Texas Instruments Corporation

Venkata Naresh Kotikelapudi

Ganapathi Shankar Krishnamurthy

Siddhartha Gopal Krishna

Krishnamurthy Ganapathi Shankar

Ashish Ojha

Ganapathi Shankar

Kaushik Alwala

David Patrick Magee

Venkatesh Guduri

Divyasree J

Sreenath Puthumana

Anand Yadav

Laxman Sreekumar

James Lockridge

J Divyasree

Varun Garg

A circuit includes an amplifier having a first input, a reference input, and an output. A pulse width modulator (PWM) controller has an input coupled to the output of the amplifier. A first switch has a control terminal coupled to an output of the PWM controller. A second switch has a second terminal coupled to the second terminal of the first switch, and has a control terminal coupled to the output of the PWM controller. An input of a current sensor is coupled to the second terminal of the first switch and is coupled to a second terminal of the second switch. An output of the current sensor is coupled to the first input of the amplifier. A duty cycle monitoring and reference signal adjustment circuit has an input coupled to the output of the PWM controller and has an output coupled to the reference input of the amplifier.

Adaptive slope compensation in solenoid drivers to avoid instability in current regulation

An example apparatus includes: memory including machine-readable instructions; programmable circuitry configured to execute the machine-readable instructions of the memory configured to: determine a first value of power transferred to a stepper motor during a first operation of the stepper motor; determine a second value of power transferred to the stepper motor during a second operation of the stepper motor; determine a load angle of power delivered by the stepper motor during the first operation and second operation of the stepper motor based on the first value, the second value, and a stall power; and compare the load angle to a stall threshold to detect a stall of the stepper motor.

Methods and apparatus to detect a stall of a stepper motor

A stepper motor controller includes a first error amplifier, a second error amplifier, and a comparator. The first error amplifier has a first input adapted to be coupled to a current sensor to receive a sensed drive current, a second input adapted to receive an expected drive current and an output to provide a first error signal based on a comparison of the sensed drive current and the expected drive current. The second error amplifier has a first input adapted to be coupled to a voltage sensor to receive a sensed drive voltage, a second input coupled to the output of the first error amplifier and an output to provide a second error signal based on a comparison of the sensed drive voltage and the first error signal. The comparator has a first input adapted to receive a reference signal, a second input coupled to the output of the second error amplifier and an output to provide a stepper motor control signal based on a comparison of the reference signal and the error signal.

Current regulation for stepper motors using dual loop control through voltage mode and current mode

A motor control system and method for controlling a brushed direct current (BDC) motor using a feedback loop based on a corrected ripple count. Motor control circuitry, for example implemented in digital logic such as a microcontroller, receives a coil current signal and a motor voltage signal. Discontinuities in the coil current signal, such as caused by commutation of the BDC motor, are counted to generate a ripple count. An observer function derives an angular frequency model estimate for the values of the coil current and motor voltage signals using a computational model for the motor. A corrected ripple count is generated based on a comparison of a commutation angle of the motor with an angular position based on the angular frequency model estimate over a time interval between discontinuity pulses. A motor drive signal is adjusted based on the corrected ripple count.

Observer-based ripple detection for speed and position measurement for brushed direct current motors

A method for controlling a stepper motor includes calculating a duty cycle of a current provided to the stepper motor and comparing a difference, between the calculated duty cycle and a base duty cycle of current provided to the stepper motor under a base load condition, to a reference duty cycle value. The method also includes adjusting a peak current level of the current provided to the stepper motor responsive to the comparison.

Peak current regulation for stepper motors

A motor control system and method for a brushed direct current (BDC) motor using a compensated and corrected ripple count. Motor control circuitry, for example implemented in digital logic such as a microcontroller, receives a coil current signal and a motor voltage signal. Discontinuities in the coil current signal, are counted to generate a ripple count. An observer function derives an angular frequency model estimate using a computational model for the motor applying motor parameters estimated in an initial estimation interval following startup of the motor. A corrected ripple count is generated based on a comparison of a commutation angle of the motor with an angular position based on the angular frequency model estimate. Compensation for cumulative error over the initial estimation interval is derived from a behavioral motor model applying the estimated motor parameters. A motor drive signal is adjusted based on the compensated corrected ripple count.

