Michael J Rovner

US Patent:

7023268, Apr 4, 2006

Filed:

Mar 22, 2004

Appl. No.:

10/805741

Inventors:

Wilson E. Taylor - Austin TX, US
Jack B. Andersen - Austin TX, US
Michael Rovner - Austin TX, US
Michael A. Kost - Austin TX, US

Assignee:

D2Audio Corporation - Austin TX

International Classification:

H03F 3/38

US Classification:

330 10

Abstract:

Systems and methods for automatically adjusting the alignment of high-side and low-side pulse width modulated signals to improve dead time and shoot-through conditions. In one embodiment, a system includes a digital amplifier controller, an amplifier output stage coupled to the controller and configured to receive audio signals from the controller, and one or more sensors coupled to the output stage. The sensors are configured to detect and/or measure various parameters, such as shoot-through current and distortion, which are associated with the operation of the output stage. The sensors provide feedback to an internal processor or modulator of the controller, which then adjusts the timing of the high-side and low-side signals to improve the operating conditions of the output stage by minimizing shoot-through current and/or distortion.

US Patent:

51893568, Feb 23, 1993

Filed:

Jan 10, 1991

Appl. No.:

7/639822

Inventors:

Michael S. Rovner - San Jose CA

Assignee:

Symbol Technologies, Inc. - Bohemia NY

International Classification:

G05B 1940

US Classification:

318685

Abstract:

A voltage drive circuit for driving a stepping motor for a laser scanning mirror in a laser bar code reader assembly. The voltage drive circuit provides a highly damped, low q drive in which resonance is virtually eliminated and wherein damping of the rotor is proportional to its angular velocity, and also the position of the rotor precisely follows an input voltage signal driving the motor. The stepping motor includes a rotor, a stator, a center-tapped AC winding and a DC winding. The motor drive circuit comprises a triangular waveform generator for generating a periodic triangular voltage signal. A driving circuit for an AC winding receives the periodic triangular voltage signal as an input, and includes a voltage feedback circuit in which the voltage across the AC winding is compared with and caused to follow the input voltage signal driving the AC winding. The drive circuit for the AC winding includes a first noninverting operational amplifier and a second inverting operational amplifier for driving respectively first and second phase sides of the AC winding. Each of the first and second operational amplifiers receive the triangular voltage signal as a first input signal and also receives as a second input a feedback signal representing respectively the voltage across the first and second phase sides of the AC winding.

US Patent:

53070259, Apr 26, 1994

Filed:

Jul 14, 1992

Appl. No.:

7/913667

Inventors:

Bryan J. Colvin - San Jose CA
Michael S. Rovner - San Jose CA

Assignee:

Media Vision, Inc. - Fremont CA

International Classification:

H03F 126

US Classification:

330267

Abstract:

An audio power amplifier is provided that includes circuitry to prevent popping noises when the amplifier is turned on and turned off. The amplifier can be powered with a single-ended voltage power supply, and thus may be used within systems such as personal computer. The amplifier includes a control circuit that prevents the fast charging of the output AC coupling capacitor when the amplifier is turned on and turned off. The control circuit controls a driver stage such that the output transistors turn on slowly when power is first applied, and such that the output transistors turn off quickly when the supply voltage is removed.