Patent Publication Number: US-2011063091-A1

Title: Radio frequency identification system

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The priority of Korean patent application Nos. 10-2009-114414 and 10-2009-86021, respectively filed on Nov. 25, 2009 and Sep. 11, 2009, the disclosure of which is hereby incorporated in its entirety by reference, is claimed. 
     BACKGROUND OF THE INVENTION 
     Embodiments of the present invention relate to a radio frequency identification (RFID) system, and more specifically, to a technology for identifying an object by communicating with a reader through transmission and reception of a radio frequency (RF) signal. 
     An RFID tag chip has been widely used to automatically identify objects using an RF signal. In order to automatically identify an object using the RFID tag chip, an RFID tag is attached to the object to be identified, and an RFID reader wirelessly communicates with the RFID tag of the object using a non-contact automatic identification scheme. The widespread use of these RFID technologies, can overcome the shortcomings of a conventional automatic identification technology, such as a barcode and an optical character recognition technology. 
     In recent times, the RFID tag has been widely used in physical distribution management systems, user authentication systems, electronic money (e-money), transportation systems, and the like. 
     For example, a physical distribution management system generally performs the classification of goods or management of goods in stock using an Integrated Circuit (IC) recording data therein, instead of using a delivery note or tag. In another example, the user authentication system generally performs an Entrance and Exit Management function or the like using an IC card including personal information or the like. 
     A non-volatile ferroelectric memory may be used as a memory in an RFID tag. 
     Generally, a non-volatile ferroelectric memory, i.e., a ferroelectric random access memory (FeRAM), has a data processing speed similar to that of a dynamic random access memory (DRAM), and preserves data even when power is turned off. This has many developers conducting intensive research into FeRAM as a next generation memory device. 
     The FeRAM has a similar structure to that of DRAM but uses a ferroelectric capacitor as a storage element. Ferroelectric material has a high remnant polarization characteristics, such that data is not lost although an electric field is removed. 
       FIG. 1  is a block diagram illustrating a general RFID device. 
     The RFID device generally includes an antenna unit  1 , an analog unit  10 , a digital unit  20 , and a memory unit  30 . 
     The antenna unit  1  receives an RF signal from an external RFID reader. The RF signal received through the antenna unit  1  is input to the analog unit  10  via antenna pads  11  and  12 . 
     The analog unit  10  amplifies the input RF signal and generates a power-supply voltage VDD which can then be used as a driving voltage of an RFID tag. The analog unit  10  detects an operation command signal from the input RF signal, and outputs a command signal CMD to the digital unit  20 . In addition, the analog unit  10  detects the output voltage VDD and outputs a power-on reset signal POR controlling a reset operation and a clock CLK to the digital unit  20 . 
     The digital unit  20  receives the power-supply voltage VDD, the power-on reset signal POR, the clock CLK, and the command signal CMD from the analog unit  10 , and outputs a response signal RP to the analog unit  10 . The digital unit  20  outputs an address ADD, input/output data (I/O), a control signal CTR, and the clock CLK to the memory unit  30 . The memory unit  30  reads, writes and stores data using a memory device. 
     In this case, the RFID device uses frequencies of various bands. In general, as the value of a frequency band is decreased, the RFID device has a lower recognition speed, operates at a shorter distance, and is less affected by the surrounding environment. In contrast, as the value of a frequency band is increased, the RFID device has a higher recognition speed, operates at a greater distance, and is considerably affected by the surrounding environment. 
     BRIEF SUMMARY OF THE INVENTION 
     Various embodiments of the present invention are directed to providing an RFID system that substantially obviates one or more problems due to limitations and disadvantages of the related art. 
     First, an embodiment of the present invention relates to an RFID technology for allocating an identification (ID) code to a driving device using an RFID device such that each driving device can be wirelessly controlled at a remote site. 
     Second, an embodiment of the present invention relates to an RFID technology for allocating an ID code to each driving device using an RFID device including an internal or an external sensor, and transmitting a specific driving command to each RFID device using an RF signal, thus establishing a specific output level. 
     Third, an embodiment of the present invention relates to an RFID technology for allocating an ID code to each driving device using an RFID device including an internal micro-controller unit (MCU) or an external MCU, and transmitting a specific driving command to each RFID device using an RF signal, thus establishing a specific output level. 
     Fourth, an embodiment of the present invention relates to an RFID device for predetermining handle values for a plurality of RFID devices using a fixed handle mode, and allowing each RFID device to be arbitrarily selected and controlled using the corresponding predetermined handle value, thus increasing the operational efficiency. 
     In accordance with one embodiment of the present invention, a radio frequency identification (RFID) system including an RFID device which reads and writes data in response to a radio frequency (RF) signal received through an antenna unit includes the RFID device. The RFID device includes a connection unit configured to be coupled to an external driving device; and a driving unit configured to output a driving signal for controlling the driving device to the connection unit in response to control signals generated by the RF signal. 
     In accordance with another embodiment of the present invention, a radio frequency identification (RFID) system including an RFID device which reads and writes data in response to a radio frequency (RF) signal received through an antenna unit includes the RFID device. The RFID device includes a connection unit configured to be coupled to an external driving device; a sensor control block configured to convert a sensing value detected by a sensing element into digital code data, and output the resultant digital code data; and a driving unit configured to output a driving signal for controlling the driving device to the connection unit in response to the digital code data. 
     In accordance with another embodiment of the present invention, a radio frequency identification (RFID) system includes an RFID device configured to read and write data in response to a radio frequency (RF) signal received through an antenna unit; and a sensor configured to be coupled to an external part of the RFID device, and output a value detected by a sensing element to the RFID device. The RFID device includes: a connection unit configured to be coupled to an external driving device; a sensor interface unit configured to receive a sensing signal from the sensor; and a driving unit configured to output a driving signal for controlling the driving device to the connection unit in response to an output signal of the sensor interface unit. 
     In accordance with another embodiment of the present invention, a radio frequency identification (RFID) system including an RFID device which reads and writes data in response to a radio frequency (RF) signal received through an antenna unit includes the RFID device. The RFID device includes a connection unit configured to be coupled to an external driving device; a Micro-Controller Unit (MCU) control block configured to program code data; and a driving unit configured to output a driving signal for controlling the driving device to the connection unit according to output data of the MCU control block. 
     In accordance with another embodiment of the present invention, a radio frequency identification (RFID) system includes an RFID device configured to read and write data in response to a radio frequency (RF) signal received through an antenna unit; and a micro-controller unit (MCU) processor configured to be coupled to an external part of the RFID device, program code data, and output the programmed code data to the RFID device. The RFID device includes: a connection unit configured to be coupled to an external driving device; a serial interface controller configured to receive code data from the MCU processor; and a driving unit configured to output a driving signal for controlling the driving device to the connection unit in response to an output signal of the serial interface controller. 
     In accordance with another embodiment of the present invention, a radio frequency identification (RFID) system including an RFID device which reads and writes data in response to a radio frequency (RF) signal received through an antenna unit includes the RFID device. The RFID device includes: a connection unit configured to be coupled to an external driving device; a driving unit configured to output a driving signal for controlling the driving device to the connection unit according to control signals generated by the RF signal; and a fixed handle mode control unit configured to output predetermined fixed handle data to the RFID device at a fixed handle mode according to a command signal generated by the RF signal. 
     It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
     It will be appreciated by persons skilled in the art that that the effects that can be achieved with the present invention are not limited to what has been particularly described hereinabove and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram illustrating an RFID device according to a conventional method. 
         FIG. 2  is a block diagram illustrating an RFID device according to a first embodiment of the present invention. 
         FIG. 3  is a detailed block diagram illustrating a digital analog converter (DAC) register unit shown in  FIG. 2  according to an embodiment of the present invention. 
         FIG. 4  is a detailed circuit diagram illustrating a non-volatile register shown in  FIG. 3  according to an embodiment of the present invention. 
         FIGS. 5 and 6  are timing diagrams illustrating operation of the non-volatile register shown in  FIG. 4  according to an embodiment of the present invention. 
         FIG. 7  is a flowchart illustrating an operation of the RFID device shown in  FIG. 2  according to an embodiment of the present invention. 
         FIG. 8  is a structural view illustrating an RFID system including the RFID device shown in  FIG. 2  according to an embodiment of the present invention. 
         FIG. 9  is a block diagram illustrating an RFID device according to a second embodiment of the present invention. 
         FIG. 10  is a block diagram illustrating an RFID device according to a third embodiment of the present invention. 
         FIG. 11  is a flowchart illustrating an operation of the RFID device shown in  FIG. 10  according to an embodiment of the present invention. 
         FIG. 12  is a structural view illustrating an RFID system including the RFID device shown in  FIG. 10 . 
         FIG. 13  is a block diagram illustrating an RFID device according to a fourth embodiment of the present invention. 
         FIG. 14  is a block diagram illustrating an RFID device according to a fifth embodiment of the present invention. 
         FIG. 15  is a timing diagram illustrating a programming method for a memory unit shown in  FIG. 13 . 
         FIG. 16  is a timing diagram illustrating a method for driving a DAC register unit shown in  FIG. 13 . 
         FIG. 17  is a timing diagram illustrating a method for driving the RFID device shown in  FIG. 13 . 
         FIG. 18  is a structural view illustrating an RFID system including the RFID device shown in  FIG. 14 . 
         FIG. 19  is a flowchart illustrating an operation of the RFID device shown in  FIG. 13 . 
         FIG. 20  is a block diagram illustrating an RFID device according to a sixth embodiment of the present invention. 
         FIG. 21  is a detailed block diagram illustrating a fixed handle mode control unit shown in  FIG. 20 . 
         FIG. 22  is a flowchart illustrating an operation of the RFID device shown in  FIG. 20 . 
         FIG. 23  is a structural view illustrating an RFID system including the RFID device shown in  FIG. 20 . 
