Digital tube driving circuit based on FZH114C

Abstract

The utility model discloses a kind of digital tube drive circuit based on FZH114C, belong to digital tube driving technical field.The circuit with FZH114C digital tube drive chip as core, cooperate main control MCU module, digital tube display module, power management module and communication module, solve the problem of many in traditional digital tube driving scheme I / O resource occupation, display is easy to flicker, luminance regulation flexibility is poor and multi-bit cascade display is not even.In which, FZH114C chip is realized single line communication by asynchronous serial port (UART) with MCU, only a small amount of IO resources are occupied, and built-in constant current drive, blanking optimization circuit, support 8 stage segment drive current and 16 level bit duty cycle adjustment;While can be through PWM control circuit dynamic adaptation brightness, and support multi-chip level expansion digital tube digit number.This circuit has the advantages of high efficiency and stability, high integration, convenient development and safe and reliable, widely used in digital tube lighting, display and indication field.

Description

Technical Field

[0001] This utility model relates to the field of digital tube driving technology, specifically to a digital tube driving circuit based on FZH114C. Background Technology

[0002] LED digital displays are widely used in electronic instruments, counters, clocks, voltmeters and other devices due to their simple structure, fast response speed and low power consumption.

[0003] Existing digital tube driver circuits, in the static driving mode, require 32 I / O ports for a 4-digit digital tube, which seriously wastes the resources of the main control chip. Although dynamic driving can save I / O resources, it is prone to flickering problems due to unreasonable refresh timing, which affects the display clarity. At the same time, it relies on an external resistor network to adjust the brightness, and uneven display brightness is prone to occur in the scenario of multiple digital tubes being cascaded.

[0004] Therefore, it is necessary to provide a digital tube driver circuit based on FZH114C to solve the above-mentioned problems. Utility Model Content

[0005] To address the aforementioned technical problems, a digital tube driving circuit based on FZH114C is provided. This technical solution solves the problems of existing digital tube driving circuits mentioned in the background. In the static driving mode, a 4-digit digital tube requires 32 I / O ports, which seriously wastes the resources of the main control chip. Although dynamic driving can save I / O resources, it is prone to flickering due to unreasonable refresh timing, affecting the display clarity. At the same time, it relies on an external resistor network to adjust the brightness, and in the case of multiple digital tubes cascaded, it is prone to uneven display brightness.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A digital tube driver circuit based on FZH114C includes a main circuit board, a main control MCU module disposed on the main circuit board, an FZH114C driver chip, a digital tube display module, a power management module, and a communication module. The main control MCU module is used to output the segment code data and control instructions required for digital tube display; The FZH114C driver chip is used to receive instructions from the main control MCU module and provide stable... A constant current output is used to drive the digital tube and achieve brightness adjustment; The digital tube display module is used to display digital information; The power management module is used to provide a stable DC power supply for the FZH114C driver chip, the digital tube display module and the main control MCU module. The communication module is used to realize data transmission between the main control MCU module and the FZH114C driver chip.

[0007] In an optional embodiment, the main control MCU module adopts a 51 series microcontroller, and its GPIO port is connected to the FZH114C driver chip through the communication module to output segment code data and control commands.

[0008] In an optional embodiment, a data latch or a level conversion module is further provided between the FZH114C driver chip and the main control MCU module. The data latch is used to improve the stability of signal transmission, and the level conversion module is used to be compatible with different voltage levels of the main control MCU module and the FZH114C driver chip.

[0009] In an optional embodiment, the digital tube display module includes at least four common cathode digital tubes, and the FZH114C driver chip drives the common cathode digital tubes through a time-division multiplexing scanning method, and has a built-in blanking processing optimization circuit to eliminate display flicker.

[0010] In an optional embodiment, a PWM brightness control circuit is also included. The PWM brightness control circuit adjusts the duty cycle of the power supply voltage or the duty cycle of the input signal of the FZH114C driver chip, and in conjunction with the 8-level drive current adjustment function and 16-level bit duty cycle adjustment function built into the FZH114C chip, realizes dynamic control of the brightness of the digital tube.

