| 摘要 |
<p>PURPOSE:To securely know a high voltage level from outside by stepping down the high voltage of a voltage boosting circuit incorporated in the nonvolatile memory by a capacitor or MOS transistor(TR) and converting it into a digital signal, supplying the signal to a register, and detecting the high voltage level with stored data. CONSTITUTION:The high voltage at the terminal 4 of a voltage boosting circuit 10 is divided by capacitors C2 and C1 to obtain the stepped-down voltage at a connection part 15. The voltage is supplied to the register 13 through an A/D converter 12 and latched. Then a read signal SR is supplied to an output latch 14, and the stored data in the register 13 are read out and outputted to an external port terminal 8. Consequently, the voltage level of the voltage boosting circuit can indirectly be detected from outside without being affected by a noise or surge. At this time, the voltage level can similarly be detected by stepping down the high voltage of the voltage boosting circuit by the MOS TR, converting the voltage into the digital signal, and supplying to the register.</p> |
