Intelligent electronic scale control circuit

Abstract

The utility model discloses a control circuit of an intelligent electronic scale, which comprises a weighing sensing module, a main control chip and a control chip, wherein the weighing sensing module is a full-bridge Wheatstone bridge composed of four strain gauges, and the output end of the weighing sensing module is connected to a differential ADC input channel of the main control chip; the integrated processing module adopts a 6239 type Bluetooth main control chip, is internally integrated with a 24-bit high-precision ADC (Analog to Digital Converter) unit and is used for directly receiving a voltage signal of a Wheatstone bridge; the segment code type LCD driving unit is provided with four COM (Component Object Model) ends (COM0-COM3) and 14 SEG (Component Object Generation) ends (SEG0-SEG13); according to the power supply module, a lithium battery outputs 3.3 V + / -2% system voltage through an XC6206P332MR type LDO chip; the man-machine interaction module is a segment code type LCD display screen directly driven by a COM / SEG port of 6239; and the data communication module establishes wireless connection with an intelligent terminal through a 6239 built-in Bluetooth unit to realize real-time transmission of weighing data, and a Wheatstone bridge is directly connected with the main control chip, so that the circuit structure is simplified, and noise is effectively filtered and the anti-interference capability of the circuit is enhanced while accurate acquisition of signals is ensured.

Description

Technical Field

[0001] This utility model relates to the field of electronic scale control technology, and in particular to an intelligent electronic scale control circuit. Background Technology

[0002] Traditional electronic scale control circuits often employ a discrete design, requiring the weighing sensor signal to be conditioned by an external instrumentation amplifier and then converted by an independent ADC chip (such as HX711), resulting in complex circuitry and high costs.

[0003] Currently, the 16-bit ADC used in the control circuit of traditional electronic scales has low resolution, which is difficult to meet the requirements of high-precision weighing. In addition, it lacks a real-time temperature compensation mechanism, and the temperature drift error can reach 0.5% / ℃. The measurement results deviate greatly under different temperature environments. At the same time, zero drift compensation relies on manual adjustment of potentiometer, which is easily affected by vibration, causing data jumps and affecting measurement accuracy. Therefore, an intelligent electronic scale control circuit is proposed here. Utility Model Content

[0004] In order to overcome the above-mentioned defects of the prior art and to achieve the above objectives, the present invention proposes the following technical solution:

[0005] A smart electronic scale control circuit includes:

[0006] Weighing sensor module: It consists of a full-bridge Wheatstone bridge composed of four strain gauges, and the output is connected to the differential ADC input channel of the main control chip.

[0007] Integrated processing module: It adopts the PHY6239 Bluetooth main control chip, which integrates a 24-bit high-precision ADC unit to directly receive the voltage signal of the Wheatstone bridge;

[0008] Segment LCD driver unit: has 4 COM terminals COM0-COM3 and 14 SEG terminals SEG0-SEG13;

[0009] Power supply module: The lithium battery outputs a system voltage of 3.3V±2% through an XC6206P332MR LDO chip;

[0010] Human-computer interaction module: a segment LCD display directly driven by the COM / SEG port of PHY6239;

[0011] Data communication module: It establishes a wireless connection with the smart terminal through the built-in Bluetooth unit of PHY6239 to realize real-time transmission of weighing data.

[0012] The power supply terminal of the Wheatstone bridge is directly connected to the GPIO power output terminal of the PHY6239.

[0013] The PHY6239 chip's ADC sampling channel is configured with an input impedance ≥1MΩ, a sampling rate of 80Hz±5%, and a built-in digital filter cutoff frequency of 20Hz.

[0014] The LCD driver unit's operating timing includes a time-division multiplexing drive mode with a duty cycle of 1 / 4.

[0015] The radio frequency circuit of the Bluetooth unit includes an F-type PCB antenna.

[0016] The PHY6239 chip firmware execution steps include:

[0017] Bridge imbalance voltage compensation, zero drift compensation value is stored in Flash block 0x1000-0x100F;

[0018] Temperature drift correction; built-in NTC temperature sensor with a sampling period of 10 seconds.

[0019] The PHY6239 chip directly processes strain gauge signals and calculates weight.

[0020] This utility model has the following beneficial effects:

[0021] 1. By using the PHY6239 Bluetooth main control chip with a 24-bit high-precision ADC unit, the resolution is greatly improved compared to the traditional 16-bit ADC, which can meet the high-precision weighing requirements. At the same time, by using the built-in NTC temperature sensor, temperature drift correction is performed with a sampling period of 10 seconds, which effectively reduces temperature drift error and reduces the impact of different temperature environments on the measurement results, ensuring measurement accuracy.

[0022] 2. The Wheatstone bridge connects directly to the main control chip, simplifying the circuit structure and reducing errors and interference from external conditioning circuits. Furthermore, the bridge's power supply is connected to the GPIO power output of the PHY6239, ensuring power supply stability. The ADC sampling channel is configured with an input impedance ≥1MΩ, a sampling rate of 80Hz±5%, and a built-in digital filter cutoff frequency of 20Hz. This ensures accurate signal acquisition while effectively filtering out noise and enhancing the circuit's anti-interference capability. Attached Figure Description

[0023] Figure 1 This is a first circuit diagram of a control circuit for an intelligent electronic scale proposed in this utility model;

[0024] Figure 2 This is a second circuit diagram of a smart electronic scale control circuit proposed in this utility model;

[0025] Figure 3 This is a third circuit diagram of a control circuit for an intelligent electronic scale proposed in this utility model;

[0026] Figure 4 This is the fourth circuit diagram of a smart electronic scale control circuit proposed in this utility model;

