, with resistors R2, R4, R6 and zener diodes D1, D2, D3 connected in series in the middle.

[0014] The cathode drive circuit includes 595 chips U2, U3, U4, filter capacitors C2, C3, C4, and drive resistors R7 - R30;

[0015] The 595 chips U2, U3, and U4 are controlled to output through 4 control signals. The 14th pin of chip U2 is connected to the 9th pin of chip U1, the 9th pin of chip U2 is connected to the 14th pin of chip U3, and the 9th pin of chip U3 is connected to the 14th pin of chip U4, forming a cascade of four 595 chips in total; the digital signal outputs of the 595 chips U2, U3, and U4 are connected to the cathodes of the digital tubes, a total of twenty-four paths, with drive resistors R7 - R30 connected in series in the middle.

[0016] The beneficial effects of the present utility model are: An elevator external call board drive circuit provided by the present utility model can provide a relatively large drive current, has strong circuit stability, and high cost performance. Description of the Drawings

[0017] Figure 1 The main circuit block diagram of the elevator external call board drive circuit of the present utility model;

[0018] Figure 2 The circuit diagram of the anode drive circuit of the present utility model;

[0019] Figure 3 The circuit diagram of the cathode drive circuit of the present utility model;

[0020] Figure 4 Schematic diagram of the digital tube of the present utility model.

[0021] The following will be described in detail with reference to the accompanying drawings in conjunction with the embodiments of the present utility model. Specific embodiments

[0022] The principles and features of the present utility model will be described below with reference to the accompanying drawings. The embodiments cited are only used to explain the present utility model and are not intended to limit the scope of the present utility model. In the following paragraphs, the present utility model will be described more specifically by way of example with reference to the accompanying drawings. The advantages and features of the present utility model will be clearer according to the following description. It should be noted that the accompanying drawings are all in a very simplified form and use non-precise scales, and are only used to facilitate and clearly assist in explaining the purpose of the embodiments of the present utility model.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present utility model belongs. The terms used in the description of the present utility model herein are only for the purpose of describing specific embodiments and are not intended to limit the present utility model. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0024] The present utility model will be further described below in conjunction with the accompanying drawings and embodiments:

[0025] A drive circuit for an elevator external call board provided by the present utility model, as Figure 1 shown, includes an MCU, an anode drive circuit, a cathode drive circuit, and a digital tube. The anode drive circuit and the cathode drive circuit are connected between the MCU and the digital tube.

[0026] The MCU issues control signals and controls both the anode drive circuit and the cathode drive circuit simultaneously. The MCU uses serial communication, and the four control signals are SCLK, RCLK, SER, and RST respectively.

[0027] Please refer to Figure 2 , the anode drive circuit includes a 595 chip U1, a filter capacitor C1, drive resistors R2, R4, R6, voltage regulator diodes D1, D2, D3, resistors R1, R3, R5, and transistors Q1, Q2, Q3.

[0028] The 595 chip U1 needs four control signals to control the output. The SQ1 signal at pin 9 is used for cascading with the 595 chip of the cathode drive circuit. The 595 chip U1 outputs digital signals Ano1, Ano2, Ano3, which are respectively used to drive the bases of transistors Q1, Q2, Q3, and resistors R2, R4, R6 and voltage regulator diodes D1, D2, D3 need to be connected in series in the middle.

[0029] The resistor is used to control the base current of the triode, making the triode in saturation conduction, with the triode voltage drop Vce as small as possible to ensure that the DC power supply voltage output by the triode is large enough.

[0030] The zener diode is used to raise the voltage of the B stage of the triode to avoid mis-turn-on of the triode.

[0031] The triodes Q1, Q2, and Q3 used are PNP transistors, which are in the saturation state when turned on, ensuring that the voltage at the C stage of the output end is close to the power supply voltage at the E stage.

[0032] Please refer to Figure 3 , the cathode drive circuit includes 595 chips U2, U3, U4, filter capacitors C2, C3, C4, and drive resistors R7 - R30.

[0033] The 595 chips U2, U3, U4 need four control signals to control the output. The 14th pin of chip U2 is connected to the 9th pin of chip U1, the 9th pin of chip U2 is connected to the 14th pin of chip U3, and the 9th pin of chip U3 is connected to the 14th pin of chip U4, altogether forming a cascade of four 595 chips. The digital signal outputs of the 595 chips U2, U3, U4 are connected to the cathodes of the digital tube, with a total of 24 paths, and the resistors R7 - R30 are connected in series in the middle to control the current of each independent light-emitting diode inside the digital tube, thereby adjusting the brightness of the digital tube.

