Patent ID: 9680424
Date: 2017-06-13
CPC Classifications: H03F

Claim:
1. A power amplifier without transformer includes: an audio isolator for receiving an audio-frequency signal and outputting an audio-frequency isolation signal; a phase detector for receiving a first AC utility power and a second AC utility power, wherein the phase detector is used for detecting potential level of the first AC utility power and the second AC utility power and outputting a phase comparison signal; a power protection controller comprising an input end, an output end and a first control unit, wherein the input end receives the first AC utility power and the second AC utility power, the first control unit connects to the phase detector for receiving the phase comparison signal, and the first control unit is controlled by the phase comparison signal for determining the output end whether to output the first AC utility power and the second AC utility power; a rectifier connected to the output end of the power protection controller for receiving the first AC utility power and the second AC utility power, wherein the rectifier outputs a DC voltage; and an amplifier connected to the audio isolator and the rectifier, wherein the amplifier receives the audio-frequency isolation signal and uses the DC voltage outputted from the rectifier as power source, the amplifier is used to amplify the audio-frequency isolation signal and output an amplifying signal.