| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a one-time PROM circuit which occupies a smaller area on a semiconductor integrated circuit. <P>SOLUTION: When information is read, transistors Q1, Q2, and Q3 functioning as switch elements are all turned off. A voltage is applied from a voltage source VB through a diode D10 to a terminal P1, and the collector currents of transistors Q4, Q6 and Q8 serving as current sources are supplied to Zener Zap diodes Z1, Z2 and Z3. At this time, the difference of resistance values due to the presence or absence of write causes the difference of a voltage drop in each PROM element, a voltage level difference is generated in each read terminal with respect to a reference voltage terminal, and this is correlated to the state 0 and 1 of digital representation. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
