Field programmable gate arrays (FPGAs) are attractive for a digital spectrometer due to its advantages of digital signal processing. However, how to improve the versatility of the spectrometer and increase the operating frequency of the digital shaper has gradually become a limitation that needs to be resolved in the FPGA-based spectrometer. A solution to improve the universality of the FPGA-based digital spectroscopy system is presented in this work, and the implementation of the real-time digital signal processing unit is improved to obtain a higher operating frequency, and then the optimal parameters of the digital trapezoidal shaper and the processing unit are also discussed through a series of experiments; finally, a FPGA-based digital spectrometer is developed. With the HPGe detector, the spectrometer achieves excellent energy resolution performance of 0.35% at 662 keV, 0.25% at 1173.2 keV, and 0.23% at 1332.5 keV.
The safe and reliable operation of power converter requires a protection circuit with fast response when the power device is subjected to the short‐circuit (SC) fault. In addition, the on‐line condition monitoring circuit is beneficial to provide a suggestion for the replacement of aged device. The silicon carbide (SiC) power devices promise the higher power density in the system performance, but is still limited by the poor SC reliability issue. Thus, it is crucial to improve the robustness of SiC‐based power converter from the circuit design. This work proposes a novel gate charge detection circuit for SiC devices. It achieves a high‐speed SC protection against hard switching fault (HSF) based on the difference of Miller capacitance between normal condition and SC fault. Meanwhile, the condition monitoring is achieved based on the high gate leakage current of aged device. A high‐precision analog amplifier circuit is designed to acquire the gate signal. The normal/fault signal is distinguished and the protection is triggered using a digital‐controlled method to reduce the hardware cost. A 600‐ns SC response time is achieved, and the monitoring circuit can differentiate the aged device from the healthy one.
Trans-impedance amplifier (TIA) based capacitance–voltage (C–V) readout circuit is an attractive choice for micro-machined gyroscope for its simplicity and superior performance. In this work, the noise and the C–V gain characteristics of the TIA circuit are analyzed in detail. Then, a TIA based readout circuit with a C–V gain of about 286 dB is designed, and a series of experiments are conducted to test the performance of the circuit. Both the analysis and test results show that T-network TIA should be avoided as far as possible for its poor noise performance. All results also show that there is a signal-to-noise ratio (SNR) limit for the TIA based readout circuit, and the SNR can only be further improved by filtering. Hence, an adaptive finite impulse response filter is designed to further improve the SNR of the sensed signal. For a gyroscope with a peak-to-peak variable capacitance of about 200 aF, a SNR of 22.8 dB can be achieved by the designed circuit and a SNR of 47 dB can be obtained by further adaptive filtering. Finally, the solution presented in this paper achieves a capacitive sensing resolution of 0.9 aF.
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