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A microaccelerometer with highly reliable, wafer-level packaged MEMS sensing element and fully differential, continuous time, low noise, BiCMOS interface circuit is fabricated. The MEMS sensing element is fabricated on a (111)-oriented SOI wafer by using the SBM (Sacrificial/Bulk Micromachining) process. To protect the silicon structure of the sensing element and enhance the reliability, a wafer level hermetic packaging process is performed by using a silicon-glass anodic bonding process. The interface circuit is fabricated using 0.8 µm BiCMOS process. The capacitance change of the MEMS sensing element is amplified by the continuous-time, fully-differential transconductance input amplifier. A chopper-stabilization architecture is adopted to reduce low-frequency noise including 1/f noise. The fabricated microaccelerometer has the total noise equivalent acceleration of 0.89 µg/√Hz, the bias instability of 490 µg, the input range of ±10 g, and the output nonlinearity of ±0.5 %FSO.

A simulation model of vibratory capacitive microgyroscope and its driving loop is designed using SPICE. The vibratory microgyroscope is basically microelectromechanical system; therefore the simulation model should be expressed mechanical and electrical properties. To modelling the microgyroscope, the Analog Behavioral Model is used. In order to design a driving loop of vibratory microgyrosope, the the Barkhausen criteria is considered. The co-simulation of MEMS sensing element and its interface circuit is performed. The SPICE simulation model of the vibratory microgyrocope is designed, and the driving loop of the microgyroscope is simulated using the designed simulation model. The simulation results demonstrate the validity of the designed model and its interface circuit

This letter describes an efficient architecture for a Software Defined Radio (SDR) Wideband Code Division Multiple Access (WCDMA) receiver using for high performance wireless communication systems. The architecture is composed of a Radio Frequency (RF) front-end, an Analog-to-Digital Converter (ADC), and a Quadrature Amplitude Modulation (QAM) demodulator. A coherent demodulator, with a complete digital synchronization scheme, achieves the bit-error rate (BER) of 10-6 with the implementation loss of 0.5 dB for a raw Quadrature Phase Shift King (QPSK) signal.

A novel CMOS LC oscillator architecture combining an LC tuned oscillator and a ring structure is presented as a new design topology to deliver improved phase noise for multiphase applications. The relative enhancement in the phase noise is estimated using a linear noise modeling approach. A three-stage LC-ring oscillator fabricated in a 0.6 mm CMOS technology achieves measured phase noise of -132 dBc/Hz at 600 kHz offset from a 900 MHz carrier and dissipates 20 mW with a 2.5 V power supply.

This paper presents a lead-lag compensator design for a MEMS-fabricated microgyroscope. The microgyroscope is basically a high Q system, thus the bandwidth is limited to be narrow. To overcome the open-loop performance limitations, a feedback controller is designed to improve the resolution, bandwidth, linearity, and bias stability of the microgyroscope. The feedback controller is applied to the z-axis microgyroscope fabricated by SBM process. In MATLAB simulations, resolution, bandwidth, input range, and bias stability of closed-loop system are improved from 0.0021 deg/sec to 0.0013 deg/sec, from 14.8 Hz to 115 Hz, from ±50 deg/sec to ±200 deg/sec, and from 0.0249 deg/sec to 0.0028 deg/sec, respectively.

In a hybrid electric vehicle (HEV), an interior permanent magnet (Nd-Fe-B) synchronous motor is widely used. However, the flux density of the Nd-Fe-B magnet is sensitive to the temperature variation. Particularly, in a HEV, the heat coming from internal combustion engine causes high temperature rise of the motor. It degrades the flux density and output torque. In this paper, a maximum torque per ampere (MTPA) control scheme for IPM motor is proposed considering the temperature dependence of the magnet field. With the use of an empirical look-up table, saturation effect is also considered. The effectiveness of the proposed control method is demonstrated through MATLAB/Simulink simulation and experiment.

A two chip implemented, wafer-level hermetically packaged accelerometer is presented. The accelerometer core is fabricated using the SBM (sacrificial bulk micromachining) process. The fabricated accelerometer core accomplishes high performance, high yield and high reliability by the inherent high-aspect-ratio, footing-free advantages of the SBM process. In order to protect the accelerometer core from environmental changes, a wafer-level hermetic packaging process is performed by using glass-silicon anodic bonding. The capacitive detection circuit adopts an EEPROM trimmable architecture to reduce the die-to-die variations. The fabricated accelerometer has the noise equivalent acceleration resolution of 43 /spl mu/g, input range of /spl plusmn/10 g, Output nonlinearity of 0.1% FSO, scale factor of 130 mV/g, and 4-hr bias stability of 1.10 mg.

This paper presents a feedback-controlled, MEMS-fabricated microaccelerometer. The microaccelerometer has received much commercial attraction, but its performance is generally limited. To improve the open-loop performance, a feedback controller is designed and experimentally evaluated. The feedback controller is applied to the x/y-axis microaccelerometer fabricated by sacrificial bulk micromachining (SBM) process. Even though the resolution of the closed-loop system is slightly worse than open-loop system, the bandwidth, linearity, and bias stability are significantly improved. The noise equivalent resolution of open-loop system is 0.615 mg and that of closed-loop system is 0.864 mg. The bandwidths of open-loop and closed-loop system are over 100 Hz. The input range, non-linearity and bias stability are improved from ±10 g to ±18 g, from 11.1 %FSO to 0.86 %FSO, and from 0.221 mg to 0.128 mg by feedback control, respectively.

This paper presents a method to measure angular velocity with two silicon-based MEMS acceleration sensors which have the resolution of 0.08 mg. This paper proposes measurement results using the technique to compensate the alignment error and estimate an angular velocity with two acceleration sensors fabricated by sacrificial bulk micromachining (SBM) process. The technique also estimates an angular velocity of a commercial cleaning robot, which has been tried to make the unit cost of production lower, by using two acceleration sensors without using a gyroscope.