Texas Instruments Corporation

Anuj Jain

Sooping Saw

Rakesh Raja

Wenchao Qu

Sudhir Nagaraj

Michael Edwin Butenhoff

David Patrick Magee

Stephen John Fedigan

Rajarshi Mukhopadhyay

Keith Ryan Green

David H Elwart, Ii

Ryan Paul Kehr

Mario Marascutti

Jeffrey Okyere

Wen Chao Qu

Matthew Hein

Modulating a gate drive current supplied to an output drive switch coupled to an electric motor by performing at least the following: obtain a gate drive current modulation profile, supply, based on the gate drive current modulation profile, a first gate drive current level as the gate drive current when the output drive switch is operating within a first region, drop the first gate drive current level to a second gate drive current level when the output drive switch transitions from the first region to operating within a Miller region, increase the second gate drive current level to a third gate drive current level within the Miller region, and set the gate drive current to a fourth gate drive current level when the output drive switch transitions from the Miller region to operating within a third region.

Low electromagnetic interference and switch loss motor driver

A transistor, e.g., field effect transistor FET, ringing adjustment circuit and method comprising the measuring of a voltage from a transistor (e.g., a node of a FET) during the transistor turning on and turning off, determining the voltage oscillation in the measured voltage by performing a derivative function on the measured voltage and detecting a switch in a voltage change rate from positive to negative or negative to positive, and comparing the voltage change rate after the detected switch to adjust drive current applied to the transistor to optimize efficiency while minimizing voltage oscillation and ringing.

Transistor ringing adjustment circuit and method

A motor control system for a permanent magnet synchronous motor (PMSM) uses two linear Hall devices to produce a first signal indicative of a strength of a first magnetic field component produced by a set of rotor magnets and to simultaneously produce a second signal indicative of a strength of second magnetic field component produced by the rotor magnets that is approximately orthogonal to the first magnetic field component. An angular position and angular velocity of the rotor is calculated based on the first signal and the second signal. A plurality of phase signals is produced based on the calculated angular position and angular velocity. Current in a plurality of field windings of the motor is controlled using the plurality of phase signals.

Linear hall device based field oriented control motor drive system

A stepper motor control system includes stepper motor error reduction. For example, first and second power switches respectively energize and de-energize a stepper motor coil during each cycle for pulse-width modulating (PWM) the coil current. During a cycle including a zero crossing microstep, a calibrator detects a type of a body diode effect that occurs in the second power switch when the second switch stops de-energization of the coil. A selected offset is adjusted in response to the type of detection of the body diode effect of the second power switch. Adjusting the selected offset controls the trigger time for a comparator for comparing an offset reference voltage to a motor voltage developed in response to the coil current. Progressively adjusting the selected offset over successive cycles compensates for delays of components in the PWM control loop and reduces errors resulting from, for example, process, voltage, and temperature variations.

Microstepper motor control circuit PWM output coupled to H-bridge gates

In a described example an apparatus includes: an FET driver circuit configured to supply current to a coil in a stepper motor, the FET driver circuit configured to regulate the current to the coil using a fixed delta current; a current chopper pulse width modulated circuit coupled to the FET driver circuit configured to supply pulses corresponding to a step control signal and a direction control signal; a back electromotive force (BEMF) monitor coupled to the current chopper circuit configured to measure an off time pulse and to output a BEMF monitor signal; and a controller coupled to the current chopper pulse width modulated circuit to supply the step and direction control signals and coupled to receive the BEMF monitor signal.

Methods and apparatus for robust and efficient stepper motor BEMF measurement

A method for verifying an operation of a Hall-effect sensor without an applied magnetic field. The method can include providing a bias signal to a first pair of terminals of a Hall-effect element, applying a Hall current signal to a second pair of terminals of the Hall-effect element, measuring a Hall output voltage across the second pair of terminals and comparing the measured Hall output voltage to an expected Hall output voltage that would be provided by a corresponding applied magnetic field.

Systems and methods for operating a hall-effect sensor without an applied magnetic field

A motor controller that includes a processing device and a drive circuit. The drive circuit may include a plurality of switches, a motor winding, and a current sensor coupled together in an H-bridge configuration. The processing device is configured to cause a drive current to drive through the motor winding for a minimum amount of time. The processing device is also configured to compare the current through the current sensor to a threshold value at the minimum amount of time. The processing device is also configured to, based on the current being at or above the threshold value at the minimum amount of time, stop the drive current for an off period of time and cause a first decay of the current for a first percentage of the off period of time and a first slow decay for a second percentage of the off period of time.

Current regulation in motors

A system and method for a decay lock loop for time varying current regulation in electric motors determines if a predetermined electrical current regulation level for an electric motor has been obtained within a tuning control time window. A coarse control loop increases or decreases a fast current decay, in response to a determination that the predetermined electrical current regulation level has not been obtained within the tuning control time window, until the predetermined electrical current regulation level falls within the tuning control time window. A fine control loop increments or decrements an amount of fast current decay during a total decay time, in response to a determination that the predetermined electrical current regulation level has been obtained within the tuning control time window, until a predetermined timing of the predetermined electrical current regulation level has been obtained.

Decay lock loop for time varying current regulation in electric motors

Stepper motor winding current regulation methods and apparatus adapt a maximum blanking period to generate an adapted blanking period that is proportional to a currently-selected current regulation set-point. Sensed winding current feedback is ignored at a current regulation controller during the adapted blanking period or during a minimum blanking period, whichever longer, to avoid attempting to track noise imposed upon a sensed winding current feedback signal at an initiation of rapid current changes di/dt. Doing so may decrease ripple in the motor winding current waveform and reduce zero-crossing distortion by decreasing overshoot of the current regulation set-point by the sensed winding current.

Sensed motor winding current adapting blanking period between max/min values

Stepper motor winding current regulation methods and apparatus continuously and bi-directionally sense winding current to determine both the magnitude of the winding current and the slope of a waveform representing the winding current. The magnitude and slope information is used to more precisely control periods of current rise and characteristics of fast and slow current decay during pulse-width modulation ('PWM') regulation cycles. Winding current rise and decay shaping is based upon the sensed magnitude of the winding current, the magnitude of the winding current regulation set-point ITRIP, whether the sensed winding current is greater than or less than ITRIP at a selected sampling time, whether the sensed winding current is increasing or decreasing when a waveform of the sensed winding current crosses over ITRIP, and whether or not the magnitude of ITRIP changes during a PWM cycle in response to a receipt of a subsequent DAC code.

Dynamic mixed-mode current decay apparatus and methods

Input codes are sequenced at a lower-resolution linear DAC and the output is converted to a linear current waveform. A first of two interconnected analog current multipliers multiplies the linear current by itself and by the inverse of a first constant current source to create a quadratic current output. A second current multiplier multiplies the quadratic output current by the linear current and by the inverse of a second constant current source to generate a cubic current output. The quadratic and cubic currents are subtracted from the linear current to generate an approximation of the first 180 degrees of a sine wave current. Alternate (pi to 2*pi) positive-going one-half sine waves may be polarity reversed to create a complete positive-going and negative-going sine-shaped electrical current of higher resolution than is available from a sine DAC of resolution equivalent to that of the lower-resolution linear DAC.

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Lewisville, TX, United States of America

Anuj Jain