| 摘要 |
PROBLEM TO BE SOLVED: To restrain power consumption in a drive circuit using a class D amplifier. SOLUTION: The drive circuit (101) includes the class D amplifier (12) for amplifying and outputting a pulse modulation signal, a low pass filter (20) connected to the class D amplifier, for eliminating a carrier wave component related to the pulse modulation from the signal output from the class D amplifier, a piezoelectric speaker (19) having a capacity component and operating based on the signal output from the low pass filter, and a damping resistor (30) connected between the piezoelectric speaker and the low pass filter. The signal output from the class D amplifier is directly supplied to the low pass filter, and after the carrier wave component of the above signal is eliminated in the low pass filter, the signal is supplied to the piezoelectric speaker via the damping resistor. COPYRIGHT: (C)2006,JPO&NCIPI |
