Patent ID: 7202727
Filing Date: 2007-04-10
Classification: H03K

Abstract:
1. A bi-directional signal level shift circuit comprising: a first analog switch including a first switching control terminal connected directly to a first directional signal stage and a first resistor, the first resistor that is directly connected to a ground, including a first input terminal adapted for connection to a first level of an operating voltage via a third resistor, and including a first output terminal connected directly to a second directional signal stage and a fourth resistor, the fourth resistor that is directly connected to the ground, the first analog switch being configured to perform a switching operation for the first input terminal and the first output terminal based on a state of a logic level of a signal output from the first directional signal stage and configured to output to the second directional signal stage a logic level having a value based on values of the third and fourth resistors; and a second analog switch including a second switching control terminal connected directly to the second directional signal stage and the fourth resistor, a second input terminal adapted for connection to a second level of an operating voltage that is different than the first level of operating voltage via a second resistor, and a second output terminal connected directly to the first directional signal stage and the first resistor, the second analog switch being configured to perform a switching operation for the second input terminal and the second output terminal based on a state of a logic level of a signal from the second directional signal stage and configured to output to the first directional signal stage a logic level having a value based on values of the first and second resistors.