FI53051C

1,265,157. Transistor amplifiers. R.C.A. CORPORATION. 26 Sept., 1969 [27 Sept., 1968], No. 46152/68. Heading H3T. A balanced phase splitter comprises an input terminal 17 connected to a common base transistor 11 (Fig. 3), from which an output is derived, a common emitter transistor 12 from which a further output is derived, and a diode 15 connected across the base emitter junction of 12. In an integrated circuit, the area of this junction and the diode junction 15 are made equal so that the current gain at both outputs is unity, i.e. the circuit is balanced. The circuit is biased to operate in the class A, AB or B mode. Transistor 11 is biased by resistor 16 and diodes 13, 14 whose junction area is twenty times that of the base emitter junction of 11. They therefore carry twenty times as much current thus allowing resistor 16 to accurately control the transistor base current. In Fig. 2, the base current for transistor 111 is supplied from a constant current source 24 and an emitter follower 23 which provides the peak base currents. The outputs may be fed to a transformer, or, as shown in Fig. 3, a class B push-pull amplifier.