AKYSC100uA digital ultramicro high-precision direct current detection equipment and method

Abstract

The invention relates to the field of current detection, in particular to AKYSC100uA digital ultramicro high-precision direct current detection equipment and method. The detection device comprises: a shielding housing unit comprising a housing made of a conductive material to provide stable electromagnetic shielding and mechanical support; the circuit board is installed in the shell, and an analog signal area, a digital processing area and a power management area are arranged on the circuit board; and the signal acquisition and protection unit comprises an input interface arranged on the shell, and an overload protection module, a micro-current sampling module and a signal conditioning module which are arranged on the circuit board. The device ingeniously balances the measurement sensitivity and the influence on a measured circuit, ensures that a detection signal which is strong enough is prevented from being submerged by noise, and also reduces the interference of an instrument on the working state of the measured circuit during measurement, so that high accuracy and high authenticity are realized in micro current measurement.

Description

Technical Field

[0001] This invention relates to the field of current detection, and more particularly to an AKYSC100uA digital ultra-micro high-precision DC detection device and method. Background Technology

[0002] In cutting-edge technology fields such as precision instruments, microelectronic device characteristic analysis, electrochemical research, and biomedical sensing, increasingly stringent requirements are being placed on the accurate measurement of microampere-level DC current. Achieving high-precision and high-stability measurement across the entire measurement range, especially in the range of 100μA and below, has become a key indicator for evaluating the performance of high-end testing equipment and a core technological bottleneck that has long plagued the industry.

[0003] Currently, the mainstream technologies for microampere-level DC measurements mainly include the microampere range of high-precision digital multimeters and feedback measurement circuits based on operational amplifiers. However, these technologies still have shortcomings in practical applications. The core of the measurement is converting a tiny current into a voltage signal through a sampling resistor. To achieve high sensitivity, a large-value resistor is theoretically required; that is, to generate a measurable 100mV voltage at a 100μA current, a 1kΩ resistor is needed. However, a large resistance value directly leads to two major problems: First, a non-negligible input voltage drop, which will be connected in series with the circuit under test, severely "loading" and altering the actual operating state of the circuit, rendering the measured value meaningless. Second, a large resistance value amplifies the resistor's thermal noise and forms a low-pass filter with the circuit's distributed capacitance, reducing the signal-to-noise ratio and limiting the system bandwidth. Conversely, if a small-value sampling resistor (such as 10Ω) is used to reduce the voltage drop, a 100μA current will only generate a weak 1mV voltage. This places extremely stringent requirements on the gain, noise, and drift performance of the back-end amplifier, making the system easily overwhelmed by noise at the low end of the full measurement range, affecting detection accuracy.

[0004] Therefore, it is necessary to provide a new AKYSC100uA digital ultra-micro high-precision DC detection device and method to solve the above-mentioned technical problems. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides an AKYSC100uA digital ultra-micro high-precision DC detection device and method.

[0006] The AKYSC100uA digital ultra-micro high-precision DC testing device provided by this invention includes: A shielding housing unit, comprising an outer shell made of conductive material to provide stable electromagnetic shielding and mechanical support; The circuit board is installed inside the housing and has an analog signal area, a digital processing area and a power management area. The signal acquisition and protection unit includes an input interface mounted on the housing, and an overload protection module, a micro-current sampling module, and a signal conditioning module mounted on the circuit board.

[0007] Preferably, the interior of the outer shell is divided into a first chamber and a second chamber by a metal partition plate; The analog signal area on the circuit board is located inside the first chamber, while the digital processing area and the power management area are located inside the second chamber.

[0008] Preferably, the outer casing is also provided with a low-impedance grounding post.

[0009] Preferably, the input interface is a Kelvin input terminal.

[0010] Preferably, the overload protection module is a multi-level protection circuit, including a self-resetting fuse connected in series in the signal circuit and a transient voltage suppression diode connected in parallel between the signal circuit and ground.

[0011] Preferably, the microcurrent sampling module includes a manganese copper resistor, a ceramic insulator for fixing the sampling resistor, and a copper heat spreader that is thermally connected to the sampling resistor. The manganese copper resistor is electrically connected to the signal conditioning module via a four-wire system, and the signal conditioning module amplifies the voltage signal.

[0012] Preferably, a temperature sensor for real-time temperature monitoring is also provided near the manganese copper resistive element.

[0013] Preferably, the signal conditioning module is provided with a shield to isolate it from electromagnetic interference with external circuits.

