Signal amplifier circuit arrangement with output current limiting function

A signal amplifier circuit arrangement comprising:

• an input amplifying circuit having a current mirror load circuit comprised of first and second transistors of a first conductivity type each having an emitter, collector and base, said emitters of said first and second transistors being connected to a power supply terminal, said bases of said first and second transistors connected to each other and said collector of said second transistor being coupled to said base of said second transistor;
• output transistor means having first, second and third terminals respectively corresponding to emitter, collector and base of a transistor of the first conductivity type, said third terminal of said output transistor means being connected to said collector of said first transistor and said second terminal of said output transistor means being connected to an output terminal of said signal amplifying circuit to be connected to a load;
• a current detection resistance element connected between said first terminal of said output transistor means and said power supply terminal;
• and
• a diode means connected between said collector of said second transistor and said first terminal of said output transistor means, said diode means being rendered conductive when a voltage drop across said current detection resistance element is greater than a sum of emitter-base voltage of said first transistor and cut-in voltage of said diode.