A low-power multi-digit digital tube display circuit with buttons

Abstract

The utility model provides a low-power multi-digit digital tube display circuit with buttons, comprising a digital tube driving power supply, a digital tube driving circuit, a digital tube group and a button circuit. The digital tube driving power supply adopts a low-power and high-conversion rate voltage conversion chip, which has high conversion efficiency and reduces the driving voltage of the digital tube to a smaller value. Under the condition of ensuring that the current flowing through the digital tube remains unchanged and the brightness remains unchanged, the resistance value of the current limiting resistor and the voltage across the resistor are reduced, thereby reducing the overall power consumption of the digital tube display circuit and increasing the effective power consumption ratio of the display circuit, thereby achieving the purpose of low power consumption and energy saving; the dynamic scanning digital tube driving mode uses 4 instrument control chip pins to realize the function of 16 control chip pins in the traditional driving mode, which can effectively reduce the number of instrument control chip pins used, thereby achieving the purpose of reducing the production cost of instrument equipment and facilitating the expansion of other functions of instrument equipment.

Description

Technical Field

[0001] The utility model relates to the technical field of digital tube display, in particular to a multi-digit digital tube display circuit with low power consumption and keys. Background Art

[0002] In industrial instruments, multi-digit digital tube display circuits with buttons have been widely used in many measurement and control instrumentation equipment because of their high display brightness, simple drive, and easy operation. They are an indispensable circuit for realizing human-machine exchange. Through the display circuit, relevant information of the instrument equipment can be provided to the user intuitively, so that the user can understand the working status of the instrument equipment simply and intuitively. Or the failure and cause of the equipment can be fed back to the user in time through the flashing of the display, so that the user can analyze and solve the failure in time. Through the buttons, the user can easily set various parameters of the instrument equipment, so that the instrument equipment can realize different functions.

[0003] The multi-digit digital tube display circuit with buttons is composed of buttons, digital tubes, digital tube segment drive circuits, current limiting resistors and digital tube position drive circuits. In the entire digital tube display circuit, the buttons, digital tube segment drive circuits and digital tube position drive circuits will occupy a large number of instrument control chip pin resources, which is not conducive to the miniaturization of the instrument control chip and the expansion of other functions of the instrument. The main energy-consuming components in the entire digital tube display circuit are digital tubes and current limiting resistors. The energy consumption of the digital tube is mainly effective energy consumption for light emission, while the energy consumption of the current limiting resistor is invalid energy consumption and is all used for heating. When the digital tube drive voltage is 5V, nearly 60% of the power consumption of the entire digital tube display circuit is consumed by the current limiting resistor. This current limiting resistor has the function of preventing the current flowing through the digital tube from being too large, so it cannot be omitted. Therefore, the current power consumption of this digital tube display circuit in the entire instrument equipment system is obviously too large, and the energy utilization rate is obviously too low. Utility Model Content

[0004] In order to solve the above problems, the utility model provides a low-power multi-digit digital tube display circuit with keys, which is characterized by comprising a digital tube driving power supply, a digital tube driving circuit, a digital tube group and a key circuit;

[0005] The digital tube driving power supply includes a SGM61220XTN6G chip, a pull-up resistor R84, a filter inductor L3, output control resistors R86 and R88, and filter capacitors C62, C58, and C59. Pin 1 of the SGM61220XTN6G chip is grounded, and the 5V power supply of the instrument equipment system is connected to pin 3 of the SGM61220XTN6G chip via filter capacitor C53. The 5V power supply of the instrument equipment system is connected to the SGM61220XTN6G chip via pull-up resistor R84 and filter capacitor C65. Pin 5 of the M61220XTN6G chip and pin 2 of the SGM61220XTN6G chip provide power to the digital tube drive circuit through the filter inductor L3 and the filter capacitors C62, C58, and C59. The filter capacitors C62, C58, and C59 are connected in parallel with each other. The output control resistors R86 and R88 are connected in series and connected between the filter inductor L3 and the filter capacitor C62. The pin 4 of the SGM61220XTN6G chip is connected between the output control resistors R86 and R88.