[0011] In an optional embodiment, the communication module adopts the asynchronous serial port UART communication protocol. Only one TX port of the main control MCU module needs to be connected to the SDA port of the FZH114C driver chip to realize single-wire data transmission. The frame structure of the UART communication protocol includes an idle bit, a start bit, 8 data bits, 1 parity bit, and 1 stop bit. The transmission time of each bit is 52us, and the data frame ends when the idle bit is high for more than 3ms and the data is written to the corresponding register of the FZH114C chip.

[0012] In an optional embodiment, the FZH114C driver chip supports an automatic address increment mode and a fixed data address mode. In the fixed data address mode, a data transmission mode command and a display address command must be sent first, followed by segment selection data and bit selection data, and finally a display control command is sent to set the brightness and start the display.

[0013] In an optional embodiment, the number of digits of the digital tube display can be expanded by cascading several FZH114C driver chips to adapt to the display requirements of different application scenarios.

[0014] Compared with the prior art, the beneficial effects of this utility model are: This solution proposes a digital tube driver circuit based on the FZH114C chip. The FZH114C driver chip provides constant current drive output, completely eliminating the problem of uneven brightness when multiple digital tubes are cascaded, and the drive current is stable, extending the service life of the digital tubes. Data transmission between the main control MCU and the FZH114 chip is achieved through UART single-wire communication, requiring only one I / O port to complete the control, significantly saving main control chip resources. The FZH114C chip has a built-in blanking processing optimization circuit, which, together with a reasonable time-division scanning timing sequence, completely eliminates display flicker and improves display clarity. The communication, decoding, latching, and driving functions are integrated into a single FZH114C chip, simplifying the circuit structure, reducing the number of components, and making it suitable for small-sized embedded devices with limited board space. It supports cascading of multiple FZH114C driver chips, which can flexibly expand the number of digital tube display bits (such as from 4 bits to 8 bits or 16 bits) to adapt to different application scenarios. No complex timing control logic is required; display and brightness control can be achieved through simple UART instructions, reducing development difficulty and cycle time. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the circuit connection of the FZH114C driver chip in this utility model; Figure 2 This is a circuit diagram of the main control MCU module in this utility model. Detailed Implementation

[0016] The following description is intended to disclose the present invention so that those skilled in the art can implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0017] Reference Figure 1-2 As shown, a digital tube driver circuit based on FZH114C includes a main circuit board, a main control MCU module, an FZH114C driver chip, a digital tube display module, a power management module, a communication module, and a PWM brightness control circuit. Furthermore, the main control MCU module, as the core of the system control, is responsible for outputting the segment code data required for the digital tube display and sending control commands to the FZH114C driver chip through the communication module. It adopts 51 series microcontrollers (such as AT89C51), STM32 series microcontrollers (such as STM32F103) or other general-purpose microcontrollers. Its GPIO port is connected to the FZH114C driver chip through the communication module, which supports simulating UART communication through ordinary IO ports, eliminating the need for a dedicated communication interface and reducing the complexity of hardware design. Specifically, the main control MCU uses a 51 series microcontroller, and its GPIO port (such as P3.1) is used as the TX port, which is connected to the SDA pin of the FZH114C chip; the VCC pin of the MCU is connected to the output of the power management module, and the GND pin is grounded to ensure normal operation.