         FIGS. 24A to 24D  illustrate a power-supply connection relationship of an RFID system according to embodiments of the present invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
       FIG. 2  is a block diagram illustrating a radio frequency identification (RFID) device according to a first embodiment of the present invention. 
     Referring to  FIG. 2 , the RFID device includes a modulator  100 , a demodulator  110 , a power-on reset unit  120 , a clock generator  130 , a digital unit  140 , a memory unit  150 , a driving unit  200 , a power-supply voltage applying pad P 1 , a ground voltage applying pad P 2 , and a plurality of output pads OP 1 ˜OPn. In this case, the driving unit  200  includes a digital analog converter (DAC) register unit  210 , a power register  220 , and a DAC driver  230 . 
     An antenna unit ANT may be used for data communication between an RFID tag, i.e., the RFID device, and an external reader or writer. The antenna unit ANT is coupled to the RFID tag through antenna pads PAD(+) and PAD(−). In this case, a radio frequency (RF) signal may be used for the RF communication between the RFID device and the external reader or writer. 
     The modulator  100  modulates a response signal RP received from the digital unit  140 , and outputs the modulated response signal to the antenna unit ANT. The demodulator  110  detects an operation command signal from an RF signal received through the antenna unit ANT, and outputs a command signal CMD to the digital unit  140 . 
     The power-on reset unit  120  detects a power-supply voltage VDD received through the power-supply voltage applying pad P 1 , and outputs a power-on reset signal POR for controlling a reset operation to the digital unit  140 . The power-on reset signal POR output from the power-on reset unit  120  is input to the DAC register unit  210  and the power register  220 . The clock generator  130  outputs a clock signal CLK to the digital unit  140 . The clock signal CLK controls the digital unit  140  in response to the power-supply voltage VDD received from the power-supply voltage applying pad P 1 . 
     The digital unit  140  interprets the command signal CMD according to the power-supply voltage VDD from the power-supply voltage applying pad P 1 , a ground voltage GND from the ground voltage applying pad P 2 , the power-on reset signal POR, and the clock signal CLK. The digital unit  140  generates control signals and processing signals, such that it outputs the response signal RP to the modulator  100 . Furthermore, the digital unit  140  outputs an address ADD, input/output (I/O) data, a control signal CTR, and the clock signal CLK to the memory unit  150 . 
     The digital unit  140  outputs I/O data I/O (using m lines (×m)), a write enable signal WE, an output enable signal OE, and a chip enable signal CE to the DAC register unit  210 , and outputs an operation signal ACT to the power register  220 . 
     The memory unit  150  includes a plurality of memory cells, and stores data related to an identification (ID) code specific to each RFID device. Each memory cell writes data in a storage element, and reads data from the storage element. 
     The memory unit  150  includes a non-volatile memory area. Generally, a ferroelectric random access memory (FeRAM) may be used in the non-volatile memory area. The FeRAM has a data processing speed similar to that of a dynamic random access memory (DRAM). The above-mentioned FeRAM has a similar structure to that of DRAM, and uses a ferroelectric material as a capacitor. The ferroelectric material has high remnant polarization characteristics, such that data is not lost although an electric field is removed. 
     In this case, the modulator  100 , the demodulator  110 , the power-on reset unit  120 , the clock generator  130 , the digital unit  140 , the memory unit  150 , and the driving unit  200  are driven by the power-supply voltage VDD from the power-supply voltage applying pad P 1  and the ground voltage GND from the ground voltage applying pad P 2 . 
     In a conventional RFID device, when the RFID device receives the RF signal through communication with the external reader, the power-supply voltage VDD is supplied through a voltage amplification unit provided inside the RFID device. However, in this embodiment, since a large amount of power is consumed by the driving unit  200 , the power-supply voltage VDD and the ground voltage GND are provided to the RFID device through the power-supply voltage applying pad P 1  and the ground voltage applying pad P 2 . 
     The DAC register unit  210  outputs driving control signals b 1 ˜bm to the DAC driver  230 , m being a positive integer. In this embodiment, the DAC register unit  210  includes a non-volatile register. The power register  220  outputs a power on/off signal ON/OFF to the DAC driver  230  in response to the operation signal ACT and the power-on reset signal POR. The DAC driver  230  outputs output signals OUT 1 ˜OUTn through the output pads OP 1 ˜OPn, respectively, n being a positive integer. 
       FIG. 3  is a detailed block diagram illustrating the DAC register unit  210  shown in  FIG. 2 . 
     Referring to  FIG. 3 , the DAC register unit  210  includes an I/O buffer  211 , a register controller  212 , a plurality of non-volatile registers R 1 ˜Rm, and a register output unit  213 . 
     The I/O buffer  211  buffers the I/O data I/O (using m lines (×m)) communicated between the DAC register unit  210  and the digital unit  140 . The register controller  212  outputs register control signals upon receiving the write enable signal WE, the output enable signal OE, and the chip enable signal CE from the digital unit  140 . The register controller  212  is reset in response to the power-on reset signal POR from the power-on reset unit  120 . 
     In this case, the register control signals include a pull-up enable signal ENP, a write enable signal WEN, a cell plate signal CPL, and a pull-down enable signal ENN. 
     The non-volatile registers R 1 ˜Rm output data D 1 ˜Dm and Db 1 ˜Dbm upon receiving from the register controller  212  the pull-up enable signal ENP, the write enable signal WEN, the cell plate signal CPL, and the pull-down enable signal ENN. The register output unit  213  controls the output data D 1 ˜Dm and Db 1 ˜Dbm from the registers R 1 ˜Rm, and outputs the driving control signals b 1 ˜bm to the DAC driver  230 . 
       FIG. 4  is a detailed circuit diagram illustrating each of the non-volatile registers R 1 ˜Rm shown in  FIG. 3 . 
     Referring to  FIG. 4 , the non-volatile register R includes a pull-up unit PU, a p-type metal-oxide-semiconductor (PMOS) latch unit (PL), an I/O unit (I_O), a non-volatile ferroelectric capacitor NSC, an n-type metal-oxide-semiconductor (NMOS) latch unit (NL), and a pull-down unit PD. 
     The pull-up unit PU includes a PMOS transistor PM 1 . The PMOS transistor PM 1  is connected between a power-supply voltage terminal VDD and the PMOS latch unit PL, and receives the pull-up enable signal ENP through a gate terminal. 
     The PMOS latch unit PL includes PMOS transistors PM 2  and PM 3 . The PMOS transistors PM 2  and PM 3  are connected between the PMOS transistor PM 1  and nodes ND 1  and ND 2 , and the gate terminals of the PMOS transistors PM 2  and PM 3  are cross-coupled. 
     The I/O unit I_O includes NMOS transistors N 1  and N 2 . In this case, the NMOS transistor N 1  is connected between the node ND 1  and a data I/O terminal D, and receives the write enable signal WEN through its gate terminal. The NMOS transistor N 2  is connected between the node ND 2  and a data I/O terminal Db, and receives the write enable signal WEN through its gate terminal. 
     The non-volatile ferroelectric capacitor NSC includes a plurality of ferroelectric capacitors FC 1 ˜FC 4 . The non-volatile ferroelectric capacitors FC 1  and FC 2  are connected between an input terminal of the cell plate signal CPL and the nodes ND 1  and ND 2 , respectively. The non-volatile ferroelectric capacitors FC 3  and FC 4  are connected between the nodes ND 1  and ND 2  and a ground voltage terminal VSS, respectively. 
     The NMOS latch unit NL includes NMOS transistors N 3  and N 4 . In this case, the NMOS transistors N 3  and N 4  are connected between the pull-down unit PD and the nodes ND 1  and ND 2 , respectively, and the gate terminals of the NMOS transistors N 3  and N 4  are cross-coupled with nodes ND 2  and ND 1 , respectively. 
     The pull-down unit PD includes an NMOS transistor N 5 . The NMOS transistor N 5  is connected between the NMOS latch unit NL and the ground voltage terminal VSS, and receives the pull-down enable signal ENN through its gate terminal. 
       FIG. 5  is a timing diagram illustrating an operation of the non-volatile register R during a power-on operation. 
     Initially, if a power-on power-supply voltage reaches a power-supply voltage level VDD, the power-on reset signal POR goes low in level such that the RFID chip is reset. If the power-on reset signal POR is transitioned to the low voltage level, the cell plate signal CPL is transitioned to a high level. Therefore, charges stored in the non-volatile ferroelectric capacitors FC 1  and FC 2  generate a voltage difference between both nodes ND 1  and ND 2  of a cell due to the capacitance load of the non-volatile ferroelectric capacitors FC 3  and FC 4 . In this case, the write enable signal WEN preserves a low voltage level. 
     Thereafter, if a sufficient voltage difference occurs between both nodes ND 1  and ND 2 , the pull-up enable signal ENP is activated to a low level, such that the PMOS transistor PM 1  is turned on. In addition, the pull-down enable signal ENN is activated to a high level, such that the NMOS transistor N 5  is turned on. Therefore, data on both nodes ND 1  and ND 2  of the cell are driven to VDD or VSS by the PMOS latch unit PL and the NMOS latch unit NL. 
     Subsequently, if data amplification is completed, the cell plate signal CPL is re-transitioned to a low level, such that high level data of the non-volatile ferroelectric capacitor FC 1  or the non-volatile ferroelectric capacitor FC 2  is recovered. 
       FIG. 6  is a timing diagram illustrating an operation of the non-volatile register R during a program mode. 
     First, if the power-on reset signal POR preserves a low voltage level, the write enable signal WEN is transitioned to a high voltage level. Accordingly, the NMOS transistors N 1  and N 2  are turned on, and data D and Db are input to the nodes ND 1  and ND 2  of the cell, respectively. 
