Input current limited power supply and audio power amplifier for high power reproduction of nondeterministic signals

a technology of input current and limited power supply, applied in power management, high-level techniques, wireless communication, etc., can solve the problems of low-voltage battery, audio fidelity, and audio power
US20150349737A1Active Publication Date: 2015-12-03MOTOROLA SOLUTIONS INC
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Patent Information

Authority / Receiving Office
US · United States
Current Assignee / Owner
MOTOROLA SOLUTIONS INC
Publication Date
2015-12-03

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Abstract

A method and apparatus for amplifying audio signals without exceeding an input current limit budgeted for the audio power amplifier circuit includes an intermediate energy storage between a battery and the audio power amplifier which provides an energy reserve to support amplifying peaks where the peaks have a peak power that is greater than the power that can be drawn from the battery due to the input current limit. Speech signals, which include substantial periodic content having short peaks relative to a pitch period, can be amplified without depleting the intermediate energy storage, allowing the intermediate energy storage to recover after a peak and before occurrence of a next peak. When an audio signal is amplified that results in depletion of the intermediate energy storage, a depletion recovery circuit reduces the overall audio gain to reduce the power demand of the audio power amplifier so as to substantially avoid distortion.
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Description

FIELD OF THE DISCLOSURE

[0001] The present disclosure relates generally to audio power amplifier circuits, and more particularly to audio power amplifiers for battery powered portable devices where current sourced by the battery is limited and the signal being amplified may require more instantaneous power than can be sourced from the battery due to the current limit.BACKGROUND

[0002] The International Electrotechnical Commission, in standard IEC 60950-1, limits the current that can be drawn from a battery having less than 30 volts open circuit voltage to 8 amperes for battery powered devices. Accordingly, this standard applies to virtually all portable two-way radio devices, many of which operate at either a 3.6 volts or a 7.2 volts nominal operating voltage. These nominal voltage levels are achieved using one equivalent lithium ion battery cell for the 3.6 V nominal output voltage, or the equivalent of two lithium ion cells connected in series to achieve the 7.2 V nominal output. Sinc...

Claims

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