A mixed-signal hall sensor IC with direction detection

The presented wheel speed sensor IC is based on hall effect. Speed and motion direction of magnetic encoder wheels or ferromagnetic target wheels as well as two specific amplitudes of the magnetic input signal are detected. A two-wire current output directly linked to the input signal frequency indicates speed. Direction information and detection of specific amplitudes of the magnetic input signal are encoded in its output pulse width. It features strictly differential sensing principle, including a new direction detection algorithm and a dynamic self-calibrated offset compensation. The IC is manufactured in a 0.6µm BiCMOS process.