| 摘要 |
PURPOSE:To disperse energy of high voltage surge applied and assure certain protective operation through enhancement of rigidity of protection element by guiding a high voltage surge to the largest conductive region in the three conductive regions to form a bipolar transistor. CONSTITUTION:The side of collectors 62, 63 of the pnp bipolar transistor Q1 and the npn bipolar transistor Q2 is respectively connected to the side of external input pad Pi. Therefore, the base and emitter of the pnp bipolar transistor Q1 are connected to the positive power source Vcc, while the base and emitter of the npn bipolar transistor Q2 to the ground potential. In this case, if any type of positive and negative high voltage surges is not applied to the input terminal pad Pi, the base to emitter voltage becomes almost zero at each transistor Q1, Q2. Therefore, these transistors maintain in the OFF (non-conductive) state. Accordingly, these can operate as the protection elements for any of positive and negative high voltage surges. |
