Texas Instruments Corporation

Stmicroelectronics Gmbh

Sooping Saw

David C McClure

Rakesh Raja

Anuj Jain

Sudhir Nagaraj

Rajarshi Mukhopadhyay

Robert Alan Wadsworth

Wen Pin Lin

Angelo William Pereira

Giacomo Calabrese

Sayantan Gupta

Raul Blecic

Balaji Narendran Chellappa

Chintan Trehan

Alphonse Chesneau

Premsagar Kittur

Jeffrey Okyere

Wen Chao Qu

Matthew Hein

Paul-Herve Aymeric Fontaine

Michel Vercier

Robert Wadsworth

A modulation device may include a variable burst regulator and a current-driven clock generator. The modulation device may include a first output terminal configured to provide a modulated voltage for an operating frequency over a modulation period. The current-driven clock generator may include a second input terminal configured to receive a buffered version of the modulated voltage. The current-driven clock generator may include a second output terminal configured to provide a modulated current during the modulation period. The operating frequency may be proportional to the modulated current. The operating frequency may control the operating frequency over the modulation period.

Adaptive spread-spectrum modulation for DC/DC converters

A method for electrically producing a stalled state in a stepper motor having a first coil and a second coil is provided. The method includes driving a first sinusoidal current through the first coil, and driving a second sinusoidal current through the second coil, wherein the first and second sinusoidal currents are in phase.

Stepper motor

A motor driver includes a low-side drive transistor, a comparator, a sense transistor, first switch, and a second switch. The low-side drive transistor is adapted to be coupled to a motor. The comparator is configured to determine a direction of a drive current flowing in the low-side drive transistor. The sense transistor is coupled to the low-side side drive transistor and is configured to pass a replica of the drive current. The first switch is configured to couple the sense transistor to the low-side drive transistor responsive to the drive current flowing in a first direction through the low-side drive transistor. The second switch is configured to couple the sense transistor to a ground responsive to the drive current flowing in a second direction, that is opposite the first direction, through the low-side drive transistor.

Motor driver current sensing

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

In one embodiment, a method includes detecting, by a stall detection sensor in a driver coupled to a stepper motor, a first set of time-off periods in a rising commutation phase of motor current during current regulation. The stall detection sensor further detects a second set of time-off periods in a falling commutation phase of motor current during current regulation. Next, the stall detection sensor compares the first set of time-off periods with the second set of time-off periods and determines whether the stepper motor is stalled based on the comparison of the first set of time-off periods with the second set of time-off periods.

Stall detection in stepper motors using differential back-EMF between rising and falling commutation phase of motor current

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

An apparatus comprises a selected volume detector that detects a selected output volume; an analog output signal amplifier; a digital volume amplifier; a boost gain control element coupled to the selected volume detector; the analog output signal amplifier; and the digital volume amplifier; wherein the boost gain control element is configured to: keep a gain of a path of the digital volume amplifier and the analog output signal amplifier substantially constant, wherein the boost gain control element can adjust both: a) a gain of the digital volume control; and b) a gain of the analog output signal amplifier; to keep the gain of the path of the digital volume amplifier and the analog output signal substantially constant and equal to the selected output volume.

Method and apparatus for circuit with low IC power dissipation and high dynamic range

An integrated circuit includes an output pad, an alarm output pad, and a test mode output pad. A first multi-bit register is programmable to store programmable data such as data that identifies a customer for whom the integrated circuit has been manufactured. A second multi-bit register is programmable to store customer specified threshold data. A first circuit selectively couples the first and second multi-bit registers to the output pad. The first circuit is operable responsive to the integrated circuit being placed into a test mode to perform parallel-to-serial conversion of either the customer identification data stored in the first multi-bit register or the customer specified threshold data stored in the second multi-bit register and drive the converted data for output through the output pad. The integrated circuit further includes a tamper detection circuit operable responsive to the customer specified threshold data to generate a tamper alarm signal. A second circuit selectively couples the tamper alarm signal to the alarm output pad and test mode output pad depending on whether the integrated circuit is in a test mode. More specifically, the second circuit operates to drive the alarm output pad with the tamper alarm signal when the integrated circuit is not in test mode and drive the test mode output pad with the tamper alarm signal when the integrated circuit is in test mode (with the alarm output pad driven to a known state).

Test mode circuitry for a programmable tamper detection circuit

An apparatus and method are disclosed for temperature measurement that includes performing a first &#x394;Vbe measurement of a first temperature of a diode circuit comprising a transistor and, subsequently, performing a first Vbe measurement of a second temperature of the diode circuit. A temperature difference is calculated between the second temperature and the first temperature. If the temperature difference is not greater than a predetermined amount, a second Vbe measurement of a third temperature of the diode circuit is subsequently performed. If the temperature difference is greater than the predetermined amount, a second &#x394;Vbe measurement of the second temperature of the diode circuit is performed.

System and method for remote temperature sensing

A relaxation oscillator includes a capacitor connected to a comparator input, current sources switched to supply power to the capacitor based on an output of the comparator, and a duplicate integrator shifting a voltage on the capacitor to offset a propagation delay through the comparator. The duplicate integrator includes current sources and a capacitor matching and switched in tandem with those within the relaxation oscillator, plus an additional current source, and is selectively switched into connection with the comparator input. By canceling the comparator propagation delay, the oscillator output frequency can be stably controlled through selection of resistive and capacitive values, using cheaper technology and tolerating large temperature, voltage and process variations.

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Sooping Saw