Adjustable constant current source high-precision calibration method and device based on gesture interaction

Abstract

The invention relates to an adjustable constant current source high-precision calibration method and device based on gesture interaction. According to the method, a gesture instruction of a user is received through a rotary encoder which is a simple and visual man-machine interaction interface, the zero setting and full scale calibration process is automatically completed by a microcontroller, and a digital mapping model is established. Calibration parameters are stored in a nonvolatile memory, and the equipment can be automatically loaded and put into high-precision work after being electrified again. A traditional analog potentiometer is completely abandoned, the three problems of low calibration efficiency, large temperature drift and poor reliability are solved, the calibration time is shortened to be within 30 seconds, the precision is improved to + / -0.5 mA, and the production efficiency and the long-term stability of products are remarkably improved. The precise current output circuit can be widely applied to various devices needing precise current output.

Description

Technical Field

[0001] This invention relates to the field of precision electronic measurement and power control technology, specifically to a high-precision calibration method and device for an adjustable constant current source based on gesture interaction. Background Technology

[0002] Constant current sources are key components in modern electronic devices, widely used in semiconductor testing, LED driving, laser power supply, battery charging, and precision sensor excitation. The accuracy and stability of their output current directly determine the performance of the entire system.

[0003] Currently, most low- to mid-range constant current source products use analog potentiometers for calibration. Before leaving the factory, technicians need to repeatedly adjust the "Zero" and "SPAN" potentiometers with a screwdriver to make the output current close to 0A at zero input and reach the nominal value (e.g., 4.00A) at maximum input. This process has the following inherent defects:

[0004] 1. Low calibration efficiency: The adjustment process relies on manual experience and feel, requiring repeated observation of the standard meter reading and minute adjustments, with each power supply taking 3-5 minutes. After adjustment, the potentiometer needs to be fixed with adhesive to prevent vibration from causing resistance changes, further increasing production time and cost.

[0005] 2. Poor temperature stability (temperature drift): Commonly used carbon film or ceramic potentiometers have a large temperature coefficient, typically ±200ppm / ℃. This means that a temperature change of 50℃ can introduce a 1% resistance change in the potentiometer itself, causing the output current to drift and failing to meet the long-term stability requirements of high-precision applications.

[0006] 3. Insufficient long-term reliability: The metal contacts and resistive film of potentiometers are prone to oxidation and wear, especially in humid or dusty environments, which can lead to poor contact, resistance jumps or slow drift, requiring the equipment to be returned to the factory for recalibration frequently, resulting in high maintenance costs.

[0007] Although some high-end devices use digital potentiometers (DigiPot) or DACs instead of analog potentiometers, their calibration processes remain cumbersome and do not fundamentally solve the problems of low interactive efficiency and reliance on experience. Therefore, the industry urgently needs a new calibration scheme that is simple to operate, efficient, and can fundamentally overcome the shortcomings of analog potentiometers. Summary of the Invention

[0008] To address the technical problems of low calibration efficiency, susceptibility to temperature drift, poor long-term reliability, and excessive reliance on human experience in existing constant current source calibration technologies, this invention provides a high-precision calibration method and apparatus for adjustable constant current sources based on gesture interaction.

[0009] This invention is achieved through the following technical solution:

[0010] A high-precision calibration method for an adjustable constant current source based on gesture interaction includes the following steps:

[0011] S1: The system powers on and enters calibration mode;

[0012] S2: Zero Calibration: The microcontroller (MCU) controls the constant current source output channel to be closed, and the theoretical output current is 0A. The operator rotates the encoder clockwise or counterclockwise, and the MCU performs high-speed sampling and quantization of the current feedback signal through the internal or external ADC module, and stores the stable average value as the zero-point quantization value AD0;

[0013] S3: Full-scale calibration: The MCU controls the constant current source output to an initial full-scale value. The operator rotates the encoder to finely adjust the output current until the high-precision standard ammeter connected to the output circuit displays the target full-scale value (e.g., 100.0A). The MCU records the quantized value AD1 of the feedback signal at this time.

[0014] S4: Mapping relationship establishment: The MCU establishes a linear mapping relationship between the quantization range of AD0 to AD1 and the target full-scale current value in the digital domain;

[0015] S5: Parameter storage: Encrypt AD0, AD1 and mapping parameters and store them in non-volatile memory;

[0016] S6: Normal Operation: After power-on, the system automatically loads calibration parameters and enters operating mode. The user can set the output current value by rotating the encoder. The MCU generates a PWM wave based on the mapping relationship and PID control algorithm to drive the power stage and achieve high-precision constant current output.