     At this moment, the cell plate signal CPL is transitioned to a high level. After a predetermined time, the pull-up enable signal ENP is transitioned to a low voltage level, and the pull-down enable signal ENN is transitioned to a high voltage level. Accordingly, the voltage levels of the nodes ND 1  and ND 2  are stored in a non-volatile way in the non-volatile ferroelectric capacitor NSC. 
       FIG. 7  is a flowchart illustrating an operation of the RFID device shown in  FIG. 2  according to an embodiment of the present invention. 
     Referring to  FIG. 7 , when the power-supply voltage VDD is input to the RFID device through the power-supply voltage applying pad P 1 , and the ground voltage GND is input to the RFID device through the ground voltage applying pad P 2 , the RFID device is powered on at step S 10 . As a result, values of the non-volatile registers R 1 ˜Rm are automatically recovered by the power-on reset signal POR at step S 11 . 
     Therefore, an output status of the DAC driver  230  is decided by initial values of the non-volatile registers R 1 ˜Rm. In other words, the levels of the output signals OUT 1 ˜OUTn are decided by the driving control signals b 1 ˜bm that are output from the DAC register unit  210 . The power on/off operation of the DAC driver  230  is controlled in response to the output of the power register  220 . 
     Thereafter, if a read command is input through the antenna unit ANT, the demodulator  110 , and the digital unit  140 , the RFID device outputs the ID code value stored in the memory unit  150 . In other words, the ID code value output from the memory unit  150  is transmitted to an external reader through the digital unit  140 , the modulator  100 , and the antenna unit ANT at step S 12 . If a plurality of RFID devices are present, an ID code of each RFID device is recognized, such that a control operation suitable for each recognized ID code can be carried out. 
     Subsequently, a DAC control command is input to the corresponding RFID device using a designated ID code at step S 13 . More specifically, the DAC control command is input to the DAC register unit  210  through the antenna unit ANT, the demodulator  110 , and the digital unit  140 . 
     If the DAC control command corresponds to a power control command, the power register  220  is activated by the operation signal ACT, such that a register value is established at step S 14 . The power register  220  outputs a power on/off signal ON/OFF to the DAC driver  230  in response to the power-on reset signal POR and the operation signal ACT. 
     Thereafter, it is determined whether the DAC control command received through the digital unit  140  is a read command or a program command for controlling the DAC register unit  210  at step S 15 . 
     If the DAC control command is the read command (corresponding to a read mode of the DAC register unit  210 ), the data stored in the DAC register unit  210  is read out at step S 16 . In other words, data corresponding to the driving control signals b 1 ˜bm stored in the DAC register unit  210  are output. The data output from the DAC register unit  210  are transmitted to the external reader through the digital unit  140 , the modulator  100 , and the antenna unit ANT. 
     In contrast, if the DAC control command is the program command corresponding to a program mode of the DAC register unit  210 , new data is programmed in the DAC register unit  210  in response to the control signals WE, OE and CE at step S 17 . Accordingly, the new data is written in the DAC register unit  210 , such that the driving control signals b 1 ˜bm are changed. 
     After that, the DAC register unit  210  outputs a plurality of driving control signals b 1 ˜bm corresponding to the programmed data to the DAC driver  230 . The DAC driver  230  outputs driving signals, i.e., the output signals OUT 1 ˜OUTn, through the output pads OP 1 ˜OPn, respectively. 
       FIG. 8  is a structural view illustrating an RFID system including the RFID device shown in  FIG. 2  according to an embodiment of the present invention. 
     Referring to  FIG. 8 , the antenna unit ANT is connected to the RFID device through the antenna pads PAD(+) and PAD(−). In other words, the antenna unit ANT is connected to input pins of the RFID device. In addition, the RFID device is connected to an external driving device through the connection pins PIN. 
     In other words, the output signals OUT 1 ˜OUTn output from the output pads OP 1 ˜OPn of the DAC driver  230  are connected to the driving device through the connection pins PIN. Therefore, the output pads OP 1 ˜OPn may correspond to a connecting unit for connecting the RFID device to the driving device. In this case, the driving device may correspond to a driving control device for controlling a light emitting diode (LED), a motor, a speaker, and the like. 
     In addition, the RFID system according to an embodiment of the present invention includes an electrostatic discharge (ESD) circuit. The ESD circuit is contained in the RFID device and is connected to the driving device through the output pads OP 1 ˜OPn and the connection pins PIN. 
       FIG. 9  is a block diagram illustrating an RFID device according to a second embodiment of the present invention 
     Referring to  FIG. 9 , the RFID device includes a modulator  100 - 1 , a demodulator  110 - 1 , a power-on reset unit  120 - 1 , a clock generator  130 - 1 , a digital unit  140 - 1 , a memory unit  150 - 1 , a driving unit  200 - 1 , a sensor control block  300 , a power-supply voltage applying pad P 1 , a ground voltage applying pad P 2 , and a plurality of output pads OP 1 ˜OPn. 
     The driving unit  200 - 1  includes a DAC register unit  210 - 1 , a power register  220 - 1 , and a DAC driver  230 - 1 . The sensor control block  300  includes a sensing controller  310 , a sensing unit  320 , a sensing signal processor  330 , and an analog digital converter (ADC)  340 . 
     An antenna unit ANT may be used for data communication between an RFID tag, i.e., the RFID device, and an external reader or writer. The antenna unit ANT is coupled to the RFID tag through antenna pads PAD(+) and PAD(−). In this case, an RF signal may be used for RF communication between the RFID device and the external reader or writer. 
     The modulator  100 - 1  modulates a response signal RP received from the digital unit  140 - 1 , and outputs the modulated response signal to the antenna unit ANT. The demodulator  110 - 1  detects an operation command signal from the RF signal received through the antenna unit ANT, and outputs a command signal CMD to the digital unit  140 - 1 . 
     The power-on reset unit  120 - 1  detects a power-supply voltage VDD received through the power-supply voltage applying pad P 1 , and outputs a power-on reset signal POR for controlling a reset operation to the digital unit  140 - 1 . The power-on reset signal POR output from the power-on reset unit  120 - 1  is input to the DAC register unit  210 - 1  and the power register  220 - 1 . The clock generator  130 - 1  outputs a clock signal CLK to the digital unit  140 - 1 . The clock signal CLK controls the digital unit  140 - 1  in response to the power-supply voltage VDD received from the power-supply voltage applying pad P 1 . 
     The digital unit  140 - 1  interprets the command signal CMD according to the power-supply voltage VDD from the power-supply voltage applying pad P 1 , a ground voltage GND from the ground voltage applying pad P 2 , the power-on reset signal POR, and the clock signal CLK. The digital unit  140 - 1  generates control signals and processing signals, such that it outputs the response signal RP to the modulator  100 - 1 . Further, the digital unit  140 - 1  outputs an address ADD, input/output (I/O) data, a control signal CTR, and the clock signal CLK to the memory unit  150 - 1 . 
     The digital unit  140 - 1  outputs I/O data I/O (using m lines (×m)), a write enable signal WE, an output enable signal OE, and a chip enable signal CE to the DAC register unit  210 - 1 , and outputs an operation signal ACT to the power register  220 - 1 . In other words, operation signals received from the external reader pass through the antenna unit ANT, the demodulator  110 - 1 , and the digital unit  140 - 1 , and are input to the DAC register unit  210 - 1  as the write enable signal WE, the output enable signal OE, and the chip enable signal CE. 
     The memory unit  150 - 1  includes a plurality of memory cells, and stores data related to an ID code of each RFID device. Each memory cell writes data in a storage element, and reads data from the storage element. 
     The memory unit  150 - 1  includes a non-volatile memory area. Generally, an FeRAM may be used as the non-volatile memory area. The FeRAM has a data processing speed similar to that of DRAM. The FeRAM has a similar structure to that of DRAM, and uses a ferroelectric material as a capacitor. The ferroelectric material has high remnant polarization characteristics, such that data is not lost although an electric field is removed. 
     In this case, the modulator  100 - 1 , the demodulator  110 - 1 , the power-on reset unit  120 - 1 , the clock generator  130 - 1 , the digital unit  140 - 1 , the memory unit  150 - 1 , and the driving unit  200 - 1  are driven by the power-supply voltage VDD from the power-supply voltage applying pad P 1  and the ground voltage GND from the ground voltage applying pad P 2 . 
     In a conventional RFID device, when the RFID device receives the RF signal through communication with the external reader, the power-supply voltage VDD is supplied through a voltage amplification unit provided inside the RFID device. However, in this embodiment, since a large amount of power is consumed by the driving unit  200 - 1  and the sensor control block  300 , the power-supply voltage VDD and the ground voltage GND are provided to the RFID device through the power-supply voltage applying pad P 1  and the ground voltage applying pad P 2 . 
     The DAC register unit  210 - 1  outputs driving control signals b 1 ˜bm to the DAC driver  230 - 1 . In this embodiment, the DAC register unit  210 - 1  includes a non-volatile register. The power register  220 - 1  outputs a power on/off signal ON/OFF to the DAC driver  230 - 1  in response to the operation signal ACT and the power-on reset signal POR. The DAC driver  230 - 1  outputs output signals OUT 1 ˜OUTn through the output pads OP 1 ˜OPn, respectively. 
     An initial setup value (also called ‘initial set value’) of the DAC register unit  210 - 1  is established by the RF signal received from the antenna unit ANT. Therefore, if a power source of the RFID device is controlled, or if data stored in the DAC register unit  210 - 1  is read out, the RF signal received from the antenna unit ANT may be used to change the initial setup value. 
