Programmable capacitor simulation board
By designing a programmable capacitor simulation board, the problem of capacitor signal simulation in the performance testing of remote interface units was solved. It realizes the generation of simulated capacitor signals and short-circuit testing within the error range, thereby improving the practicality and applicability of the test.
Patent Information
- Application Number
- CN202423188646.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-23
- Publication Date
- 2025-11-14
- Estimated Expiration
- 2034-12-23
AI Technical Summary
In the performance testing of remote interface units, existing technologies cannot effectively utilize capacitive sensors to simulate capacitive signals, especially in tests simulating short circuit conditions.
A programmable capacitor simulation board was designed, including a main control module, a capacitor simulation module, an input circuit, an output circuit, a digital-to-analog converter, and a power conversion module. Customized PCI bus control is achieved through an FPGA chip and a CPCI bridge chip. It can generate simulated capacitor signals within the error range and simulate short-circuit conditions, making it suitable for various applications.
It enables the provision of simulated capacitor signals within the error range, effectively testing the performance of remote interface units, improving the practicality and applicability of the test, and simulating short-circuit conditions for testing.
Smart Images
Figure CN223552020U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of capacitor signal simulation technology, and in particular to a programmable capacitor simulation board. Background Technology
[0002] During the research and development and production of remote interface units, various performance tests are required, including tests on the capacitance signal acquisition interface. While capacitance signal input in practical applications partly comes from capacitive sensors, these sensors cannot be used for performance testing. Therefore, a programmable capacitance simulation board needs to be designed to provide simulated capacitance signals to the device under test (DUT) during testing, simulating the output of a real capacitive sensor to test the DUT's performance. The required simulated capacitance signal must meet the error range, and the simulation board must also be able to simulate short-circuit conditions to perform relevant tests on the DUT. Utility Model Content
[0003] In response to the above-mentioned problems and technical requirements, the inventors have proposed a programmable capacitor simulation board.
[0004] The technical solution of this utility model is as follows:
[0005] A programmable capacitor simulation board includes a main control module and multiple capacitor simulation modules. Each capacitor simulation module includes an input circuit, an output circuit, and a digital-to-analog converter.
[0006] The input circuit is adapted to and connected to the device under test (DUT) and the digital-to-analog converter (DAC), and is used to receive the excitation signal output by the DUT and output a reference signal to the DAC based on the excitation signal; the main control module is connected to the DAC, the DAC is connected to the output circuit, and the main control module controls the DAC to generate a simulated capacitance signal based on the reference signal and output it to the DUT through the output circuit.
[0007] A further technical solution is that the output circuit includes operational amplifier U1A, operational amplifier U1B, capacitor C225, capacitor C226, resistors R245, R246, R247, R248, R249, R250, and TVS diode D4, wherein...
[0008] The output terminal of the digital-to-analog converter is connected to the non-inverting input terminal of the operational amplifier U1A through capacitor C225. The non-inverting input terminal of the operational amplifier U1A is grounded through resistor R246. The inverting input terminal of the operational amplifier U1A is grounded through resistor R249 and connected to the output terminal of the operational amplifier U1A through resistor R250. The output terminal of the operational amplifier U1A is connected to the non-inverting input terminal of the operational amplifier U1B through resistor R245.
[0009] A further technical solution is that the non-inverting input terminal of the operational amplifier U1B is grounded through resistor R247, the inverting input terminal of the operational amplifier U1B is connected to the output terminal of the operational amplifier U1B through resistor R248, the output terminal of the operational amplifier U1B is connected to the device under test through capacitor C226, and the output terminal of the operational amplifier U1B is grounded through TVS diode D4.
[0010] A further technical solution includes a power conversion module, which is connected to the main control module and multiple capacitor simulation modules, and is used to supply power to the main control module and multiple capacitor simulation modules.
[0011] A further technical solution is that the main control module includes a CPCI bridging chip and an FPGA chip, the CPCI bridging chip is connected to the FPGA chip, and the FPGA is connected to multiple digital-to-analog converters.
[0012] The further technical solution is that the FPGA chip model includes XC7A75T-2FGG484I, and the CPCI bridge chip model includes PCI9054.
[0013] A further technical solution is that the model of the digital-to-analog converter includes DAC8831ICRGY.
[0014] A further technical solution includes an analog-to-digital converter (ADC), which is connected to the device under test (DUT) and the FPGA chip.
