Patent ID: 8472643
Filing Date: 2013-06-25
Classification: H03F,H04R

Abstract:
1. An improved power amplifier, comprising: an input amplifier unit, being coupled to an input source to receive input signals and configured to amplify the input signals to output amplified signals; at least one pulse modulation unit, being coupled to the input amplifier unit to receive the amplified signals and configured to perform pulse modulation on the amplified signals to output pulse-modulated signals; at least one pre-drive unit, being coupled to the pulse modulation unit to receive the pulse-modulated signals and configured to control a circuit unit of a next stage according to the pulse-modulated signals; at least one output stage transistor set, being coupled to the pre-drive unit, wherein the pre-drive unit receives the pulse-modulated signals outputted by the pulse modulation unit and, according to the pulse-modulated signals, controls the on/off status of the output stage transistor set so that the output stage transistor set outputs power signals; a power amplifier positive output terminal, being coupled to the output stage transistor sets to receive the power signals for driving a load; a power amplifier negative output terminal, being coupled to the output stage transistor set to receive the power signals for driving the load; and an output power restraint unit, being coupled between the power amplifier positive output terminal, the power amplifier negative output terminal and the input amplifier unit to receive the power signals and restrain power of the improved power amplifier, the output power restraint unit comprising: