| 摘要 |
PURPOSE:To expand easily an input dynamic range by changing the ratio of resistances connected to bases of a pair of transistors comprising a differential pair. CONSTITUTION:When a control signal V1 is applied, the base potential of one transistor TRQ1 of a differential pair comes to a V1'. A reference voltage is applied to the base of the other transistor TRQ2 of a differential pair. Since the voltage level is added to the base of the TRQ1 through a resistance R2, the voltage V1' is decided according to expression I, V1'-E1=(V1-E1)XR2/(R1+ R2) in the condition where both voltages are balanced. Here, if R2/(R1+R2) is large, the level change of the voltage V1' becomes large when the level of the control signal V1 is controlled. The level change of the voltage V1' with respect to a reference voltage E1 can be obtained as an output voltage DELTAV due to the differentiating and amplifying actions of the TRQ1 and TRQ2. |
