초록 ▼

A magnetic field sensor for low power applications includes a magnetic field sensing element that, during sample intervals, provides a signal proportional to a sensed magnetic field and also includes a comparator circuit that, during the sample intervals, compares the magnetic field signal to thresh

A magnetic field sensor for low power applications includes a magnetic field sensing element that, during sample intervals, provides a signal proportional to a sensed magnetic field and also includes a comparator circuit that, during the sample intervals, compares the magnetic field signal to threshold levels to generate a sensor output signal indicative of a strength of the magnetic field. According to a dual sample rate feature, initially the magnetic field signal is sampled at a first predetermined sample rate and, following detection of a transition of the sensor output signal, is sampled at a second, faster predetermined sample rate for a predetermined interval. According to a user-programmable sample rate feature, a user may select to operate the sensor at a fixed, predetermined sample rate or at a user-specified sample rate. The magnetic field sensor may also or alternatively detect the speed and/or direction of rotation of a rotating magnetic article.

대표청구항 ▼

What is claimed is: 1. A magnetic field sensor, comprising:a semiconductor substrate on which are provided two, spaced magnetic field sensing elements, each providing a magnetic field signal proportional to a sensed magnetic field associated with a magnetic article;a circuit configured to process ea

What is claimed is: 1. A magnetic field sensor, comprising:a semiconductor substrate on which are provided two, spaced magnetic field sensing elements, each providing a magnetic field signal proportional to a sensed magnetic field associated with a magnetic article;a circuit configured to process each of the magnetic field signals only during sample intervals occurring at a sample rate and to generate a first sensor output signal indicative of a speed of rotation of the magnetic article and a second sensor output signal indicative of a direction of rotation of the magnetic article; anda clock circuit providing a clock signal to the circuit, wherein the sample rate is controlled by the clock signal and is one of a first predetermined sample rate or a second, faster predetermined sample rate, wherein the clock circuit is responsive to the first sensor output signal and is configured initially to provide the clock signal corresponding to the first predetermined sample rate and to provide the clock signal corresponding to the second predetermined sample rate in response to a change of state of the first sensor output signal.