     The sensing controller  310  controls operation of the digital unit  140 - 1 , the sensing signal processor  330 , and the ADC  340 . The sensing unit  320  includes a variety of sensing elements for detecting various sensing parameters such as temperature, pressure, acceleration, gas, light, and the like. For example, the sensing unit  320  detects the sensing parameters such as temperature, pressure, acceleration, gas, light, etc., as voltage values, converts the detected voltage values into current values, and outputs the current values as a sensing signal. In this embodiment, the sensing element may include a complementary metal-oxide-semiconductor (CMOS) image sensor, a pixel element, a diode element, a resistor element, etc. Therefore, if the sensing parameter is the temperature, a current value corresponding to the detected temperature is output as the sensing signal. 
     The sensing signal processor  330  compensates for an offset of the sensing signal received from the sensing unit  320 , and amplifies the compensated sensing signal. 
     The ADC  340  converts the sensing signal acting as an analog signal received from the sensing signal processor  330  into digital code data in response to a control signal from the sensing controller  310 . The digital code data output from the ADC  340  is transmitted to an I/O data bus, such that it may be input to the digital unit  140 - 1  or the DAC register unit  210 - 1  through the I/O data bus. 
     In this embodiment, the control signals WE, OE and CE may determine whether the digital code data applied to the I/O data bus is to be input to the digital unit  140  or the DAC register unit  210 - 1 . 
     In other words, the external reader may sometimes recognize sensing data of the sensing unit  320 . In this case, in order to transmit the sensing signal of the sensing unit  320  to the external reader, the sensing signal is transmitted to the digital unit  140 - 1  through the sensing signal processor  330 , the ADC  340  and the I/O data bus. Thereafter, the sensing signal is transmitted to the external reader through the demodulator  110 - 1  and the antenna unit ANT. 
     In contrast, in order to program new data into the register by outputting the sensing signal of the sensing unit  320  to the DAC register unit  210 - 1 . The sensing signal is transmitted to the DAC register unit  210 - 1  through the sensing signal processor  330 , the ADC  340 , and the I/O data bus. 
     The DAC register unit  210 - 1  includes an internal register to store the digital code data transmitted from the ADC  340 . In addition, the DAC register unit  210 - 1  compares set data preset by the RF signal with data stored in the internal register and outputs the driving control signals b 1 ˜bm according to the result of the comparison. 
       FIG. 10  is a block diagram illustrating an RFID device according to a third embodiment of the present invention. 
     Referring to  FIG. 10 , the RFID device includes a modulator  100 - 2 , a demodulator  110 - 2 , a power-on reset unit  120 - 2 , a clock generator  130 - 2 , a digital unit  140 - 2 , a memory unit  150 - 2 , a driving unit  200 - 2 , a sensor interface unit  400 , a power-supply voltage applying pad P 1 , a ground voltage applying pad P 2 , a plurality of output pads OP 1 ˜OPn, and a plurality of sensing pads SP 1 ˜SP 3 . 
     In this embodiment, the driving unit  200 - 2  includes a DAC register unit  210 - 2 , a power register  220 - 2 , and a DAC driver  230 - 2 . The sensor interface unit  400  includes a sensing controller  410  and a serial interface port  420 . In accordance with this embodiment of the present invention, an external sensor is located outside the RFID device. The sensor interface unit  400  receives a sensing signal from the external sensor through the sensing pads SP 1 ˜SP 3  to program the DAC register unit  210 - 2  using the received sensing signal. 
     An antenna unit ANT may be used for data communication between the RFID device and an external reader or writer. The antenna unit ANT is coupled to the RFID device through antenna pads PAD(+) and PAD(−). In this case, an RF signal may be used for the RF communication between the RFID device and the external reader or writer. 
     The modulator  100 - 2  modulates a response signal RP received from the digital unit  140 - 2 , and outputs the modulated response signal to the antenna unit ANT. The demodulator  110 - 2  detects an operation command signal from the RF signal received through the antenna unit ANT, and outputs a command signal CMD to the digital unit  140 - 2 . 
     The power-on reset unit  120 - 2  detects a power-supply voltage VDD received from the power-supply voltage applying pad P 1 , and outputs a power-on reset signal POR (for controlling a reset operation) to the digital unit  140 - 2 . The power-on reset signal POR output from the power-on reset unit  120 - 2  is input to the DAC register unit  210 - 2  and a power register  220 - 2 . The clock generator  130 - 2  outputs a clock signal CLK to the digital unit  140 - 2 . The clock signal CLK controls the digital unit  140 - 2  in response to the power-supply voltage VDD received from the power-supply voltage applying pad P 1 . 
     The digital unit  140 - 2  interprets the command signal CMD based on the power-supply voltage VDD from the power-supply voltage applying pad P 1 , a ground voltage GND from the ground voltage applying pad P 2 , the power-on reset signal POR, and the clock signal CLK. The digital unit  140 - 2  generates control signals and processing signals, such that it outputs the response signal RP to the modulator  100 - 2 . Furthermore, the digital unit  140 - 2  outputs an address ADD, I/O data, a control signal CTR, and the clock signal CLK to the memory unit  150 - 2 . 
     The digital unit  140 - 2  outputs I/O data I/O (using m lines (×m)), a write enable signal WE, an output enable signal OE, and a chip enable signal CE to the DAC register unit  210 - 2 , and outputs an operation signal ACT to the power register  220 - 2 . In other words, operation signals received from the external reader pass through the antenna unit ANT, the demodulator  110 - 2 , and the digital unit  140 - 2 , and are input to the DAC register unit  210 - 2  as the write enable signal WE, the output enable signal OE, and the chip enable signal CE. 
     The memory unit  150 - 2  includes a plurality of memory cells, and stores data related to an ID code of each RFID device. Each memory cell writes data in a storage element, and reads data from the storage element. 
     The memory unit  150 - 2  includes a non-volatile memory area. Generally, an FeRAM may be used as the non-volatile memory area. The FeRAM has a data processing speed similar to that of DRAM. The FeRAM has a similar structure to that of DRAM, and uses a ferroelectric material as a capacitor. The ferroelectric material has high remnant polarization characteristics, such that data is not lost although an electric field is removed. 
     In this case, the modulator  100 - 2 , the demodulator  110 - 2 , the power-on reset unit  120 - 2 , the clock generator  130 - 2 , the digital unit  140 - 2 , the memory unit  150 - 2 , and the driving unit  200 - 2  are driven by the power-supply voltage VDD from the power-supply voltage applying pad P 1  and the ground voltage GND from the ground voltage applying pad P 2 . 
     In a conventional RFID device, when the RFID device receives the RF signal through communication with the external reader, the power-supply voltage VDD is supplied through a voltage amplification unit provided inside the RFID device. However, in this embodiment, since a large amount of power is consumed by the driving unit  200 - 2  and the sensor interface unit  400 , the power-supply voltage VDD and the ground voltage GND are provided to the RFID device through the power-supply voltage applying pad P 1  and the ground voltage applying pad P 2 . 
     The DAC register unit  210 - 2  outputs driving control signals b 1 ˜bm to the DAC driver  230 - 2 . In this embodiment, the DAC register unit  210 - 2  includes a non-volatile register. The power register  220 - 2  outputs a power on/off signal ON/OFF to the DAC driver  230 - 2  in response to the operation signal ACT and the power-on reset signal POR. The DAC driver  230 - 2  outputs output signals OUT 1 ˜OUTn through the output pads OP 1 ˜OPn, respectively. 
     An initial setup value (also called ‘initial set value’) of the DAC register unit  210 - 2  is established by the RF signal received from the antenna unit ANT. Therefore, if a power source of the RFID device is controlled, or if data stored in the DAC register  210 - 2  is read out, the RF signal received from the antenna unit ANT may be used to change the initial setup value. 
     The sensing controller  410  controls operation of the digital unit  140 - 1  and the serial interface port  420 . The serial interface port  420  may include an inter-integrated circuit (I2C) port. The serial interface port  420  controls sensing data received from the external sensor to perform a serial interface between the RFID device and the external sensor. The RFID device includes the sensing pads SP 1 ˜SP 3  to perform an interfacing operation with the external sensor. The serial interface port  420  receives a clock signal SCL through the sensing pad SP 1 , data SDA through the sensing pad SP 2 , and an interrupt signal /INT through the sensing pad SP 3 . 
     In this case, the clock signal SCL may be indicative of a serial clock signal used by the I2C port, and the data SDA may be indicative of a serial data open drain used by the I2C port. The interrupt signal /INT may represent an interrupt and data ready signal. 
     The external sensor located outside the RFID device may include a variety of sensing elements for detecting various sensing parameters such as temperature, pressure, acceleration, gas, light, and the like. For example, the external sensor may detect the sensing parameters such as temperature, pressure, acceleration, gas, light, etc., as voltage values, converts the detected voltage values into current values, and outputs the current values as the sensing signal. In this embodiment, the sensing element may include a CMOS image sensor, a pixel element, a diode element, a resistor element, etc. Therefore, if the sensing parameter is the temperature, a current value corresponding to the detected temperature is output as the sensing signal. 
     The sensing signal received through the sensing pads SP 1 ˜SP 3  is applied to the serial interface port  420 . The sensing signal is then applied to the digital unit  140 - 2  through the sensing controller  410 . The digital unit  140 - 2  compensates for an offset of the sensing signal received from the sensing controller  410 , and amplifies the compensated signal. The digital unit  140 - 2  converts the sensing signal, which is transmitted in the form of an analog signal from the sensing controller  410 , into digital code data. The digital code data output from the digital unit  140 - 2  is transmitted to the DAC register unit  210 - 2  through an I/O data bus. 
     In the meantime, the external reader may sometimes recognize a register value of the DAC register unit  210 - 2 . In this case, in order to transmit the register value stored in the DAC register unit  210 - 2  to the external reader, the stored register value is transmitted to the external reader through the digital unit  140 - 2 , the demodulator  110 - 2 , and the antenna unit ANT. 