[0015] A further technical solution is that the programmable capacitor simulation board includes multiple relays that are adapted and connected to the device under test.
[0016] A further technical solution is that the power conversion module includes multiple power conversion chips.
[0017] The beneficial technical effects of this utility model are:
[0018] The programmable capacitor simulation board provided by this invention can receive excitation signals from a remote interface unit and provide simulated capacitor signals required for testing the remote interface unit within the error range. It can also simulate short-circuit conditions to test the short-circuit performance of the remote interface unit. The programmable nature of the capacitor simulation board also makes it suitable for various applications, allowing for flexible configuration for different application scenarios, greatly improving its practicality and applicability. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of one embodiment of the special signal simulation module provided by this utility model.
[0020] Figure 2This is a schematic diagram of one embodiment of the programmable capacitor simulation board provided by this utility model.
[0021] Figure 3 This is a circuit diagram of one embodiment of the output circuit provided by this utility model.
[0022] Figure 4 This is a pin diagram of one embodiment of the FPGA power conversion chip provided by this utility model.
[0023] Figure 5 This is a layout block diagram of one embodiment of the programmable capacitor simulation board provided by this utility model. Detailed Implementation
[0024] The specific embodiments of this utility model will be further described below with reference to the accompanying drawings.
[0025] This utility model provides a programmable capacitor simulation board, including a main control module and multiple capacitor simulation modules. Each capacitor simulation module includes an input circuit, an output circuit, and a digital-to-analog converter.
[0026] The input circuit is adapted to and connected to the device under test (DUT) and the digital-to-analog converter (DAC), and is used to receive the excitation signal output by the DUT and output a reference signal to the DAC based on the excitation signal; the main control module is connected to the DAC, the DAC is connected to the output circuit, and the main control module controls the DAC to generate a simulated capacitance signal based on the reference signal and output it to the DUT through the output circuit.
[0027] Specifically, the device under test (DUT) can be a remote interface unit. The remote interface unit needs to be tested using a remote interface unit testing device, which includes a special signal simulation module, such as... Figure 1 As shown, the programmable capacitor simulation board is generally set up together with the speed simulation board and other components in the special signal simulation module.
[0028] The remote interface unit includes multiple sets of signal terminals, each set including an output terminal and an input terminal. During testing, each set of signal terminals of the remote interface unit is connected one-to-one with the capacitance simulation module; that is, the output terminal of each set of signal terminals is connected to the input circuit of the capacitance simulation module, and the input terminal is connected to the output circuit of the capacitance simulation module. Figure 2 As shown, an excitation signal is input from the output terminal of the remote interface unit to the input terminal of the input circuit. The input circuit outputs a reference signal to the reference terminal of the digital-to-analog converter (DAC) based on the excitation signal. Under the control of the main control module, the DAC generates a simulated capacitance signal based on the reference signal and outputs it to the input terminal of the remote interface unit through the corresponding output circuit. In this embodiment, a total of 15 capacitance simulation modules are set, which can simultaneously receive 15 excitation signals and generate 15 simulated capacitance signals for testing by the remote interface unit.
[0029] Specifically, the output circuit includes operational amplifier U1A, operational amplifier U1B, capacitor C225, capacitor C226, resistors R245, R246, R247, R248, R249, R250, and TVS diode D4, wherein...
[0030] like Figure 3 As shown, the output of the digital-to-analog converter is connected to the non-inverting input of operational amplifier U1A via capacitor C225. The non-inverting input of operational amplifier U1A is also grounded via resistor R246. The inverting input of operational amplifier U1A is grounded via resistor R249 and connected to the output of operational amplifier U1A via resistor R250. The output of operational amplifier U1A is connected to the non-inverting input of operational amplifier U1B via resistor R245. The non-inverting input of operational amplifier U1B is also grounded via resistor R247. The inverting input of operational amplifier U1B is connected to the output of operational amplifier U1B via resistor R248. The output of operational amplifier U1B is connected to the device under test (DUT) via capacitor C226 and is also grounded via TVS diode D4. Capacitor C225 acts as a DC blocking capacitor to filter out DC signals, and TVS diode D4 is a bidirectional TVS diode used to protect the circuit from transient overvoltage damage.
[0031] The input circuit can also be formed based on two operational amplifiers and corresponding components. Its specific form can be set according to actual needs, as long as it can convert the excitation signal into the reference signal required by the digital-to-analog converter. In this embodiment, the reference signal is a 2.5V voltage signal. The input terminal of the input circuit is also grounded through a bidirectional TVS diode to provide transient overvoltage protection. The operational amplifier used in the input and output circuits can be an OPA2189, and the digital-to-analog converter can be a DAC8831ICRGY.
