Design Of The Interface ASIC For Three Tips Fluxgate

As a weak magnetic field measurement solid-state devices,fluxgate sensor is widely used in the aerospace,marine,exploration,drilling and other fields. the trend of Fluxfate system is miniaturization, integration and low power consumption.It is significant for fluxgate to entry consumer electronics and expand rate of the global sensor marketAccording to the principle of fluxgate sensor,The interface ASIC of three tips fluxgate sensor is designed by CMOS analog integrated circuit technology.The design,simulation,layout design and testing performance parameters of the chip are also introduced. A lot of research work about fluxgate sensor and interface ciucuit has been done,in order to solve poor linearity,stability of dual-core fluxgate the interface ASIC of three tips fluxgate is pretended.The design of interface circuit was based on second-harmonic principle.Interface circult is made of two parts:driver circuit and detection circuit.The driver circuit uses an external crystal oscillators as part of the signal sources,the frequenecy of signal is divided 10khz driven pulse and 20khz phase-sensitive switch control pulse,to ensure the synchronization and consistency between them.After a boost circuit modulates the signal turns to 0-10V pulse for the preparation of CMOS switching network. Finally, CMOS switching network output sync and reverse pulse to drive three tips fluxgate. Detection circuit is made of band pass filter,phase sensitive Demodulator,integrator and the feedback resistor.Band-pass filter out the second harmonic,then,the phase sensitive demodulator solves signal to character the direction.finally,integrator output voltage is characterized by integral fluxgate sensors"sense"of the external magnetic field. the interface circuit uses close-loop structure to increase system accurary and stability,also improves the traditional phase sensitive demodulation circuit to enhance efficiency,which improve the performance of the system.This paper also design the interface circuit layout ,analyze and solve the layout design of non-ideal effects. The design process based on 0.5μm n well 2p2m MOS model simulation,and cast film processing. Measurement results show that:in 0-10V power supply conditions;the magnetic range is±100μ,sensitivity is 30.8μV/nT,non-linear error is less than 0.62%,power consumotion is 100mW,higher system bandwidth is 200hz,interface circuit area is only 2000×2100μm2...