Patent application number | Description | Published |
20080239543 | METHODS AND APPARATUS FOR GENERATING A HARD DRIVE WRITE SIGNAL - Methods and apparatus for generating a hard drive write signal are here in disclosed. A disclosed method comprises generating a hard drive write signal on an output of a switch based on an edge of the first control signal and reducing the hard drive write signal based on an edge of a second control signal via a second switch. | 10-02-2008 |
20080239558 | METHODS AND APPARATUS FOR DURATION CONTROL OF HARD DRIVE WRITE SIGNALS - Methods and apparatus for controlling the duration of a pulse in a hard drive write system are disclosed. A disclosed method comprises generating a current pulse, reducing the current of the pulse and conveying a portion of the current pulse to a hard drive write system. In addition, a method is disclosed whereby a portion of the current pulse is truncated. | 10-02-2008 |
20080239563 | METHODS AND APPARATUS FOR TEMPERATURE COMPENSATION FOR HARD DISK DRIVE WRITE OVERSHOOT CURRENT - Methods and apparatus for temperature compensation for hard disk drive writer overshoot current are disclosed. A disclosed system comprises creating a first delay based on the temperature of the hard disk drive, creating a second delay based on the temperature of the hard disk drive, and creating a pulse based on the first and second delay. | 10-02-2008 |
20090140797 | Rapidly Activated Current Mirror System - One embodiment of the invention includes a current mirror system. The system comprises a master circuit configured to conduct a first current in response to an activation state of an activation signal. The system also comprises a slave circuit configured to generate at least one second additional current in response to the activation state of the activation signal. Each of the at least one additional current can be proportional to the first current. The system further comprises a current path circuit that is configured as a substantial copy of the master circuit, the current path circuit being configured to conduct the first current in response to a deactivation state of the activation signal. | 06-04-2009 |
20090244757 | Methods and Apparatus for Low Power Hard Disk Drive Servo Writers - Methods and apparatus to for low power hard disk drive servo writers. A disclosed servo writer comprises a distribution circuit to receive one or more pulses from a pulse generator, the distribution circuit having a biasing circuit have one of a first write mode or a second write mode based on an operating condition signal; and a first signal generator to form a first write signal and a second signal generator to form a second write signal, the first and second signal generators being actuated by the distribution circuit, wherein the distribution circuit actuates one of the first and second signal generators in the first write mode and the distribution circuit actuates the first and second signal generators in the second write mode. | 10-01-2009 |
20120019947 | TECHNIQUE FOR PROGRAMMABLE RISE TIME IN HARD DISK DRIVE WRITER - A write channel for a hard disk drive has a write current with a programmably adjustable rise time, and includes first and second analog write data signal paths having respective resistive nodes. First and second programmable capacitors are connected to the resistive nodes, whereby changes in capacitance of the first and second capacitors changes the rise time of the write current. A programmer selectively programs the first and second programmable capacitors. The rise time programmed is selected to provide a decreased bit error rate of an on-track write process and reduced adjacent-track interference. | 01-26-2012 |
20130027804 | WRITE DATA SWITCHING FOR MAGNETIC DISK DRIVES - One embodiment of the invention includes a system for writing data onto a magnetic disk. An output driver provides a first write current through a first output transistor in a first state and provides a second write current through a second output transistor in a second state. The first and second write currents can be provided to a disk write head to store opposing binary values, respectively. A bias current generator switches a first bias current between an intermediate voltage node in the second state and a first control node in the first state, and switches a second bias current between the intermediate voltage node in the first state and a second control node in the second state. The first and second bias currents can be provided to set a bias voltage at the first and second control nodes to bias the first and second output transistors, respectively. | 01-31-2013 |
20130278335 | High Speed, Low Power Write Current Switching Scheme for HDD Preamplifier - A hard drive write preamplifier includes a first differential pair of PNP BJTs having a first PNP BJT and a second PNP BJT; a first tail current source coupled into emitter of the PNP BJTs of the first differential pair; a second differential pair of NPN BJTs having a first NPN BJT and a second NPN BJT; a second tail current source coupled into the emitters of the NPN BJTs of the second differential pair; wherein a collector of each of the PNP BJTs of the first differential pair are coupled to a corresponding collector the NPN BJTs of the second differential pair; a first shift up PNP BJT having emitter coupled to the collector of a first PNP BJT of the first differential pair; a second shift up PNP BJT having an emitter coupled to the collector of the second PNP BJT of the first differential pair. | 10-24-2013 |
20130308222 | DISK-DRIVE PULSE DURATION CONTROL SYSTEM - One embodiment includes a pulse duration control system for a magnetic disk-drive system. A rise delay system generates first control voltages in response to a write data input signal changing between a first state and a second state. A fall delay system generates second control voltages in response to the write data input signal changing between the first and second states. A comparator system generates a rising-edge overshoot signal and a falling-edge overshoot signal based on a comparison of the first and second control voltages. The rising-edge overshoot signal can set a duration of a positive overshoot current pulse for a write current at a transition of the write data input signal from the first state to the second state, and the falling-edge overshoot signal can set a duration of a negative overshoot current pulse for the write current at a transition from the second state to the first state. | 11-21-2013 |
20140301173 | DIFFERENTIAL LASER DIODE DRIVER APPARATUS AND SYSTEMS - Apparatus and systems create differential drive signals suitable for HAMR data recording. A laser diode differential driver provides heating current pulses at a time Φ | 10-09-2014 |