Low-voltage direct-current power supply ripple automatic testing device

Abstract

The invention discloses a low-voltage direct-current power supply ripple automatic testing device, and relates to the technical field of automatic testing, the device comprises a testing host, a signal acquisition module, an anti-interference shielding assembly and an automatic control module, the front side of the testing host is provided with a display panel, and an operation key group is arranged below the display panel; the signal acquisition module is fixedly installed on the left side in the test host, the input end of the signal acquisition module is connected with an external interface through a wire, and the external interface is embedded in the left side wall surface of the test host; the anti-interference shielding assembly is arranged on the periphery of the signal acquisition module and comprises a shielding shell, a filter bank and a grounding ring; the automatic control module is arranged on the right side in the test host, the automatic control module comprises a main control chip, a relay group and a signal processing unit, and the device realizes the automatic test of the ripple of the low-voltage direct-current power supply.

Description

Technical Field

[0001] The present invention relates to the technical field of automatic testing, and specifically to an automatic testing device for the ripple of a low-voltage DC power supply. Background Art

[0002] With the continuous improvement of the requirements for power supply stability of electronic devices, low-voltage DC power supplies are increasingly widely used in fields such as consumer electronics, industrial control, and medical equipment. As a core indicator for evaluating power supply performance, the test accuracy, efficiency, and anti-interference ability of ripple parameters directly affect the optimization of power supply design, production quality inspection, and the reliability of equipment operation.

[0003] However, traditional methods for testing the ripple of low-voltage DC power supplies often face the following problems when dealing with high-precision measurement, complex electromagnetic environments, and automated testing requirements: First, insufficient anti-interference ability: Most traditional testing devices use single-layer metal shielding or simple filter circuits, which are difficult to effectively suppress external electromagnetic radiation and self-circuit noise, resulting in too high measurement errors of the effective ripple value and unable to meet the accuracy requirements in precision scenarios; Second, low testing efficiency: In the manual operation mode, it is necessary to frequently switch test channels, adjust attenuation ratios, and bandwidth parameters manually, and the time-consuming for a single complete test is long. When facing product testing, manual operation easily leads to an extended test cycle and may cause mismeasurement due to operational negligence; In addition, the signal processing means are single: Traditional solutions only directly calculate the effective ripple value in the time domain, unable to analyze the frequency components of the signal and difficult to locate the specific source of abnormal ripples. Summary of the Invention

[0004] The purpose of the present invention is to provide an automatic testing device for the ripple of a low-voltage DC power supply to solve the problems raised in the prior art.

[0005] To achieve the above purpose, the present invention provides the following technical solution: An automatic testing device for the ripple of a low-voltage DC power supply, the device includes a test host, a signal acquisition module, an anti-interference shielding component, and an automated control module. Among them, a display panel is provided on the front side of the test host, and an operation button group is provided below the display panel; The signal acquisition module is fixedly installed on the left side inside the test host, and the input end of the signal acquisition module is connected with an external interface through a wire, and the external interface is embedded in the left wall surface of the test host; The anti-interference shielding component is arranged around the signal acquisition module, and the anti-interference shielding component includes a shielding housing, a filter bank, and a grounding ring; The automated control module is arranged on the right side inside the test host, and the automated control module includes a main control chip, a relay group, and a signal processing unit.

[0006] An expansion interface group is provided at the top of the test host. The expansion interface group includes an analog signal input interface, a digital signal input interface, and a communication interface. The analog signal input interface and the digital signal input interface are respectively connected to the input end of the signal acquisition module through wires, and the communication interface is connected to the main control chip through a data line. Support feet are provided at the bottom of the test host.

[0007] The shielding housing is a double-layer metal structure. An absorbing material is coated on the inner surface of the shielding housing, and a number of uniformly distributed heat dissipation holes are provided on the outer surface of the shielding housing. The filter group is arranged on the inner bottom surface of the shielding housing, and the filter group includes a low-pass filter and a band-stop filter. The grounding ring surrounds the outside of the shielding housing, and the grounding ring is connected to the grounding terminal of the test host through a wire.

