Patents by Inventor Robert D. Christie
Robert D. Christie has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 10924052Abstract: A system is provided for driving a load such as a multi-phase motor. The system includes a motor driver that has a plurality of switches coupled to a motor to drive a current through each of a plurality of phase coils of the motor. A polarity detection circuit detects a polarity of the current in one or more of the phase coils of the motor to generate a polarity value that represents the detected current polarity. The polarity detection circuit can include at least one comparator that has a first input coupled to a node between two of the plurality of switches, a second input coupled to receive a threshold value, and an output from which the polarity value is provided. Further included is a controller that is configured to provide a plurality of pulse width modulated (PWM) output control signals to the plurality of switches to control the switches to drive the current through the plurality of phase coils of the motor.Type: GrantFiled: August 8, 2019Date of Patent: February 16, 2021Assignee: Allegro MicroSystems, LLCInventors: Kamyar Khosravi, Masahira Kurihara, Gianluca Allegrini, Robert D. Christie
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Publication number: 20210044242Abstract: A system is provided for driving a load such as a multi-phase motor. The system includes a motor driver that has a plurality of switches coupled to a motor to drive a current through each of a plurality of phase coils of the motor. A polarity detection circuit detects a polarity of the current in one or more of the phase coils of the motor to generate a polarity value that represents the detected current polarity. The polarity detection circuit can include at least one comparator that has a first input coupled to a node between two of the plurality of switches, a second input coupled to receive a threshold value, and an output from which the polarity value is provided. Further included is a controller that is configured to provide a plurality of pulse width modulated (PWM) output control signals to the plurality of switches to control the switches to drive the current through the plurality of phase coils of the motor.Type: ApplicationFiled: August 8, 2019Publication date: February 11, 2021Applicant: Allegro MicroSystems, LLCInventors: Kamyar Khosravi, Masahira Kurihara, Gianluca Allegrini, Robert D. Christie
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Patent number: 10819257Abstract: Systems and methods for computing an average supply current to a motor include a current sensor that is configured to sense a current through the motor. A converter is configured to sample the output of the current sensor at times that are established by a trigger signal and convert the samples into digital current values. A trigger signal generator generates the trigger signal based on one or more pulse width modulated (PWM) motor control signals within a PWM cycle. An average supply current value that indicates the average supply current to the motor is computed by a controller using the digital current values received from the converter.Type: GrantFiled: September 5, 2019Date of Patent: October 27, 2020Assignee: Allegro MicroSystems, LLCInventors: Kamyar Khosravi, Masahira Kurihara, Andrew Adib, Robert D. Christie
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Patent number: 10511223Abstract: Methods and apparatus for a voltage regulator having a boost module and a charge pump module. In embodiments, the charge pump module is configured to operate in multiple modes. In embodiments, an IC package includes the boost module and the charge pump with a shared component, such as a capacitor.Type: GrantFiled: December 6, 2017Date of Patent: December 17, 2019Assignee: Allegro MicroSystems, LLCInventors: James McIntosh, Robert Stoddard, Robert D. Christie
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Publication number: 20180166984Abstract: Methods and apparatus for a voltage regulator having a boost module and a charge pump module. In embodiments, the charge pump module is configured to operate in multiple modes. In embodiments, an IC package includes the boost module and the charge pump with a shared component, such as a capacitor.Type: ApplicationFiled: December 6, 2017Publication date: June 14, 2018Applicant: Allegro MicroSystems, LLCInventors: James McIntosh, Robert Stoddard, Robert D. Christie
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Patent number: 9935452Abstract: A method for signaling between a controller and a driver includes receiving, at a pin of the driver coupled to the controller, a command signal generated by the controller and generating, by the driver at the pin coupled to the controller, a fault signal indicating a fault condition. The driver can be configured to drive a switch and the command signal can be configured to cause the driver to open the switch when the command signal is in a first state and to close the switch when the command signal is in a second state. The command signal being in the first state may correspond to the command signal having a voltage level above a first predetermined threshold and the command signal being in the second state may correspond to the command signal having a voltage level below a second predetermined threshold.Type: GrantFiled: November 13, 2015Date of Patent: April 3, 2018Assignee: Allegro MicroSystems, LLCInventors: Christy Looby, Robert D. Christie
