Abstract: 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.

Abstract: A positioning driver (32) for a voice coil motor (22) in a disk drive system (10) is disclosed. Pulse-width-modulated prestage drivers (46) are coupled to power transistors (50) arranged in an “H” bridge for driving the voice coil motor (22), biased with a power supply voltage (VM). The pulse-width-modulated prestage drivers (46) drive the power transistors (50) according to a comparison between an error signal from an error amplifier (36) and a ramp clock signal (RMP) generated by a ramp clock generator (46). The ramp clock generator (46) includes a control circuit (68) that modulates the high and low limits of the ramp clock signal (RMP) in response to variations in the power supply voltage (VM). This modulation of the high and low limits compensates for variations in the gain of the power transistors (50) resulting from variations in the power supply voltage (VM).

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.