Tide level meter circuit

Abstract

The utility model relates to the technical field of circuits, in particular to a tide level meter circuit, which comprises a power supply module, a serial port 1 module, a serial port 2 module, an SD (Secure Digital) card module, a temperature sensor, a power supply voltage detection module and an MCU (Microprogrammed Control Unit) module, an automatic boost-buck chip IC2 is arranged in the power supply module, and TPS63051RMWR is adopted as the automatic boost-buck chip IC2; and an active crystal oscillator Y1 and an STM32 chip are arranged in the MCU module. According to the active crystal oscillator scheme adopted by the utility model, the frequency deviation is improved from 60ppm to less than 5ppm, and the problems that an uninsulated crystal oscillator is not easy to start oscillation and easy to stop oscillation are greatly avoided. According to the utility model, the STM32 single-chip microcomputer is used as a power supply, an automatic boost-buck chip TPS63051RMWR is used, so that a conventional lithium battery which can only select the voltage of 2.5-3.6 V originally is expanded to a common high-capacity 18650 polymer lithium battery and the like of 2.5-4.5 V, and meanwhile, reliable operation of the STM32 single-chip microcomputer is guaranteed by the accurate output voltage of 3.4 V.

Description

Technical Field

[0001] The utility model relates to the technical field of circuits, in particular to a tide level meter circuit. Background Art

[0002] The RTC (32768Hz) crystal oscillator of the previous tide gauge circuit used a passive crystal oscillator, which often failed to start, was easily affected by power fluctuations and stopped abnormally, and had excessive clock offset due to poor load matching. In addition, the power chip uses a boost or buck chip, which makes it impossible to deeply tap the battery life. The nominal voltage value of the microcontroller is 3.3V. If a simple boost chip is used, when the voltage is higher than 3.6V, since the chip is in pass-through mode at this time, the voltage may be higher than 3.6V (higher than the voltage range of the microcontroller), causing the microcontroller to run unstably. If a buck solution is used, when the voltage is lower than 3V, the chip will continue to buck, resulting in exceeding the lower limit of the microcontroller voltage, causing the microcontroller to not work stably. Utility Model Content

[0003] The utility model aims to provide a tide meter circuit to solve the problems mentioned in the background technology that the tide meter circuit often fails to start oscillation, is easily affected by power supply fluctuations and stops oscillating abnormally, and has excessive clock offset due to poor load matching.

[0004] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0005] A tide meter circuit includes a power module, a serial port 1 module, a serial port 2 module, an SD card module, a temperature sensor, a power supply voltage detection module and an MCU module;

[0006] The power module has a built-in automatic buck-boost chip IC2, and the automatic buck-boost chip IC2 adopts TPS63051RMWR;

[0007] The MCU module has a built-in active crystal oscillator Y1 and an STM32 chip.

[0008] Preferably, the power supply of the active crystal oscillator Y1 is connected to the 3.3V power supply network via the magnetic bead L2 via pin 4, pin 1 is connected to two parallel capacitors C29 and C30 to ground, pin 2 is directly connected to ground, and pin 3 is connected to pin 3 of the STM32 microcontroller via a coupler resistor R28.

[0009] Preferably, the model of the active crystal oscillator Y1 is 1XZA032768AD19, and the frequency is 32KHz.

[0010] Preferably, the capacitance value of capacitor C29 is 1 uF, and the capacitance value of capacitor C30 is 0.1 uF.

[0011] Preferably, input pins 10, 11, and 12 of the buck-boost chip IC2 are connected to the input end of the battery, pin 9 is grounded, pin 8 is connected to a voltage regulating resistor connected to a 1M ohm resistor connected to output pin 4, pin 7 is grounded through a starting capacitor C11 to achieve soft start, pin 6 is grounded to select PFM mode, pin 5 FB is directly connected to output pin 4 to achieve a fixed voltage output of 3.4V, pin 3 and pin L1 are connected through L1, L1 serves as an external matching inductor, and pin 2 is grounded.

[0012] Preferably, the resistance of the resistor R28 is 100Ω.

[0013] Preferably, the automatic step-up and step-down chip IC2 is used to automatically step-up and step-down the power input voltage to 3.4V.

[0014] Preferably, the power input voltage is 2.4-5.5V.

[0015] Preferably, the power source is a 2.4-3V dry cell, a 3.0-4.2V lithium cell, or a 3.7-4.5V nickel-hydrogen cell.