[0017] An apparatus for implementing the above method includes:

[0018] - Gesture input module: used to generate calibration commands and setting commands, which is a rotary encoder, preferably a photoelectric or magnetoelectric encoder;

[0019] -Signal Processing and Control Module: This is the core microcontroller unit (MCU), used to acquire encoder pulses, recognize gesture direction and speed, execute calibration algorithms, calculate mapping relationships, and run control algorithms.

[0020] - Current sampling and analog-to-digital conversion module: including sampling resistors, high-precision operational amplifiers and ADC chips, used to acquire output current signals and convert them into digital quantities;

[0021] - Data storage module: a non-volatile memory, such as EEPROM or FRAM, used to securely store calibration parameters;

[0022] - Power output module: including PWM controller, MOSFET or IGBT power transistors, inductor, etc., driven by the PWM signal output by MCU, to provide constant current power to the load.

[0023] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0024] 1. Extremely high efficiency: Reduces the calibration time of a single device from 3-5 minutes to less than 30 seconds, significantly improving production efficiency.

[0025] 2. Ultra-high precision: Eliminates all errors caused by mechanical potentiometers, and the current control accuracy can reach ±0.5mA (relative accuracy of 0.0005% based on a 100A range).

[0026] 3. Excellent stability: With no moving mechanical contact parts, the problems of temperature drift and oxidation are completely solved, and the long-term stability is improved by more than an order of magnitude.

[0027] 4. Strong anti-interference capability: The hardware adopts RC filtering and the software adopts digital filtering (such as moving average and Kalman filtering) to effectively suppress noise.

[0028] 5. Simple and intuitive operation: No professional tools or experience are required, reducing the technical requirements for operators and achieving "foolproof" calibration.

[0029] 6. High versatility: The method and apparatus described can be widely used for the calibration of single-channel, multi-channel constant current sources and constant voltage sources. Attached Figure Description

[0030] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0031] Figure 1 This is a schematic diagram of the constant current source control system structure according to an embodiment of the present invention.

[0032] Figure 2 This is a schematic diagram of the phase relationship and rotation direction determination of the encoder dual-path pulses (phase A and phase B) in an embodiment of the present invention.

[0033] Figure 3 This is a flowchart of the calibration mode operation according to an embodiment of the present invention.

[0034] Figure 4 This is a schematic diagram of the current feedback signal error amplification according to an embodiment of the present invention. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0036] Reference Figures 1-4 A high-precision calibration method for an adjustable constant current source based on gesture interaction is disclosed, comprising: receiving gesture commands input by a user via a rotary encoder, wherein the gesture commands are used to perform zeroing and full-scale calibration operations in calibration mode and to set the output current value in working mode; a microcontroller acquiring dual-channel pulse signals output by the rotary encoder, determining the rotation direction by judging the phase difference between the two signals, and counting the number of pulses to determine the rotation amplitude; in the zeroing calibration operation, the microcontroller controls the constant current source output to zero, acquires the current feedback signal, and records its quantized value as the zero point AD0; in the full-scale calibration operation, the microcontroller controls the constant current output to an initial value, acquires the current feedback signal, and records its quantized value as the full-scale value AD1 based on the feedback signal adjusted by the user through the rotary encoder; establishing a linear mapping relationship between the quantization interval AD0 to AD1 and the target full-scale current value; storing AD0, AD1, and mapping parameters in a non-volatile memory; automatically loading the parameters when the system is powered on again, and driving the power output stage based on the mapping relationship and control algorithm to achieve high-precision constant current output.

[0037] An apparatus for implementing the method of claim 1, characterized in that it comprises: a gesture input module, which is a rotary encoder, for generating calibration and control commands; a microcontroller module, for processing encoder signals, executing calibration procedures, calculating mapping relationships, and running control algorithms; a current sampling and analog-to-digital conversion module, for acquiring output current feedback signals and converting them into digital quantized values; a non-volatile storage module, for securely storing calibration parameters; and a power output and control module, driven by the PWM signal output by the microcontroller, for providing constant current power to the load.

[0038] Furthermore, the non-volatile memory is EEPROM, Flash, or FRAM.

[0039] Furthermore, the control algorithm is either a proportional-integral-derivative (PIT) control algorithm or a fuzzy control algorithm.

[0040] Furthermore, the rotary encoder can be a photoelectric or magnetoelectric encoder.

[0041] Furthermore, the device is suitable for single-channel or multi-channel constant current source systems.

[0042] Furthermore, the zeroing and full-scale calibration operations can be repeated multiple times, and the AD0 and AD1 obtained from the multiple calibrations are averaged to use the final average value as the calibration parameter.

[0043] Furthermore, the method and apparatus are also applicable to the calibration and control of constant pressure sources.

