| 摘要 |
PROBLEM TO BE SOLVED: To surely protect a circuit element and a driving circuit using it from abnormal voltage and abnormal current caused by load by conducting the continuity operation before exceeding breakdown voltage in applying the voltage above a breakdown voltage. SOLUTION: To normally operate a circuit when there is a current inflow such as abnormal discharge, a protection diode is constructed for withstanding drain voltage rise due to inflow charges, and a breakdown voltage between the drain and source of an output element 12b is set above the voltage obtained by adding the forward voltage drop of the pull-up side protection diode 11a to the supply voltage. In a driving circuit of a plasma display taking a discharge cell as load, the breakdown voltage in a continuity state is more important than that when an element breakdown voltage is normally cur off. A forward voltage drop including the transient state of the protection diode is made smaller enough, simultaneously the breakdown voltage of the output element during the rated operation is kept above the power supply voltage, and the gate-source voltage is kept stable to hold down lowering of the element breakdown voltage in the operating condition to the utmost. |
