A novel micromechanical bridge-shaped voltage-controlled oscillator with high Q value was fabricated. The core of this kind of oscillators is an electrothermally excited and piezoresistively detected micromechanical bridge resonator. Its resonance frequency can be adjusted by changing the DC voltage applied to the Wheatstone bridge. Theoretical analysis and experimental data show that its resonance frequency is linear with the square of the DC voltage. The linearity is better than 0.16% and the adjustable frequency range excels 17.15%.
HAN Jianqiang ZHU Changchun ZHAO Hongpo LIU Junhua SHAO Jun
An IGBT subcircuit model is proposed and optimized,which is fully SPICE compatible.Based on analytical equations describing the semiconductor device physics,the model parameters are extracted accurately from the measured data without device destruction.The IGBT n - layer conductivity modulated resistor is effectively modeled as a voltage controlled resistor.The proposed model can be used to accurately predict the IGBT output I-V characteristics and low current gain etc.The simulation results are verified by the comparison with measurements and found to be in good agreement with them.The error in average is within 8%,which is better than the results of semi-mathematical models reported previously.
