Design Of Digital Circuit Of The Angle Sensor In Advanced Front-lighting System

Advanced Front-Lighting System (AFS) is a sophisticated system which can provide safety protection to automobiles by regulating the front light to keep accordance with external environment. Steering angle sensor is an irreplaceable part in AFS which supply accurate information to the system. Several sorts of angle sensors have been employed in industry, and the one based on the principle of electromagnetic-induction has a simple structure and less expensive. Compared with traditional electromagnetic angle sensors, the angle sensor proposed in this paper has a stronger anti-interfere ability, and its application prospect is very extensive.In this paper, the electromagnetic-induction angle sensor has been investigated, and the operating principle, the design idea and the design of the digital integrated circuits are introduced in detail. The design focus on the following aspects: the upper limit searching mode, the lower limit searching mode, the zero degree demarcated mode, the decoding calibration mode and the normal working mode are realized by analyzing the system architecture and the sensor errors; the analog signal path control module, the computing module, the angle decoding module and the control units of each module, such as EEPROM controller, are designed by analyzing the functional modules and their reusability; the I2C module and initialization module which are used to realize real-time system status monitoring and configuration are completed by analyzing the flexibility requirement of the sensor. After optimization, synthesis, place & route, simulation and verification, the digital circuit can be working properly and its decoding accuracy is 0.05°which meets the system requirements.