The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 30, 2004
Filed:
Jul. 12, 2001
John Barry French, Caledon East, CA;
Charles Robert May, Spencerville, CA;
Indigo Manufacturing Inc., Markham, CA;
Abstract
A power amplifier for receiving an input signal and providing a corresponding amplified output signal. One embodiment of the power amplifier includes a positive half circuit for supplying power to an amplifier during positive half waves of the output signal and a negative half circuit for supplying power to the amplifier during negative half waves of the output signal. Each half circuit has a main power supply, which is typically a switching regulator, and which supplies a first power signal to the amplifier. The slew rate of this first power signal is intentionally limited to control EMI emissions. Each half circuit also has a transient power supply which may be selectively engaged to provide a second power signal to the amplifier when the first power signal is insufficient to power the amplifier. Each half circuit may also include a low voltage power supply which provides a third power signal to the amplifier, allowing the main power supply to be disabled when a low power level is required, further reducing EMI emissions. Each half circuit has a control circuit which regulates the power output from the main and transient power supplies. The control circuit may provide a pulse width modulated control signal or a pulse density modulated control signal to control the switching regulator. If a pulse density control signal is provided, the switching regulator may be a resonant switching regulator. The power amplifier may be modified for use with a bridge amplifier, with multiple channels and may incorporate an overload detection circuit. In another embodiment of power amplifier the transient power supply is replaced with a transient control circuit that, when the first power supply is insufficient to power the amplifier, temporarily forces the first power supply to a 100% duty cycle, and then for a longer period, increases the duty cycle from its normal level to allow the first power supply to adequately power the amplifier more quickly.