SWITCHING AMPLIFIER CONTROLLER

摘要

PURPOSE: To prevent the increase of the distortion of a waveform anytime when a switching amplifier is operated by controlling the magnitude of the output of the amplifier as the function of a relative delay time between first and second delay signals. CONSTITUTION: A synchronizing pulse duplexing circuit 14 divides a carrier signal M1 of a message generator 10 into a first signal S1 delayed only by a prescribed time, and a second signal S2 having one pulse each time the state of the carrier signal M1 is changed. A pulse delay circuit 22 of a variable output level control circuit 20 generates a second delay signal S1A obtained by further delaying the first delay signal S1 by a prescribed time, and those two delay signals S1 and S1A are conditioning-processed by a logic circuit. Thus, an adding amplifier 26 outputs a logical signal with a different phase to a switching amplifier 38, and maintains the magnitude of the current output of a sine waveform to an acceptable limit under a situation that a short- circuited or low impedance state is continuously present on a power line 46.