| 摘要 |
PURPOSE:To realize a floating type variable impedance circuit by using a couple of differential transistors. CONSTITUTION:Input voltages V1 and V2 are applied to V-I converter 10 to obtain currents (i3) and (i4). Currents (i3) and (i4) flow through PN junction couple 25 in current amplifier 20 and voltages developed here are applied to respective bases of differential transistor couple 27. As a result, currents (i5) and (i6) flow to a couple of idfferential output terminals 23 and 24 of current amplifier 20, current sources 31 and 32 are constituted to supply currents a half as much as that of current source 28, when the transfer conductance of the V-I converter is denoted K1, currents (i5) and (i6) will be expressed by (3) and (4). Namely, conductance equivalent to K1.I2/I1 can be obtained between terminals 1 and 2 without reference to the earth voltage. In other words, floating type constitution is realized and a circuit can be obtained which provides various applications and the simplification of integration. |