[0014] A method for detecting AKYSC100uA digital ultra-micro high-precision DC signals includes the following steps: S1, Signal Access; The current signal to be measured is connected to the testing equipment through the Kelvin terminal; S2, Initial data collection; The measured current flows through the manganese copper resistor, which converts the microampere-level current signal into a weak voltage signal. S3, Secondary data acquisition; The voltage signal is amplified using a signal conditioning module. The amplified voltage signal is then sampled a second time by an analog-to-digital converter and converted into a digital signal. S4. Information processing and output; A digital filtering algorithm is applied to the original digital signal to suppress random noise, and then the filtered digital signal is compensated in real time to correct measurement errors caused by temperature changes. The temperature-compensated digital signal is combined with the current system gain and resistance value to calculate the final DC current value, which is then output through a display unit or communication interface.

[0015] Compared with related technologies, the AKYSC100uA digital ultra-micro high-precision DC detection device provided by the present invention has the following beneficial effects: The device cleverly balances measurement sensitivity with its impact on the circuit under test, ensuring a sufficiently strong detection signal to avoid being drowned out by noise, while reducing the interference of the instrument on the working state of the circuit under test during measurement. Thus, it achieves both high accuracy and high fidelity in the measurement of minute currents. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a preferred embodiment of the AKYSC100uA digital ultra-micro high-precision DC detection device and method provided by the present invention. Figure 2 This is a schematic diagram of the structure of the shielding housing unit shown in this invention; Figure 3 This is a schematic diagram of the circuit board structure shown in this invention; Figure 4 This is a schematic diagram of the signal acquisition and protection unit shown in this invention; Figure 5 This is a schematic diagram of the overload protection module shown in this invention; Figure 6 This is a schematic diagram of the microcurrent sampling module shown in this invention; Figure 7 This is a schematic diagram of the measurement method shown in this invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0018] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0019] Please see Figures 1 to 7 The present invention provides an AKYSC100uA digital ultra-micro high-precision DC testing device and method. The AKYSC100uA digital ultra-micro high-precision DC testing device includes a shielded housing unit, a circuit board, and a signal acquisition and protection unit.

[0020] For shielded housing units; Please see Figure 2 The shielded housing unit includes an outer shell, inside which a metal isolation plate is provided, dividing the interior of the outer shell into a first chamber and a second chamber. A grounding post of the resistance group is also provided on the outer shell.

[0021] It should be noted that the shielding housing unit, as the external basic structure of the entire device, is mainly made of conductive material. This housing can stably support the components installed inside, effectively block the intrusion of external electromagnetic fields, and suppress the leakage of electromagnetic signals generated when the internal circuit is working, thereby forming a stable detection environment. A metal isolation plate is fixed inside the outer shell. The metal isolation plate is made of the same material as the outer shell and divides the interior of the outer shell into two independent chambers, namely the first chamber and the second chamber, thereby realizing the functional partitioning and physical isolation of the internal circuit of the device. A low-impedance grounding post is also installed on the outside of the casing. This grounding post is preferably made of a high-conductivity metal material. Its function is to provide a reliable, low-impedance reference potential point and a discharge channel for this shielding system. That is, when the device encounters external static electricity or surge interference, the interference energy can be quickly conducted to the ground through this grounding post, and the high-frequency noise generated by the internal circuit can also be effectively guided and absorbed through this path, thereby further ensuring the internal stability.

[0022] For circuit boards; Please see Figure 3 The circuit board is installed inside the housing, and the circuit board is provided with an analog signal area located inside the first chamber and a digital processing area and a power management area located inside the second chamber.

[0023] It should be noted that the circuit board is installed inside the housing and has an analog signal area, a digital processing area, and a power management area to achieve regional adjustment and control. The analog signal area on the circuit board is located inside the first chamber. This area is mainly used to install weak signal processing circuits that are extremely sensitive to electromagnetic interference. These include a resistor structure for converting microampere-level current into a voltage signal, a low-noise operational amplifier circuit responsible for the initial amplification of the weak voltage, and a highly stable component that provides a voltage reference. All these components operate in the analog signal domain and typically process continuously changing small voltage or current signals, which are highly susceptible to external noise interference. Therefore, they are placed in a separate first chamber to maximize the isolation from noise from digital circuits and power supply circuits, thereby ensuring the high fidelity and purity of the original analog signal throughout the entire process from acquisition to initial amplification. The digital processing area and power management area of ​​the circuit board are located inside the second chamber. The digital processing area mainly integrates microcontrollers, digital memory, and communication interface chips for logic operations and data processing. These digital components generate high-frequency square wave signals and harmonic noise during operation, which are the main sources of interference inside the device. The power management area houses DC-DC conversion modules and linear regulators that convert external input power into various voltages required by the device. Their switching operations also introduce ripple and conducted interference. Therefore, by placing these two noisy components together in the second chamber and separating them from the analog signal area with a metal isolation plate, the state switching noise of the digital circuit and the switching ripple of the power circuit are confined within the second chamber. This reduces the intensity of their coupling to the analog signal area of ​​the first chamber through spatial radiation or internal circuit board traces, thereby improving detection accuracy.

