| 摘要 |
PURPOSE:To cut down an area occupied by transistors in the entire circuit by connecting a second current mirror in series to the lowest-order-bit transistor constituting a first current mirror, the former mirror being made of parallel low-order-bit transistor that constitute bits even lower than said lowest-order bit. CONSTITUTION:In a current mirror circuit which may be used for such as a D/A conversion circuit, in series connection to the transistor 6b constituting the lowest-order bit among the bit transistors 6a-6g constituting the first current mirror, the low-order-bit transistors 11b-11d connected in parallel connection with each other for the necessary bits even in lower order than the lowest bit of the transistor 6b that constitute the second current, is connected. Switches 8b-8g are provided for all the bit transistors of both mirrors. By thus adding the second current mirror consisting of the low-order-bit transistors 11b-11d, the bit number of the first current mirror can be made smaller, and associatively, the chip area of the entire transistors can be narrowed, hence the coverage proportion that they occupy in the current mirror circuit can also be made smaller.
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