| 摘要 |
PURPOSE:To separate an output transistor from a circuit at the prestage reasonably, by obtaining a control voltage of a current limiting transistor from the base of a transistor constituting a current amplifying state. CONSTITUTION:Resistors 32, 33 are inserted between the emitters and an output terminal 28 of output transistors(TR) 25, 27 in push-pull constitution and a current flowing to the output terminal 28 is supplied through the resistors 32, 33. Since a voltage determined by the output current is produced at both the ends of the resistors 32, 33, a higher voltage by the voltage between the base and emitter of the output TRs is produced between the base and the output terminal of the output TRs 25, 27. Further, this voltage depends on the output current. Thus, current limiting TRs 38, 39 can be operated when the output current reaches a given value or more, by applying this voltage between the base and the emitter of the TRs 38, 39 after dividing this voltage by resistors 34, 35 or 36, 37. |
