| 摘要 |
An integrated circuit chip 602 is fabricated with an operational active device Q2 and a nearly-identical, exemplary active device Q1. The exemplary device is connected in series with a current reference element 610 so that current flow through the reference element will be substantially duplicated in the exemplary device. A difference amplifier U1 senses the output voltage VD1 of the exemplary device; compares it to a provided reference voltage VDD; and generates a gate biasing level VB1 at the gate G1 of the exemplary device to force the output voltage of the exemplary device to the reference voltage. The basing level at the gate G1 is duplicated at the gate G2 of the operational device, thereby creating a condition wherein the output current of the operational device Q<2> will be a precise replica of the current flow through the reference element 610 when the reference voltage is duplicated across the output of the operational device. Further stages may be added, and the circuit may be used in a phase locking system (Fig. 5). <IMAGE> |