[0008] The main control chip is connected to the display panel and the operation button group through a data bus. The output end of the main control chip is connected to the relay group through a control signal line. The output end of the relay group is connected to the control end of the signal acquisition module through a wire, and the output end of the signal acquisition module is connected to the signal processing unit through a data line. The output end of the signal processing unit is connected to the main control chip through a data line.

[0009] The number of the support feet is four and they are distributed in a rectangle at the four corners of the bottom of the test host. Anti-slip pads are provided at the bottom of the support feet. Among them, the material of the anti-slip pads is silicone.

[0010] The test host receives the signal of the low-voltage DC power supply to be tested through the BNC interface and transmits the signal to the signal acquisition module. After the signal acquisition module preliminarily processes the signal, it transmits the processed signal to the signal processing unit. After the signal processing unit performs analog-to-digital conversion and digital signal processing on the signal, it transmits the processing result to the main control chip. The main control chip controls the display panel to display the test result according to the processing result. Among them, the signal acquisition module collects data through the control of the ADC and performs preliminary processing according to the collected data to calculate the ripple coefficient. The specific steps are as follows;

[0011] The definition of the ripple coefficient is as follows:

[0012] Use the ADC to collect the output voltage data within a certain period of time;

[0013] Filter the collected data to filter out the noise;

[0014] Calculate the average value of the collected data to obtain the DC voltage;

[0015] Calculate the effective value of the ripple voltage. Among them, there are two calculation methods for calculating the effective value of the ripple voltage:

[0016] Calculation method 1: First subtract the DC component, and then calculate the root mean square value of the remaining AC component;

[0017] Calculation method 2: Use the Fast Fourier Transform (FFT) to analyze the frequency components of the signal, calculate the energy of the ripple frequency, and then convert it into the effective value;

[0018] Calculate the ripple coefficient, where the ripple coefficient is calculated by the ratio of the effective value of the ripple voltage to the DC output voltage.

[0019] An insulating layer is provided between the inner layer and the outer layer of the shielding housing, and the material of the insulating layer is asbestos fiber; a detachable cover plate is provided at the top of the shielding housing, and the material of the cover plate is aluminum alloy.

[0020] During the signal acquisition process, the anti-interference shielding component shields the signal acquisition module from electromagnetic interference. The double-layer metal structure and the inner layer absorbing material of the shielding housing absorb external electromagnetic interference. The heat dissipation holes on the outer layer of the shielding housing can ensure the heat dissipation performance of the signal acquisition module. The low-pass filter and the band-stop filter in the filter bank can filter out high-frequency interference and interference in specific frequency bands in the signal. The grounding ring can conduct the static charge on the shielding housing into the grounding terminal of the test host, so as to ensure the normal operation of the signal acquisition module.

[0021] The automatic control module controls the switch state of the relay group through the main control chip and controls the input channel selection of the signal acquisition module. After the signal processing unit performs analog-to-digital conversion and digital signal processing on the signal collected by the signal acquisition module, it transmits the processing result to the main control chip. The main control chip displays the test result according to the processing result and outputs the test data through the communication interface.

[0022] A low-voltage DC power supply ripple automatic test device includes two parts: hardware and software. Specifically:

[0023] The hardware part includes: input interface, protection circuit, signal conditioning circuit, analog-to-digital converter, microcontroller, display screen, keys, power supply and housing. Among them, the input interface includes a BNC connector: used to connect the power supply under test; the protection circuit includes overvoltage protection and overcurrent protection to prevent damage to the instrument due to incorrect operation; the signal conditioning circuit includes an attenuator (used to attenuate high-voltage signals to an appropriate range to protect subsequent circuits), an amplifier (used to amplify weak ripple signals to improve measurement accuracy) and a filter; the filter includes a low-pass filter, a high-pass filter and a differential amplifier. The low-pass filter: used to filter out high-frequency noise and improve the signal-to-noise ratio; the high-pass filter (optional): used to filter out the DC component and only retain the ripple signal; the differential amplifier (important): converts a single-ended signal into a differential signal to suppress common-mode noise, which is the key to anti-interference of handheld devices; the resolution of the analog-to-digital converter: at least 12 bits, preferably 16 bits or higher to ensure measurement accuracy; the sampling rate: selected according to the ripple frequency range of the power supply under test, at least more than 2 times the highest frequency of the measured signal (Nyquist sampling theorem); the microcontroller is used to control the ADC to perform data acquisition, process the acquired data, calculate the ripple coefficient, control the display screen to display the test results, process key inputs, and manage the power supply; among them, the microcontroller selects an MCU with sufficient processing power and storage space; select an MCU with low-power characteristics to extend the battery life; common selections include ARM Cortex-M series MCUs; the display screen types include: LCD and OLED; the keys are used to set parameters, start tests, select display modes, etc., and the number of keys is determined according to functional requirements; the power supply includes: a battery (using a rechargeable lithium battery to provide sufficient battery life) and a power management chip (used to manage the charging and discharging of the battery and protect the battery); the housing is made of strong and durable materials, such as ABS plastic or metal;

