Systems and methods for processing temperature data or other signals

Patent metadata

Field	Value
Publication number	US-2016238671-A1
Application number	US-201615138559-A
Country	US
Kind code	A1
Filing date	Apr 26, 2016
Priority date	Dec 26, 2012
Publication date	Aug 18, 2016
Grant date	—

Abstract

In an embodiment, a circuit is configured to produce a magnetic field signal having a frequency spectrum. The circuit may also produce a temperature signal. A modulation circuit may modulate the temperature signal with a frequency outside the frequency spectrum of the magnetic field signal. The modulated signal and the magnetic field signal may be combined to produce a combined signal. A separation circuit may be configured to separate component signals from the combined signal. The separation circuit may include a first filter, which, when applied to the combined signal, produces a filtered signal; a modulation circuit configured to shift the data representing the temperature signal to a baseband frequency; and a second filter configured to separate the data representing the temperature signal from the combined signal.

First claim

What is claimed is:

1 . A magnetic field sensor comprising:
a back bias magnet configured to generate a magnetic field; a circuit configured to produce an magnetic field signal having a frequency spectrum, wherein the magnetic field signal represents a strength of an ambient magnetic field; a temperature sensing circuit configured to produce a temperature signal for calibrating the magnetic field signal; a first modulation circuit configured to modulate the temperature signal to a frequency outside the frequency spectrum of the magnetic field signal, resulting in a first modulated signal; a combining circuit configured to combine the magnetic field signal with the first modulated temperature signal to produce a combined signal; and an output operative to provide the combined signal to a digital processing circuit.

2 . The magnetic field sensor of claim 1 wherein the back bias magnet comprises a molded magnet.

3 . The magnetic field sensor of claim 1 further comprising a separation circuit configured to separate data representing the temperature signal from the digital signal to produce a temperature reading.

4 . The magnetic field sensor of claim 3 wherein the separation circuit comprises one or more of:
a second modulation circuit configured to shift the data representing the temperature signal to a baseband frequency, resulting in a second modulated signal; and
a filter coupled to receive the second modulated signal and configured to separate the data representing the temperature signal from the second modulated signal.

5 . The magnetic field sensor of claim 3 wherein the circuit configured to produce the magnetic field signal is a circuit for detecting speed or position of a target object and a width of the frequency spectrum is defined by the speed of the target object.

6 . The magnetic field sensor of claim 5 further comprising a magnetic field sensing element, wherein the target object is a wheel having teeth, wherein peaks on the magnetic field signal are produced as the teeth of the wheel move past the magnetic field sensing element.

Assignees

• Allegro Microsystems Llc

Inventors

• Drouin Mathew
• Fernandez Devon
• Taylor William P

Classifications

• G01R33/0017

  Means for compensating offset magnetic fields or the magnetic flux to be measured; Means for generating calibration magnetic fields · CPC title

• G01R33/09

  Magnetoresistive devices · CPC title

• G01R33/07

  Hall effect devices · CPC title

• G01R33/0082 Primary

  Compensation, e.g. compensating for temperature changes · CPC title

• G01K7/01

  using semiconducting elements having PN junctions (G01K7/02, G01K7/16, G01K7/30 take precedence) · CPC title