1. Field of the Invention
The present invention relates to a semiconductor integrated circuit for discriminating trimming failure.
2. Description of the Related Art
An example of conventional circuit having trimming structure is shown in FIG. 8. In FIG. 8, the resistance between a terminal 811 and a negative power supply VSS corresponds to a resistance 841 by cutting a fuse 821. Further, if the fuse 821 is not cut, the resistance between the terminal 811 and the negative power supply VSS corresponds to a combined resistance of the resistance 841 and a resistance 842. A voltage of the terminal 811 of the circuit in FIG. 8 is controlled by the resistance ratio to a resistance 843.
In the conventional trimming structure, a non-conforming article is generally produced if trimming is not performed correctly. However, there is a possibility that a conforming article is nonetheless provided without performing trimming depending on a range of an efficiency voltage of a test. In this case, even if a laser is radiated to a position away from the fuse location so that trimming fails to be performed because of positional deviation of trimming alignment, or the like, a conforming article may be provided at the time of the test. In addition, there is a fear that the radiation of a laser to the wrong position affects long-term reliability of the device, and thus, the non-conforming article has to be correctly discriminated.
In order to solve the above-described problems, an object of the present invention is to provide a semiconductor integrated circuit having a structure in which a dummy fuse is used to discriminate failure in accordance with an output thereof in the case of a trimming error. The semiconductor integrated circuit as structured above has a strong point in that success or failure of trimming can be discriminated in accordance with whether the output is fixed to VSS or VDD or not. Further, such a structure is adopted in which, if trimming is not performed, short circuit is established between positive and negative power supply voltages, whereby the success or failure of trimming can be discriminated by examining a consumption current.