[0024] The software part includes: ADC driver, data processing, display driver, key processing and power management. Among them, the ADC driver controls the ADC to perform data acquisition; the data processing processes the acquired data and calculates the ripple coefficient; the display driver controls the display screen to display the test results; the key processing processes key inputs; the power management manages the power supply.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] 1. The present invention constructs a three-dimensional anti-interference system of "double-layer metal shielding + multi-stage filtering + intelligent grounding". Through the electromagnetic reflection of the double-layer metal shell and the energy absorption of the wave-absorbing material, wide-band interference is suppressed. The low-pass filter and the band-stop filter are used to specifically filter out high-frequency noise and interference in specific frequency bands. Combining with the static charge discharge mechanism of the grounding ring, a full-link noise suppression from signal acquisition to processing is formed, which is different from the single-layer shielding or simple filtering design in the prior art.

[0027] 2. The present invention introduces an automatic control module and a multi-channel switching mechanism. The automatic control module realizes the multi-channel automatic switching function through the main control chip and the relay group, improving the test efficiency while reducing manual intervention. Compared with the manual switching method, the test time is shortened.

[0028] 3. By dynamically analyzing the frequency components and time-domain characteristics of the ripple signal, combining multiple dimensions such as the DC voltage, the effective value of the ripple voltage, the ripple coefficient, and the energy proportion of each frequency component, through the fast Fourier transform (FFT) and the power superposition algorithm, the source of the ripple and abnormal components are identified. Different from the single time-domain effective value calculation in the prior art, the present invention captures the complex coupling relationship between the time domain and the frequency domain in the signal, realizing the comprehensive evaluation of the power supply performance in multiple dimensions. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is the ripple test principle block diagram of an automatic ripple test device for a low-voltage DC power supply according to the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0031] In the embodiment: As Figure 1 shown, the present invention provides a technical solution, an automatic ripple test device for a low-voltage DC power supply. The device includes a test host, a signal acquisition module, an anti-interference shielding component, and an automatic control module. Among them, a display panel is provided on the front side of the test host, and an operation button group is provided below the display panel; the signal acquisition module is fixedly installed on the left side inside the test host, and the input end of the signal acquisition module is connected with an external interface through a wire, and the external interface is embedded in the left side wall surface of the test host; the anti-interference shielding component is arranged around the signal acquisition module, and the anti-interference shielding component includes a shielding shell, a filter group, and a grounding ring; the automatic control module is arranged on the right side inside the test host, and the automatic control module includes a main control chip, a relay group, and a signal processing unit.

[0032] An expansion interface group is provided at the top of the test host. The expansion interface group includes an analog signal input interface, a digital signal input interface, and a communication interface. The analog signal input interface and the digital signal input interface are respectively connected to the input end of the signal acquisition module through wires, and the communication interface is connected to the main control chip through a data line. Support feet are provided at the bottom of the test host.

[0033] The shielding housing is a double-layer metal structure. An absorbing material is coated on the inner surface of the shielding housing, and a plurality of uniformly distributed heat dissipation holes are provided on the outer surface of the shielding housing. The filter group is arranged on the inner bottom surface of the shielding housing. The filter group includes a low-pass filter and a band-stop filter. The grounding ring surrounds the outside of the shielding housing, and the grounding ring is connected to the grounding terminal of the test host through a wire.