[0032] Furthermore, the main control module includes a CPCI bridging chip and an FPGA chip, the CPCI bridging chip is connected to the FPGA chip, and the FPGA is connected to multiple digital-to-analog converters.
[0033] In this embodiment, the FPGA chip used is the Xilinx XC7A75T-2FGG484I, which has abundant built-in Block RAM resources and 75,520 logic units. The CPCI bridge chip used is the PCI9054, a 32-bit, 33MHz PCI bus master I / O accelerator from PLX. The FPGA chip is also connected to a JTAG interface, a FLASH chip, and a clock chip providing a clock reference. The capacitor simulation board is equipped with both a CPCI standard connector and a PXI standard connector. The CPCI standard connector receives PCI signals and transmits them to the FPGA chip via the CPCI bridge chip. The FPGA chip then controls the digital-to-analog converter based on the PCI signals. This application combines the FPGA chip and the CPCI bridge chip to achieve customized PCI bus control and data processing functions. It can be programmed and configured according to requirements to adapt to different application scenarios.
[0034] The programmable capacitor simulation board also includes an analog-to-digital converter (ADC), which is connected to the device under test (DUT) and the FPGA chip. Specifically, the ADC can be an AD7616BSTZ model. The input of the ADC can receive an excitation signal, which is converted into a corresponding digital signal and transmitted to the FPGA chip. The FPGA chip then determines the correctness of the excitation signal.
[0035] Furthermore, the programmable capacitor simulation board also includes a power conversion module, which is connected to the main control module and multiple capacitor simulation modules, and is used to supply power to the main control module and multiple capacitor simulation modules.
[0036] Specifically, the power conversion module includes multiple power conversion chips, including power conversion chip U2 for powering the digital-to-analog converter, and power conversion chips U3 and U4 for powering operational amplifiers U1A and U1B. Power conversion chip U2 converts a 12V power supply voltage to a 5V power supply voltage to power the analog-to-digital converter; power conversion chip U3 converts a 12V power supply voltage to a 14V power supply voltage and applies it to the positive power supply terminals of operational amplifiers U1A and U1B; and power conversion chip U4 converts a 12V power supply voltage to a -14V power supply voltage and applies it to the negative power supply terminals of operational amplifiers U1A and U1B.
[0037] The power conversion module also includes an FPGA power conversion chip for powering the FPGA chip. The FPGA power conversion chip can be a TPS54821RHLR. Figure 4The pin diagram of the FPGA power conversion chip is shown. The FPGA power conversion chip includes VIN pin, EN pin, PVIN1 pin, PVIN2 pin, BOOT pin, PH1 pin, PH2 pin and V_SNS pin.
[0038] The PVIN1, PVIN2, and VIN pins are grounded via capacitor C185. They are also grounded and connected to the input voltage via capacitor C187. Capacitors C185 and C187 act as voltage regulators and filters. The input voltage, 5V, can be introduced from the power supply pins of the CPCI bridge chip. The EN pin is connected to the PVIN1, PVIN2, and VIN pins via resistor R217. The FPGA power conversion chip also includes a COMP pin, which is grounded via resistor R222 and capacitor C194. Resistor R222 and capacitor C194 are connected in series and then in parallel with capacitor C193.
[0039] The BOOT pin is connected to the PH1 and PH2 pins via capacitor C186. The PH1 and PH2 pins are connected to one end of resistor R218 and the power supply pins of the FPGA chip via inductor L6. The other end of resistor R218 is connected to the V_SNS pin and grounded via resistor R220. The power supply pins of the FPGA chip are grounded via capacitor C188, which is connected in parallel with capacitor C189. The FPGA power conversion chip converts the 5V input voltage to a 1V supply voltage to power the FPGA chip. It should be noted that the power conversion module also includes multiple power conversion chips for powering CPCI bridge chips and analog-to-digital converters, converting the supply voltage to the operating voltage required by the corresponding chip.
[0040] Furthermore, the programmable capacitor simulation board also includes multiple relays that are adapted and connected to the device under test (DUT) to simulate a port short circuit in the DUT, i.e., the remote interface unit.