     In contrast, in order to program new data in the DAC register unit  210 - 2  by using the sensing signal from the external sensor, the sensing signal received through the sensing pads SP 1 ˜SP 3  are transmitted to the serial interface port  420 . Then, the digital code data is input to the DAC register unit  210 - 2  through the sensing controller  410 , the digital unit  140 - 2 , and the I/O data bus. 
     The DAC register unit  210 - 2  includes an internal register to store the digital code data transmitted from the digital unit  140 - 2 . In addition, the DAC register unit  210 - 2  compares set data preset by the RF signal with data stored in the internal register and outputs the driving control signals b 1 ˜bm according to the result of the comparison. 
       FIG. 11  is a flowchart illustrating an operation of the RFID device shown in  FIG. 10  according to an embodiment of the present invention. 
     Referring to  FIG. 11 , when the RFID device receives the power-supply voltage VDD from the power-supply voltage applying pad P 1  and the ground voltage GND from the ground voltage applying pad P 2 , the RFID device is powered on at step S 20 . As a result, a value of the DAC register unit  210 - 2  is automatically recovered by the power-on reset signal POR at step S 21 . Accordingly, if a sensing control mode is automatically activated, a control signal corresponding to the sensing signal is automatically generated at step S 22 . 
     By the initial setup value of the DAC register unit  210 - 2  that is recovered, the output state data of the DAC driver  230 - 2  is decided. That is, levels of the output signals OUT 1 ˜OUTn are decided by the driving control signals b 1 ˜bm output from the DAC register unit  210 - 2 . In addition, a power state of the DAC driver  230 - 2  is controlled by a state of the power register  220 - 2 . 
     Thereafter, if the sensing signal of the external sensor is changed, a new update event is generated at step S 23 . In this case, the sensing signal received through the sensing pads SP 1 ˜SP 3  is input to the DAC register unit  210 - 2  through the serial interface port  420 , the sensing controller  410 , and the digital unit  140 - 2 . 
     Therefore, a program mode of the DAC register unit  210 - 2  is activated, such that new data is programmed in the DAC register unit  210 - 2  in response to the control signals WE, OE and CE received from the digital unit  140 - 2  at step S 24 . Thus, the new data is stored in the DAC register unit  210 - 2 , such that several of the driving control signals b 1 ˜bm are changed to have different values. 
     Thereafter, the DAC register unit  210 - 2  outputs the driving control signals b 1 ˜bm corresponding to the programmed data to the DAC driver  230 - 2 . Therefore, the DAC driver  230 - 2  outputs the output signals OUT 1 ˜OUTn through the output pads OP 1 ˜OPn, respectively. 
       FIG. 12  is a structural view illustrating an RFID system including the external sensor SEN and the RFID device shown in  FIG. 10 . 
     Referring to  FIG. 12 , the antenna unit ANT is connected to the RFID device through the antenna pads PAD(+) and PAD(−). In other words, the antenna unit ANT is connected to the input pins of the RFID device. In addition, the RFID device is connected to the driving device through the connection pins PIN. 
     In other words, the output signals OUT 1 ˜OUTn transmitted from the output pads OPn˜OPn of the DAC driver  230 - 2  are input to the driving device through the connection pins PIN. In this case, the driving device may correspond to a driving control device for controlling an LED, a motor, a speaker, and the like. 
     In addition, the RFID system according to an embodiment of the present invention includes an ESD circuit. The ESD circuit is contained in the RFID device, and connected to the driving device through the output pads OP 1 ˜OPn and the connection pins PIN. 
     The sensor SEN may be coupled to the RFID device through a serial interface bus (SIB) outside the RFID device. The sensing signal of the sensor SEN may be input to the RFID device through the sensing pads SP 1 ˜SP 3  of the RFID device. 
     The RFID system includes a function of the RFID device for recognizing the ID code and a function of a ubiquitous sensor network (USN) based on the sensor, such that it can control operation of the driving device. Therefore, a user can remotely control the driving device using the RFID device including either the internal sensor or the external sensor. 
     In this embodiment of the present invention, for convenience of description and better understanding of the present invention, the structure including the modulator  100 - 2 , the demodulator  110 - 2 , the power-on reset unit  120 - 2 , the clock generator  130 - 2 , the digital unit  140 - 2 , the memory unit  150 - 2 , the driving unit  200 - 2 , and the sensor interface unit  400  is referred to as the RFID device. If the external sensor SEN is further added to the above-mentioned structure, the structure including the external sensor SEN is referred to as the RFID system. 
       FIG. 13  is a block diagram illustrating an RFID device according to a fourth embodiment of the present invention. 
     Referring to  FIG. 13 , the RFID device includes a modulator  100 - 3 , a demodulator  110 - 3 , a power-on reset unit  120 - 3 , a clock generator  130 - 3 , a digital unit  140 - 3 , a memory unit  150 - 3 , a driving unit  200 - 3 , a micro controller unit (MCU) control block  500 , a power-supply voltage applying pad P 1 , a ground voltage applying pad P 2 , and a plurality of output pads OP 1 ˜OPn. 
     The driving unit  200 - 3  includes a DAC register unit  210 - 3 , a power register  220 - 3 , and a DAC driver  230 - 3 . The MCU control block  500  includes an interface unit  510  and an MCU processor  520 . In accordance with this embodiment of the present invention, the MCU control block  500  is located inside the RFID device. 
     An antenna unit ANT may be used for data communication between an RFID tag, i.e., the RFID device, and an external reader or writer. The antenna unit ANT is coupled to the RFID tag through antenna pads PAD(+) and PAD(−). In this case, an RF signal may be used for the RF communication between the RFID device and the external reader or writer. 
     The modulator  100 - 3  modulates a response signal RP received from the digital unit  140 - 3 , and outputs the modulated response signal to the antenna unit ANT. The demodulator  110 - 3  detects an operation command signal from the RF signal received through the antenna unit ANT, and outputs a command signal CMD to the digital unit  140 - 3 . 
     The power-on reset unit  120 - 3  detects a power-supply voltage VDD received through the power-supply voltage applying pad P 1 , and outputs a power-on reset signal POR for controlling a reset operation to the digital unit  140 - 3 . The power-on reset signal POR output from the power-on reset unit  120 - 3  is input to the DAC register unit  210 - 3  and the power register  220 - 3 . The clock generator  130 - 3  outputs a clock signal CLK to the digital unit  140 - 3 . The clock signal CLK controls the digital unit  140 - 3  in response to the power-supply voltage VDD received from the power-supply voltage applying pad P 1 . 
     The digital unit  140 - 3  interprets the command signal CMD based on the power-supply voltage VDD from the power-supply voltage applying pad P 1 , a ground voltage GND from the ground voltage applying pad P 2 , and the power-on reset signal POR, and the clock signal CLK. The digital unit  140 - 3  generates control signals and processing signals, such that it outputs the response signal RP to the modulator  100 - 3 . The digital unit  140 - 3  outputs an address ADD, I/O data, a control signal CTR, and the clock signal CLK to the memory unit  150 - 3 . 
     The digital unit  140 - 3  outputs I/O data I/O (using m lines (×m)), a write enable signal WE, an output enable signal OE, and a chip enable signal CE to the DAC register unit  210 - 3 , and outputs an operation signal ACT to the power register  220 - 3 . In other words, operation signals received from the external reader pass through the antenna unit ANT, the demodulator  110 - 3 , and the digital unit  140 - 3 , and are input to the DAC register unit  210 - 3  as the write enable signal WE, the output enable signal OE, and the chip enable signal CE. 
     The memory unit  150 - 3  includes a plurality of memory cells, and stores data related to an ID code of each RFID device. Each memory cell writes data in a storage element, and reads data from the storage element. 
     The memory unit  150 - 3  includes a non-volatile memory area. Generally, an FeRAM may be used as the non-volatile memory area. The FeRAM has a data processing speed similar to that of DRAM. The FeRAM has a similar structure to that of DRAM, and uses a ferroelectric material as a capacitor. The ferroelectric material has high remnant polarization characteristics, such that data is not lost although an electric field is removed. 
     In this case, the modulator  100 - 3 , the demodulator  110 - 3 , the power-on reset unit  120 - 3 , the clock generator  130 - 3 , the digital unit  140 - 3 , the memory unit  150 - 3 , and the driving unit  200 - 3  are driven by the power-supply voltage VDD from the power-supply voltage applying pad P 1  and the ground voltage GND from the ground voltage applying pad P 2 . 
     In a conventional RFID device, when the RFID device receives the RF signal through communication with the external reader, the power-supply voltage VDD is supplied through a voltage amplification unit provided inside the RFID device. However, in this embodiment, since a large amount of power is consumed by the driving unit  200 - 3  and the MCU control block  500 , the power-supply voltage VDD and the ground voltage GND are provided to the RFID device through the power-supply voltage applying pad P 1  and the ground voltage applying pad P 2 . 
     The DAC register unit  210 - 3  outputs driving control signals b 1 ˜bm to the DAC driver  230 - 3 . In this embodiment, the DAC register unit  210 - 3  includes a non-volatile register. The power register  220 - 3  outputs a power on/off signal ON/OFF to the DAC driver  230 - 3  in response to the operation signal ACT and the power-on reset signal POR. The DAC driver  230 - 3  outputs output signals OUT 1 ˜OUTn through the output pads OP 1 ˜OPn, respectively. 
     An initial setup value (also called ‘initial set value’) of the DAC register unit  210 - 3  is established by the RF signal received from the antenna unit ANT. Therefore, if a power source of the RFID device is controlled, or if data stored in the DAC register unit  210 - 3  is read out, the RF signal received from the antenna unit ANT may be used to change the initial setup value. 
     The interface unit  510  controls the digital unit  140 - 3  and the MCU processor  520 . In order to program new data in the DAC register unit  210 - 3  by outputting data programmed by the MCU processor  520  to the DAC register unit  210 - 3 , the programmed data is transmitted to the DAC register  210 - 3  through the interface unit  510 , the digital unit  140 - 3  and the I/O data bus. 
