| 摘要 |
<p>PURPOSE:To perform the protection of a transmission line at the time of the short-circuit and to detect the short-circuit by adding a simple circuit. CONSTITUTION:This device is provided with a first transistor 11 for driving connected between the transmission line 41 and ground, a second transistor 21 for overcurrent protection connected between the base of the first transistor 11 and the ground and a third transistor 31 for short-circuit detection connected between a power supply line 34 and the ground. The base of the first transistor 11 is connected through an input resistor 12 to an input terminal 13, the collector is connected to the transmission line 41 and the emitter is grounded through a resistor 22 for current amount detection. The collector of the second transistor 21 is connected to the base of the first transistor 11, the emitter is grounded and the base of the second transistor 21 and the base of the third transistor 31 are connected in common. The collector of the third transistor 31 is connected through the resistor 32 to the power supply line 34 and the emitter is grounded.</p> |