[0041] In this embodiment, a total of 16 double-pole double-throw relays of model 5-1462039-5 are provided. For any set of signal terminals of the remote interface unit, the input terminal is connected to the output terminal through the normally open contact of a relay to simulate a short circuit between the input terminal and the output terminal when the relay is energized; the input terminal is grounded through the normally open contact of another relay to simulate a short circuit to ground when the relay is energized.
[0042] Furthermore, the aforementioned components are mounted on a PCB to form a programmable capacitor simulation board. The programmable capacitor simulation board has planar dimensions of 160mm*189mm, meeting the dimensions of a 5U chassis expansion card. The simulation board is equipped with expansion plates on its side, with corresponding baffles 6T wide (6×5.08mm) to accommodate various component heights. A single capacitor simulation board supports up to 15 channels of simulated capacitor signal output, and the simulated capacitor signals can be freely configured from 0.1pF to 1000pF, with a minimum resolution of 0.05pF. The expansion plates have guide rails for easy insertion and removal. Figure 5 A block diagram of the capacitor simulation board layout in this embodiment is shown. The capacitor simulation board has a front side and a corresponding back side. The relays, operational amplifiers and components in the output circuit, digital-to-analog converters, power conversion modules, and main control modules are all located on the front side of the board, while the operational amplifiers and components in the input circuit, as well as the analog-to-digital converters, are located on the back side of the board.
[0043] The above descriptions are merely preferred embodiments of the present invention, and the present invention is not limited to the above embodiments. It is understood that other improvements and variations that can be directly derived or conceived by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included within the protection scope of the present invention.
Claims
1. A programmable capacitor simulation board, characterized in that, It includes a main control module and multiple capacitor simulation modules. Each capacitor simulation module includes an input circuit, an output circuit, and a digital-to-analog converter. The input circuit is adapted to and connected to the device under test (DUT) and the digital-to-analog converter (DAC), and is used to receive the excitation signal output by the DUT and output a reference signal to the DAC based on the excitation signal; the main control module is connected to the DAC, the DAC is connected to the output circuit, and the main control module controls the DAC to generate a simulated capacitance signal based on the reference signal and output it to the DUT through the output circuit.
2. The programmable capacitor simulation board according to claim 1, characterized in that, The output circuit includes operational amplifier U1A, operational amplifier U1B, capacitor C225, capacitor C226, resistors R245, R246, R247, R248, R249, R250, and TVS diode D4. The output terminal of the digital-to-analog converter is connected to the non-inverting input terminal of the operational amplifier U1A through capacitor C225. The non-inverting input terminal of the operational amplifier U1A is grounded through resistor R246. The inverting input terminal of the operational amplifier U1A is grounded through resistor R249 and connected to the output terminal of the operational amplifier U1A through resistor R250. The output terminal of the operational amplifier U1A is connected to the non-inverting input terminal of the operational amplifier U1B through resistor R245.
3. The programmable capacitor simulation board according to claim 2, characterized in that, The non-inverting input terminal of the operational amplifier U1B is grounded through resistor R247, the inverting input terminal of the operational amplifier U1B is connected to the output terminal of the operational amplifier U1B through resistor R248, the output terminal of the operational amplifier U1B is connected to the device under test through capacitor C226, and the output terminal of the operational amplifier U1B is grounded through TVS diode D4.
4. The programmable capacitor simulation board according to claim 1, characterized in that, It also includes a power conversion module, which is connected to the main control module and multiple capacitor simulation modules, and is used to supply power to the main control module and multiple capacitor simulation modules.
5. The programmable capacitor simulation board according to claim 1, characterized in that, The main control module includes a CPCI bridging chip and an FPGA chip. The CPCI bridging chip is connected to the FPGA chip, and the FPGA is connected to multiple digital-to-analog converters.
6. The programmable capacitor simulation board according to claim 5, characterized in that, The FPGA chip model includes XC7A75T-2FGG484I, and the CPCI bridge chip model includes PCI9054.
7. The programmable capacitor simulation board according to claim 1, characterized in that, The model of the digital-to-analog converter includes DAC8831ICRGY.
8. The programmable capacitor simulation board according to claim 5, characterized in that, It also includes an analog-to-digital converter (ADC) connected to the device under test (DUT) and the FPGA chip.
9. The programmable capacitor simulation board according to claim 1, characterized in that, The programmable capacitor simulation board includes multiple relays that are adapted and connected to the device under test.
10. The programmable capacitor simulation board according to claim 4, characterized in that, The power conversion module includes multiple power conversion chips.