Texas Instruments Corporation

Teuta K Williams

Wei Lu

William E Grose

Philomena Cleopha Brady

Benjamin Lee Amey

Vikram Joseph Mani

Bala Krishnan D Achie

Anti-lock and intelligent braking systems have become ubiquitous in modern vehicles, which employ wheel speed sensors or WSSs. These WSSs generally uses current-domain signals (transmitted through power wires) to reduce the size of the vehicle's wiring harness, but because a vehicle is an inherently noisy environment, mixed signal circuit or MSC (used to decode these signals for a microcontroller) should be able to filter out or compensate for noise. However, traditional MSCs have been plagued with problems, partly due to errors in time base measurement due to noise (as well as other factors). Here, an MSC is provided that accurately calculates a wheel speed pulse width (which is used for time base measurements) by observing the wheel speed pulse as it passes through several thresholds.

Slew rate compensated wheel speed sensor signal processing method and system

An apparatus is provided. The apparatus comprises a reference circuit and a startup circuit. The reference circuit is adapted to provide a startup current, while the startup circuit receives the startup current and outputs an output voltage. The startup circuit includes a current mirror, a first NMOS transistor, a second NMOS transistor, diodes, and a third NMOS transistor, and a control circuit. The first and second NMOS transistors are coupled to the current mirror at their sources and are coupled to one another and to the reference circuit at their gates. The diodes are coupled between the gate of the second NMOS transistor and the source of the second NMOS transistor, and the third NMOS transistor is coupled to the source of the second NMOS transistor at its gate (which also provides the output voltage at its source). The control circuit is then coupled to the drains of the first and second NMOS transistors.

Reference circuit with reduced current startup

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Dallas, TX, United States of America

Teuta K Williams