[0006] The digital tube group consists of two 4-bit digital tubes and three groups of single LED lights;

[0007] The digital tube driving circuit is composed of digital tube segment driving transistors Q6~Q13, current limiting resistors R52~R59, R60~R67, digital tube position driving chips U13 and U14, filter capacitors C48 and C49 and an inversion circuit. The digital tube segment driving transistors Q6~Q13 are 9012 transistors, the instrument control chip is connected to the base of the segment driving transistors Q6~Q13 through the GPIO_SA~GPIO_SP pins through the current limiting resistors R52~R59, the collector of the segment driving transistors Q6~Q13 leads to SA_LED~SP_LED pins through the current limiting resistors R60~R67 to connect to the corresponding pins of two 4-bit digital tubes and three groups of single LED lamps, the digital tube segment driving chips U13 and U14 are SN74LS145DR decoding chips, and the 3.3V power of the instrument equipment system is 10V. The source is connected to the No. 16 pins of U13 and U14 through filter capacitors C48 and C49 to power them. The LED1-LED8 pins of U13 and the LED9-LED12 pins of U14 are connected to the corresponding pins of two 4-bit digital tubes and three groups of single LED lights. The control pin SL3 of U14 is connected to the control pin / SL3 of U13 through an inversion circuit. The inversion circuit is composed of resistors R71, R72 and transistor Q14. The 3.3V power supply of the instrument equipment system is connected to the collector of the transistor Q14 through resistor R72. The control pin SL3 is connected to the base of the transistor Q14 through resistor R71. The control pin / SL3 is connected to the collector of the transistor Q14. The emitter of the transistor Q14 is grounded. The instrument control chip controls the outputs of U14 and U13 through control pins SL0, SL1, SL2 and SL3.

[0008] The key circuit is composed of keys K1, K2, K3 and cut-off diodes D19, D32, D45. One end of the keys K1, K2, K3 is connected to the GPIO_KEY pin of the instrument control chip via the cut-off diodes D19, D32, D45, and the other end is connected to the 1st, 2nd, 3rd pins of the U14 chip in the digital tube drive circuit.

[0009] The beneficial effects of the present invention compared with the prior art are as follows:

[0010] 1. This circuit can realize low-power multi-digit digital tube display, which meets the current user's demand for low power consumption of digital tube display;

[0011] 2. This circuit can realize 8-bit digital tube and 24 LED light display, which meets the current user's demand for multi-digit digital tube display;

[0012] 3. This circuit can realize the control of the display of 8-bit digital tube and the acquisition of the switch status of 3 buttons with fewer instrument control chip pins, which meets the current user's demand for simple connection between modules;

[0013] 4. This circuit can realize the key scanning function, which meets the current user's needs for operating instrument equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art 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 labor.

[0015] Figure 1 It is a structural block diagram of a low-power multi-digit digital tube display circuit with buttons;

[0016] Figure 2 It is a structural diagram of the digital tube driving power supply part;

[0017] Figure 3 This is the pin diagram of the digital tube group;

[0018] Figure 4 It is a structural schematic diagram of the key circuit;

[0019] Figure 5 This is a schematic diagram of the digital tube driving circuit structure. DETAILED DESCRIPTION

[0020] The embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as being limited to the embodiments described herein. Instead, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.

[0021] With the development of society and the rapid progress of industrial automation, people have higher and higher requirements for the low power consumption performance of instrument equipment, and the digital tube display circuit accounts for the largest proportion of energy consumption in the entire instrument equipment, so the traditional digital tube display circuit is increasingly unsuitable for the current instrument equipment display requirements, which is mainly reflected in the following problems:

[0022] 1. The power consumption accounts for a large proportion and the utilization rate is low. Since the digital tube driving power supply generally directly adopts the 5V power supply of the instrument equipment system, and the 5V power supply voltage is too high for the digital tube driving, a current limiting resistor with a larger resistance value must be added. The current limiting resistor with a large resistance value will convert most of the power consumption into heat energy and waste it, so the effective utilization rate of the power consumption of the entire digital tube display circuit is only about 40%. This will cause a lot of energy waste, which is not conducive to the requirements of energy saving and environmental protection.

[0023] 2. The heat generated by the current limiting resistor will increase the temperature inside the instrument, which is not conducive to the operation of the instrument in a high temperature environment. It will also cause the integrated circuit chip to fail to work normally due to excessive temperature, thereby affecting the reliability of the instrument. High temperature will also accelerate the aging of the instrument, greatly shortening its service life.

[0024] 3. It occupies a large number of instrument control chip pin resources, which is not conducive to the miniaturization and cost reduction of instrument control chips. Because the instrument control chip has too many pins, the area of ​​the instrument control chip will be larger and the price will be higher. This will increase the production cost of the instrument equipment. Occupying too many instrument control chip pins will also cause a shortage of instrument control chip pin resources when the instrument equipment expands other functions.

