| 摘要 |
PURPOSE:To alleviate the power loss of a DC/DC converter due to a starting circuit by stopping the operation of a starting transistor by a reverse bias circuit which is made of a capacitor charging a rectified voltage after starting. CONSTITUTION:At starting time, a starting transistor Tr is conducted via a resistor R1 by a power source E, a base current is supplied to a switching transistor Q through the transistor Tr, thereby conducting the switching transistor Q. As a result, the transistor Q operates in switching as known and supplies a DC output to a load R0. After the transistor Q is started, a voltage is produced at an auxiliary coil nk by the operation of a transformer T, a capacitor C3 is always charged in the shown polarity, thereby operating to reversely bias the transistor Tr. In this manner, the starting circuit is stopped, thereby reducing the power loss due to the starting circuit. |
