| 摘要 |
<p>A class D amplifier capable of stabilizing the power supply voltage and reducing the power consumption. A class D amplifier (10) includes a DC-DC converter (COV) that smoothes a DC voltage supplied from a DC voltage source (ME) by use of an output voltage in accordance with a predetermined reference voltage (Vref), thereby generating predetermined power supply voltages (+Vs,-Vs); and field effect transistors (Q1,Q2) that generate an output signal (Sout) by switching, based on modified signals of rectangular waveform, voltages supplied through power supply lines (P1,G1) connected to the DC-DC converter (COV). The class D amplifier (10) further includes voltage detecting parts (17,18) for detecting voltages appearing on the power supply lines (P1,G1); voltage variation determining parts (19,20) that determine, based on output voltages (Vdp,Vdg) of the voltage detecting parts (17,18), whether any voltage variation has occurred on the power supply lines (P1,G1) due to occurrence of an offset in the output signal (Sout); and a control signal generating part (21) that generates a control signal (CNT) for causing the DC-DC converter (COV) to stop the switching when the voltage variation determining parts (19,20) determine the occurrence of a voltage variation.</p> |
