| 摘要 |
A current source circuit includes a series-circuit connected between a power source node and ground and comprising a reference current source circuit, a first transistor Q1 of an NPN type having its collector and base connected to each other and a second transistor Q2 having a multi-emitter area (N) and having a multi-emitter configuration. The current source circuit further includes a third transistor Q3 of an NPN type connected at its collector to the power source node, at its base to the base of the first transistor Q1 and at its emitter connected to the base of the second transistor and has an emitter area (M) and an input current source circuit connected between the emitter of the third transistor Q3 and ground to allow a flow of an input current Iin. The current source circuit still further includes a fourth transistor Q4 of an NPN type connected at its collector-to-emitter circuit between a current output node and the ground and at its base connected to the collector of the second transistor to allow a flow of an output current Iout. Relative to an input current Iin, the output current Iout is proportional to the reciprocal of a product (MxN) of emitter areas of the third transistor Q3 and second transistor Q2.
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