An Inductive 2-D Position Detection IC With 99.8% Accuracy for Automotive EMR Gear Control System
SangYun Kim, Hamed Abbasizadeh, İmran Ali, Hongjin Kim, SungHun Cho, YoungGun Pu, Sang‐Sun Yoo, Minjae Lee, Keum Cheol Hwang, Youngoo Yang, Kang-Yoon Lee · IEEE Transactions on Very Large Scale Integration (VLSI) Systems · 2017
In this paper, the analog front end (AFE) for an inductive position sensor in an automotive electromagnetic resonance gear control applications is presented. To improve the position detection accuracy, a coil driver with an automatic two-step impedance calibration is proposed which, despite the load variation, provides the desired driving capability by controlling the main driver size. Also, a time shared analog-to-digital converter (ADC) is proposed to convert eight-phase signals while reducing the current consumption and area to 1/8 of the conventional structure. A relaxation oscillator with temperature compensation is proposed to generate a constant clock frequency in vehicle temperature conditions. This chip is fabricated using a 0.18-$\mu \text{m}$CMOS process and the die area is 2 mm$\times 1.5$mm. The power consumption of the AFE is 23.1 mW from the supply voltage of 3.3 V to drive one transmitter (Tx) coil and eight receiver (Rx) coils. The measured position detection accuracy is greater than 99.8 %. The measurement of the Tx shows a driving capability higher than 35 mA with respect to the load change.