| 摘要 |
<p>PURPOSE:To obtain a different input level in accordance with an input voltage value by changing the write depth of a PROM cell and freely reporting the threshold value of a memory cell. CONSTITUTION:Similar to the writing in a normal PROM product, the writing is performed by applying a high voltage to signals D and E from a write circuit H against a PROM cell C. By operating on the applying duration and the applied voltage value of the signals D and E, the write depth of the cell C is varied. Employing the write depth as a detection value and letting the threshold value as Valpha1, and when a power supply voltage V1 is V1<Valpha1, the cell C is OFF and the output of the sense-amplifier B becomes an 'L' level. When V1>Valpha1, the cell C is ON, the output of the sense-amplifier B becomes an 'H', the variation of the input voltage V1 is detected and the discrimination is done by the level of an output signal A.</p> |
