| 摘要 |
<p>A self-excited oscillation circuit of the invention includes a turn-OFF transistor Tr1 that turns OFF a transistor Q1, a turn-OFF capacitor C3 that outputs a voltage Vb to the base of the turn-OFF transistor Tr1, and a bias resistance R1 that charges the turn-OFF capacitor C3 with a voltage in magnitude corresponding to a drain current Id that flows when the transistor Q1 turns ON. A resistance R3 is connected between the turn-OFF capacitor C3 and a power supply portion 50. Accordingly, charges are accumulated in the turn-OFF capacitor C3 so that the voltage Vb will not drop to or below a bias voltage. It thus becomes possible to make the bias resistance R1 smaller, which can in turn reduce an energy loss at the bias resistance R1.</p> |
