| 摘要 |
PURPOSE:To make conduction ratio of a switching circuit perfect by driving at least one of a main switching circuit and a switching circuit for flywheel by logical product of a controlling signal that on/off controls the circuits and frequency higher than the controlling signal. CONSTITUTION:A motor M and a main switching circuit SW are connected in series as load to U phase and V phase of a single-phase AC power source S, and a switching circuit FW for flywheel is connected in parallel to the motor M. A high frequency outputting circuit 10 is constituted of a blocking oscillating circuit having positive feedback circuit by transformer coupling. A transistor TR 2 is for external trigger, and a controlling signal Y of higher frequency than output X of the AC power source S is inputted to the base. Accordingly, when the controlling signal is H level, the TR 2 becomes on and oscillation is stopped, and when the controlling signal becomes L level, TR 2 becomes off, and oscillation is started. That is, the high frequency outputting circuit 10 outputs logical product of the controlling signal Y and oscillation output. |
