| 摘要 |
PROBLEM TO BE SOLVED: To provide a constant voltage type output buffer circuit that operates at a high speed and can adjust an amplitude and a common mode voltage of differential signals independently.SOLUTION: A differential output buffer includes first and third switches and second and fourth switches connected in series, respectively, between a first voltage source and a current source, and a replica circuit includes a second voltage source equivalent to the first voltage source, a fifth switch equivalent to the first or second switch in an on state, and a constant current source for causing a flow of constant current along a current path including the second voltage source and the fifth switch. A current control circuit controls a current flowing through the current source such that a voltage of a third node between two resistive elements of the same resistance value connected in series between a first node between the first and third switches and a second node between the second and fourth switches becomes equal to a reference voltage, and a voltage control circuit generates a control signal such that a voltage of any node of the current path other than an output terminal of the second voltage source becomes equal to a second reference voltage. |
