Mark E Donovan

US Patent:

8577634, Nov 5, 2013

Filed:

Dec 15, 2010

Appl. No.:

12/968353

Inventors:

Mark J. Donovan - Derry NH, US
Craig S. Petrie - Merrimack NH, US
Nevenka Kozomora - Manchester NH, US
Michael C. Doogue - Manhester NH, US

Assignee:

Allegro Microsystems, LLC - Worcester MA

International Classification:

G01R 25/00

US Classification:

702 79

Abstract:

A magnetic field sensor including a bidirectional node is configured to perform at least one of generating sensor data, storing sensor data, or communicating sensor data in a serial data signal in response to a trigger signal received at the bidirectional node. An alternative sensor having a node that may or may not be a bidirectional node is configured to reset at least one of a sensor data signal, a clock, a register, or a counter in response to a trigger signal received at the node and is further configured to communicate the sensor data signal in response to the trigger signal.

US Patent:

20120262155, Oct 18, 2012

Filed:

Apr 12, 2011

Appl. No.:

13/084745

Inventors:

Mark J. Donovan - Derry NH, US
Ryan Metivier - Nashua NH, US
Michael C. Doogue - Manchester NH, US

Assignee:

ALLEGRO MICROSYSTEMS, INC. - Worcester MA

International Classification:

G01B 7/30

US Classification:

3242072, 32420725

Abstract:

A magnetic field sensor and a method used therein provide an output signal in angle units representative of an angle of rotation of a target of and also an output signal in speed units representative of a speed of rotation of the target object. A power control circuit can cycle a magnetic field sensor on and off in accordance with a sensed rotation speed of the object.

US Patent:

20130046488, Feb 21, 2013

Filed:

Aug 19, 2011

Appl. No.:

13/213406

Inventors:

Mark J. Donovan - Derry NH, US
Michael C. Doogue - Manchester NH, US
Ryan Metivier - Nashua NH, US

Assignee:

ALLEGRO MICROSYSTEMS, INC. - Worcester MA

International Classification:

G06F 19/00

US Classification:

702 57

Abstract:

A magnetic field sensor and a method used therein provide a measured signal representative of an angular speed of rotation of a target object. The magnetic field sensor, in accordance with the measured speed of rotation, can automatically change various characteristics of the magnetic field sensor.

US Patent:

20130080087, Mar 28, 2013

Filed:

Sep 28, 2011

Appl. No.:

13/247139

Inventors:

Mark J. Donovan - Derry NH, US
Bryan Cadugan - Bedford NH, US

Assignee:

ALLEGRO MICROSYSTEMS, INC. - Worcester MA

International Classification:

G06F 19/00
G01R 33/07

US Classification:

702 57

Abstract:

Circuits and methods provide an ability to track a direction of a magnetic field, and, more particular, to track a direction of a rapidly rotating magnetic field. The circuits and methods use a plurality of magnetic field sensing elements, for example, as may be embodied in a circular vertical Hall (CVH) sensing element. However, the circuits and methods can track the direction of the sensed magnetic field by processing at any time fewer than all of the plurality of magnetic field sensing elements, for example, one or two of the plurality of magnetic field sensing elements.

US Patent:

56547161, Aug 5, 1997

Filed:

Mar 27, 1996

Appl. No.:

8/622838

Inventors:

Mark J. Donovan - Derry NH
James C. Patrikis - Nashua NH
Irl W. Smith - Concord MA

Assignee:

Raytheon Company - Lexington MA

International Classification:

G01S 740

US Classification:

342 98

Abstract:

A low cost automatic frequency control system measures short duration radio frequencies with high a degree of accuracy within 0. 5 MHz. The system is programmable to allow applicability over a wide range of frequencies within the required accuracy and various signal durations. The system includes circuits to digitize the source signal to a digital pulse train and asynchronously sample the pulse train to obtain a count of the positive edges of the pulses over a sufficient number of samples. A microprocessor computes the statistical average of the count and accurately determines the frequency of the source signal. The system further includes a feedback path to implement correction to the source signal based on the measured frequency.

US Patent:

6122281, Sep 19, 2000

Filed:

Feb 14, 1997

Appl. No.:

8/800363

Inventors:

Mark J. Donovan - Derry NH
Stephen D. Augusta - Nashua NH
Christopher J. Oliver - Rochester NH

Assignee:

Cabletron Systems, Inc. - Rochester NH

International Classification:

H04L 1256
H04I 316
H04J 324

US Classification:

370401

Abstract:

A packet of data is received from a LAN and transmitted over a WAN, by retaining the native LAN frame format of the packet during transmission across the WAN. Thus, LAN data may be transmitted over a SONET point-to-point link within a WAN network without the interim steps of creating ATM cells or other WAN transport packaging protocols. Instead, the LAN data may be transmitted directly over the SONET link as raw data, and reconstructed directly at the receiving end of the SONET link. A first buffer stores data from the LAN so that a corresponding packet size may be determined, and a second buffer stores data from the WAN to account for any speed difference between the LAN circuitry and WAN circuitry.