| 摘要 |
<p>PURPOSE: To accurately control the output voltage by providing an EEPROM IC 300 including a high voltage switch, a Vpp switch and a voltage regulator input circuit and reducing the need to use a p-channel MOSFET having the rated voltage higher than a specific level. CONSTITUTION: A high voltage switch 306 has its feature never to set the voltage higher than 12CV, for example, between two terminals of a p-channel MOSFET. When 24V is applied to the switch 306, a voltage divider 702 outputs a signal of about 17.1V to a node N3. When Vpp input IN has a low level, another voltage divider outputs a signal of about 12V to another node. An input transistor conducts against high input IN and grounds the relevant node. Therefore, the voltage drops among three pieces of p-channel MOSFET. Then a Vpp switch functions to keep the voltage lower than 12V even against high input IN between two terminals of the MOSFET. Thus, a voltage regulator input circuit 318 reduces the need to use the p-channel MOSFET having the rated voltage higher than 12V.</p> |
