摘要 |
A pre-buffer level shifter and an I/O buffer apparatus are provided. The pre-buffer level shifter includes a switchable current source, a current mirror, a buffer unit, a first clamping circuit and a second clamping circuit. Because of a clamping circuit inside a thin oxide MOS transistor device of the pre-buffer level shifter, the present invention can control the voltage swing of the signal for driving an output buffer within a suitable voltage range. Thus, the pre-buffer level shifter can correctly drive the output buffer made of thin oxide MOS transistor devices, increase the operating speed and ensure the reliability thereof.
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