[0024] The signal acquisition and protection unit includes an input interface, an overload protection module, a micro-current sampling module, and a signal conditioning module. Please see Figure 4 The input interface is a Kelvin input terminal.

[0025] It should be noted that the input interface adopts Kelvin input terminals (also known as four-wire connection method), which is a unique connection method designed for high-precision measurement. That is, the terminal consists of four independent wiring ports, divided into two groups: one group is the current terminal, which is used to guide the current to be measured to the sampling resistor inside the device; the other group is the voltage terminal, which is used to directly read the voltage signal across the sampling resistor, so as to achieve complete separation of current transmission and voltage measurement. Meanwhile, since the voltage detection terminal is connected to the high-impedance circuit inside the instrument, the current flowing through the voltage detection wire is almost zero. Therefore, the resistance of the wire in the voltage detection path will not generate an additional voltage drop. That is, the voltage value read by the instrument comes only from the sampling resistor itself, eliminating the influence of the resistance of all connecting wires. This makes the measurement results more realistic and reliable, and will not change due to the length, thickness or tightness of the test wire, thus ensuring the accuracy of the measurement.

[0026] Please see Figure 5 The overload protection module is a multi-level protection circuit, including a current-sensitive protection element connected in series in the signal circuit and a voltage-sensitive protection element connected in parallel between the signal circuit and ground.

[0027] It should be noted that the overload protection module is mainly designed to ensure the safety of the internal precision circuitry when the device is subjected to abnormal electrical shocks, without affecting the normal microampere-level measurement accuracy. The current-sensitive protection element is preferably a self-resetting fuse. Therefore, when a continuous overcurrent occurs in the circuit due to an unexpected situation, its resistance will increase rapidly, thereby effectively limiting the current and protecting the downstream components from damage. After the fault is cleared, the element can automatically return to its initial state without manual replacement. Voltage-sensitive protection components are preferably transient voltage suppression diodes and other devices. Therefore, when a momentary high voltage pulse or electrostatic discharge occurs in the line, it can respond quickly to form a low-impedance path and rapidly discharge the dangerous overvoltage energy to ground, thereby suppressing the voltage spike at the input terminal and preventing the fragile semiconductor device from being broken down. In this design, the current-sensitive protection element mainly deals with continuous or slowly changing overcurrent threats, while the voltage-sensitive protection element specializes in transient overvoltage impacts. The two work together to achieve circuit safety protection. Moreover, under normal measurement conditions, these protection elements all exhibit a high-resistance state and will not introduce additional leakage current or impedance into the measurement circuit, thus not interfering with the accurate measurement of microampere current.

[0028] Please see Figure 6 The microcurrent sampling module includes a sampling resistor, a mounting base for fixing the sampling resistor, and a heat transfer component that is thermally connected to the sampling resistor. The sampling resistor is electrically connected to the signal conditioning module via a four-wire connection, and the signal conditioning module amplifies the voltage signal. A temperature sensor for real-time temperature monitoring is also provided near the sampling resistor.

[0029] It should be noted that for sampling resistors, manganese copper resistors are preferred. Manganese copper has an extremely low temperature coefficient, so its resistance can remain constant when the ambient temperature changes or when the resistor heats up due to its own current. Moreover, manganese copper material also has the characteristic of low thermoelectric potential to copper. That is, when two different metals are connected, a small potential difference related to temperature, i.e. thermoelectric potential, will be generated at the contact point. Since the wires and pads in the circuit are usually made of copper, using manganese copper as the resistor can minimize the thermoelectric potential generated when the resistor pins are connected to the external copper circuit. For the heat transfer component, a copper heat spreader is preferred, which is in direct contact with the sampling resistor, thereby quickly and evenly dispersing the heat generated by the resistor during operation, avoiding the formation of local hot spots, and reducing reading drift caused by uneven internal temperature. The temperature sensor is designed for sampling resistors and can monitor the operating temperature of the resistors in real time. The obtained data is directly transmitted to the processing system, which can then compensate and correct the current measurement value in real time.

[0030] Please see Figure 7The signal conditioning module is equipped with a shield to isolate it from electromagnetic interference with external circuits.

[0031] A method for detecting AKYSC100uA digital ultra-micro high-precision DC signals includes the following steps: S1, Signal Access; The current signal to be measured is connected to the testing equipment through the Kelvin terminal; S2, Initial data collection; The measured current flows through the manganese copper resistor, which converts the microampere-level current signal into a weak voltage signal. S3, Secondary data acquisition; The voltage signal is amplified using a signal conditioning module. The amplified voltage signal is then sampled a second time by an analog-to-digital converter and converted into a digital signal. S4. Information processing and output; A digital filtering algorithm is applied to the original digital signal to suppress random noise, and then the filtered digital signal is compensated in real time to correct measurement errors caused by temperature changes. The temperature-compensated digital signal is combined with the current system gain and resistance value to calculate the final DC current value, which is then output through a display unit or communication interface.