[0025] After research, the inventor found that the digital tube display can be realized by combining a low-power and high-conversion-rate voltage conversion chip with a dynamic scanning digital tube driving mode. On the one hand, the low-power and high-conversion-rate voltage conversion chip has a high conversion efficiency and reduces the driving voltage of the digital tube to a smaller value. While ensuring that the current flowing through the digital tube remains unchanged and the brightness remains unchanged, the resistance value of the current limiting resistor and the voltage across the resistor are reduced, thereby reducing the overall power consumption of the digital tube display circuit and increasing the effective power consumption ratio of the display circuit, thereby achieving the purpose of low power consumption and energy saving; the dynamic scanning digital tube driving mode can effectively reduce the number of instrument control chip pins used. The dynamic scanning digital tube driving mode uses 4 control chip pins to achieve the function of 16 control chip pins under the traditional driving mode, thereby achieving the purpose of reducing the production cost of instrument equipment and facilitating the expansion of other functions of instrument equipment.

[0026] like Figure 1 As shown, a low-power multi-digit digital tube display circuit with buttons provided in an embodiment of the present disclosure includes a digital tube driving power supply, a digital tube driving circuit, a digital tube group and a button circuit;

[0027] refer to Figure 2 The digital tube drive power supply includes SGM61220XTN6G chip, pull-up resistor R84, filter inductor L3, output control resistors R86 and R88 and filter capacitors C62, C58, C59. SGM61220XTN6G chip is a low-power and high-conversion-rate voltage conversion chip. Pin 1 of SGM61220XTN6G chip is grounded. The 5V power supply of the instrumentation system is connected to pin 3 of SGM61220XTN6G chip through filter capacitor C53 to power SGM61220XTN6G chip. The 5V power supply of the instrumentation system is connected to enable pin 5 of SGM61220XTN6G chip through pull-up resistor R84 and filter capacitor C65, so that SGM61220XTN6G chip can operate normally after power-on. Pin 2 of the SGM61220XTN6G chip is an output pin. The output pin provides power to the digital tube drive circuit through the filter inductor L3 and the filter capacitors C62, C58, and C59. The filter capacitors C62, C58, and C59 are connected in parallel. The output control resistors R86 and R88 are connected in series, and one end is connected between the filter inductor L3 and the filter capacitor C62. Pin 4 of the SGM61220XTN6G chip is connected between the output control resistors R86 and R88. The output voltage is determined by the ratio of the resistors R86 and R88 between pins 2 and 4 of the SGM61220XTN6G chip. When the brightness of the digital tube remains unchanged, the ratio of the resistors R86 and R88 is adjusted to make the output of the SGM61220XTN6G chip 2.5V, which can effectively reduce the power consumption of the digital tube display circuit.

[0028] refer to Figure 3 The digital tube group consists of two 4-bit digital tubes and three groups of single LED lights. The use of 4-bit digital tubes can greatly reduce the number and difficulty of wiring when drawing the PCB board;

[0029] refer to Figure 4 The key circuit is composed of keys K1, K2, K3 and cut-off diodes D19, D32, D45. One end of keys K1, K2, K3 is connected to the GPIO_KEY pin of the instrument control chip through the cut-off diodes D19, D32, D45, and the other end is connected to the 1st, 2nd, and 3rd pins of the U14 chip in the digital tube drive circuit. When the instrument control chip lights up the corresponding digital tube display group through the 1st, 2nd, and 3rd pins of the U14 chip each time, the switch status of keys K1, K2, and K3 can be known by reading the status of the GPIO_KEY pin at the same time;

[0030] refer to Figure 5The digital tube driving circuit is composed of digital tube segment driving transistors Q6~Q13, current limiting resistors R52~R59, R60~R67, digital tube position driving chips U13 and U14, filter capacitors C48 and C49, and an inversion circuit. The digital tube segment driving transistors Q6~Q13 are 9012 transistors. The instrument control chip is connected to the base of the segment driving transistors Q6~Q13 through the GPIO_SA~GPIO_SP pins through the current limiting resistors R52~R59, thereby controlling the conduction of the transistors Q6~Q13 to realize the lighting of a certain segment of the digital tube. The collector of the segment driving transistors Q6~Q13 leads to SA_LED~SP_LED through the current limiting resistors R60~R67. The pins are connected to the corresponding pins of two 4-bit digital tubes and three groups of single LED lights. The brightness of the digital tube is determined by the output LEDVCC of the digital tube driving power supply and the size of the current limiting resistors R60~R67. The useless loss in the digital tube display circuit is mainly concentrated on the current limiting resistors R60~R67. In order to reduce the useless loss of the digital tube display circuit and ensure that the brightness of the digital tube remains unchanged, the resistance value of the resistors R60~R67 needs to be limited to less than 10 ohms. At this time, the digital tube driving power LEDVCC is only 2.5V. The digital tube segment driver chips U13 and U14 are SN74LS145DR decoding chips. The 3.3V power supply of the instrument equipment system is connected through filter capacitors C48 and C49. To pin 16 of U13 and U14 to supply power, LED1~LED8 pins of U13 and LED9~LED12 pins of U14 are connected to the corresponding pins of two 4-bit digital tubes and three groups of single LED lights. The instrument control chip has only four digital tube bit drive control pins SL0, SL1, SL2 and SL3, and one SN74LS145DR decoding chip requires four control pins. Therefore, in order to control two SN74LS145DR decoding chips, it is necessary to connect the control pin SL3 of U14 to the control pin / SL3 of U13 through an inversion circuit. The inversion circuit is composed of resistors R71, R72 and transistor Q14. The 3 .3V power supply is connected to the collector of transistor Q14 through resistor R72, control pin SL3 is connected to the base of transistor Q14 through resistor R71, control pin / SL3 is connected to the collector of transistor Q14, and the emitter of transistor Q14 is grounded, thus realizing the inversion function, SL0, SL1, SL2, SL3 control the output of U14, SL0, SL1, SL2, / SL3 control the output of U13, thus realizing that the instrument control chip controls two SN74LS145DR decoding chips through the four-bit data lines SL0, SL1, SL2, SL3, and can control the display of 8-bit digital tubes and 24 LED lights, greatly saving the use of the IO port of the instrument control chip.