[0016] Compared with the prior art, the utility model has the following beneficial effects: in the tide meter circuit, the automatic buck-boost chip IC2 adopts TPS63051RMWR; the MCU module has built-in active crystal oscillator Y1 and STM32 chip, and the active crystal oscillator solution adopted increases the frequency deviation from 60ppm to less than 5ppm, which greatly avoids the problem that the crystal oscillator is difficult to start and easy to stop. The use of the automatic buck-boost chip TPS63051RMWR makes it possible to expand the conventional lithium battery with a voltage of 2.5-3.6V to the commonly used large-capacity 18650 and polymer lithium batteries with a voltage of 2.5-4.5V, and the precise output voltage of 3.4V ensures the reliable operation of the STM32 microcontroller. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, further detailed explanation is provided, but the accompanying drawings do not constitute a limitation to the present invention.

[0018] Figure 1 It is the general circuit principle diagram of the utility model;

[0019] Figure 2 It is a circuit principle diagram of the buck-boost circuit in the utility model;

[0020] Figure 3 It is a circuit principle diagram of the active crystal oscillator in the utility model. DETAILED DESCRIPTION

[0021] The following will combine the embodiments of the utility model and the drawings of the specification to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0022] In the description of the present invention, it should be understood that the terms "center", "vertical", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicating orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0023] A tide gauge circuit, such as Figure 1-Figure 3 As shown, it includes power module, serial port 1 module, serial port 2 module, SD card module, temperature sensor, power supply voltage detection module and MCU module; the power module has built-in automatic buck-boost chip IC2, and the automatic buck-boost chip IC2 uses TPS63051RMWR; the MCU module has built-in active crystal oscillator Y1 and STM32 chip, and the active crystal oscillator solution used increases the frequency deviation from 60ppm to less than 5ppm, which greatly avoids the problem that the crystal oscillator is difficult to start and easy to stop. The use of the automatic buck-boost chip TPS63051RMWR makes it possible to expand the conventional lithium battery with a voltage of 2.5-3.6V to the commonly used large-capacity 18650 and polymer lithium batteries with a voltage of 2.5-4.5V. At the same time, the precise output voltage of 3.4V ensures the reliable operation of the STM32 microcontroller. After fine component selection, careful PCB design, and professional testing and verification, it is proposed to use high-performance active crystal oscillators and automatic buck-boost chips to overcome the two shortcomings of the previous circuit. Currently, there is no low-frequency 32768Hz, high-precision clock crystal oscillator found in the market or in professional information for STM32 microcontrollers, and no one has introduced related successful experiences.

[0024] Furthermore, the power supply of the active crystal oscillator Y1 is connected to the 3.3V power supply network through the magnetic bead L2 from pin 4, the 1st pin connects two parallel capacitors C29 and C30 to the ground, the 2nd pin is directly connected to the ground, and the 3rd pin is connected to the 3rd pin of the STM32 microcontroller through the coupler resistor R28. The model of the active crystal oscillator Y1 is 1XZA032768AD19, and the frequency is 32KHz. The 1XZA032768AD19 active crystal oscillator is used. Since the crystal oscillator is an active crystal oscillator, there is no problem of failure to start or stop oscillation due to voltage instability. In addition, the processing accuracy of the crystal oscillator is very high, which can reach 5ppm, so the frequency deviation is much higher than the 20ppm of the general passive crystal oscillator. In addition, Figure 3 As shown in the figure, the active crystal oscillator can be effectively isolated from the power supply by the magnetic bead L2, so the probability of abnormal oscillation caused by power supply voltage fluctuation is greatly reduced. The requirements of active crystal oscillator for load capacitance are much lower than those of passive crystal oscillator. The conventional C29 and C30 (1uF and 0.1uF) can achieve accurate oscillation. Through continuous engineering practice, the coupling resistor R28 can work stably with 100 ohms.

[0025] Among them, the capacitance value of capacitor C29 is 1uF, and the capacitance value of C30 is 0.1uF.

[0026] Specifically, input pins 10, 11, and 12 of the buck-boost chip IC2 are connected to the input end of the battery, pin 9 is grounded, pin 8 is connected to a 1M ohm resistor connected to output pin 4, pin 7 is grounded through a start capacitor C11 to achieve soft start, pin 6 is grounded to select the PFM mode, pin 5 FB is directly connected to output pin 4 to achieve a fixed voltage output of 3.4V, pin 3 and pin L1 are connected through L1, L1 serves as an external matching inductor, pin 2 is grounded, and the resistance of resistor R28 is 100Ω. The automatic buck-boost chip IC2 is used to automatically boost the power input voltage to 3.4V. The power input voltage is 2.4-5.5V, and the power supply uses a 2.4-3V dry battery, a 3.0-4.2V lithium battery, and a 3.7-4.5V nickel-hydrogen battery.

