Papers by Author: Zhi Gang Mao

Abstract: A novel CMOS interface circuit with high resolution is designed and realized to achieve the integration of interface circuit for liquid suspended rotor micro-gyroscope. The detecting circuit adopts continuous-time current sensing circuit for capacitance measurement. The equivalent output noise power spectral density of phase-sensitive demodulation is 120 nV/Hz1/2. The whole circuitry is realized with 0.5 μm 2P2M CMOS process and its testing results show the circuit has a relative capacitance resolution of 1×10-8, in which the power supply is 18 V and the power consumption is 30 mW. The area of the chip is merely 18.5 mm2.

Abstract: This paper presents the design of low noise CMOS pre-amplifiers based on photoelectric detection systems, which can directly affect the detecting precision of the whole systems. The design of pre-amplifier circuit from photoelectric detector was introduced. The photoelectric conversion circuit, amplifier circuit bandwidth, amplifier circuit noise, amplifier circuit stabilization and other questions were mainly discussed, and an amplifier circuit capable of effectively decreasing the noise, the temperature drift and a large dynamic range was designed. This paper analyzes the sources of photoelectric detection circuit internal noise, and gives the formulas of internal noise, designs a variable equivalent load photoelectric conversion circuit, and is verified by experiments. Then the result is used to reduce the noise of CMOS based operational amplifiers and finally implement the design work of pre-amp using 0.5μm CMOS Technology.

Abstract: A new manufacture mainly for polymethyl methacrylate (PMMA) microfluidic chips is presented in this paper. In this technique, polymer microfluidic microchannels were fabricated by microcutter which temperature is controlled and stabilized by PID methord. There are so many techniques, such as hot embossing, laser direct-write, for mass-production of polymer microfluidic chip. However, we may feel different kinds of shortages when we use these techniques. In this paper, the experiment result shows that microcutter’s movement velocity and temperature have effert on microfluidic microchannel’s roughness.

Abstract: This paper presents a complete set of SIMULINK models, which allow exhaustive behavioral simulations of fluxgate system to be performed. The model construction is detailed and it is applied to the Vacquier-type fluxgate sensor. Well known characteristics of these sensors are confirmed through the simulations. In spite of this simplicity, the model has been successfully used to describe the variation of the output of a Vacquier-type fluxgate sensor with the amplitude and the frequency of the driving current. Using a previously developed 2nd harmonic fluxgate magnetometer, some preliminary experimental results are obtained confirming the appearance at its output.