[0018] Furthermore, the FZH114C driver chip, as the core driver of the digital tube, integrates digital communication circuits, decoding circuits, data latches, oscillators, and LED constant current drive circuits. It is responsible for receiving instructions from the main control MCU module, parsing them, and outputting segment selection and digit selection signals to drive the digital tube display. It is also used to provide constant current drive output to eliminate the problem of uneven brightness when multiple digital tubes are cascaded. It supports 8-level segment drive current adjustment and 16-level digit duty cycle adjustment. It works with the PWM brightness control circuit to achieve dynamic brightness adaptation and has a built-in blanking processing optimization circuit to eliminate display flicker during dynamic scanning. The FZH114C driver chip pin connections include: power supply pin (VDD): connected to the +5V output of the power management module; GND pin: grounded; communication pin (SDA): connected to the TX port of the main control MCU module via the communication module for single-wire data transmission; and drive output pins (SEG1-SEG8 / CR6, CR1-CR5): connected to the segment pins (AG, DP) and digit pins (DIG1-DIG5) of the digital tube respectively for segment selection and digit selection control. Specifically, for the FZH114C chip, pin 5 (VDD) is connected to the +5V power supply, and pin 7 (GND) is grounded; pin 12 (SDA) is connected to the TX port of the main control MCU to realize UART communication; pins 1-4, 6, 8-11, and 13-16 (SEG1-SEG8 / CR6, CR1-CR5) are connected to the segment pins and digit pins of the digital tube respectively; the circuit also includes a 104 / 50V capacitor for power supply filtering to improve power supply stability. The FZH114C driver chip pins support both auto-address and fixed-address data modes for data transmission. This solution prioritizes the fixed-address data mode, requiring data to be sent in the following order: “mode command - address command - segment selection data - bit selection data - display control command” to ensure the accuracy of display control.

[0019] Furthermore, the digital tube display module adopts a 4-digit or more common cathode digital tube. The segment pins (A, B, C, D, E, F, G, DP) of the digital tube are connected to the SEG1-SEG8 pins of the FZH114C driver chip, and the bit pins (DIG1-DIGn) are connected to the CR1-CRn pins of the FZH114C driver chip. Display principle: The FZH114C driver chip uses a time-division multiplexing scanning method to sequentially light up each digit of the digital tube, achieving a "flicker-free" static display effect by utilizing the persistence of vision effect of the human eye.

[0020] Furthermore, the power management module provides a stable DC power supply for the entire drive circuit, including a +5V DC voltage for the FZH114C driver chip and the digital tube, and an adapter voltage (such as 3.3V or 5V, depending on the MCU model) for the main control MCU module. The power management module must have overvoltage protection and overcurrent protection functions to ensure that the circuit operates stably when the power supply fluctuates and to avoid chip damage.

[0021] Furthermore, the communication module adopts the asynchronous serial port (UART) communication protocol, and the data frame structure is as follows: Idle bit: High level. When the idle time is greater than 3ms, the data frame ends and the data is written from the temporary register to the corresponding register of the FZH114C chip. Start bit: A high-to-low level transition, with a low level lasting 52µs (1 bit time), indicates the start of data transmission; Data bits: 8 bits (D0-D7), with the least significant bit sent first, transmitting segment code data or control instructions for the digital tube; Parity bit: 1 bit, used for parity checking based on the number of "1"s in the data bits (if the number of "1"s in the 8 data bits is odd, the parity bit is 0, otherwise it is 1), to ensure the accuracy of data transmission; Stop bit: High level, lasting 52µs, indicates the end of a character data transmission; Hardware connection: Only one TX port of the main control MCU module needs to be connected to the SDA port of the FZH114C driver chip to achieve single-wire communication and significantly reduce I / O resource usage.

[0022] Furthermore, the PWM brightness control circuit adjusts the duty cycle of the power supply voltage or the duty cycle of the input signal of the FZH114C driver chip, combined with the built-in 8-segment drive current and 16-level duty cycle adjustment function of the FZH114C chip, to change the working current of the digital tube, thereby achieving dynamic control of brightness. The PWM brightness control circuit supports multi-level brightness switching and can adaptively adjust according to the application scenario (such as daytime and nighttime) to improve display effect and energy saving.

