| 摘要 |
<p>PURPOSE:To attain the check of a short-circuited output terminal by inserting a non-doped nMOS transistor(TR) to a conventional CMOS output buffer circuit. CONSTITUTION:The non-doped nMOS TR 6 whose gate and drain are connected in common is inserted between an output terminal 4 and the power supply side pMOS TR 3 of a CMOS circuit comprising the series connection of an nMOS TR 2 and a pMOS TR 3. Enhancement MOS TRs are used for all the MOS TRs. The non-doped nMOS TR 6 is formed on the same substrate or a well as the nMOS TR 2 and the threshold voltage is negligibly small in comparison with that of the nMOS TR 2. The 'H' level of the output of the circuit is a value obtained by subtracting the threshold voltage of the nMOS TR 6 from the power voltage, but it is nearly equal to the power voltage practically.</p> |
