Sophisticated nvSRAM based transponder architecture provides novel features for field programming and safety

A new Transponder architecture offers the ability to reprogram the transponder in the field. The current implementation of flash based memories for code and/or parameter storage impede this feature due to significant current consumption over a long time for store operation. The proposed sophisticated approach uses the low current consumption of embedded nvSRAM memories. The nvSRAM embedded memory combines the fast unlimited access of a SRAM bitcell backed up by a SONOS based storage device. The store and erase procedure are based on Fowler-Nordheim erase and programming of the SONOS device. This field emission tunneling consumes very small current and provides the capability of programming all memory cells at the same time. The necessary charge is stored on a capacitor that was charged up very smoothly during power on by controlled current source technique to avoid the feedback on transponder operation. Based on this concept the code and/or parameters could be stored by hardware control of the transponders microcontroller, by software control insight and outsight of the system or even in case of emergency system power down. Beside the field programming capability a proprietary store procedure control allows to store additional information of the store procedure itself to flag the successful store operation. This capability provides the new powerful feature of logging the store procedure in a very low current consuming environment and checks the validity after re-powering the system. This paper gives an introduction in different approaches for transponder architectures by using nvSRAM memory architecture, presents the advantage and introduces new safety features in very low current consuming systems.