Low-noise output driver having separate supply lines and sequenced operation for transient and steady-state portions

Abstract

The present invention discloses an output circuit which comprises an input terminal for receiving an input signal having a predetermined logic level, an output terminal held at a potential corresponding to the logic level of the input signal, first and second power sources, separated from each other, third and fourth power sources, separated from each other, a fast potential changing circuit, which is connected between the first and third power sources, for instantaneously changing the potential at said output terminal when a logic level of the input signal changes, potential maintaining circuit connected between said second and fourth power sources, for maintaining the potential of the output terminal at the same level after the potential is changed by the rapid potential changing circuit, a first controlling circuit for controlling the fast potential changing circuit such that the fast potential changing circuit starts operating when the logic level of the input signal changes and stops operating after a predetermined time of period elapses, and a second controlling circuit for controlling the potential maintaining circuit such that the potential maintaining circuit starts operating after the fast potential changing circuit starts operating.

Dependencies are inferred from the claim text.