Patent ID: 7868659
Filing Date: 2011-01-11
Classification: H03K

Abstract:
1. An I/O buffer with twice the supply voltage tolerance using normal supply voltage devices comprising: a driver, for receiving a mode control signal and a data output signal and generating a first driving signal and a second driving signal; a first level converter, for receiving the first driving signal to convert a first voltage range of the first driving signal into a second voltage range and output a level translating signal; a gate-controlled circuit, for receiving the mode control signal and an I/O terminal signal and generating a first gate-controlled signal and a second gate-controlled signal; and a dynamic source output stage circuit having a first output circuit, a second output circuit and an I/O terminal, the first output circuit and the second output circuit having a plurality of transistors; wherein the first output circuit is in the second voltage range and controlled by the level translating signal and the first gate-controlled signal; the second output circuit is in the first voltage range and controlled by the second gate-controlled signal and the second driving signal, such that the voltage across any two terminals of the transistors is not higher than the normal supply voltage and the I/O terminal is used for transmitting or receiving double the supply voltage.