[0027] Figure 5 This is the fifth circuit diagram of a smart electronic scale control circuit proposed in this utility model;

[0028] Figure 6 This is the sixth circuit diagram of an intelligent electronic scale control circuit proposed in this utility model. Detailed Implementation

[0029] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0030] Example 1:

[0031] like Figure 1-5 As shown, the intelligent electronic scale control circuit proposed in this utility model includes:

[0032] Weighing sensor module: Composed of a full-bridge Wheatstone bridge with four strain gauges, the output is connected to the differential ADC input channel of the main control chip; Integrated processing module: Uses a PHY6239 Bluetooth main control chip, with an integrated 24-bit high-precision ADC unit, directly receiving the voltage signal from the Wheatstone bridge; Segment LCD driver unit: Has 4 COM terminals COM0-COM3 and 14 SEG terminals SEG0-SEG13; Power supply module: Lithium battery outputs 3.3V±2% system voltage through XC6206P332MR LDO chip; Human-machine interface module: Segment LCD display directly driven by the COM / SEG port of PHY6239; Data communication module: Establishes a wireless connection with the smart terminal through the built-in Bluetooth unit of PHY6239 to realize real-time transmission of weighing data;

[0033] The power supply terminal of the Wheatstone bridge is directly connected to the GPIO power output terminal of the PHY6239. The ADC sampling channel of the PHY6239 chip is configured with an input impedance ≥1MΩ, a sampling rate of 80Hz±5%, and a built-in digital filter cutoff frequency of 20Hz. The LCD driver unit's operating timing includes a time-division multiplexing drive mode with a duty cycle of 1 / 4. The Bluetooth unit's RF circuit includes an F-type PCB antenna. The firmware execution steps of the PHY6239 chip include: bridge imbalance voltage compensation, with zero drift compensation values ​​stored in Flash blocks 0x1000-0x100F; temperature drift correction, with a built-in NTC temperature sensor sampling period of 10s; and the PHY6239 chip directly processes strain gauge signals and calculates weight.

[0034] In this embodiment, a full-bridge Wheatstone bridge consisting of four metal foil strain gauges (120Ω±0.5%) is arranged on the PCB. Strain gauges R1 and R3 are axially attached to the tension surface of the weighing beam, and strain gauges R2 and R4 are attached to the compression surface. The output of the bridge is directly connected to the differential input channels ADC1+ (P0.3) and ADC1- (P0.4) of the PHY6239 chip. The power supply of the bridge is driven by the 3.3V output of the chip's GPIO_PWR (P1.2), and filtered by a 0.1μF ceramic capacitor.

[0035] A 3.7V lithium polymer battery is used, and a 3.3V regulated output is achieved through an XC6206P332MR chip. A 100μF electrolytic capacitor and a 10μF ceramic capacitor are connected in parallel at the LDO input and output terminals, respectively. The VBAT pin of the PHY6239 chip is connected to the regulated output. A 0.1μF decoupling capacitor is placed between the VDD_IO pin and GND. A 6-bit semi-transparent segment LCD (model LCE0603) is selected, and the COM0-COM3 pins of the display are connected to P2.0-P2.3 of the PHY6239, while SEG0-SEG13 are connected to P3.0-P3.6 and P4.0-P4.6, respectively. During PCB routing, the SEG traces and COM traces are orthogonally laid out with a spacing of ≥0.3mm to avoid cross coupling.

[0036] A radiator measuring 26.8 mm × 6.2 mm was etched on an FR4 substrate (dielectric constant 4.4). The feed point was located 3.2 mm from the ground terminal and connected to the RF_ANT pin of the PHY6239 via a π-type matching network (a combination of a 2.2 nH inductor and a 1 pF capacitor).

[0037] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A control circuit for an intelligent electronic scale, characterized in that, include: Weighing sensor module: It consists of a full-bridge Wheatstone bridge composed of four strain gauges, and the output is connected to the differential ADC input channel of the main control chip. Integrated processing module: It adopts the PHY6239 Bluetooth main control chip, which integrates a 24-bit high-precision ADC unit to directly receive the voltage signal of the Wheatstone bridge; Segment LCD driver unit: has 4 COM terminals COM0-COM3 and 14 SEG terminals SEG0-SEG13; Power supply module: The lithium battery outputs a system voltage of 3.3V±2% through an XC6206P332MR LDO chip; Human-computer interaction module: a segment LCD display directly driven by the COM / SEG port of PHY6239; Data communication module: It establishes a wireless connection with the smart terminal through the built-in Bluetooth unit of PHY6239 to realize real-time transmission of weighing data.

2. The intelligent electronic scale control circuit according to claim 1, characterized in that: The power supply terminal of the Wheatstone bridge is directly connected to the GPIO power output terminal of the PHY6239.

3. The intelligent electronic scale control circuit according to claim 1, characterized in that: The PHY6239 Bluetooth main control chip has an ADC sampling channel configuration of input impedance ≥1MΩ, sampling rate 80Hz±5%, and built-in digital filter cutoff frequency 20Hz.

4. The intelligent electronic scale control circuit according to claim 1, characterized in that: The LCD driving unit's operating timing includes a time-division multiplexing driving mode with a duty cycle of 1 / 4.

5. The intelligent electronic scale control circuit according to claim 1, characterized in that: The radio frequency circuit of the Bluetooth unit includes an F-type PCB antenna.

6. The intelligent electronic scale control circuit according to claim 1, characterized in that: The zero-drift compensation value of the PHY6239 Bluetooth master control chip is stored in Flash block 0x1000-0x100F; The PHY6239 Bluetooth main control chip has a built-in NTC temperature sensor with a sampling period of 10 seconds.

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