An Ultrasonic Sensor IC for Automotive Parking Assist With Module ID Detection

Abstract

This article presents an integrated circuit (IC) for automotive parking assistance, which performs ultrasonic time-of-flight (ToF) ranging and module identification. The IC integrates a bidirectional transducer driver for a center-tapped transformer, a low-noise high-gain analog front-end (AFE) with programmable gain and bandpass filtering, a 12-bit successive-approximation register analog-digital converter, and a digital back-end (DBE) for envelope extraction and ID detection based on $\pi $ /4-differential quadrature phase shift keying (DQPSK). To cope with severe acoustic echo attenuation over long distances, the receive path provides up to 108-dB system gain while maintaining adequate bandwidth around the 58-kHz ultrasonic transducer resonance frequency. Fabricated in 130-nm CMOS, the IC operates directly from a 12-V automotive battery, occupies 14.43 mm2, and dissipates 399.7 mW, excluding the transducer driver current. The IC also supports ID detection for various sensor modules. Measurements in an anechoic chamber demonstrate a detectable range of 0.25–9.8 m in normal mode and experimentally verify 10-cm detection in the indirect mode, while geometric path analysis indicates a 2-cm theoretical limit. The measured distance error is 2.51 mmrms at an object distance of 1 m. These results confirm the practicality of the proposed IC for long-range, ID-aware ultrasonic parking-assistance systems.