| 摘要 |
PURPOSE:To provide the differential circuit which exhibits exponent characteristics against a differential input voltage by driving one transistor, between a pair of transistors consisting of a differential pair, by a constant current and driving the other transistor by a current equal to a collector current to be inputted. CONSTITUTION:This circuit is provided with two transistors Q1 and Q2 consisting of the differential pair, the transistor Q1 is driven by a constant current IO of a constant current source, and the transistor Q1 is driven by a current IC2 of a current source to generate the current equal to the inputted collector current IC2. One collector current of the differential pair applying this dynamic bias current technique is provided with the exponent characteristics. This can be just expressed by replacing a voltage between the base and emitter of a bipolar transistor with the differential input voltage, replacing a saturated current with the constant current in the relational formula of the voltage between the base and the emitter and the collector current and just with parameters to be fully electrically programmed. Namely, the circuit which exhibits the exponent characteristics corresponding against the differential input voltage. |
