| 摘要 |
PURPOSE:To secure the drive current for an external connection element and to stabilize a logic action by flowing the current of the 3rd series controller after limiting the detection current and the output current flowing through the 1st series controller with increase of the detection current flowing through the 2nd series controller. CONSTITUTION:When the collector current of a transistor TR 132 is less than the current level of a constant current source 134, a TR 131 is turned on and the current of a constant current source 7 is equal to the collector current level of the TR 131 together with a TR 31 turned off. Then a connection terminal T3 flows only the bias current and the detection current of a logic circuit 9. When the detection current increases, the collector currents of a TR 41 and the TR 132 are also increased. Therefore the base current of the TR 31 is increased with decrease of the base current to be supplied to both TR 11 and TR 21 and the decrease of the collector current of the TR 131. Thus the output current of the TR 11 is limited and the TR 31 is activated. |
