| 摘要 |
PURPOSE:To exactly split a current to plural currents having necessary weight, by providing a unit emitter area having the same size and shape on a current source transistor, by the number corresponding to its weighting, and not only decreasing the number of active elements but also reducing an error. CONSTITUTION:Base currents of current source transistors 67-71 are supplied from bias compensating transistors 72-76, respectively, and each collector of the transistors is connected to current fetch terminals 17-21, respectively. As a result, each collector current of the transistors 72-76 becomes a corresponding weighted current, and is supplied to the base of the corresponding current source transistors 67-71, therefore, an error due to this current is removed. Also, the emitter area ratio of these transistors 67-71 and 72-76 is made equal to the split weight ratio. In this way, an exact current split is executed. Also, its component active element consists of only the transistors 67-76, therefore, its number is a very few. |
