Abstract: In some embodiments, a differential input stage comprises a first n-type metal oxide semiconductor transistor (NMOS) pair coupled to a first input and a second input, a second NMOS pair coupled to the first input, a first output node, the second input, and a second output node, a first diode coupled to the first NMOS pair and the first output node, a second diode coupled to the first NMOS pair and the second output node, and a cascaded current source coupled to the first NMOS pair and the second NMOS pair.

Abstract: In some embodiments, a differential input stage comprises a first n-type metal oxide semiconductor transistor (NMOS) pair coupled to a first input and a second input, a second NMOS pair coupled to the first input, a first output node, the second input, and a second output node, a first diode coupled to the first NMOS pair and the first output node, a second diode coupled to the first NMOS pair and the second output node, and a cascaded current source coupled to the first NMOS pair and the second NMOS pair.

Abstract: One example includes an amplifier system. The system includes a gain stage configured to conduct a gain current in response to an input voltage. The system also includes a current limit stage coupled to the gain stage and being configured to one of source and sink the gain current and to define a limit amplitude of the gain current during a current limit condition. The system further includes an output stage coupled to the gain stage and configured to conduct an output current through an output node in response to the gain current, the output current having a maximum amplitude during the current limit condition that is proportional to the limit amplitude.

Abstract: A current driver is coupled to an inductor; a digital control for regulation of the current driver turns the current driver on or off coupled to the current driver; a comparator output coupled to the input of the digital control for regulation of the driver with inputs to compare a voltage of the inductor to a target voltage, a digital control for selection of one of a set of peaks and valleys of allowable current levels of the current driver, the digital control for selection of one of a set of peaks and valleys coupled to the output of the comparator and an input of the current driver, the digital control for the peak/valley current to monitor the duration of each high and low output state of the comparator output to determine the selection of one of the set of peak and valley of allowable current levels for the current driver.

Abstract: One example includes an amplifier system. The system includes a gain stage configured to conduct a gain current in response to an input voltage. The system also includes a current limit stage coupled to the gain stage and being configured to one of source and sink the gain current and to define a limit amplitude of the gain current during a current limit condition. The system further includes an output stage coupled to the gain stage and configured to conduct an output current through an output node in response to the gain current, the output current having a maximum amplitude during the current limit condition that is proportional to the limit amplitude.

Abstract: One example includes an amplifier system. The system includes a gain stage configured to conduct a gain current in response to an input voltage. The system also includes a current limit stage coupled to the gain stage and being configured to one of source and sink the gain current and to define a limit amplitude of the gain current during a current limit condition. The system further includes an output stage coupled to the gain stage and configured to conduct an output current through an output node in response to the gain current, the output current having a maximum amplitude during the current limit condition that is proportional to the limit amplitude.

Abstract: One example includes an amplifier system. The system includes a gain stage configured to conduct a gain current in response to an input voltage. The system also includes a current limit stage coupled to the gain stage and being configured to one of source and sink the gain current and to define a limit amplitude of the gain current during a current limit condition. The system further includes an output stage coupled to the gain stage and configured to conduct an output current through an output node in response to the gain current, the output current having a maximum amplitude during the current limit condition that is proportional to the limit amplitude.

Abstract: An apparatus, comprises three driver FETs coupled at their sources; note-driver circuit; a first sense FET coupled to the sources of the three driver FETs; a current mirror having the first sense FET and a mirror FET; wherein the first sense FET is coupled to the mirror FET; a first transconductance amplifier coupled to the first sense FET; a second amplifier coupled to the current mirror, and an output of the first transconductance amplifier is an input to the second amplifier.

Abstract: An apparatus for use with a hard disk drive, comprising: a selectable notch filter with a selectable notch frequency; a shock sensor of the hard disk drive, coupled to the selectable notch filter, the shock sensor having at least one resonance frequency; a flip flop coupled to an output of the notch filter and an output of the shock sensor; a calibration logic coupled to an output of the flip flop, wherein an output of the calibration logic is coupled to a selection input of the selectable notch filter.

Abstract: An apparatus for use with a hard disk drive, comprising: a selectable notch filter with a selectable notch frequency; a shock sensor of the hard disk drive, coupled to the selectable notch filter, the shock sensor having at least one resonance frequency; a flip flop coupled to an output of the notch filter and an output of the shock sensor; a calibration logic coupled to an output of the flip flop, wherein an output of the calibration logic is coupled to a selection input of the selectable notch filter.

Abstract: A current driver is coupled to an inductor; a digital control for regulation of the current driver turns the current driver on or off coupled to the current driver; a comparator output coupled to the input of the digital control for regulation of the driver with inputs to compare a voltage of the inductor to a target voltage, a digital control for selection of one of a set of peaks and valleys of allowable current levels of the current driver, the digital control for selection of one of a set of peaks and valleys coupled to the output of the comparator and an input of the current driver, the digital control for the peak/valley current to monitor the duration of each high and low output state of the comparator output to determine the selection of one of the set of peak and valley of allowable current levels for the current driver.

Abstract: An apparatus, comprises three driver FETs coupled at their sources; note-driver circuit; a first sense FET coupled to the sources of the three driver FETs; a current mirror having the first sense FET and a mirror FET; wherein the first sense FET is coupled to the mirror FET; a first transconductance amplifier coupled to the first sense FET; a second amplifier coupled to the current mirror, and an output of the first transconductance amplifier is an input to the second amplifier.

Abstract: One embodiment of the invention includes a disk-drive write head fault detection system. The system includes an output stage configured to generate a monitored current through the disk-drive write head. The system also includes an open-circuit fault detector configured to compare a magnitude of a first reference current with a magnitude of the monitored current to detect an open-circuit fault condition associated with the disk-drive write head. The system further includes a short-to-ground fault detector configured to compare a magnitude of a second reference current with the magnitude of the monitored current to detect a short-to-ground fault condition associated with the disk-drive write head.

Abstract: One embodiment of the invention includes a disk-drive write head fault detection system. The system includes an output stage configured to generate a monitored current through the disk-drive write head. The system also includes an open-circuit fault detector configured to compare a magnitude of a first reference current with a magnitude of the monitored current to detect an open-circuit fault condition associated with the disk-drive write head. The system further includes a short-to-ground fault detector configured to compare a magnitude of a second reference current with the magnitude of the monitored current to detect a short-to-ground fault condition associated with the disk-drive write head.