| 摘要 |
PURPOSE:To ensure the amplification with high gain and satisfactory linearity by using a constant current circuit to amplify the current output of a transistor connected to a differential pair by (n) times and obtaining the final output from said amplified output current and a load resistance. CONSTITUTION:Transistors (Tr) Q1 and Q2 are connected to a differential pair; while Trs Q3 and Q4 form a current mirror circuit. Both Trs Q3 and Q4 have emitters of the same size. A current I1 is flowed from a power supply +VCC, and a current I1' which is approximately equal to the I1 is flowed to the TrQ4. Here I1approx.=I1' is set at nXI0(0<n<2: n is integer). A shunt current I2 of the current I1' is changed to n.I0 from n.I0-2I0 between the perfect ON and OFF of the TrQ2. The current I2 is supplied to a TrQ5 via diodes D1-D3. The Trs Q5 and Q6 and resistance R2 and R3 form a current mirror circuit of an m-fold current ratio in response to the multi-emitter of the TrQ6. Then the output voltage Vout is obtained at an end of a load resistance RL. Thus an input dynamic range VinD and the gain GV can be increased by decreasing the value of (n) even after the value of VCC and VCE(sat) equal to the saturated voltage of the TrQ6 are decided.
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