Texas Instruments Corporation

Siddhartha Gopal Krishna

Krishnamurthy Ganapathi Shankar

Venkata Naresh Kotikelapudi

Ashish Ojha

Ganapathi Hegde

Priyank Anand

Divyasree J

David Patrick Magee

Ganapathi Shankar Krishnamurthy

Kaushik Alwala

Sarangan Thirumavalavan

James Lockridge

Laxman Sreekumar

A control circuit regulates the propagation delay of a field effect transistor (FET) before the FET transitions to the Miller region by applying a pre-charge current for a fixed duration to the gates of the FET. After the fixed duration, the current is reduced to a lower drive current level which is based on a desired output voltage slew rate. After the FET transitions to the Miller region, the output voltage slews down in accordance with the output voltage slew rate. By regulating the slew-rate of the output voltage in the Miller region and regulating the propagation delay of the FET prior to the Miller region, the control circuit reduces electromagnetic interference (EMI) caused by the switching of the FET, thereby improving electromagnetic compatibility (EMC) of switch mode driver systems without increasing the propagation delay of the FET.

Systems and methods for regulation of propagation delay in DC motor drivers

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

An apparatus for regulating a slew time of an output voltage of a motor driver system includes a gate current control circuit which has a first input coupled to receive a target slew time and a second input coupled to receive a slew time. The gate current control circuit provides an incremented gate current if the slew time is greater than the target slew time and provides a decremented gate current if the slew time is less than the target slew time. The apparatus includes a gate driver which has a first input coupled to receive a PWM signal and a second input coupled to receive the gate current. The gate driver provides a gate drive signal.

Systems and methods for regulating slew time of output voltage of DC motor drivers

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 circuit includes a first transistor, a second transistor, and a sense transistor. The first current terminals of the first and second transistors are coupled together at a power supply node. The control terminals of the second and third transistors are coupled together. The second current terminals of the first, second, and third transistors are coupled together. The sense resistor is coupled between the first current terminals of the first and second transistors and the first current terminal of the third transistor. The first and second transistors are configured such that during a first mode of operation, current to a load flows through the first and second transistors, and during a second mode of operation, current to a load is discontinued through the first transistor yet flows through the second transistor.

Over-current protection circuit

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.

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Siddhartha Gopal Krishna