International Business Machines Corporation

Steven Dennis Keidl

Mark Kenneth Hoffmeyer

Patrick Kevin Egan

David J Braun

James Aloysius Hagan

Gary Allen Thompson

Timothy Charles Daun-Lindberg

Steven William Steele

John Gregory Stephanie

Karl A Shidler

Charles J Guenther

Jeffrey Scot Rotter

Vincent W Ting

A plurality of regulator phases are connected in parallel between a regulator input and a regulator output, each phase including a regulator receiving an input voltage and providing an output voltage. A multi-phase controller is coupled to each of the plurality of regulator phases, where one or more phases are provided for enabling redundancy. The multi-phase controller receives a feedback output voltage and a respective detected current signal from each of the plurality of regulator phases. The multi-phase controller generates control signals to sequentially activate each of the plurality of regulator phases for predetermined periods of time to generate controlled current sharing between phases. To achieve redundancy at a phase level, each of the plurality of regulator phases includes an output ORing device to limit reverse current flow into each phase and an input protection device for providing input over current protection and output over voltage protection of each phase. A current sharing method maintains current sharing between the active phases after a failure of one or more phases with one or more phases provided for enabling redundancy.

Method and phase redundant regulator apparatus for implementing redundancy at a phase level

An apparatus for electrically interconnecting circuit boards and providing controlled low impedance current paths. A first conductive member has a first surface, a second surface and a third planar surface, the first surface attaches to a first circuit board or CIM and the second surface attaches to a second circuit board or CIM. An insulative sheet having dielectric properties is aligned parallel to the third surface of the first conductive member. A second conductive member has a fourth surface, a fifth surface and a sixth planar surface, the fourth surface connects to the first circuit board and the fifth surface is for attaching to the second CIM. The sixth planar surface is aligned parallel to the insulative sheet, such that a controlled low impedance high current interconnect can be achieved between the first CIM and the second circuit board responsive to the dielectric properties of the insulative sheet.

Controlled low impedance high current circuit board interconnect

A battery charging aparatus and method are provided for charging a battery using current control with a switching power supply charging circuit coupled to the battery. During a first charging phase, a predetermined constant charging current is applied to the battery. The battery voltage is monitored and a second charging phase is started when the battery voltage reaches a predetermined threshold voltage. During a second charging phase, a sequence of stepwise decreasing-amplitude current pulses are applied to the battery. The envelope for the decreasing current pulses is exponential which is characteristic of the current for voltage controlled charging methods. The battery voltage is maintained at a temperature compensated target with a 1% tolerance. The charging current is compared to a predetermined minimum amplitude value and a third charging phase is started when the sequential charging current pulse equals the predetermined minimum amplitude value. During a third charging phase, predetermined charging current pulses having the predetermined minimum amplitude value are applied to the battery. The battery voltage is maintained at a temperature compensated target with a 1% tolerance.

Battery charging method and apparatus using current control

Disclosed is a circuit board and a process for the manufacture thereof providing a circuit board comprising a metal core having parallel first and second major faces and exhibiting high thermal and electrical conductivity. The circuit board includes electrical insulating layers of thermally conductive, dielectric material applied to the first and second major faces of the metal core. Protecting the dielectric layer and copper conductors is a solder mask layer applied to the dielectric layers and forming outward facing major surfaces. A plurality of insulated and grounded vias having electrically conductive interior rings connecting the major surfaces are provided through the board. Conductive sleeves within the vias are either electrically insulated from the metal core by dielectric material or in electrical contact to the metal core for grounding.

Metal substrate double sided circuit board

Control information for a flexible magnetic disk storage assembly is recorded on the periphery of the disk in a region not used for recording data. The control information is read through the protective cover or envelope which encloses the disk by means of a magnetic transducer such as a four track audio cassette head which bears against the envelope. By recording index and sector pulses as part of the control information, hard sectoring can be inexpensively and accurately achieved. A recorded fixed frequency control signal can be read and used as part of the feedback loop in a phase locked oscillator used to control a d.c. motor driving the spindle. The control information can also include servo tracks which assist in registering the data transducer directly over data tracks on media which has changed its dimensions.

Magnetic disk-control track read through envelope

A single gap transducer simultaneously senses recorded control or servo signals and records data signals. A magnetic medium used with this invention is preferably a single coating magnetic medium. During recording, the recording signal is appropriately subtracted from the readback signal for removing write signal effects on the readback signal. The servo signals are preferably deeply recorded into the magnetic coating whereas the data signals are preferably recorded in an outer surface portion of the magnetic coating.

Buried control signal recording systems and method

Stepper motor control circuitry including a phase locked loop circuit formed by a phase detector outputted to a filter and a voltage controlled triangular and square wave generator which has a frequency control input terminal connected to the output of the filter and which provides a square wave on an output thereof connected as an input to the phase detector. An oscillator drives the phase detector, and the outputs of the generator are connected as inputs to a pulse width modulated driver which has its outputs connected to the coils of the stepper motor. A differential amplifier is connected across one of the coils of the motor, and a balanced modulator synchronous detector or multiplier has two inputs one of which constitutes an output of the differential amplifier and the other of which is a connection to the square wave output of the generator. The output of the multiplier constitutes an error signal which is supplied to a summing junction between the filter and generator so that, upon the application of an instantaneous load to the stepper motor, the error signal causes a very quick return to normal speed of the motor.

Closed loop stepper motor circuitry without encoder

A recurrent digital sweep signal starts an integrator fed by a constant current. The integrator includes push-pull Darlington stages, which act as alternately conducting controlled current sources for split deflection coils outside the integrator feedback loop. A phase shifter provides arcsine correction. A time-out circuit avoids excessive dissipation if the sweep signal should be lost.

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Rochester, MN, United States of America

Steven Dennis Keidl