[0034] The 595 chip of the anode drive circuit receives four control signals from the MCU and outputs three signals Ano1, Ano2, Ano3, which respectively drive three triodes Q1, Q2, Q3. After passing through the three triodes, a DC power supply of VCC5V is provided for the digital tube LED1, that is, the three common anodes Anode1, Anode2, Anode3 of the digital tube LED1 are driven. This triode has a large current drive capacity and can be used to drive various digital tubes.

[0035] The cathode drive circuit also receives four control signals from the MCU. After passing through three 595 digital chips, it controls the output of a total of 24 signals Cathiode1 - Cathiode24. This signal passes through the drive resistors R7 - R30 and then connects to the cathodes of the digital tube LED1. By changing the resistance value of the drive resistor, the conduction current of each independent light-emitting diode inside the digital tube LED1 can be changed, thereby controlling the brightness of the digital tube LED1.

[0036] Please refer to Figure 4, the digital tube LED1 uses a common anode digital tube, that is, the anodes of the light-emitting diodes are connected together to form a common anode. The digital tube LED1 has a total of 3 common anodes, and each common anode is respectively combined with the cathodes of 24 light-emitting diodes, so there are a total of 3 * 24 = 72 light-emitting diodes. The characteristic of this digital tube is that the number of common anodes is small, which will cause a relatively large current to flow through the common anode. Therefore, a large current is required to drive the anode; while the number of cathodes is relatively large, and the current flowing through each cathode is small after shunting, and it can be directly driven by a 595 chip.

[0037] An elevator external call board driving circuit provided by the present invention can provide a large driving current, has strong circuit stability and high cost performance.

[0038] The present invention has been described exemplarily above in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited by the above-mentioned manner. As long as various improvements are made by adopting the method concept and technical solution of the present invention, or directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. An elevator external call board driving circuit, characterized in that, It includes an MCU, an anode drive circuit, a cathode drive circuit, and a digital tube; the anode drive circuit and the cathode drive circuit are connected between the MCU and the digital tube; the MCU sends control signals to control the anode drive circuit and the cathode drive circuit; the MCU uses serial communication, with four chip pins to output four control signals.

2. The drive circuit of an elevator external call board according to claim 1, wherein The anode drive circuit receives four control signals from the MCU, outputs three signals to drive three triodes respectively, and then through the triodes, provides power for the digital tube to drive the anode of the digital tube.

3. The drive circuit of an elevator external call board according to claim 2, characterized in that The cathode drive circuit receives four control signals from the MCU, passes through three digital chips, controls the output of a total of twenty-four signals, and the twenty-four signals are connected to the cathodes of the digital tube through drive resistors.

4. The drive circuit of an elevator external call board according to claim 3, characterized in that The digital tube used is a common-anode digital tube, which has three common anodes, and each common anode is respectively combined with the cathodes of twenty-four light-emitting diodes.

5. The drive circuit of an elevator external call board according to claim 4, characterized in that, The anode drive circuit includes 595 chip U1, filter capacitor C1, drive resistors R2, R4, R6, zener diodes D1, D2, D3, resistors R1, R3, R5, triodes Q1, Q2, and Q3; The 595 chip U1 is controlled to output through four control signals, and the SQ1 signal of pin 9 is used for cascading with the 595 chip U2 of the cathode drive circuit; the 595 chip U1 outputs digital signals Ano1, Ano2, Ano3 to drive the bases of triodes Q1, Q2, Q3 respectively, with resistors R2, R4, R6 and zener diodes D1, D2, D3 connected in series in the middle.

6. The drive circuit of an elevator external call board according to claim 5, characterized in that, The cathode drive circuit includes 595 chips U2, U3, U4, filter capacitors C2, C3, C4, and drive resistors R7 - R30; The 595 chips U2, U3, U4 are controlled to output through 4 control signals. The 14th pin of chip U2 is connected to the 9th pin of chip U1, the 9th pin of chip U2 is connected to the 14th pin of chip U3, and the 9th pin of chip U3 is connected to the 14th pin of chip U4, forming a cascade of four 595 chips in total; the digital signal outputs of the 595 chips U2, U3, U4 are connected to the cathodes of the digital tube, with a total of twenty-four paths, and drive resistors R7 - R30 are connected in series in the middle.

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