Donald Walter Janz

US Patent:

6504669, Jan 7, 2003

Filed:

Jun 10, 1999

Appl. No.:

09/329612

Inventors:

Donald W. Janz - Oklahoma City OK
John C. Morris - Minneapolis MN
Brian G. Molloy - Natick MA
David A. Sluzewski - Edina MN
John S. Wright - Bloomington MN

Assignee:

Seagate Technology LLC - Scotts Valley CA

International Classification:

G11B 5596

US Classification:

360 7805

Abstract:

A disc drive head positioning apparatus includes a head, a suspension which supports the head, a piezoelectric microactuator which is operatively coupled to the suspension, and a charge feedback driver which is operatively coupled to the piezoelectric microactuator. A method of positioning the head relative to a storage medium is also provided.

US Patent:

6778347, Aug 17, 2004

Filed:

Jul 13, 2001

Appl. No.:

09/904721

Inventors:

Donald W. Janz - Oklahoma City OK

Assignee:

Seagate Technology LLC - Scotts Valley CA

International Classification:

G11B 502

US Classification:

360 69, 360 75, 3602663, 360 772

Abstract:

A load balancing circuit which operates to balance the output voltages of a dual polarity power supply with single polarity voltage regulation. The power supply outputs a positive voltage at a positive voltage with respect to a reference level and a negative voltage with respect to the reference level. The power supply further applies voltage regulation to a selected one of the positive and negative voltages and leaves the remaining one of the positive and negative voltages in an unregulated state. Positive and negative loads are coupled to receive the positive and negative voltages. The load balancing circuit detects a change in impedance of a selected one of the positive and negative loads and applies a corresponding impedance to the power supply to maintain the power supply in a nominally balanced state.

US Patent:

48644340, Sep 5, 1989

Filed:

Nov 25, 1988

Appl. No.:

7/275854

Inventors:

Donald W. Janz - Oklahoma City OK

Assignee:

Magnetic Peripherals Inc. - Minneapolis MN

International Classification:

G11B 502

US Classification:

360 55

Abstract:

Servo data, including three types of servo patterns distinguishable by phase, are stored in concentric servo tracks on a magnetic information storage disk. Each servo track includes a plurality of only one type of pattern, with consecutive tracks arranged in a repeating sequence of the three servo pattern types. For phase recognition, the pattern types further are arranged in a repeating sequence of angular sectors, each sector having a plurality of but one type of pattern. The servo patterns in a given storage track thus are always angularly offset from the servo patterns in the next adjacent tracks. This permits the use of servo patterns having a radial dimension greater than the separation between adjacent tracks, increasing servo signal reliability and transducer dynamic range.

US Patent:

61780553, Jan 23, 2001

Filed:

Jun 26, 1998

Appl. No.:

9/105554

Inventors:

Donald W. Janz - Oklahoma City OK

Assignee:

Seagate Technology LLC - Scotts Valley CA

International Classification:

G11B 509
G11B 502
H03B 100
G05F 110

US Classification:

360 46

Abstract:

An apparatus and method are disclosed for generating a low ripple negative voltage suitable for use in a disc drive. A negative voltage supply comprises a pulse generator circuit which generates first and second driver signals in relation to a load of the negative voltage supply. The first driver signal comprises a series of periodically occurring first pulses and the second driver signal comprises a series of periodically occurring second pulses. The first and second pulses are mutually exclusive in time so that at least a minimum delay of selected, nonzero length is provided between transitions of subsequently occurring first and second pulses. The negative voltage supply further comprises a regulator circuit, operably coupled to the pulse generator circuit, which generates the negative voltage in response to the first and second driver signals utilizing a pair of storage capacitors which alternately accumulate and transfer charge to an output capacitor in response to the first and second driver signals.

