Patent Application
20130217322
1. Field of the Invention
The disclosure generally relates to an NFC (Near Field Communication) system, and more particularly, relates to an NFC system including a memory device that can work normally even if a power source is removed therefrom or turned off.
2. Description of the Related Art
In an NFC system, an NFC controller can be used as a card (e.g., a card emulation mode defined in the NFC Forum) for many applications, such as Metro passing, banking, etc. The NFC controller requires an NVM (Non-Volatile Memory) so as to keep important data when a power source of the NFC system is removed therefrom or turned off
An NVM is usually an EEPROM (Electrically Erasable Programmable Read Only Memory) or a flash memory. The data stored in the NVM can be kept even when battery power is turned off. The drawbacks of the NVM are directed to its large size and high cost. The size of an EEPROM is much larger than a volatile memory, and the data density of the EEPROM is very low. On the other hand, a flash memory requires extra masks and special process, which costs a lot. Nowadays, there is still no mature NVM solution for advanced process, e.g. 40 nm or 65 nm, such that development of an NFC system with advanced processes continues to be problematic.
In one exemplary embodiment, the disclosure is directed to an NFC (Near Field Communication) system, comprising: a power source; a capacitor, charged by the power source; an NFC controller, comprising an independent power domain which is supplied by the power source and/or the capacitor; and a memory device, disposed in the independent power domain, and maintaining data, wherein the independent power domain is supplied by the capacitor when the power source is removed therefrom or turned off
In another exemplary embodiment, the disclosure is directed to an NFC (Near Field Communication) system, comprising: a power source; a capacitor, charged by the power source; an NFC controller, comprising an independent power domain which is supplied by the power source and/or the capacitor; an LDO (Low Dropout Regulator), disposed in the independent power domain, and converting a power voltage into a low voltage, wherein the power voltage is provided by the power source and/or the capacitor; and a memory device, disposed in the independent power domain, coupled to the low voltage of the LDO, and maintaining data, wherein the independent power domain is supplied by the capacitor when the power source is removed therefrom or turned off.
The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:
The NFC controller 130 further comprises a memory device 150 disposed in the independent power domain 140. The power source 110 and/or the capacitor 120 provide electrical power for the independent power domain 140 and all components disposed in the independent power domain 140, such as the memory device 150, which is supplied by the independent power domain 140. The memory device 150 is configured to maintain data. In a preferred embodiment, the memory device 150 is a volatile memory, such as an SRAM (Static Random Access Memory) or one or more D-flip flops. In some embodiments, the data comprises an application configuration data and/or a patch code for use in a processor (not shown in
It is note that when the power source 110 is removed therefrom or turned off, the independent power domain 140 is supplied by only the capacitor 120. The voltage difference of the capacitor 120 can be kept for several hours, depending on the size of the capacitor 120. Therefore, the memory device 150 disposed in the independent power domain 140 can maintain the data even if the power source 110 is removed therefrom or turned off. The memory device 150 of the NFC system 100 can be used as an NVM (Non-Volatile Memory). The size of a volatile memory (e.g., an SRAM) is much smaller than that of an NVM (e.g. an EEPROM or a flash memory), and furthermore, the volatile memory just requires a standard process. Neither special processes nor extra masks are required in the invention.
The invention provides a novel NFC system with a capacitor which serves as a UBS (Uninterruptible Power Supply). Therefore, any kind of memory device of the NFC system can be used as an NVM. In a preferred embodiment, a volatile memory may be used in the NFC system, and it just requires a standard process. Neither special processes nor extra masks are required in the invention.
Use of ordinal terms such as “first”, “second”, “third”, etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish the claim elements.
While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.
