| 摘要 |
PURPOSE:To simplify the structure and to obtain high integrated circuit, in the PNPN switch wherein two elements are connected in reverse positions in parallel, by employing an MOSFET in an errornesous operation preventing circuit wherein critical voltage increasing rate is low. CONSTITUTION:In the PNPN switch wherein the PNPN elements Th1 and Th2 are connected in parallel, the circuit, which prevents the erroneous operation caused by the high critical voltage increasing rate (dv/dt), is constituted by a plurality of transistors (TR) and diodes (D). Instead of conventional bipolar transistors, N MOS transistors TR4 and TR5 are used. In this constitution, e.g., if the abruptly increasing voltage which are higher than those at terminals T1 and T2 are applied, the TR4 is conducted and the erroneous operation of Th1 is prevented. Likewise, the erroneous operation of Th2 can be prevented by TR2. By employing the MOS element, this circuit does not require an elements separating structure and also does not require high accuracy in a diffusing process. Since the structure and the processes can be simplified, the PNPN switching elements can be highly integrated. |
