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US 7,843,271 B2Granted
Audio amplifier and methods for use therewith
AssigneeFreescale Semiconductor, Inc.
InventorCharles Eric Seaberg
Life of this patent
Estimating the term…
Abstract
An audio amplifier includes an output stage for generating an output stage voltage in response to an input signal and an output stage quiescent current. A controlled current source controls the output stage quiescent current in response to a quiescent current signal during a start-up cycle.
Claims13
An audio amplifier comprising:
- an output stage for generating an output stage voltage in response to an input signal and an output stage quiescent current;
- a controlled current source, operatively coupled to the output stage, for controlling the output stage quiescent current in response to a quiescent current signal during a start-up cycle;
- a ramp generator, operatively coupled to the output stage, for generating a ramp signal during the start-up cycle;
- wherein the output stage, based on the ramp signal, ramps the output stage voltage from a supply voltage to a quiescent voltage;
- and
- a signal operatively coupled to the ramp generator, for generating the quiescent current signal as a function of the ramp signal.
3 more elements
An audio amplifier comprising:
- an output stage for generating an output stage voltage in response to an input signal and an output stage quiescent current;
- a controlled current source, operatively coupled to the output stage, for controlling the output stage quiescent current in response to a quiescent current signal during a start-up cycle;
- and
- wherein the output stage quiescent current has a magnitude and the output stage voltage ramps during the start-up cycle and wherein the controlled current source controls the magnitude of the output stage quiescent current to increase monotonically with the ramping of the output stage voltage during the start-up cycle.
1 more element
An method comprising:
- controlling an output stage quiescent current of an audio amplifier during a start-up cycle and in response to a quiescent current signal;
- ramping an output stage voltage of the audio amplifier from a supply voltage to a quiescent voltage during the start-up cycle;
- and
- wherein the quiescent current signal is a function of the output stage voltage during the start-up cycle.
1 more element
An method for starting an audio amplifier comprising:
- applying an output stage quiescent current to an output stage of the audio amplifier;
- ramping an output voltage of the output stage from a supply voltage to a quiescent voltage;
- increasing a magnitude of the output stage quiescent current to an operating current level;
- applying an input voltage to the audio amplifier after the output voltage has reached the quiescent voltage and the magnitude of the output stage quiescent current has reached the operating current level;
- and
- wherein the step of increasing the magnitude of the output stage quiescent current includes controlling the magnitude of the output stage quiescent current as a function of the output stage voltage.
3 more elements
Dependencies are inferred from the claim text.