Patent ID: 7679421

Claim:
A level shift circuit, comprising: a first switch element, having a control terminal coupled to a first input signal, a first terminal coupled to a first voltage source, and a second terminal coupled to a first output terminal; a second switch element, having a control terminal coupled to a second input signal, a first terminal coupled to the first voltage source, and a second terminal coupled to a second output terminal, wherein the second input signal is an inverse of the first input signal; a third switch element, having a control terminal coupled to the second output terminal, a first terminal, and a second terminal coupled to the first output terminal; a fourth switch element, having a control terminal coupled to the first output terminal, a first terminal, and a second terminal coupled to the second output terminal; a first current source module, coupled between a second voltage source and the first terminal of the third switch element, for letting a current passing through the third switch element smaller than a current passing through the first switch element when the first switch element and the third switch element are conducted; and a second current source module, coupled between the second voltage source and the first terminal of the fourth switch element, for letting a current passing through the fourth switch element smaller than a current passing through the second switch element when the second switch element and the fourth switch element are conducted; wherein the first current source module comprises: a fifth switch element, having a control terminal directly connected to the first output terminal, a first terminal coupled to the second voltage source, and a second terminal directly connected to the first terminal of the third switch element; and the second current source module comprises: a sixth switch element, having a control terminal directly connected to the second output terminal, a first terminal coupled to the second voltage source, and a second terminal directly connected to the first terminal of the fourth switch element.