[0023] Working principle and implementation: The power management module starts up, providing a stable DC power supply to the main control MCU module, FZH114C driver chip, and digital tube display module; the main control MCU module initializes, sets UART communication parameters (such as baud rate, data bits, and parity bits), and sends a data transmission mode command (selecting fixed address mode) and a display address command (setting the display start address of the digital tube) to the FZH114C driver chip; the main control MCU module generates segment selection data (corresponding to the AG and DP segments of the digital tube) and digit selection data (corresponding to the DIG1-DIGn bits of the digital tube) according to the content to be displayed, and sends them to the FZH114C via UART communication. The driver chip: The main control MCU module sends display control commands to set the brightness level of the digital tube (in conjunction with the PWM brightness control circuit) and starts the display; After receiving the command, the FZH114C driver chip outputs segment selection and digit selection signals through the built-in decoding circuit and constant current drive circuit, and drives the digital tube display in a time-division multiplexing scanning mode; If brightness adjustment is required, the main control MCU module sends a brightness adjustment command, which, in conjunction with the PWM brightness control circuit, adjusts the output current of the FZH114C driver chip to achieve dynamic brightness adaptation.

[0024] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A digital tube driving circuit based on FZH114C, characterized in that, It includes a main circuit board, a main control MCU module mounted on the main circuit board, an FZH114C driver chip, a digital tube display module, a power management module, and a communication module; The main control MCU module is used to output the segment code data and control instructions required for digital tube display; The FZH114C driver chip is used to receive instructions from the main control MCU module and provide stable... A constant current output is used to drive the digital tube and achieve brightness adjustment; The digital tube display module is used to display digital information; The power management module is used to provide a stable DC power supply for the FZH114C driver chip, the digital tube display module and the main control MCU module. The communication module is used to realize data transmission between the main control MCU module and the FZH114C driver chip.

2. The FZH114C-based character tube driving circuit according to claim 1, wherein The main control MCU module uses a 51 series microcontroller, and its GPIO port is connected to the FZH114C driver chip through the communication module to output segment code data and control commands.

3. The FZH114C-based character tube driving circuit according to claim 1, wherein A data latch or level conversion module is also provided between the FZH114C driver chip and the main control MCU module. The data latch is used to improve the stability of signal transmission, and the level conversion module is used to be compatible with the different voltage levels of the main control MCU module and the FZH114C driver chip.

4. The FZH114C-based character tube driving circuit according to claim 1, wherein The digital tube display module includes at least 4 common cathode digital tubes. The FZH114C driver chip drives the common cathode digital tubes through a time-division multiplexing scanning method and has a built-in blanking processing optimization circuit to eliminate display flicker.

5. The FZH114C-based character tube driving circuit according to claim 1, wherein It also includes a PWM brightness control circuit, which adjusts the duty cycle of the power supply voltage or the duty cycle of the input signal of the FZH114C driver chip, and works in conjunction with the 8-level drive current adjustment function and 16-level bit duty cycle adjustment function built into the FZH114C chip to achieve dynamic control of the brightness of the digital tube.

6. The FZH114C-based character tube driving circuit according to claim 1, wherein The communication module adopts the asynchronous serial port UART communication protocol. Only one TX port of the main control MCU module needs to be connected to the SDA port of the FZH114C driver chip to realize single-wire data transmission. The frame structure of the UART communication protocol includes an idle bit, a start bit, 8 data bits, 1 parity bit, and 1 stop bit. The transmission time of each bit is 52us, and the data frame ends when the idle bit is high for more than 3ms and the data is written to the corresponding register of the FZH114C chip.

7. A digital tube driving circuit based on FZH114C according to claim 1, characterized in that, The FZH114C driver chip supports an automatic address increment mode and a fixed data address mode. In the fixed data address mode, a data transmission mode command and a display address command must be sent first, followed by segment selection data and bit selection data, and finally a display control command is sent to set the brightness and start the display.

8. A digital tube driving circuit based on FZH114C according to claim 1, characterized in that, The number of digits in a digital tube can be expanded by cascading several FZH114C driver chips to meet the display needs of different application scenarios.

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