| 摘要 |
PURPOSE:To simply reduce leakage current and residual voltage at the same time, by providing a current shunt path consisting of a semiconductor switching element in parallel with a current limit element. CONSTITUTION:When an output of a detection circuit 2 is at L level, an emitter follower output from a transistor Q22 is at L, and no SCR2 is triggered and an off-output state is obtained between the output terminals (a) and (b). Thus, the resistance value of a resistor 21 is increased and the leakage current between the output terminals (a) and (b) can be reduced. When an output of the detection circuit 2 is at H level, since the Q22 turns on, the SCR2 is triggered and an on- state can be obtained between the output terminals (a) and (b). Since a current flows to the base of a Q21, current shunt path is formed in parallel with the resistor R21 and sufficient driving current can be applied to the internal circuit of a contactless switch even if the conduction angle of the SCR2 is sufficiently large, and the residual voltage can be reduced. |