     The DAC register unit  210 - 3  includes an internal register to store data transmitted from the digital unit  140 - 3 . The DAC register unit  210 - 3  compares set data preset by the RF signal with data stored in the internal register and outputs the driving control signals b 1 ˜bm according to the result of the comparison. 
     The MCU processor  520  uses a part of the memory unit  150 - 3  for code data and working data memory. Therefore, it is possible to change the driving control signals b 1 ˜bm of the DAC register  210 - 3  by changing an internal program of the MCU processor  520 . The interface unit  510  may control the digital unit  140 - 3  and the MCU processor  520 . 
       FIG. 14  is a block diagram illustrating an RFID device according to a fifth embodiment of the present invention. 
     Referring to  FIG. 14 , the RFID device includes a modulator  100 - 4 , a demodulator  110 - 4 , a power-on reset unit  120 - 4 , a clock generator  130 - 4 , a digital unit  140 - 4 , a memory unit  150 - 4 , a driving unit  200 - 4 , a serial interface controller  600 , a power-supply voltage applying pad P 1 , a ground voltage applying pad P 2 , a plurality of output pads OP 1 ˜OPn, and a plurality of pads SP 4 ˜SP 6 . 
     The driving unit  200 - 4  includes a DAC register unit  210 - 4 , a power register  220 - 4 , and a DAC driver  230 - 4 . The serial interface controller  600  may include a serial interface unit  610  and a serial interface port  620 . In accordance with this embodiment of the present invention, an MCU processor is located outside the RFID device, and the serial interface controller  600  receives a serial interface signal through the pads SP 4 ˜SP 6  to program the DAC register unit  210 - 4  using the received interface signal. 
     An antenna unit ANT may be used for data communication between an RFID tag, i.e., the RFID device, and an external reader or writer. The antenna unit ANT is coupled to the RFID tag through antenna pads PAD(+) and PAD(−). In this case, an RF signal may be used for the RF communication between the RFID device and the external reader or writer. 
     The modulator  100 - 4  modulates a response signal RP received from the digital unit  140 - 4 , and outputs the modulated response signal to the antenna unit ANT. The demodulator  110 - 4  detects an operation command signal from the RF signal received through the antenna unit ANT, and outputs a command signal CMD to the digital unit  140 - 4 . 
     The power-on reset unit  120 - 4  detects a power-supply voltage VDD received through the power-supply voltage applying pad P 1 , and outputs a power-on reset signal POR for controlling a reset operation to the digital unit  140 - 4 . The power-on reset signal POR output from the power-on reset unit  120 - 4  is input to the DAC register unit  210 - 4  and the power register  220 - 4 . The clock generator  130 - 4  outputs a clock signal CLK to the digital unit  140 - 4 . The clock signal CLK controls the digital unit  140 - 4  in response to the power-supply voltage VDD received from the power-supply voltage applying pad P 1 . 
     The digital unit  140 - 4  interprets the command signal CMD based on the power-supply voltage VDD from the power-supply voltage applying pad P 1 , a ground voltage GND from a ground voltage applying pad P 2 , the power-on reset signal POR, and the clock signal CLK. The digital unit  140 - 4  generates control signals and processing signals, such that it outputs the response signal RP to the modulator  100 - 4 . Further, the digital unit  140 - 4  outputs an address ADD, I/O data, a control signal CTR, and the clock signal CLK to the memory unit  150 - 4 . 
     The digital unit  140 - 4  outputs I/O data I/O (using m lines (×m)), a write enable signal WE, an output enable signal OE, and a chip enable signal CE to the DAC register unit  210 - 4 , and outputs an operation signal ACT to the power register  220 - 4 . In other words, operation signals received from the external reader pass through the antenna unit ANT, the demodulator  110 - 4 , and the digital unit  140 - 4 , and are input to the DAC register unit  210 - 4  as the write enable signal WE, the output enable signal OE, and the chip enable signal CE. 
     The memory unit  150 - 4  includes a plurality of memory cells, and stores data related to an ID code of each RFID device. Each memory cell writes data in a storage element, and reads data from the storage element. 
     The memory unit  150 - 4  includes a non-volatile memory area. Generally, an FeRAM may be used as the non-volatile memory area. The FeRAM has a data processing speed similar to that of DRAM. The FeRAM has a similar structure to that of DRAM, and uses a ferroelectric material as a capacitor. The ferroelectric material has high remnant polarization characteristics, such that data is not lost although an electric field is removed. 
     In this case, the modulator  100 - 4 , the demodulator  110 - 4 , the power-on reset unit  120 - 4 , the clock generator  130 - 4 , the digital unit  140 - 4 , the memory unit  150 - 4 , and the driving unit  200 - 4  are driven by the power-supply voltage VDD from the power-supply voltage applying pad P 1  and the ground voltage GND from the ground voltage applying pad P 2 . 
     In a conventional RFID device, when the RFID device receives the RF signal through communication with the external reader, the power-supply voltage VDD is supplied through a voltage amplification unit provided inside the RFID device. However, in this embodiment, since a large amount of power is consumed by the driving unit  200 - 4  and the serial interface controller  600 , the power-supply voltage VDD and the ground voltage GND are provided to the RFID device through the power-supply voltage applying pad P 1  and the ground voltage applying pad P 2 . 
     The DAC register unit  210 - 4  outputs driving control signals b 1 ˜bm to the DAC driver  230 - 4 . In this embodiment, the DAC register unit  210 - 4  includes a non-volatile register. Therefore, new program data applied to the DAC register unit  210 - 4  is stored in the register. 
     The power register  220 - 4  outputs a power on/off signal ON/OFF to the DAC driver  230 - 4  in response to the operation signal ACT and the power-on reset signal POR. For example, if a driving object to be controlled by the driving device is an LED, data stored in the power register  220 - 4  may establish when the LED will be turned on or off after a command signal has been input to the power register  220 - 4 . The DAC driver  230 - 4  outputs output signals OUT 1 ˜OUTn through the output pads OP 1 ˜OPn, respectively. 
     An initial setup value (also called ‘initial set value’) of the DAC register unit  210 - 4  is established by the RF signal received from the antenna unit ANT. Therefore, if a power source of the RFID device is controlled, or if data stored in the DAC register unit  210 - 4  is read out, the RF signal received from the antenna unit ANT may be used to change the initial setup value. 
     The serial interface unit  610  controls operation of the digital unit  140 - 4  and the serial interface port  620 . The serial interface port  620  may include an I2C port. The serial interface port  620  controls serial data received from the external MCU processor to perform a serial interface between the RFID device and the external MCU processor. The RFID device includes the pads SP 4 ˜SP 6  to perform an interfacing operation with the external MCU processor. The serial interface port  620  receives a clock signal SCL through the pad SP 4 , data SDA through the pad SP 5 , and an interrupt signal /INT through the pad SP 6 . 
     In this embodiment, the clock signal SCL may be indicative of a serial clock signal used by the I2C port, and the data SDA may be indicative of a serial data open drain used by the I2C port. The interrupt signal /INT may represent an interrupt and data ready signal. 
     The MCU processor located outside the RFID device generates a signal to drive the DAC register unit  210 - 4  through its internal program operation. For this purpose, the external MCU processor outputs a programmed code as the serial interface signal to the pads SP 4 ˜SP 6 . 
     The programmed code received through the pads SP 4 ˜SP 6  is input to the serial interface port  620 , and then input to the digital unit  140 - 4  through the serial interface unit  610 . The programmed code from the serial interface unit  610  is transmitted to the DAC register unit  210 - 4  through the I/O data bus. 
     In the meantime, the external reader may sometimes recognize a register value of the DAC register unit  210 - 4 . In this case, in order to transmit the register value stored in the DAC register unit  210 - 4  to the external reader, the stored register value is transmitted to the external reader through the digital unit  140 - 4 , the demodulator  110 - 4 , and the antenna unit ANT. 
     In contrast, in order to program new data in the DAC register unit  210 - 4  by using the programmed code transmitted from the external MCU processor, the programmed code received through the pads SP 4 ˜SP 6  is input to the serial interface port  620 . Then, the digital code data is input to the DAC register unit  210 - 4  through the serial interface unit  610 , the digital unit  140 - 4 , and the I/O data bus. 
     The DAC register unit  210 - 4  includes an internal register to store the digital code data received from the digital unit  140 - 4 . In addition, the DAC register unit  210 - 4  compares set data preset by the RF signal with data stored in the internal register and outputs the driving control signals b 1 ˜bm according to the result of the comparison. 
       FIG. 15  is a timing diagram illustrating a programming method for the memory unit  150 - 3  shown in  FIG. 13  according to an embodiment of the present invention. 
     Referring to  FIG. 15 , if the RFID device receives the RF signal from the antenna unit ANT, the command signal CMD and data DATA are transmitted to the memory unit  150 - 3  through the demodulator  110 - 3  and the digital unit  140 - 3  and programmed in the memory unit  150 - 3 . In other words, in an active area, information including an ID code of the RFID device is pre-programmed in the memory unit  150 - 3  based on the command signal CMD and the data DATA. 
       FIG. 16  is a timing diagram illustrating a method for driving the DAC register unit  210 - 3  according to an embodiment of the present invention. 
     Referring to  FIG. 16 , if a program command from the external MCU processor or the internal MCU processor is input to the digital unit  140 - 3 , the digital unit  140 - 3  activates the chip enable signal CE, the output enable signal OE, and the write enable signal WE, and outputs the activated signals CE, OE and WE. 
     The chip enable signal CE, the output enable signal OE and the write enable signal WE are input to the DAC register unit  210 - 3  through the I/O data bus, such that the register value is programmed in the DAC register unit  210 - 3 . In this case, the operation signal ACT is activated such that the power register  220 - 3  maintains an activation status. As a result, the DAC driver  230 - 3  starts its operation. 
