Method and apparatus for detecting and selecting voltage supplies for flash memory

摘要

An integrated circuit having internal power supplies includes circuitry for selecting either the external supply voltages or the internal power supplies to supply voltages to the remaining circuitry of the integrated circuit. The integrated circuit comprises voltage detector circuits for detecting the external voltage levels and a control circuit for selecting either the external supply voltages or the internal power supplies in response to the detected external voltages. The integrated circuit may be a flash EEPROM, and the external voltages may be the operating supply voltage VCC and the programming supply voltage VPP.