Kevin K Christian

US Patent:

7332959, Feb 19, 2008

Filed:

Jul 26, 2004

Appl. No.:

10/565451

Inventors:

Kevin Christian - Freeland WA, US

Assignee:

Dobbs-Stanford Corporation - Dallas TX

International Classification:

H03F 3/38

US Classification:

330 10

Abstract:

The invention is a power amplifier circuit for providing a signal acceptable for use in audio amplifiers or similar applications without requiring a stable power supply free from fluctuation. An alternating current power supply signal rectified to a direct current signal is processed by two voltage multipliers. A voltage divider establishes a unity gain level, and the variance from this voltage is squared by the first voltage multiplier. This squared voltage is then multiplied with a triangular wave signal to generate a modulated triangular wave signal. The modulated triangular wave signal and a signal to be amplified, typically an audio signal, are processed by an internal comparator to generate a pulse width modulated signal. This modulated signal is processed by a power transistor network and filter to provide an amplified signal to a load device. By modulating the triangle wave signal to compensate for fluctuations in the power supply to the amplifier circuit, noise or ripples present in the power supply are demodulated, eliminating the requirement for a regulated power supply.

US Patent:

7619467, Nov 17, 2009

Filed:

Jan 17, 2008

Appl. No.:

12/016113

Inventors:

Kevin Scott Christian - Freeland WA, US

Assignee:

Dobbs-Stanford Corporation - Dallas TX

International Classification:

H03F 3/38

US Classification:

330 10

Abstract:

The invention is a power amplifier circuit for providing a signal acceptable for use in audio amplifiers or similar applications without requiring a stable power supply free from fluctuations. An alternating current power supply signal rectified to a direct current signal is processed by two voltage multipliers. A voltage divider establishes a unity gain level, and the variance from this voltage is squared by the first voltage multiplier. This squared voltage is then multiplied with a triangular wave signal to generate a modulated triangular wave signal. The modulated triangular wave signal and a signal to be amplified, typically an audio signal, are processed by an internal comparator to generate a pulse width modulated signal. This modulated signal is processed by a power transistor network and filter to provide an amplified signal to a load device. By modulating the triangle wave signal to compensate for fluctuations in the power supply to the amplifier circuit, noise or ripples present in the power supply are demodulated, eliminating the requirement for a regulated power supply.

US Patent:

20110050338, Mar 3, 2011

Filed:

Nov 17, 2009

Appl. No.:

12/620480

Inventors:

Kevin Scott Christian - Freeland WA, US

Assignee:

DOBBS-STANFORD CORPORATION - Dallas TX

International Classification:

H03F 1/30

US Classification:

330149

Abstract:

The invention is a power amplifier circuit for providing a signal acceptable for use in audio amplifiers or similar applications without requiring a stable power supply free from fluctuations. An alternating current power supply signal rectified to a direct current signal is processed by two voltage multipliers. A voltage divider establishes a unity gain level, and the variance from this voltage is squared by the first voltage multiplier. This squared voltage is then multiplied with a triangular wave signal to generate a modulated triangular wave signal. The modulated triangular wave signal and a signal to be amplified, typically an audio signal, are processed by an internal comparator to generate a pulse width modulated signal. This modulated signal is processed by a power transistor network and filter to provide an amplified signal to a load device. By modulating the triangle wave signal to compensate for fluctuations in the power supply to the amplifier circuit, noise or ripples present in the power supply are demodulated, eliminating the requirement for a regulated power supply.

US Patent:

55662374, Oct 15, 1996

Filed:

Feb 3, 1994

Appl. No.:

8/191512

Inventors:

James F. Dobbs - Irving TX
Kevin S. Christian - Seattle WA

Assignee:

Dobbs-Stanford Corporation - Dallas TX

International Classification:

H03G 500

US Classification:

381103

Abstract:

An audio selection circuit (10) having time selectable equalization, comprising a plurality of inputs (24, 26) for coupling the audio selection circuit to a plurality of audio signal sources, a variable equalization circuit (32) having an equalization input and an equalization output, the variable equalization circuit (32) providing variable attenuation in a plurality of frequency bands to an audio signal coupled to the equalization input, processing means (12) operatively coupled to the plurality of inputs (24, 26) and to the variable equalization circuit (32), memory means (12) operatively coupled to the processing means (12) and timebase means (14) operatively coupled to the processing means (12), the timebase means (14) enabling the processing means (12) to determine a time of day, wherein the processing means (12) is operative to couple one of the plurality of inputs (24, 26) to the equalization input and to vary the attenuation of the variable equalization circuit (32) when the time of day is equal to or past a stored time of day stored in the memory (12), the coupling of one of the plurality of inputs (24, 26) and the varying of the attenuation being done according to parameters stored in the memory. Other systems, devices and methods are disclosed.