Read Rite Corporation

Power Integrations, Inc.

Derek Jan Kroes

Marcos Moises Lederman

Daniel A Nepela

Samuel Wonder Yuan

Erich P Valstyn

Techniques are disclosed to limit the current in a switch of a switching power supply. An example switching regulator circuit includes a switch to be coupled to an energy transfer element. A controller is coupled to the switch to control switching of the switch. A current sensor is included in the controller. The current sensor includes first and second comparators coupled to compare a current in the switch with first and second current limits, respectively. The controller is to open the switch for a remainder of a current switching cycle of the switch until a next switching cycle of the switch in response to the first or second comparators. A frequency adjuster is also included in the controller and coupled to the second comparator. The frequency adjuster is to adjust an oscillating frequency of an oscillator included in the controller in response to the second comparator.

Method and apparatus to limit maximum switch current in a switch of a switching power supply

A thin film read-write magnetic head useful in a tape apparatus includes a magnetic circuit consisting of two thin film magnetic layers which form a magnetic yoke that is divided into three closely spaced sections, the central section of at least one of the magnetic layers containing an interspace in which a flux sensing element, such as a magnetoresistive device or Hall effect device, is located. The three section yoke forms a continuous magnetic circuit, except for the transducing gap, which circuit consists of three sections corresponding to the three sections of the yoke. The total gap width determines the width of the data track being recorded. During the write mode, a magnetic valve including an electrical conductor provides a shunt path to bypass the flux sensing means so that all three sections of the head operate for recording. During the read mode, only the central yoke section and its transducing gap portion sense the data signal recorded on the magnetic tape, and the read element detects the sensed signal. A saturation current is directed to the valve conductor during the read mode so that the shunt path is open, thereby allowing the flux sensing means to operate and sense the readout signal.

Magnetic tape head with flux sensing element

A magnetoresistive (MR) read sensor fabricated on a substrate comprises an MR layer of magnetoresistive material, a soft adjacent layer (SAL) of soft magnetic material, and a manganese-based metallic antiferromagnetic (AFM) layer between the MR layer and the SAL layer. The AFM layer is in direct contact with the SAL layer and is separated from the MR layer by a non-magnetic spacer layer. A non-magnetic texturing layer is disposed between the SAL layer and the substrate. This structure exhibits a much larger pinning field than read sensors using oxide-based antiferromagnets.

Magnetoresistive sensor having a pinned soft magnetic layer

A giant magnetoresistive (GMR) thin film transducer employs a pair of flux guide pole members that define a magnetic transducing gap. A GMR structure formed of a stack of multiple layers is located between spaced portions of one of the flux guide pole members and away from the transducing gap. Bias current is supplied in a CPP (current perpendicular to the plane) mode. In an alternative embodiment, a plurality of such GMR structures are connected together serially to provide a larger output signal than that obtained with a single GMR stack.

Growing community of inventors

Fremont, CA, United States of America

Derek Jan Kroes