US Patent:

61250473, Sep 26, 2000

Filed:

Jun 11, 1996

Appl. No.:

8/182201

Inventors:

Donald W. Janz - Oklahoma City OK

Assignee:

Seagate Technology, Inc. - Scotts Valley CA

International Classification:

H02M 318

US Classification:

363 60

Abstract:

An inverting power supply (10) having first and second charging capacitors (22, 24) that are alternately connected to a positive power source (12) and a negative output terminal (18) which is to be maintained at a negative voltage with respect to a common ground for the power source and the power supply. Switches (34, 36) connect a positive plate of each charging capacitor to the power supply positive terminal during alternate half cycles of a two-phase clock (20) and charge is bled from the positive plates by switching transistors (46, 50) during the other half cycle to enable charge to be transferred via diodes (52, 54) from the negative output terminal to negative plate of the charging capacitors during the other half cycle. The base-emitter currents of the switching transistors are controlled by a charge transfer control circuit (56) in relation to the voltage at the negative output terminal to regulate the voltage at the negative output terminal by controlling the rate of charge transfer to the negative output terminal. Additional regulation can be provided by a current control circuit (106) that adjusts the switching transistor base-emitter currents in relation the collector currents of the switching transistors.

US Patent:

52414302, Aug 31, 1993

Filed:

Oct 5, 1990

Appl. No.:

7/593668

Inventors:

Donald W. Janz - Oklahoma City OK

Assignee:

Seagate Technology, Inc. - Scotts Valley CA

International Classification:

G11B 1512
G11B 509

US Classification:

360 62

Abstract:

A circuit for enabling the writing of servo data by a servo transducer to a dedicated servo surface of a hard disk drive during the manufacture of the drive while enabling only the reading of servo data at subsequent times that the drive is mated to a computer. The circuit receives power on selected terminals of a connector and includes a level detector that provides a first control signal in response to a power supply voltage level that is below a level selected to exceed voltage levels available from the power supply of a user computer and a second control signal in response to a power supply voltage above the selected level. The second control signal is transmitted to a switch assembly that responds by providing a direct connection between the servo transducer and data terminals of the connector. The first control signal is transmitted to switches by means of which an amplifier, having inputs connected to the transducer and outputs connected to the data terminals, is supplied with electrical power. Servo patterns are written at the time of manufacture of the hard disk drive by operating the circuit from a power supply that provides a voltage level that exceeds the selected level and are read by operating the circuit from the computer power supply.

US Patent:

50953931, Mar 10, 1992

Filed:

Aug 24, 1989

Appl. No.:

7/398166

Inventors:

Donald W. Janz - Oklahoma City OK

Assignee:

Seagate Technology, Inc. - Scotts Valley CA

International Classification:

G11B 5596

US Classification:

360 7705

Abstract:

Servo disk, including three types of servo patterns distinguishable by phase, are stored in concentric tracks on a magnetic information storage disk. For phase recognition, the pattern types are arranged in triplets of sectors, each sector having a radially extending plurality of only one type of pattern with consecutive patterns in a sector being separated by three track spacings. The patterns are further arranged in radially repeating frames, each including one of each type of pattern, and the patterns are radially offset within a frame by one track spacing from one type of pattern to the next. The patterns have a radial width greater than a track spacing and, in one embodiment, are divided radially into two portions spaced apart by a distance less than one track spacing.

US Patent:

49125761, Mar 27, 1990

Filed:

Dec 14, 1988

Appl. No.:

7/284134

Inventors:

Donald W. Janz - Oklahoma City OK

Assignee:

Magnetic Peripherals Inc. - Minneapolis MN

International Classification:

G11B 555
G11B 558

US Classification:

360 7707

Abstract:

Servo data, distinguishable by phase, are stored in concentric servo tracks on a magnetic information storage disk. Each servo track includes a plurality of one type of servo pattern, with consecutive tracks arranged in a repeating sequence of the servo pattern types. For phase recognition, the pattern types further are arranged in a repeating sequence of angular sectors, each sector having a plurality of servo patterns. The servo patterns in a given storage track thus are always angularly offset from the servo patterns in the tracks adjacent thereto, permitting the use of servo patterns radially dimensioned to be greater than the separation distance between adjacent tracks, thereby increasing servo signal reliability and transducer dynamic range.