| 摘要 |
PROBLEM TO BE SOLVED: To improve the efficiency of a self-exciting switching power source circuit by reducing unnecessary losses caused by self-oscillation. SOLUTION: A serial circuit of a third switching transistor Q4 and a resistor R9 is connected to a resistor R1 which becomes the flowing passage of the base current of a first switching transistor Q1 and the collector current of a second switching transistor Q2. The base of the third transistor Q4 is connected to one end of the resistor R3 through a capacitor C4 so that the third transistor Q4 can complementarily operate synchronously to the second transistor Q2. The resistance value of the resistor R9 is set to such a value that allows a base current IB1 of the magnitude required for turning on the first transistor Q1 to flow and the resistance value of the resistor R1 is set to such a value that allows the electric current required for conducting the first transistor Q1 to flow and is larger than the resistance value of the resistor R9. |