[0034] The main control chip is connected to the display panel and the operation button group through a data bus. The output end of the main control chip is connected to the relay group through a control signal line. The output end of the relay group is connected to the control end of the signal acquisition module through a wire. The output end of the signal acquisition module is connected to the signal processing unit through a data line. The output end of the signal processing unit is connected to the main control chip through a data line.

[0035] The number of the support feet is four and they are distributed in a rectangle at the four corners of the bottom of the test host. Anti-slip pads are provided at the bottom of the support feet. Among them, the material of the anti-slip pads is silica gel.

[0036] The test host receives the signal of the low-voltage DC power supply to be tested through the BNC interface and transmits the signal to the signal acquisition module. After the signal acquisition module preliminarily processes the signal, it transmits the processed signal to the signal processing unit. After the signal processing unit performs analog-to-digital conversion and digital signal processing on the signal, it transmits the processing result to the main control chip. The main control chip controls the display panel to display the test result according to the processing result. Among them, the signal acquisition module collects data through the control of the ADC and performs preliminary processing according to the collected data, and calculates the ripple coefficient. The specific steps are as follows;

[0037] The ripple coefficient is defined as follows:

[0038] Use the ADC to collect the output voltage data within a certain period of time;

[0039] Filter the collected data to filter out noise;

[0040] Calculate the average value of the collected data to obtain the DC voltage;

[0041] Calculate the effective value of the ripple voltage. Among them, there are two calculation methods for calculating the effective value of the ripple voltage:

[0042] Calculation method 1: First subtract the DC component, and then calculate the root mean square value of the remaining AC component;

[0043] Calculation method 2: Use the Fast Fourier Transform (FFT) to analyze the frequency components of the signal, calculate the energy of the ripple frequency, and then convert it into the effective value;

[0044] Calculate the ripple coefficient, where the ripple coefficient is calculated by the ratio of the effective value of the ripple voltage to the DC output voltage.

[0045] An insulating layer is provided between the inner layer and the outer layer of the shielding housing, and the material of the insulating layer is asbestos fiber; a detachable cover plate is provided at the top of the shielding housing, and the material of the cover plate is aluminum alloy.

[0046] During the signal acquisition process, the anti-interference shielding component shields the signal acquisition module from electromagnetic interference. The double-layer metal structure and the inner layer absorbing material of the shielding housing absorb external electromagnetic interference. The heat dissipation holes on the outer layer of the shielding housing can ensure the heat dissipation performance of the signal acquisition module. The low-pass filter and the band-stop filter in the filter bank can filter out high-frequency interference and interference in specific frequency bands in the signal. The grounding ring can conduct the static charge on the shielding housing into the grounding terminal of the test host, thus ensuring the normal operation of the signal acquisition module.

[0047] The automatic control module controls the switch state of the relay group through the main control chip and controls the input channel selection of the signal acquisition module. After the signal processing unit performs analog-to-digital conversion and digital signal processing on the signal collected by the signal acquisition module, it transmits the processing result to the main control chip. The main control chip displays the test result according to the processing result and outputs the test data through the communication interface.

[0048] Specifically, connection device: Use a BNC interface cable to firmly connect the low-voltage DC power supply to be tested to the BNC interface of the test host to ensure stable electrical connection;

[0049] Power on: Turn on the power switch of the test host. The internal power supply module of the test host supplies power to each component and starts initialization;

[0050] Signal access and preliminary conditioning: The ripple signal of the power supply to be tested is transmitted into the signal acquisition module through the BNC interface. The attenuator in the signal acquisition module attenuates the high-voltage signal to an appropriate range according to the input voltage situation (such as attenuating the 0-300V signal to the range that the ADC can withstand); the amplifier amplifies the weak ripple signal to enhance the signal strength; the filter bank performs preliminary filtering on the signal to filter out some high-frequency noise;