[0027] The automatic buck-boost chip TPS63051RMWR can stabilize the final voltage output value at 3.4V, which meets the 3.0-3.6V voltage range requirement of the STM32 microcontroller. Because it is an automatic buck-boost chip, this chip can automatically buck-boost the input voltage (2.4-5.5V) to 3.4V, so the wider voltage adaptation range can adapt to ordinary dry batteries (2.4-3V), lithium batteries (3.0-4.2V) or (3.7-4.5V) and other batteries, broadening the range of battery selection and increasing the battery life. At the same time, due to the stable 3.4V power supply of the microcontroller, the reliability of the microcontroller is guaranteed.

[0028] The working principle of the tide level meter circuit of the utility model is as follows: the power supply of the active crystal oscillator Y1 is connected to the 3.3V power supply network through the 4-pin magnetic bead L2 (power isolation function), the 1-pin is connected to the two parallel capacitors C29 and C30 to the ground, the 2-pin is directly connected to the ground, and the 3-pin is connected to the 3-pin (OSC IN) of the STM32 microcontroller through the coupler resistor R28 (100 ohms).

[0029] Input pins 10, 11, and 12 of the buck-boost chip IC2 (TPS63051RMWR) are connected to the input end of the battery (there are anti-reverse connection networks Q1, D1, D2, and R1 in the figure. Since they do not belong to the improvement scope of the utility model, the principle will not be explained), pin 9 is grounded, pin 8 is connected to the voltage regulating resistor, and a 1M ohm resistor is connected to output pin 4, pin 7 is grounded through the start capacitor C11 to achieve soft start, pin 6 is grounded to select the PFM mode, pin 5 FB is directly connected to output pin 4 to achieve a fixed voltage output of 3.4V, pin 3 and pin L1 are connected through L1, L1 is used as an external matching inductor, and pin 2 is grounded.

[0030] The above shows and describes the basic principle, main features and advantages of the utility model. Those skilled in the art should understand that the utility model is not limited by the above embodiments. The above embodiments and descriptions are only preferred examples of the utility model and are not used to limit the utility model. Without departing from the spirit and scope of the utility model, the utility model may have various changes and improvements, which fall within the scope of the utility model to be protected. The scope of protection of the utility model is defined by the attached claims and their equivalents.

Claims

1. A tide meter circuit, including a serial port 1 module, a serial port 2 module, an SD card module, a temperature sensor, and a power supply voltage detection module, characterized in that: It also includes power module and MCU module; The power module has a built-in automatic buck-boost chip IC2, and the automatic buck-boost chip IC2 adopts TPS63051RMWR; The MCU module has a built-in active crystal oscillator Y1 and an STM32 chip.

2. The tide meter circuit according to claim 1, characterized in that: The power supply of the active crystal oscillator Y1 is connected to the 3.3V power supply network through the magnetic bead L2 by pin 4, the two parallel capacitors C29 and C30 are connected to the ground by pin 1, the pin 2 is directly connected to the ground, and the pin 3 is connected to the pin 3 of the STM32 microcontroller through the coupler resistor R28.

3. The tide meter circuit according to claim 2, characterized in that: The model of the active crystal oscillator Y1 is 1XZA032768AD19, and the frequency is 32KHz.

4. The tide meter circuit according to claim 2, characterized in that: The capacitance value of capacitor C29 is 1uF, and the capacitance value of C30 is 0.1uF.

5. The tide meter circuit according to claim 1, characterized in that: The input pins 10, 11, and 12 of the buck-boost chip IC2 are connected to the input end of the battery, pin 9 is grounded, pin 8 is connected to the voltage regulating resistor and a 1M ohm resistor connected to output pin 4, pin 7 is grounded through the starting capacitor C11 to achieve soft start, pin 6 is grounded to select the PFM mode, pin 5 FB is directly connected to output pin 4 to achieve a fixed voltage output of 3.4V, pin 3 and pin L1 are connected through L1, L1 serves as an external matching inductor, and pin 2 is grounded.

6. The tide meter circuit according to claim 2, characterized in that: The resistance of the resistor R28 is 100Ω.

7. The tide meter circuit according to claim 5, characterized in that: The automatic step-up and step-down chip IC2 is used to automatically step-up and step-down the power input voltage to 3.4V.

8. The tide meter circuit according to claim 7, characterized in that: The power input voltage is 2.4-5.5V.

9. The tide meter circuit according to claim 7, characterized in that: The power source adopts 2.4-3V dry cell, 3.0-4.2V lithium cell and 3.7-4.5V nickel-hydrogen cell.

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