Patent ID: 6400177
Filing Date: 2002-06-04
Classification: H03K

Abstract:
An output driver comprising:a pull-up transistor coupled to a pad and to a voltage source, the pull-up transistor comprising a first terminal, a second terminal, and a third terminal; a first voltage response circuit coupled to the pull-up transistor and to the pad, the first voltage response circuit modifying a voltage difference between the first terminal and the second terminal of the pull-up transistor in response to a change in a voltage difference between the third terminal and the second terminal of the pull-up transistor for restraining a decline of an output current level during a low-to-high transition of a signal; a pull-down transistor coupled to the pad and to a ground, the pull-down transistor comprising a first terminal, a second terminal, and a third terminal; a second voltage response circuit coupled to the pull-down transistor and to the pad, the second voltage response circuit modifying a voltage difference between the first terminal and the second terminal of the pull-down transistor in response to a change in a voltage difference between the third terminal and the second terminal of the pull-down transistor for restraining a decline of an output current level during a high-to-low transition of the signal; a first switch coupled to an input terminal and to the first voltage response circuit for enabling the first voltage response circuit and the pull-up transistor during the low-to-high transition of the signal; and a second switch coupled to the input terminal and to the second voltage response circuit for enabling the second voltage response circuit and the pull-down transistor during the high-to-low transition of the signal.