A power output circuit supplies an audio power output signal that is adjusted to prevent clipping when needed based on an estimate of available energy from the power supply supplying the power output circuit. The power output circuit may be an audio power output circuit that generates an audio power output signal from samples of an audio program that are stored in a buffer. A processing block determines an energy requirement for producing the audio power output signal from the audio program and adjusts an amplitude of the audio power output signal in conformity with the determined energy requirement and an available energy determined for the power supply so that the audio power output signal is reproduced without clipping of the audio power output signal.