[0051] Anti-interference processing: The preliminarily conditioned signal enters the anti-interference shielding component. The double-layer metal shell isolates external electromagnetic interference. The low-pass filter filters out high-frequency clutter. The band-stop filter specifically suppresses specific frequency interference (such as power frequency interference). The grounding ring ensures good grounding to further reduce noise;

[0052] ADC sampling: The pure ripple signal after anti-interference processing reaches the ADC for sampling, converting the analog signal into a digital signal for subsequent processing;

[0053] Digital signal processing: The digital signal obtained by ADC sampling is transmitted to the signal processing unit, and the signal processing unit performs digital filtering, amplification and other processing on the digital signal to further improve the signal quality;

[0054] Spectrum analysis and ripple calculation: The signal processing unit performs spectrum analysis on the processed digital signal (such as using the fast Fourier transform FFT algorithm), analyzes the frequency components of the ripple signal, and calculates parameters such as the effective value and peak value of the ripple;

[0055] Display results: The main control chip transmits the calculated ripple parameters (such as the effective value of the ripple voltage, frequency components, etc.) to the display panel for display, and displays the total voltage and ripple coefficient. The operator can directly read the test results;

[0056] Data storage and communication: The main control chip stores the test data.

[0057] An automatic test device for the ripple of a low-voltage DC power supply includes two parts: hardware and software. Specifically:

[0058] The hardware part includes: input interface, protection circuit, signal conditioning circuit, analog-to-digital converter, microcontroller, display screen, buttons, power supply and housing. Among them, the input interface includes a BNC connector: used to connect the power supply under test; the protection circuit includes overvoltage protection and overcurrent protection to prevent damage to the instrument due to incorrect operation; the signal conditioning circuit includes an attenuator (used to attenuate high-voltage signals to an appropriate range to protect subsequent circuits), an amplifier (used to amplify weak ripple signals to improve measurement accuracy) and a filter; the filter includes a low-pass filter, a high-pass filter and a differential amplifier. The low-pass filter: used to filter out high-frequency noise and improve the signal-to-noise ratio; the high-pass filter (optional): used to filter out the DC component and only retain the ripple signal; the differential amplifier (important): converts a single-ended signal into a differential signal to suppress common-mode noise, which is the key to anti-interference of handheld devices; the resolution of the analog-to-digital converter: at least 12 bits, preferably 16 bits or higher to ensure measurement accuracy; the sampling rate: selected according to the ripple frequency range of the power supply under test, at least more than 2 times the highest frequency of the measured signal (Nyquist sampling theorem); the microcontroller is used to control the ADC for data acquisition, process the acquired data, calculate the ripple coefficient, control the display screen to display the test results, process button inputs, and manage the power supply; among them, the microcontroller selects an MCU with sufficient processing power and storage space; select an MCU with low-power characteristics to extend the battery life; common selections include ARM Cortex-M series MCUs; the display screen types include: LCD and OLED; the buttons are used to set parameters, start tests, select display modes, etc., and the number of buttons is determined according to functional requirements; the power supply includes: a battery (using a rechargeable lithium battery to provide sufficient battery life) and a power management chip (used to manage the charging and discharging of the battery and protect the battery); the housing is made of a strong and durable material, such as ABS plastic or metal;

[0059] The software part includes: ADC driver, data processing, display driver, button processing and power management. Among them, the ADC driver controls the ADC for data acquisition; the data processing processes the acquired data and calculates the ripple coefficient; the display driver controls the display screen to display the test results; the button processing processes button inputs; the power management manages the power supply.

[0060] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-described exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention. Any reference signs in the claims should not be construed as limiting the claims involved.

Claims

1. An automatic test device for the ripple of a low-voltage DC power supply, characterized in that: The device includes a test host, a signal acquisition module, an anti-interference shielding component, and an automatic control module. Among them, a display panel is provided on the front side of the test host, and an operation button group is provided below the display panel; the signal acquisition module is fixedly installed on the left side inside the test host, and the input end of the signal acquisition module is connected with an external interface through a wire, and the external interface is embedded in the left wall surface of the test host; the anti-interference shielding component is arranged around the signal acquisition module, and the anti-interference shielding component includes a shielding shell, a filter group, and a grounding ring; the automatic control module is arranged on the right side inside the test host, and the automatic control module includes a main control chip, a relay group, and a signal processing unit.

