| 摘要 |
PROBLEM TO BE SOLVED: To ensure the start of a switching transistor. SOLUTION: When a power supply is turned on, a DC voltage charges a capacitor C3 through a resistor R1 from a rectifier circuit side 3. When the charged potential increases, a trigger diode TD turns on, a current flows in the gate of a transistor Tr2, and it is turned on. When the transistor Tr2 turns on, a charging current of capacitors C1, C2 flows in the transistor Tr2 side part through the primary side of a saturable transformer CT. At that time, charges which have been charged in the capacitor C3 and not yet discharged flow in the transistor Tr2 side part through a diode D, a resistor R and the primary side of the saturable transformer CT, so that the peak value and the pulse width of a voltage generated in a CT 22 on the secondary side of the saturable transformer CT can be increased. Therefore, starting energy for turning on the transistor Tr2 can be increased and the transistor Tr2 can be surely turned on. |