       FIG. 17  is a timing diagram illustrating a method for controlling the driving of the RFID device according to an embodiment of the present invention. 
     Referring to  FIG. 17 , if the RF signal from the antenna unit ANT is input to the RFID device, and the command signal CMD passes through the demodulator  110 - 3  and the digital unit  140 - 3 , the operation signal ACT is activated and programmed in the power register  220 - 3 . Meanwhile, if the program command from the external MCU processor or the internal MCU processor is input to the digital unit  140 - 3 , the operation signal ACT is activated. In other words, the operation signal ACT for controlling the power source may be activated by the RF signal received through the antenna unit ANT or the program command from the MCU processor. 
       FIG. 18  is a structural view illustrating an RFID system including an external MCU processor  630  according to an embodiment of the present invention. 
     Referring to  FIG. 18 , the antenna unit ANT may be coupled to the RFID device through the antenna pads PAD(+) and PAD(−). In other words, the antenna unit ANT may be coupled to the input pins PIN of the RFID device. The RFID device may be coupled to the driving device through the connection pins PIN. 
     In other words, the output signals OUT 1 ˜OUTn output through the output pads OP 1 ˜OPn of the DAC driver  230 - 4  are coupled to the driving device through the connection pins PIN. In this case, the driving device may correspond to a driving control device for controlling operations of an LED, a motor, a speaker, etc. 
     In addition, the RFID device according to the embodiment of the present invention includes an ESD circuit. The ESD circuit is located in the RFID device, and connected to the driving device through the output pads OP 1 ˜OPn and the connection pins PIN. 
     The MCU processor  630  may be coupled to the RFID device through a serial interface bus SIB at the outside of the RFID device. The program information of the MCU processor  630  is input to the RFID device through the pads SP 4 ˜SP 6  of the RFID device. 
     In accordance with the RFID system of the present invention, a plurality of application devices are arranged in rows and columns. One external MCU processor  630  may be coupled to a plurality of RFID devices through the serial interface bus SIB as shown in  FIG. 18 . 
     Resistors R 1  and R 2  are coupled to a clock (SCL) applying bus and a data (SDA) applying bus. In this case, the resistors R 1  and R 2  pull the serial interface bus SIB up, such that each of the resistors R 1  and R 2  may be used as a pull-up load for establishing a default value having a high level. 
     Generally, the RFID device is characterized as having a small power consumption, a short recognition length, and a rapid recognition speed. In contrast, ZigBee, wireless fidelity (Wi-Fi), and the like serving as a near field communication (NFC) unit among wireless communication protocols are generally applied to a home automations system. A chip size for ZigBee or Wi-Fi serving as the NFC unit is larger than that of the RFID device. For example, the chip size for ZigBee or Wi-Fi serving as the NFC unit may be about ten times larger than that of the RFID device. Therefore, the embodiment of the present invention can remotely control the driving device as well as store the ID code. In accordance with the above-mentioned embodiment of the present invention, the RFID system when used for a device capable of remotely controlling the driving device driving a driving object such as an LED, resulting in a reduction in costs of the remote control device. 
     In this embodiment of the present invention, for convenience of description and better understanding of the present invention, an entire structure including the modulator  100 - 4 , the demodulator  110 - 4 , the power-on reset unit  120 - 4 , the clock generator  130 - 4 , the digital unit  140 - 4 , the memory unit  150150 - 4 , the driving unit  200 - 4 , and the serial interface controller  600  is referred to as the RFID device. If the external MCU processor  630  is further added to the above-mentioned structure, a structure including the external MCU processor  630  is referred to as the RFID system. 
       FIG. 19  is a flowchart illustrating an operation of the RFID device shown in  FIG. 13  according to an embodiment of the present invention. 
     Referring to  FIG. 19 , when the power-supply voltage VDD is input to the RFID device through the power-supply voltage applying pad P 1 , and the ground voltage GND is input to the RFID device through the ground voltage applying pad P 2 , the RFID device is powered on at step S 30 . Thus, the register value of the DAC register unit  210 - 3  is automatically recovered by the power-on rest signal POR at step S 31 . 
     Thereafter, the RFID device receives an RFID check command through the antenna unit ANT, the demodulator  110 - 3 , and the digital unit  140 - 3  at step S 32 . When ID code data stored in the memory unit  150 - 3  is transmitted to the external reader through the digital unit  140 - 3 , the modulator  100 - 3 , and the antenna unit ANT, the external reader determines whether the transmitted ID code data is identical to ID code data corresponding to the RFID device that is pre-stored therein at step S 33 . If the pre-stored ID code data is identical to the transmitted ID code data, the RFID device is activated and an RFID control command is input to the RFID device through the antenna unit ANT at step S 34 . 
     Subsequently, if an MCU control mode is activated at step S 35 , the program mode of the DAC register unit  210 - 3  is activated and new data is programmed in the DAC register unit  210 - 3  in response to the control signals WE, OE and CE received from the digital unit  140 - 3  at step S 36 . As the new data is programmed in the DAC register unit  210 - 3 , the driving control signals b 1 ˜bm are changed. 
     Thereafter, the DAC register unit  210 - 3  outputs the driving control signals b 1 ˜bm corresponding to the programmed data to the DAC driver  230 - 3 . Thus, the DAC driver  230 - 3  outputs the output signals OUT 1 ˜OUTn through the output pads OP 1 ˜OPn, respectively. 
       FIG. 20  is a block diagram illustrating an RFID device according to a sixth embodiment of the present invention. 
     Referring to  FIG. 20 , the RFID device includes a modulator  100 - 5 , a demodulator  110 - 5 , a power-on reset unit  120 - 5 , a clock generator  130 - 5 , a digital unit  140 - 5 , a memory unit  150 - 5 , a driving unit  200 - 5 , a power-supply voltage applying pad P 1 , a ground voltage applying pad P 2 , a plurality of output pads OP 1 ˜OPn, and a fixed handle mode control unit  700 . 
     The driving unit  200 - 5  includes a DAC register unit  210 - 5 , a power register  220 - 5 , and a DAC driver  230 - 5 . The fixed handle mode control unit  700  may be contained in the digital unit  140 - 5 . 
     An antenna unit ANT may be used for data communication between an RFID tag, i.e., the RFID device, and an external reader or writer. The antenna unit ANT is coupled to the RFID tag through antenna pads PAD(+) and PAD(−). In this case, an RF signal may be used for the RF communication between the RFID device and the external reader or writer. 
     The modulator  100 - 5  modulates a response signal RP received from the digital unit  140 - 5 , and outputs the modulated response signal to the antenna unit ANT. The demodulator  110 - 5  detects an operation command signal from the RF signal received through the antenna unit ANT, and outputs a command signal CMD to the digital unit  140 - 5 . 
     The power-on reset unit  120 - 5  detects a power-supply voltage VDD received through the power-supply voltage applying pad P 1 , and outputs a power-on reset signal POR for controlling a reset operation to the digital unit  140 - 5 . The power-on reset signal POR output from the power-on reset unit  120 - 5  is input to the DAC register unit  210 - 5  and the power register  220 - 5 . The clock generator  130 - 5  outputs a clock signal CLK to the digital unit  140 - 5 . The signal CLK controls the digital unit  140 - 5  in response to the power-supply voltage VDD received from the power-supply voltage applying pad P 1 . 
     The digital unit  140 - 5  interprets the command signal CMD based on the power-supply voltage VDD from the power-supply voltage applying pad P 1 , a ground voltage GND from the ground voltage applying pad P 2 , and the power-on reset signal POR, and the clock signal CLK. The digital unit  140 - 5  generates control signals and processing signals, such that it outputs the response signal RP to the modulator  100 - 5 . The digital unit  140 - 5  outputs an address ADD, I/O data, a control signal CTR, and the clock signal CLK to the memory unit  150 - 5 . 
     The digital unit  140 - 5  outputs I/O data I/O (using m lines (×m)), a write enable signal WE, an output enable signal OE, and a chip enable signal CE to the DAC register unit  210 - 5 , and outputs an operation signal ACT to the power register  220 - 5 . 
     The memory unit  150 - 5  includes a plurality of memory cells, and stores data related to an ID code of each RFID device. Each memory cell writes data in a storage element, and reads data from the storage element. 
     The memory unit  150 - 5  includes a non-volatile memory area. Generally, a FeRAM may be used as the non-volatile memory area. The FeRAM has a data processing speed similar to that of DRAM. The FeRAM has a similar structure to that of DRAM, and uses a ferroelectric material as a capacitor. The ferroelectric material has high remnant polarization characteristics, such that data is not lost although an electric field is removed. 
     In this case, the modulator  100 - 5 , the demodulator  110 - 5 , the power-on reset unit  120 - 5 , the clock generator  130 - 5 , the digital unit  140 - 5 , the memory unit  150 - 5 , and the driving unit  200 - 5  are driven by the power-supply voltage VDD from the power-supply voltage applying pad P 1  and the ground voltage GND from the ground voltage applying pad P 2 . 
     In a conventional RFID device, when the RFID device receives the RF signal through communication with the external reader, the power-supply voltage VDD is supplied through a voltage amplification unit provided inside the RFID device. However, in this embodiment, since a large amount of power is consumed by the driving unit  200 - 5 , the power-supply voltage VDD and the ground voltage GND are provided to the RFID device through the power-supply voltage applying pad P 1  and the ground voltage applying pad P 2 . 
     The DAC register unit  210 - 5  outputs driving control signals b 1 ˜bm to the DAC driver  230 - 5 . In this embodiment, the DAC register unit  210 - 5  includes a non-volatile register. The power register  220 - 5  outputs a power on/off signal ON/OFF to the DAC driver  230 - 5  in response to the operation signal ACT and the power-on reset signal POR. The DAC driver  230 - 5  outputs output signals OUT 1 ˜OUTn through the output pads OP 1 ˜OPn, respectively. 
