| 摘要 |
<p>PURPOSE:To protect parts against breakdown or burning by controlling a switching element while confirming reset of a high frequency transformer through a magnetism detecting element for detecting leakage flux of the high frequency transformer. CONSTITUTION:Complete reset of a high frequency transformer T is detected through a Hall element 4 and switching of a transistor Q is controlled to prevent accumulation of flux in the core of a high frequency transformer. A gate circuit for passing a PWM signal is controlled based on the output signal from an amplifier 36 in order to confirm reset of the high frequency transformer. Since no PWM signal can pass through the gate when remanence is detected, the transistor Q is not turned ON by means of a drive circuit 35 and since the high frequency transformer T is excited through the transistor Q while being reset completely, magnetic saturation does not occur.</p> |
