A flash IC card with programmable security code

A flash IC card with programmable security code and embedded 2 Kb flash memory has been developed. Using the NORST (NOR with Select Transistor) flash EEPROM cell make this flash memory suitable for the embedded applications. The needed high positive and negative boosted voltages when programming and erasing are provided by the Dickson charge pump on chip. Two circuit techniques are proposed for the charge pump in order to minimize the influence of the body effect and threshold voltage. There are two main parts to the whole card: digital control logic and analog macro cell. A two level fuse circuit is adopted to distinguish the state of testing and normal use.