Patent ID: 7893732
Filing Date: 2011-02-22
Classification: H03K

Abstract:
1. A driver circuit that changes a voltage level of an output signal in correspondence with a change in voltage level of an input signal, said driver circuit comprising: a first power source and a second power source; an input terminal, which receives said input signal; an output terminal, from which said output signal is outputted; a first transistor of a predetermined conductive type, which is connected between said first power source and a predetermined first node, and has a gate connected to said input terminal; a second transistor of said predetermined conductive type, which is connected between said first node and a predetermined second node; a first unilateral current driving element, one end of which is connected to a third node connected with a gate of said second transistor, and which supplies the third node with a voltage for bringing said second transistor into an on-state; a second unilateral current driving element, one end of which is connected to said second node; a first capacitive element, which is connected between said first node and said third node; a third transistor of said predetermined conductive type, which is connected between said first power source and said output terminal, and has a gate connected to said input terminal; a fourth transistor of said predetermined conductive type, which is connected between said second power source or a voltage generating circuit for generating an active-level voltage and said output terminal; and a push-pull circuit, which transmits a voltage signal of said first node to a gate of said fourth transistor, wherein a pull-up transistor that shifts said gate of said fourth transistor to the active level in said push-pull circuit has a higher driving ability than said second transistor, said second unilateral current driving element previously supplies said second node with a predetermined voltage such that a voltage for turning on said fourth transistor is supplied to said first node through said second transistor when said first transistor is turned off, and said driver circuit is configured such that a voltage change of said second node occurs in correspondence with a voltage change of said output terminal when said fourth transistor is turned on, and a gate-source voltage of said fourth transistor is further increased due to a voltage change of said first node caused by said voltage change of said second node.