Allegro Microsystems, LLC

Robert Douglas Christie

James McIntosh

Gianluca Allegrini

Kamyar Khosravi

Masahira Kurihara

Thomas Ross

Robert J Stoddard

Aldo Togneri

Christy Looby

Andrew Adib

Colin Hall

Douglas Bryce

James Mcintosh

Alistair Wood

Peter Morris

Edward Chappell

Walter Morrison Stewart Wilson

James A Mcintosh

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. In response to the polarity value, the controller is configured to alter a duty cycle of the plurality of PWM output control signals to modify a voltage applied to the plurality of phase coils of the motor.

Motor control system with phase current polarity detection

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.

Reconstruction of an average motor supply current using phase current measurement

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.

Voltage regulator having boost and charge pump functionality

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.

Circuits and techniques for signaling between devices

A driver circuit is provided for driving a load, such as a multi-phase motor. The driver circuit includes a gate driver for providing a control signal to switching elements coupled to the driver circuit. A first switching element is coupled between a high supply voltage and a switching node of the load, and a second switching element is coupled between the switching node and a low supply voltage. To detect zero crossings of a current through the load, a zero crossing detector includes a first counter coupled to the switching node and a second counter coupled to the control signal. The first counter and second counter count in a predetermined direction based on a detected voltage of the switching node and based on a detected voltage of the control signal, respectively. The zero crossing detector generates an output signal based upon the difference between the first and the second counter.

Motor control current zero crossing detector

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.

Systems and methods for sensing current through a low-side field effect transistor

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.

Electric motor drive isolation circuit

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.

Multi-stage slew rate control profiling for transistor drive applications

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.

Growing community of inventors

Fife, United Kingdom

Robert Douglas Christie