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.