Texas Instruments Corporation

Other

Kevin William Ziemer

Alaa Y El-Sherif

Fredrick W Trafton

Eugene Francis Plutowski

Mehedi Hassan

Hector Torres

Ricky Dale Jordanger

Bertram John White

Lawrence James Gewax

Gene Plutowski

Alaa-Eldin Y El-Sherif

An IC chip, a system and a method of operating the IC chip in response to an event trigger are provided. The method includes responsive to the event trigger, coupling a pin to a source of constant current to charge an external capacitor coupled to the pin and monitoring a capacitor voltage on the pin. If the magnitude of the capacitor voltage is greater than a rising threshold, detection of a falling threshold is enabled. If the magnitude of the capacitor voltage is greater than a voltage threshold, a first response is triggered and the pin is coupled to the lower rail to discharge the external capacitor. If detection of the falling threshold is enabled and the magnitude of the capacitor voltage is less than the falling threshold, the first response is also triggered.

Multiple chip synchronization via single pin monitoring of an external timing capacitor

Short circuit protection is provided for an isolation component that has a parasitic diode as an inherent part of its construction. The isolation component may or may not be contained in an integrated circuit. In response to detecting a short circuit condition based on voltages at one or more input terminals of the integrated circuit, or based on current between the terminals, the isolation component is activated to facilitate current flow through the isolation component, such as to reduce total power dissipation in the isolation component during at least part of the short circuit condition.

Short circuit protection for a power isolation device and associated diode

A positioning driver () for a voice coil motor () in a disk drive system () is disclosed. Pulse-width-modulated prestage drivers () are coupled to power transistors () arranged in an 'H' bridge for driving the voice coil motor (), biased with a power supply voltage (V). The pulse-width-modulated prestage drivers () drive the power transistors () according to a comparison between an error signal from an error amplifier () and a ramp clock signal (RMP) generated by a ramp clock generator (). The ramp clock generator () includes a control circuit () that modulates the high and low limits of the ramp clock signal (RMP) in response to variations in the power supply voltage (V). This modulation of the high and low limits compensates for variations in the gain of the power transistors () resulting from variations in the power supply voltage (V). The control circuit () may also modulate the slope of the ramp clock signal (RMP) according to variations in the power supply voltage (V), for example to maintain a constant frequency.

Rejection of power supply variations for gain error cancellation in pulse-width-modulated motor controllers

One aspect of the present invention provides a motor control system that includes a linear control system operative, in a linear mode, to provide a plurality of control signals for driving an associated motor based on an error signal. The system also includes control logic operative, in a pulse-width modulation (PWM) mode, to provide the plurality of control signals for driving the motor, at least some of the plurality of control signals being pulse-width-modulated signals based on the error signal. An error system generates the error signal based on an indication of a sensed electrical characteristic of the motor relative to a predetermined reference signal. A feedback network is coupled across the error system. The feedback configured to have transfer function characteristics that substantially match responses in the linear mode and the PWM mode of motor control system, which facilitates transitions between the linear mode and the PWM mode.

Closed-loop control system to mitigate PWM switching noise

A dual-mode positioning driver for a voice coil motor in a disk drive system is disclosed. Linear prestage drivers and pulse-width-modulated prestage drivers are both coupled to power transistors arranged in an 'H' bridge for driving the voice coil motor. The positioning driver is thus operable to drive the power transistors in either a linear mode or a pulse-width-modulated class D mode. In a transition period while switching from the pulse-width-modulated mode to linear mode, comparators compare the phase voltages in the 'H' bridge with a reference voltage. The outputs of the comparators are applied to the PWM output amplifiers to drive the power transistors, so that the phase voltages are preconditioned toward their linear bias points. Discontinuities in the drive current through the voice coil motor are minimized as a result.

Efficient transition from class D to linear operation in dual-mode voice coil motor controllers

A spindle motor control circuit for controlling a motor; including a control circuit to control the motor during at least a low state, a pulse state and a high state, the motor braking during said low state, the control circuit receiving a flyback voltage from the motor during the pulse state and the control circuit receiving a reduced flyback voltage from the motor during the high state.

Disk drive servo arm retract and spindle brake circuit

A protection system for an integrated circuit is disclosed. A detection system detects an overvoltage condition and provides an overvoltage condition signal to indicate a condition in which overvoltage protection may be desired. In response to the overvoltage condition signal, one or more variable resistance devices in the system, such as power devices of associated driver circuitry, are controlled to limit the voltage across such devices.

System and method for overvoltage protection of an integrated circuit

A predriver receives control information and provides an output signal for implementing control of an associated power switch device. The control information triggers a change in the output signal, such as from a first generally stable level to a second generally stable level. During the change in the output signal, the predriver operates in at least two transitional modes to control the output signal. The different transitional modes, for example, cause the output signal of the predriver to change at different rates. An associated pair of high side and low side predrivers further can be implemented in combination with a set of respective high side and low side power switches so as to form a driver.

Growing community of inventors

Plano, TX, United States of America

Kevin William Ziemer