| 摘要 |
<p>A pulse width modulated signal amplifier comprises a DC power supply for rectifying an AC input voltage to produce a pair of DC voltages of opposite polarity, a pulse width modulated signal amplifying circuit supplied with a pulse width modulated signal to produce a demodulated signal through a low pass filter, and a detecting circuit responsive to an abnormal level of the DC voltages to produce a detecting signal when a smoothing condenser of the DC power supply is overcharged by a current flowing through the low pass filter in one direction. Such detecting signal is desirably employed to prevent the appearance of the output signal from the pulse width modulated amplifying circuit.</p> |
