Soft pre-charge H/V switch for charge pump with NAND flash memory using external power

Abstract

This letter describes a soft pre-charge high voltage switch for a program/erase charge pump (P/E Pump) with NAND flash memory using an external high voltage of 12 V. The use of a external high voltage reduces the P/E Pump stage and improves the power efficiency. The external high voltage is used as input power of the P/E Pump. The soft pre-charge high voltage switch is proposed to transfer the external high voltage without a breakdown issue. The proposed high voltage switch passes the external high voltage of +12 V to be ramped up linearly at the start-up phase.