[0031] The exemplary implementation scheme of the low-power multi-digit digital tube display circuit with buttons proposed by the present invention is described in detail above with reference to the preferred embodiments. However, it can be understood by those skilled in the art that, without departing from the concept of the present invention, various modifications and alterations can be made to the above-mentioned specific embodiments, and various technical features and structures proposed by the present invention can be combined in various ways without exceeding the protection scope of the present invention, which is determined by the attached claims.

Claims

1. A low-power multi-digit digital tube display circuit with buttons, characterized in that: It includes a digital tube driving power supply, a digital tube driving circuit, a digital tube group and a key circuit; The digital tube driving power supply includes a SGM61220XTN6G chip, a pull-up resistor R84, a filter inductor L3, output control resistors R86 and R88, and filter capacitors C62, C58, and C59. Pin 1 of the SGM61220XTN6G chip is grounded, and the 5V power supply of the instrument equipment system is connected to pin 3 of the SGM61220XTN6G chip via filter capacitor C53. The 5V power supply of the instrument equipment system is connected to the SGM61220XTN6G chip via pull-up resistor R84 and filter capacitor C65. Pin 5 of the M61220XTN6G chip and pin 2 of the SGM61220XTN6G chip provide power to the digital tube drive circuit through the filter inductor L3 and the filter capacitors C62, C58, and C59. The filter capacitors C62, C58, and C59 are connected in parallel with each other. The output control resistors R86 and R88 are connected in series and connected between the filter inductor L3 and the filter capacitor C62. The pin 4 of the SGM61220XTN6G chip is connected between the output control resistors R86 and R88. The digital tube group consists of two 4-bit digital tubes and three groups of single LED lights; The digital tube driving circuit is composed of digital tube segment driving transistors Q6~Q13, current limiting resistors R52~R59, R60~R67, digital tube position driving chips U13 and U14, filter capacitors C48 and C49 and an inversion circuit. The digital tube segment driving transistors Q6~Q13 are 9012 transistors, the instrument control chip is connected to the base of the segment driving transistors Q6~Q13 through the GPIO_SA~GPIO_SP pins through the current limiting resistors R52~R59, the collector of the segment driving transistors Q6~Q13 leads to SA_LED~SP_LED pins through the current limiting resistors R60~R67 to connect to the corresponding pins of two 4-bit digital tubes and three groups of single LED lamps, the digital tube segment driving chips U13 and U14 are SN74LS145DR decoding chips, and the 3.3V power of the instrument equipment system is 10V. The source is connected to the No. 16 pins of U13 and U14 through filter capacitors C48 and C49 to power them. The LED1-LED8 pins of U13 and the LED9-LED12 pins of U14 are connected to the corresponding pins of two 4-bit digital tubes and three groups of single LED lights. The control pin SL3 of U14 is connected to the control pin / SL3 of U13 through an inversion circuit. The inversion circuit is composed of resistors R71, R72 and transistor Q14. The 3.3V power supply of the instrument equipment system is connected to the collector of the transistor Q14 through resistor R72. The control pin SL3 is connected to the base of the transistor Q14 through resistor R71. The control pin / SL3 is connected to the collector of the transistor Q14. The emitter of the transistor Q14 is grounded. The instrument control chip controls the outputs of U14 and U13 through control pins SL0, SL1, SL2 and SL3. The key circuit is composed of keys K1, K2, K3 and cut-off diodes D19, D32, D45. One end of the keys K1, K2, K3 is connected to the GPIO_KEY pin of the instrument control chip via the cut-off diodes D19, D32, D45, and the other end is connected to the 1st, 2nd, 3rd pins of the U14 chip in the digital tube drive circuit.

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