| 摘要 |
PURPOSE:To prevent a through current and to faithfully reproduce a waveform in a low frequency band by inhibiting a PWM signal for a predetermined period of time when a polarity is switched. CONSTITUTION:An input signal is converted to a pulse by a comparator 13, and delayed for a predetermined time T by a delay circuit 14. This delay pulse is applied to an exclusive OR circuit 15 together with the pulse before delaying, and the a pulse having a width T is output. Then, one-shot multivibrator 16 outputs a PWM wave inhibit pulse having a width of 2T synchronously with it. After this pulse is inverted by an inverter 17, input to AND gates 18, 19, a PWM signal is input from a PWM signal generator 3, and its passage is inhibited during the period of the PWM wave inhibit pulse to form a dead band A. The output pulse of the circuit 14 is used also as a polarity switching signal, applied to the base of a fourth TrQ4 through a line 20, and also applied to the base of a third TrQ3 through an inverter 21. |
