| 摘要 |
A method is provided for amplifying audio signals without exceeding an input current limit, for example a limit on the current that may be drawn from a battery in accordance with technical standards. An amplifier system 500 includes a capacitor 518 acting as an intermediate energy store between a battery 502 and an audio power amplifier 522. The capacitor is replenished via a boost converter 504, which may include current limiting. The capacitor provides an energy reserve to support the amplification of signals whose peak power 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 (306, fig.3) relative to a pitch period (302, fig.3) can be amplified without depleting the energy store. During such signals, the store may recover after one peak and before occurrence of the next peak. When an audio signal is amplified that results in depletion of the stored energy, a depletion recovery circuit 530 reduces the overall audio gain to reduce the power demand of the audio power amplifier, substantially avoiding distortion. |
