| 摘要 |
PURPOSE:To increase the eliminating ratio of power supply voltage ripple, by minimizing the power supply voltage ripple component at the point of collector output of the 1st-stage transistor in a minor signal amplifying circuit having the active load. CONSTITUTION:The input signal applied to a terminal 25 is supplied to a transistor (TR)1. The collector of the TR1 is connected to the TR7. The input signal supplied to the TR1 is delivered from a point 27 of connection between the emitters of TR10 and TR11 that form an SEPP circuit and at the same time fed back to a terminal 28 to set the DC potential. The collector of the TR1 is furthermore connected to a power supply voltage supply terminal 26 via a constant current output circuit 102. On the other hand, the output of a constant current output circuit 103 passes through a bias compensating circuit 106 and is inverted by a current Miller circuit 101 to be applied to the emitter of the TR1. The base of the TR1 is connected to the circuit 106 via a resistance 17 and then to a bias circuit 107. In such way, the equal voltage is secured between the collector and the base of TR3 and TR4 of the circuits 102 and 103, and thus the noise component is minimized at the collector output point of the TR1. |