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Patent number: 9735773Abstract: Systems and techniques detecting a reverse current are disclosed. An apparatus comprises a switching circuit coupled to a load and a reference node. The switching circuit may be capable of conducting a reverse current from the reference node to the load when a voltage at the load is lower than a voltage at the reference node. A voltage source has a first terminal coupled to the load, a second terminal configured to follow a voltage at the load, and produces a voltage proportional to a voltage drop across the switching circuit. A comparator circuit is coupled to compare a voltage at the second terminal of the voltage source to the voltage at the reference node and configured to indicate when the reverse current has a magnitude greater than a predetermined threshold.Type: GrantFiled: April 29, 2014Date of Patent: August 15, 2017Assignee: Allegro Microsystems, LLCInventors: James McIntosh, Robert D. Christie, Douglas Bryce, Walter Morrison Stewart Wilson
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Publication number: 20170141562Abstract: A method for signaling between a controller and a driver includes receiving, at a pin of the driver coupled to the controller, a command signal generated by the controller and generating, by the driver at the pin coupled to the controller, a fault signal indicating a fault condition. The driver can be configured to drive a switch and the command signal can be configured to cause the driver to open the switch when the command signal is in a first state and to close the switch when the command signal is in a second state. The command signal being in the first state may correspond to the command signal having a voltage level above a first predetermined threshold and the command signal being in the second state may correspond to the command signal having a voltage level below a second predetermined threshold.Type: ApplicationFiled: November 13, 2015Publication date: May 18, 2017Applicant: ALLEGRO MICROSYSTEMS, LLCInventors: Christy Looby, Robert D. Christie
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Patent number: 9496708Abstract: An isolation circuit is coupled between motor driver half bridge circuits and an electric motor. A motor controller circuit supplies motor drive signals to the motor driver half bridge circuits. The isolation circuit includes transistors coupled in series with the motor windings. Low to medium power diodes are coupled between a reference voltage source and control terminals of the transistors.Type: GrantFiled: April 3, 2015Date of Patent: November 15, 2016Assignee: Allegro MicroSystems, LLCInventors: Edward Chappell, Robert D. Christie, James McIntosh, Peter Morris
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Patent number: 9294084Abstract: A transistor drive circuit uses multi-stage slew rate control to drive one or more switching transistors. After a decision is made to change transistor state, a first drive current may be applied to an input terminal of the transistor for a predetermined time duration. After the predetermined time duration, a second drive current may be applied to the input terminal. When the transition between states is substantially complete, the current drive to the input terminal may be changed to a voltage drive. In some embodiments, the predetermined time duration may be based on the start time of a Miller plateau during the transition period.Type: GrantFiled: November 26, 2014Date of Patent: March 22, 2016Assignee: Allegro Microsystems, LLCInventors: James McIntosh, Robert D. Christie, Colin Hall, Alistair Wood
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Publication number: 20150311894Abstract: Systems and techniques detecting a reverse current are disclosed. An apparatus comprises a switching circuit coupled to a load and a reference node. The switching circuit may be capable of conducting a reverse current from the reference node to the load when a voltage at the load is lower than a voltage at the reference node. A voltage source has a first terminal coupled to the load, a second terminal configured to follow a voltage at the load, and produces a voltage proportional to a voltage drop across the switching circuit. A comparator circuit is coupled to compare a voltage at the second terminal of the voltage source to the voltage at the reference node and configured to indicate when the reverse current has a magnitude greater than a predetermined threshold.Type: ApplicationFiled: April 29, 2014Publication date: October 29, 2015Applicant: Allegro Microsystems, LLCInventors: James McIntosh, Robert D. Christie, Douglas Bryce, Walter Morrison Stewart Wilson
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Publication number: 20150288304Abstract: An isolation circuit is coupled between motor driver half bridge circuits and an electric motor. A motor controller circuit supplies motor drive signals to the motor driver half bridge circuits. The isolation circuit includes transistors coupled in series with the motor windings. Low to medium power diodes are coupled between a reference voltage source and control terminals of the transistors.Type: ApplicationFiled: April 3, 2015Publication date: October 8, 2015Applicant: ALLEGRO MICROSYSTEMS, LLCInventors: Edward Chappell, Robert D. Christie, James McIntosh, Peter Morris
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Patent number: 7649325Abstract: A circuit includes a capacitive element for coupling across a load element to be energized by a DC signal, a first sense element to monitor an instantaneous sum of currents through the load element and the capacitive element, a switching element to control current through the first sense element, a second sense element coupled to the switching element to sense current through the switching element, an energy storage element coupled to the switching element, a unidirectional current flow element allowing current flow to the load element, and a converter circuit to control the switching element, wherein the converter circuit regulates to the current level monitored across the first sense element, and wherein a converter regulation loop includes a dominant pole to average the current sensed through the first sense element.Type: GrantFiled: April 3, 2006Date of Patent: January 19, 2010Assignee: Allegro Microsystems, Inc.Inventors: James A. McIntosh, Aldo Togneri, Robert D. Christie