| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a fuse PROM circuit that has a large circuit operation margin in a normal circuit operation mode and a large maximum resistance value that can be detected in a verify mode, with respect to a fuse element in which writing is completed. <P>SOLUTION: The fuse PROM circuit includes a write terminal that supplies a write current to the fuse element, a current source that generates a read current, a protection diode that supplies the read current to the fuse element upon reading and protects an internal circuit upon writing, and a switching element that controls a parasitic transistor of the protection diode. The protection diode is composed of an anode of a p-type diffused layer formed on a p-type semiconductor substrate, a cathode of a first n-type diffused layer formed in the p-type diffused layer, and a substrate separating layer of a second n-type diffused layer formed around the p-type diffused layer. One end of the switching element is connected to the anode, and the other end is connected to the substrate separating layer. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