Compensation for historical error in dynamic observer-based ripple detection in brushed direct current motors

In accordance with at least one example of the description, a circuit is adapted to be coupled to a coil of a motor via an H-bridge circuit. The circuit includes a duty sensor, a subtractor, and a comparator. The duty sensor is coupled to the coil of the motor and is configured to provide raw run duty data responsive to a coil current through the coil. The subtractor is coupled to the duty sensor and is configured to provide a differential duty signal responsive to a stall duty signal and a run duty signal obtained using the raw run duty data. The comparator is coupled to the subtractor and is configured to provide a stall signal indicative of a stall condition for the motor responsive to the differential duty signal and a threshold value.

Power transfer based stall detection techniques for stepper motor

A stepper motor driver includes an H-bridge including first and second outputs. The H-bridge includes a low-side transistor coupled between the first output and a ground. A reference current circuit is configured to produce a reference current. The reference current circuit has a reference output. An averager circuit includes an input and output. The input of the averager circuit is coupled to the first output of the H-bridge. A comparator includes first and second comparator inputs. The first input of the comparator is coupled to the output of the average circuit and the second input of the comparator is coupled to the reference output.

Average current control in stepper motor

A driver circuit includes a first switch which has a first terminal coupled to a voltage supply terminal, a second terminal coupled to a high-side gate, and a third terminal coupled to receive a voltage supply enable signal. The first switch is operable to connect the voltage supply terminal to the high-side gate responsive to the voltage supply enable signal. The driver circuit includes a second switch which has a first terminal coupled to a charge pump terminal, a second terminal coupled to the high side gate, and a third terminal coupled to receive a charge pump enable signal. The second switch is operable to connect the charge pump terminal to the high-side gate responsive to the charge pump enable signal.

Driver circuit for full-bridge DC motor driver system

An integrated circuit includes an H-bridge circuit having a first output node for coupling to a high-side terminal of an inductor and a second output node for coupling to a low-side terminal of the inductor. A current source is coupled in series with a current sense FET between a digital upper supply voltage and the first output node, wherein during a fast decay mode, a gate of the current sense FET is coupled to be turned on. A current-sense comparator includes a first input coupled to a sensing node between the current source and the current sense FET, a second input coupled to the lower supply voltage and an output coupled to a driver control circuit.

Current sensing and regulation for stepper motor driver

A circuit includes an input terminal, a first transistor, a second transistor, a comparator, a voltage reference circuit, and a control circuit. The first transistor includes a first terminal coupled to the input terminal. The second transistor includes a first terminal coupled to the input terminal. The comparator includes a first terminal coupled to the input terminal. The voltage reference circuit is coupled to a second terminal of the comparator. The control circuit includes an input, a first output, and a second output. The input is coupled to an output of the comparator. The first output is coupled to a second terminal of the first transistor. The second output is coupled to a second terminal of the second transistor.

Open load detection circuits

An integrated circuit includes an H-bridge circuit having a first output node for coupling to a high-side terminal of an inductor and a second output node for coupling to a low-side terminal of the inductor. A current sense FET is coupled between a current source and the lower supply voltage to provide a reference current that includes a peak current limit at a sensing node. A current-sense comparator has a first input coupled to the sensing node, a second input coupled to the second output node and an output coupled to send an output signal towards a driver control circuit. A FET linear detection circuit is coupled to receive a gate voltage of an active low-side power FET and has an output coupled to enable the current-sense comparator when the active low-side power FET is operating in a linear region.

A stepper driver for a motor includes an H-bridge, a sense transistor coupled to the H-bridge, a voltage-to-current (Vtol) converter, and a sine digital-to-analog converter (DAC). The Vtol converter has a Vtol converter input and a Vtol converter output. The Vtol converter output is coupled to the sense transistor. The sine DAC has a sine DAC digital input, a reference input, and a sine DAC output. The sine DAC output is coupled to the Vtol converter input. The sine DAC includes an R-2R network, an offset control circuit coupled to the R-2R network, and a gain control circuit also coupled to the R-2R network.

Growing community of inventors

Bengaluru, India

Venkata Naresh Kotikelapudi