An Improved Linearizing Digital Interface for Shaft Angle Sensors with Sine–Cosine Characteristic

In this article, an efficient Linearizing Digital Interface (LDI) is proposed to obtain a linear output from angle sensors with sine-cosine characteristic. The LDI implements a simple ratiometric linearization scheme, with the help of an enhanced dual-slope-based circuit, to measure the angular position. The LDI output, obtained using the proposed oscillator-free circuit, is found to be minimally sensitive to several circuit and sensor nonidealities. Fundamental analysis and performance verification studies are carried out to validate the operation of the LDI and the linearizing scheme. The proposed LDI can also be used to detect the angular position of a shaft, rotating at a constant speed. Tests are conducted with the tunneling magnetoresistance (TMR)-based angle sensor. The obtained results confirm a linear output versus input characteristic for a complete 360° range. Additional (misalignment-related) experiments are also carried out to validate the efficacy of the proposed LDI. The LDI can be used in automobile, robotics, aerospace, defense, and many other fields for different applications.