Abstract: A multi-channel wheel speed sensor having a custom integrated interface circuit. The interface circuit is configured with voltage programmable threshold adjustment allowing the circuit sensitivity to be specially tuned to detect wheel speeds in very specific ranges for a variety of applications. This feature can be implemented in ABS and/or traction control systems wherein in ABS mode a lower sensitivity adjustment can be used since wheel speeds below 5 mph do not need to sensed and processed precisely and in traction control mode very low wheel speeds, 1-1.5 mph are sensed and processed especially at non-drive wheels which provide speed reference for slipping or spinning drive wheels. The interface circuit is also configured with a test circuit for testing the integrity of the speed sensors and for providing information to the controller about the sensor/tone wheel gap.

Abstract: In accordance with the teachings of the present invention, a wheel speed sensor signal conditioning circuit is provided for conditioning sensor output signals received from a variable reluctance wheel speed sensor. The conditioning circuit includes filtering circuitry and peak detecting circuitry that detects the positive and negative voltage peaks of a sensor output signal irrespective of the sensor output signal crossing a reference voltage level. When the sensor output signal exceeds a predetermined peak to peak voltage level, the peak detecting circuitry limits the amplitude of the output signal and forms a dynamic high pass filter. A comparator circuit is coupled to the peak detecting circuitry and outputs a first signal when the peak detecting circuitry detects a positive voltage peak and outputs a second signal when the peak detecting circuitry detects a negative voltage peak of the sensor output signal.

Abstract: An electronic interface custom integrated circuit which provides interfacing between micro-controller devices and field effect transistors in truck or car anti-lock braking systems for controlling solenoid valves to modulate the pressure in the brake chambers or brake cylinders. The interface circuit includes built-in diagnostic and safety features including fault protection interlock, safety interlocks, status indication outputs and a special purpose analog output for enhancing the performance of anti-lock braking system electronic control units.