| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of driving a D-class amplifier capable of reducing spurious noise generated in PWM modulation and capable of reducing audible sound noise generated from an ultrasonic speaker, and to provide a drive circuit of the D-class amplifier. SOLUTION: The method is used for driving a D-class amplifier. The D-class amplifier has at least a set of circuits composed of totem pole type output circuits in each of which a high-side switching element connected to a first power supply is connected to a low-side switching element connected to a second power supply or the ground and a low-pass filter connected to the output end side of the output circuit. In this case, a PWM signal in which an input signal is subjected to PWM modulation turns on or off each switching element in the output circuit for power amplification. When the input signal includes a carrier at a prescribed frequency, the basic frequency of the PWM signal is set to be an integral multiple of the carrier frequency. COPYRIGHT: (C)2008,JPO&INPIT
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