[0032] Its specific usage process is not yet available. First, the DC current signal to be measured is connected through the Kelvin input terminal in the device. This four-wire terminal can guide the current to be measured to the internal sampling resistor and detect the voltage across the resistor separately. Before entering the core circuit, the current will first pass through a multi-stage overload protection circuit. This circuit can suppress and absorb possible instantaneous overvoltage or overcurrent surges to improve the protection effect of the entire device. The introduced current then flows through the manganese copper resistor located in the analog signal region, and the manganese copper resistor converts the current signal into a weak voltage signal that is proportional to it. The weak voltage signal obtained is usually only at the millivolt or even microvolt level and is easily drowned out by noise. At this time, the signal is sent to the signal conditioning module to amplify the voltage signal through the operational amplifier so that it reaches the input range of the subsequent analog-to-digital converter. Then, the amplified analog voltage is sampled a second time and converted into the original digital signal. The digital signal is first processed by a digital filtering algorithm (such as moving average filtering) applied by the microprocessor to remove high-frequency noise and improve the stability and signal-to-noise ratio of the readings. At the same time, the system calls the real-time temperature data collected by the temperature sensor installed next to the sampling resistor and performs real-time software compensation on the signal based on the pre-stored high-precision temperature-resistance characteristic model to accurately correct the measurement error caused by changes in ambient temperature or slight temperature drift of components. Finally, the system calculates the final DC current value by combining the filtered and temperature-compensated digital signal with the system gain of the current range and the precise resistance value of the sampling resistor. This high-precision result is presented to the user intuitively on the display screen or sent to the host computer system through the communication interface to complete the entire measurement process.

[0033] The above are merely embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. An AKYSC100uA digital ultra-micro high-precision DC testing device, characterized in that, The detection equipment includes: A shielding housing unit, comprising an outer shell made of conductive material to provide stable electromagnetic shielding and mechanical support; The circuit board is installed inside the housing and has an analog signal area, a digital processing area and a power management area. The signal acquisition and protection unit includes an input interface mounted on the housing, and an overload protection module, a micro-current sampling module, and a signal conditioning module mounted on the circuit board.

2. The AKYSC100uA digital ultra-micro high-precision DC testing equipment according to claim 1, characterized in that, The interior of the outer shell is divided into a first chamber and a second chamber by a metal partition plate; The analog signal area on the circuit board is located inside the first chamber, while the digital processing area and the power management area are located inside the second chamber.

3. The AKYSC100uA digital ultra-micro high-precision DC testing equipment according to claim 2, characterized in that, The outer casing is also equipped with a low-impedance grounding post.

4. The AKYSC100uA digital ultra-micro high-precision DC testing equipment according to claim 1, characterized in that, The input interface is a Kelvin input terminal.

5. The AKYSC100uA digital ultra-micro high-precision DC testing equipment according to claim 1, characterized in that, The overload protection module is a multi-level protection circuit, including a self-resetting fuse connected in series in the signal circuit and a transient voltage suppression diode connected in parallel between the signal circuit and ground.

6. The AKYSC100uA digital ultra-micro high-precision DC testing equipment according to claim 1, characterized in that, The microcurrent sampling module includes a manganese copper resistor, a ceramic insulator for fixing the sampling resistor, and a copper heat spreader that is thermally connected to the sampling resistor. The manganese copper resistor is electrically connected to the signal conditioning module via a four-wire system, and the signal conditioning module amplifies the voltage signal.

7. The AKYSC100uA digital ultra-micro high-precision DC testing equipment according to claim 6, characterized in that, A temperature sensor for real-time temperature monitoring is also provided near the manganese copper resistor.

8. The AKYSC100uA digital ultra-micro high-precision DC testing equipment according to claim 1, characterized in that, The signal conditioning module is equipped with a shield to isolate it from electromagnetic interference with external circuits.

9. The AKYSC100uA digital ultra-micro high-precision DC detection method according to claims 1-8, characterized in that, Includes the following steps: S1, Signal Access; The current signal to be measured is connected to the testing equipment through the Kelvin terminal; S2, Initial data collection; The measured current flows through the manganese copper resistor, which converts the microampere-level current signal into a weak voltage signal. S3, Secondary data acquisition; The voltage signal is amplified using a signal conditioning module. The amplified voltage signal is then sampled a second time by an analog-to-digital converter and converted into a digital signal. S4. Information processing and output; A digital filtering algorithm is applied to the original digital signal to suppress random noise, and then the filtered digital signal is compensated in real time to correct measurement errors caused by temperature changes. The temperature-compensated digital signal is combined with the current system gain and resistance value to calculate the final DC current value, which is then output through a display unit or communication interface.

Images