| 摘要 |
PURPOSE:To detect all overcurrent of each voltage line at the secondary side of a switching transformer with a transistor(TR) having a low breakdown voltage by connecting an overcurrent detection circuit to an earth line. CONSTITUTION:When a fault takes place in a load at a secondary side of a switching transformer 1 and an overcurrent flows to a 100V or 15V output, the current returns to the switching transformer 1 through an earth line from the switching transformer 1. Even when an overcurrent flows to either of a 100V output and a 15V output line, the overcurrent is detected by connecting an overcurrent detection circuit comprising resistors 10-13, an electrolytic capacitor 14 and a TR 15 to the earth line. Furthermore, since the TR 15 for detecting the overcurrent is connected to the earth line, the TR 15 with a low breakdown voltage is enough and the cost is reduced. |
