George L Dohanich

US Patent:

56105037, Mar 11, 1997

Filed:

May 10, 1995

Appl. No.:

8/438636

Inventors:

John K. Fogg - Durham NC
Wayne Utter - Endicott NY
George Dohanich - Endicott NY

Assignee:

Celestica, Inc. - Ontario

International Classification:

G05F 140

US Classification:

323283

Abstract:

A dc-to-dc converter circuit for generating an output voltage from a source voltage includes a plurality of first metal oxide semiconductor field effect transistors (MOSFETs) connected in parallel and collectively defining a gate, a source and a drain. A driver circuit preferably includes a bipolar transistor connected to the gate for turning on the first MOSFETs. A second MOSFET is preferably connected to the gate for turning off the plurality of first MOSFETs. The dc-to-dc converter also preferably includes a clamp circuit connected to the plurality of first MOSFETs across the drain and source thereof. Protection, soft-start and status features are also preferably incorporated into the dc-to-dc converter. A voltage divider is connected to a reference voltage for dividing a first reference voltage to thereby generate a second reference voltage less than a desired output voltage. An error amplifier is connected to the voltage divider for generating an error signal based upon a difference between the second reference voltage and an actual output voltage.

US Patent:

39315550, Jan 6, 1976

Filed:

May 20, 1974

Appl. No.:

5/471624

Inventors:

George J. Dohanich - Endicott NY
John C. Rohde - Endicott NY
Gary A. Trudgen - Endwell NY

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

H02P 516

US Classification:

318314

Abstract:

A digital pulse source generates a frequency analog of a desired velocity to which a d-c motor is accelerated. The acceleration circuit comprises a circuit means for converting a frequency analog signal to a frequency dependent direct voltage and a sawtooth voltage. A comparison circuit generates a motor drive signal having a duty cycle dependent on the relative voltage levels of the direct and sawtooth voltages. The comparative duty cycle of motor drive signal for two different velocities is regulated to be proportional to the square of the ratio of the two velocities.

US Patent:

39506827, Apr 13, 1976

Filed:

Dec 19, 1974

Appl. No.:

5/534250

Inventors:

George J. Dohanich - Endicott NY

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

H02P 516

US Classification:

318314

Abstract:

A velocity control system for a motor is provided wherein first counter means are reset by feedback pulses from the motor to record the feedback period. Decode means responsive to the first counter means determines whether the feedback period is long or short and the status of this is put into storage means. An up-down counter is responsive to the storage means for adjusting the motor drive pulse width and second counter means are reset by the motor feedback pulses to terminate the drive to the motor. Comparing means are responsive to the up-down counter and said second counter means for controlling the motor drive to maintain a precise motor velocity.