[0044] Example 1: Single-channel constant current source calibration

[0045] A single-channel adjustable constant current source calibration device includes an STM32G series MCU, an EC11 rotary encoder, an ADS1115 16-bit ADC, an AT24C02 EEPROM, and a Buck power circuit composed of MOSFETs.

[0046] - After the initial programming, the device will automatically enter calibration mode upon power-up.

[0047] - Zeroing: The MCU outputs a PWM with a 0% duty cycle, theoretically outputting 0A. The operator slightly rotates the encoder, and the MCU continuously samples the voltage on channel 0 of the ADS1115 (corresponding to the voltage drop across the sampling resistor) and displays it in real-time on the LCD. After stabilization, pressing and holding the encoder causes the MCU to store the average value of the samples taken over the past 100ms into the EEPROM, denoted as AD0.

[0048] - Full-scale calibration: The MCU outputs a PWM with a preset duty cycle, providing approximately 100A of current. The operator rotates the encoder to fine-tune the current until the standard meter displays 100.00A. Pressing and holding the encoder again causes the MCU to record the current sample value as AD1.

[0049] The MCU calculates the linear mapping coefficient K = (Target_FullScale - 0) / (AD1 - AD0). Afterward, the device automatically restarts, loads parameters, and enters operating mode. The user can set the output current by rotating the encoder; the set value is I_set = K * (AD_current - AD0).

[0050] Example 2: Calibration of Multi-channel Constant Current Source

[0051] For multi-channel systems, each channel is equipped with an independent sampling amplification circuit. The MCU selects each channel's ADC for sampling in turn via analog switches. The calibration process is similar to that in Example 1, but it needs to be performed channel by channel. The AD0, AD1, and K values ​​of all channels are independently stored in different sectors of the EEPROM and are independently called during operation to ensure the output accuracy and independence of each channel.

[0052] Example 3: High-precision mode and averaging algorithm

[0053] To improve calibration accuracy, a "high-precision mode" option is added based on Example 1. In this mode, the system automatically executes the calibration process three times consecutively (zeroing -> full scale) and records three sets of AD0 and AD1 values ​​respectively. The final value stored in the memory is the average of the three results, i.e., AD0_final = (AD01 + AD02 + AD03) / 3, effectively suppressing random noise and accidental errors.

[0054] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-precision calibration method for an adjustable constant current source based on gesture interaction, characterized in that, include: The rotary encoder receives user-input gesture commands, which are used to perform zeroing and full-scale calibration operations in calibration mode and to set the output current value in working mode. The microcontroller acquires the dual-channel pulse signals output by the rotary encoder, determines the rotation direction by judging the phase difference between the two signals, and counts the number of pulses to determine the rotation amplitude. During the zero-calibration operation, the microcontroller controls the constant current source output to zero, collects the current feedback signal and records its quantized value as the zero point AD0. During the full-scale calibration operation, the microcontroller controls the constant current output to an initial value, collects the current feedback signal, and records its quantized value as the full-scale value AD1 based on the feedback signal adjusted by the user through the rotary encoder. Establish a linear mapping relationship between the quantization interval from AD0 to AD1 and the current value from 0 to the target full-scale range; AD0, AD1, and the mapping parameters are stored in non-volatile memory; When the system is powered on again, the parameters are automatically loaded, and the power output stage is driven based on the mapping relationship and control algorithm to achieve high-precision constant current output.

2. An apparatus for implementing the method of claim 1, characterized in that, include: The gesture input module is a rotary encoder used to generate calibration and control commands; The microcontroller module is used to process encoder signals, execute calibration procedures, calculate mapping relationships, and run control algorithms. The current sampling and analog-to-digital conversion module is used to acquire the output current feedback signal and convert it into a digital quantized value; Non-volatile memory modules are used to securely store calibration parameters; The power output and control module, driven by the PWM signal output by the microcontroller, provides constant current power to the load.

3. The high-precision calibration method for an adjustable constant current source based on gesture interaction according to claim 1, characterized in that: The non-volatile memory is EEPROM, Flash, or FRAM.

4. The high-precision calibration method for an adjustable constant current source based on gesture interaction according to claim 1, characterized in that: The control algorithm is either a proportional-integral-derivative (PIT) control algorithm or a fuzzy control algorithm.

5. The high-precision calibration method for an adjustable constant current source based on gesture interaction according to claim 1, characterized in that: The rotary encoder is either a photoelectric or magnetoelectric encoder.

6. The high-precision calibration method for an adjustable constant current source based on gesture interaction according to claim 1, characterized in that: The zeroing and full-scale calibration operations can be repeated multiple times, and the AD0 and AD1 obtained from the multiple operations are averaged respectively, with the final average value used as the calibration parameter.

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