Patent ID: 6922093

Claim:
A radio frequency power apparatus comprising: a power amplifier that has an output power range and that is driven by a rectangular pulse wave with a controllable pulse width and a controllable pulse height over said output power range; at least one circuit that monitors a variable condition and provides a signal representing said variable condition; and a pulse wave controller that generates said rectangular pulse wave, wherein said controller, based on said signal, controls said pulse height and said pulse width to provide said rectangular pulse wave with a first duty ratio and a first pulse height that operates said power amplifier with a first efficiency and a first power loss in an upper portion of said output power range and with a second duty ratio and a second pulse height that operates said power amplifier with a second efficiency and a second power loss in a lower portion of said output power range, and wherein said first efficiency is higher than said second efficiency and said first power loss is lower than said second power loss.