2. The automatic ripple test device for low-voltage DC power supply according to claim 1, characterized in that: An expansion interface group is provided on the top of the test host, and the expansion interface group includes an analog signal input interface, a digital signal input interface, and a communication interface; the analog signal input interface and the digital signal input interface are respectively connected with the input end of the signal acquisition module through wires, and the communication interface is connected with the main control chip through a data line; support feet are provided at the bottom of the test host.

3. The automatic test device for low-voltage DC power supply ripple according to claim 1, wherein: The shielding shell is a double-layer metal structure, an absorbing material is coated on the inner surface of the shielding shell, and a plurality of uniformly distributed heat dissipation holes are provided on the outer surface of the shielding shell; the filter group is arranged on the inner bottom surface of the shielding shell, and the filter group includes a low-pass filter and a band-stop filter; the grounding ring surrounds the outside of the shielding shell, and the grounding ring is connected with the grounding terminal of the test host through a wire.

4. The automatic ripple testing device for low-voltage DC power supply according to claim 1, wherein: The main control chip is connected with the display panel and the operation button group through a data bus, and the output end of the main control chip is connected with the relay group through a control signal line; the output end of the relay group is connected with the control end of the signal acquisition module through a wire, and the output end of the signal acquisition module is connected with the signal processing unit through a data line; the output end of the signal processing unit is connected with the main control chip through a data line.

5. The automatic ripple test device for low-voltage DC power supply according to claim 2, wherein: The number of the support feet is four and they are distributed in a rectangle at the four corners of the bottom of the test host; an anti-slip pad is provided at the bottom of the support feet, and the material of the anti-slip pad is silica gel.

6. The automatic ripple test device for low-voltage DC power supply according to claim 5, characterized in that: The test host receives the signal of the low-voltage DC power supply to be tested through the external interface and transmits the signal to the signal acquisition module. After the signal acquisition module preliminarily processes the signal, it transmits the processed signal to the signal processing unit. After the signal processing unit performs analog-to-digital conversion and digital signal processing on the signal, it transmits the processing result to the main control chip. The main control chip controls the display panel to display the test result according to the processing result. Among them, the signal acquisition module collects data through the control of the ADC and performs preliminary processing according to the collected data, and calculates the ripple coefficient. The specific steps are as follows; The definition of the ripple coefficient is as follows: Use the ADC to collect the output voltage data within a certain period of time; Filter the collected data to filter out noise; Calculate the average value of the collected data to obtain the DC voltage; Calculate the effective value of the ripple voltage; Calculate the ripple coefficient, where the ripple coefficient is calculated by the ratio of the effective value of the ripple voltage to the DC output voltage.

7. An automatic ripple test device for low-voltage DC power supplies according to claim 3, characterized in that: An insulating layer is provided between the inner layer and the outer layer of the shielding housing, and the material of the insulating layer is asbestos fiber; a detachable cover plate is provided at the top of the shielding housing, and the material of the cover plate is aluminum alloy.

8. An automatic low-voltage DC power supply ripple testing device according to claim 7, characterized in that: During the signal acquisition process, the anti-interference shielding component shields the signal acquisition module from electromagnetic interference. The double-layer metal structure of the shielding housing and the inner layer absorbing material absorb external electromagnetic interference. The heat generated by the signal acquisition module is discharged through the evenly distributed heat dissipation holes on the outer layer of the shielding housing. The low-pass filter and the band-stop filter in the filter bank respectively filter out high-frequency interference and specific frequency band interference in the signal. The grounding ring conducts the static charges on the shielding housing into the grounding terminal of the test host.

9. An automatic low-voltage DC power supply ripple testing device according to claim 8, characterized in that: The automatic control module controls the switching state of the relay group through the main control chip and controls the input channel selection of the signal acquisition module. After the signal processing unit performs analog-to-digital conversion and digital signal processing on the signals collected by the signal acquisition module, it transmits the processing results to the main control chip. The main control chip displays the test results according to the processing results and outputs the test data through the communication interface.

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