| 摘要 |
PURPOSE: An output driver is provided to up-count or down-count first to fifth codes, thereby adjusting pull-up driving power of PMOS transistors. CONSTITUTION: A reference voltage generating unit(20) distributes a voltage according to a resistance value ratio of resistors which are connected in series between an external voltage and a ground voltage to generate a reference voltage. A comparison unit(21) generates a comparison voltage by comparing the level of a driving voltage with the level of a reference voltage. A code counting unit(22) performs a down-counting operation to reduce bit values of first to fifth codes when a comparison voltage of a logic high level is inputted. A driving unit(23) drives a driving voltage outputted to an output pad(24) in response to the first to fifth codes or first to third pull down signals. |
