Patent ID: 7586369
Filing Date: 2009-09-08
Classification: H03F

Abstract:
1. A pulse modulation type electric power amplifier comprising: a pulse modulator that receives as input a clock and an input signal, and converts the input signal to a pulse train; an output control circuit that receives as input the pulse train output by the pulse modulator, and controls output of the pulse train; an output circuit that performs switching according to the pulse train output by the output control circuit; a digital converter that converts an output terminal voltage of the output circuit to a high or a low digital value; a short-circuit determination circuit that determines whether an output short circuit has occurred based on a state of an output signal of the digital converter, and outputs an output prohibition signal to the output control circuit when an output short circuit is detected; and a counter that measures, based on the clock, the time period during which the short-circuit determination circuit determines that an output short circuit has occurred, wherein the output control circuit controls output of the pulse train when the output prohibition signal is input, so that the output circuit stops the switching operation.