Seagate Technology Incorporated

Thomas Lee Schick

Robert Matousek

Todd Michael Lammers

Alfredo Sam Chu

Jon David Trantham

Wenzhong Zhu

Housan Dakroub

Timothy Francis Ellis

Sunil Anuprasad Patel

A compact printed circuit board assembly includes a printed circuit board (PCB) and a preamplifier subassembly. The preamplifier subassembly includes a preamplifier and an insulating endcap abutting one another and arranged in a plane parallel to the PCB. An electrical via formed within the first insulating endcap provides an electrical connection between a decoupling capacitor and the PCB to reduce noise detectable in current flowing between the preamplifier and a current source.

Compact printed circuit board assembly with insulating endcap via

An apparatus may include a preamplifier configured to be connected to a plurality of magnetic read/write heads, wherein each of the magnetic read/write heads includes a read sensor to read data from a disc and a write element to write data to the disc. The preamplifier may include a first set of registers configured to indicate a first head of the plurality of magnetic read/write heads that is selected for reading data, a second set of registers configured to indicate a second head of the plurality of magnetic read/write heads that is selected for reading data, an input line configured to receive a control signal to activate reading data from the first head substantially simultaneously with reading data from the second head, a first output to provide data from the first head, and a second output to provide data from the second head.

Independent head, dual reader control logic

A preamplifier may have a freeze bit that when set, puts the preamplifier in a static state, which prevents the preamplifier from implementing subsequent programming commands. The freeze state may continue until an unfreeze bit is programmed. In a multiple preamplifier system, preamplifiers can be differently and individually configured over a single interface. Preamplifiers may be released from the static state (frozen) by either programming the unfreeze bit (which can release all of the preamps) or by programming the freeze bit to a '0' state (releases the individual preamp). An inversion control circuit can allow inversion of a control signal to a preamplifier. The inversion control circuit may be enabled and disabled based on a physical conductive connection to a logic high voltage or a logic low voltage. One or more programmable control lines can determine whether the inversion function is activated when the inversion control circuit is enabled.

Individually programmable preamplifier

Systems and methods of laser bias calibration are presented. A preamplifier circuit may configure a laser current supplied to a laser emitter to be a first laser current of the plurality of laser currents during the writing of one or more first sectors. The preamplifier may further detect one or more gaps in a write power signal while the laser current of the laser emitter is configured to be the first laser current. In response to the detection of the one or more gaps in the write power signal, the preamplifier may configure the laser current supplied to the laser emitter to be a second laser current of the plurality of laser currents during the writing of one or more second sectors. The preamplifier circuit may be utilized in a heat assisted magnetic recording device.

Laser current calibration using preamplifier

A preamplifier circuit can include a control line dedicated to receive a control signal that corresponds to indicating a specific register of the preamplifier circuit, which can allow the preamplifier to switch between utilizing two or more registers to control a current output of the preamplifier circuit. The preamplifier circuit may also have a serial input to program multiple registers of the preamplifier circuit in a serial fashion. In some embodiments, the current output may be a laser bias current. The preamplifier may adjust an output current that drives a laser emitter based on a control signal indicating which specific registers controls the output current. Further, a controller, such as a system-on-chip controller, may selectively vary the control signal to affect the current output of the preamplifier circuit. These systems and methods may be particularly useful for lasers and heat-assisted magnetic recording (HAMR).

Laser bias current control

Methods, apparatuses, and systems for allowing a single-die preamp to act as two or more virtual preamps for reading or writing data through multiple heads or elements concurrently. A selection register of a preamplifier is set to enable access to a primary register map. Values of registers in the primary register map are set to program a primary preamp channel for performing read or write operations to a first head. The selection register is then set to enable access to a secondary register map, and values of registers in the secondary register map are set to program a secondary preamp channel for performing read or write operations to a second head. Read or write operations can be performed to the first head through the primary preamp channel at a same time that read or write operations are performed to the second head through the second preamp channel.

Multiple virtual preamps in a single die

A first parameter associated with a writer preamp is defined. A write current of the writer preamp is adjusted in accordance with the first parameter so that an asymmetric signal is applied at a write head. The asymmetric signal results in symmetric writing of bits to a medium.

Growing community of inventors

Arvada, CO, United States of America

Thomas Lee Schick