     The fixed handle mode control unit  700  may receive the command signal CMD from the demodulator  110 - 5 . In this embodiment, the fixed handle mode control unit  700  may be a circuit block including a random number generator. The fixed handle mode control unit  700  generates a random number in a normal mode. In a fixed handle mode, the fixed handle mode control unit  700  includes a non-volatile register for storing fixed handle data and outputs a fixed handle value. 
     In accordance with this embodiment of the present invention, a plurality of RFID devices may be arranged in row and column directions, and fixed random numbers may be sequentially assigned to the RFID devices. If there is no fixed handle mode control unit  700  and RFID devices receive a call signal from the external reader, each RFID device may continuously output the response signal RP until the same random number as that of an RFID device desired by the reader is detected. In this case, it takes a long time until the desired RFID device reacts to the call signal. 
     Therefore, in accordance with an embodiment of the present invention, the order of the plurality of RFID devices responding to the call signal from the external reader is pre-stored in the fixed handle mode control unit  700 . In this case, if the RFID device receives the call signal from the external reader, the RFID device may pre-recognize which one of the RFID devices will respond to the call signal. In this embodiment, different fixed handle values may be pre-established in such a manner that the responses of the RFID devices do not overlap. 
       FIG. 21  is a detailed block diagram illustrating the fixed handle mode control unit  700  shown in  FIG. 20 . 
     Referring to  FIG. 21 , the fixed handle mode control unit  700  includes a fixed handle command decoder  710 , a fixed handle controller  720 , a non-volatile register  730 , a random number generator  740 , and a selection unit  750 . 
     The fixed handle command decoder  710  decodes the command signal CMD received from the demodulator  110 - 5 , and interprets whether or not the command signal CMD applied to the RFID device is related to the fixed handle control. 
     An output signal of the fixed handle command decoder  710  may be input to the fixed handle controller  720 . If the signal received from the fixed handle command decoder  710  corresponds to the fixed handle mode, the fixed handle controller  720  activates a handle operation signal H_ACT and outputs the activated handle operation signal H_ACT. In contrast, if the signal received from the fixed handle command decoder  710  does not correspond to the fixed handle mode, the fixed handle controller  720  deactivates the handle operation signal H_ACT and outputs the deactivated handle operation signal H_ACT. 
     The non-volatile register  730  stores a signal received from the fixed handle controller  720  as non-volatile data. That is, the non-volatile register  730  programs new handle data therein. The handle data HD stored in the non-volatile register  730  is output to the selection unit  750 . The random number generator  740  generates a random number RN in the normal mode, and outputs the random number RN to the selection unit  750 . New handle data is programmed in the fixed handle non-volatile register  730 . 
     The selection unit  750  selects one of the random number RN and the handle data HD in response to the handle operation signal H_ACT from the fixed handle controller  720 . The selection unit  750  then outputs an output signal RN_out. The selection unit  750  may include a multiplexer. 
       FIG. 22  is a flowchart illustrating an operation of the RFID device shown in  FIG. 20 . 
     Referring to  FIG. 22 , when the power-supply voltage VDD is input to the RFID device through the power-supply voltage applying pad P 1  and the ground voltage GND is input to the RFID device through the ground voltage applying pad P 2 , the RFID device is powered on at step S 40 . Thus, the register value of the DAC register unit  210 - 5  is automatically recovered by the power-on reset signal POR at step S 41 . 
     In order to set regular handle values in several RFID devices arranged in rows and columns, a fixed handle program mode command is input to the RFID device. 
     If the command signal CMD received from the demodulator  110 - 5  is determined to correspond to the fixed handle program mode command at step S 42 , new handle data is programmed in the fixed handle non-volatile register  730  in response to a control signal of the fixed handle controller  720  at step S 43 . 
     In the meantime, in order to use the handle data HD programmed in the non-volatile register  730  or the random number RN in the normal mode as the output signal RN_out, command signals for the following two modes may be input to the RFID device. 
     First, if the command signal CMD received from the demodulator  110 - 5  is determined to correspond to a fixed handle activation mode command at step S 44 , the fixed handle controller  720  activates the handle operation signal H_ACT and outputs the activated signal H_ACT. Therefore, the selection unit  750  selects the fixed handle data HD from the non-volatile register  730 , and outputs the selected fixed handle data HD as the output signal RN_out at step S 45 . 
     In other words, if the fixed handle activation mode command is input from the demodulator  110 - 5 , the fixed handle data HD of the RFID device that is pre-established in the non-volatile register  730  is output to the outside of the RFID device through the response signal RP. 
     On the other hand, if the command signal CMD from the demodulator  110 - 5  is determined to correspond to a normal mode command at step S 46 , the fixed handle controller  720  deactivates the handle operation signal H_ACT, and outputs the deactivated handle operation signal H_ACT to the selection unit  750 . Therefore, the selection unit  750  selects the random number RN generated from the random number generator  740 , and outputs the selected random number RN as the output signal RN_out at step S 47 . RN16, i.e., fixed 16-bit Random Number, data may be established as the random number RN. 
     The embodiment of the present invention can easily determine an RFID device to be called using the fixed handle data HD pre-established in the fixed handle mode control unit  700 . That is, since a fixed ID is assigned to the RFID device using the fixed handle data HD of the fixed handle mode control unit  700 , the response order of the RFID devices can be easily recognized. 
     In this case, the RN16 data may be indicative of a random number of 16 bits. In the normal mode, undefined random data may be output according to the combination of 16-bit data. That is, each of all RFID devices contained in a recognition area of the external reader outputs random RN16 data in response to a call from the external reader, thereby responding to the call of the external reader. 
     However, since the RN16 data may be a random number arbitrarily generated from the RFID device, it is impossible to predict which data will be generated as the RN16 data. 
     In the meantime, in accordance with an embodiment of the present invention, the fixed handle data HD is pre-established as a specific value in the non-volatile register  730 , and, if the fixed handle activation mode command is input to the RFID device, the specific value pre-established in the non-volatile register  730  is output as the fixed handle data HD. Therefore, after a query command is input to the RFID device, the RFID device outputs the fixed handle data HD pre-established therein to the outside thereof. 
     In accordance with an embodiment of the present invention, since the response order of the RFID devices is predetermined, it is not necessary that a unique ID code output from each RFID device is changed when a desired RFID device responds. 
     In other words, since the response order of the RFID devices is predetermined, fixed handle data HD corresponding to a fixed ID is assigned to the fixed handle mode control unit  700  to identify individual RFID devices. If the command signal CMD from the external reader is input to the RFID device, the fixed handle data HD pre-established in the fixed handle mode control unit  700  is output to the external reader. As a result, the external reader needs only to verify whether or not an expected value is output from the called RFID device. 
     Therefore, if the command signal CMD corresponds to the normal mode command, the multiplexer  750  selects the output of the random number generator  740  and outputs the RN16 data. If the command signal CMD corresponds to the fixed handle activation mode command, the multiplexer  750  selects the output of the non-volatile register  730  and outputs the fixed handle data HD. 
       FIG. 23  is a structural view illustrating an RFID system including the fixed handle mode control unit  700 . 
     Referring to  FIG. 23 , the antenna unit ANT is coupled to the RFID device through the antenna pads PAD(+) and PAD(−). In other words, the antenna unit ANT is coupled to the input pins of the RFID device. In addition, the RFID device is coupled to the driving device through the connection pins PIN. 
     The output signals OUT 1 ˜OUTn output from the output pads OP 1 ˜OPn of the DAC driver  230 - 5  are coupled to the driving device through the connection pins PIN. In this case, the driving device may correspond to a driving control device for controlling an LED, a motor, a speaker, and the like. 
     An RF processor  810  may transmit and receive RF signals to and from the RFID device at the exterior of the RFID device. In other words, an antenna  800  of the RF processor  810  may wirelessly transmit and receive a command signal and data to and from the antenna unit ANT of the RFID device. 
     In the RFID system, several application devices are arranged in rows and columns. One RF processor  810  may communicate with several RFID devices using RF signals. 
     In this case, handle data (0, 0)˜handle data (m, n) are sequentially programmed in individual RFID devices, such that a fixed value for a corresponding RFID device may be determined. Therefore, the RF processor  810  activates the fixed handle activation mode command, and transmits the activated fixed handle activation mode command to the RFID device. In this case, the individual RFID devices store their unique handle data (m, n), and thus the RF processor  810  can wirelessly control the individual RFID devices using the handle data (m, n). 
       FIGS. 24A to 24D  illustrate a power connection relationship between an RFID device and a driving device to be used as a driving object according to embodiments of the present invention.  FIGS. 24A to 24D  exemplarily illustrate that the driving object to be driven by the driving device is an LED. 
       FIG. 24A  illustrates that an external power-supply voltage V 1  is converted to a power-supply voltage V 2  by a power-supply controller, and the power-supply voltage V 2  is provided to the RFID device and the LED of the RFID system. For example, the external power-supply voltage V 1  is set to 220V, and the power-supply voltage V 2  is set to 3.3V. The power-supply controller may include a voltage converter or a transformer. 
       FIG. 24A  illustrates that a single power-supply voltage is provided to a single RFID device.  FIG. 24B  illustrates that an RFID system for allowing one RFID device to simultaneously control several LEDs is powered on by a power-supply unit. 
     Referring to  FIG. 24C , one RFID device is coupled to one LED, and an RFID system including several pairs of RFID devices and LEDs is powered on by a power-supply unit. Referring to  FIG. 24D , an LED group including several LEDs are coupled to one RFID device, and an RFID system including the RFID devices and their corresponding LED groups is powered on by a power-supply unit. 
     In recent times, an illumination lamp installed in a building or the like may generally include a plurality of LED elements. In this case, several LED elements are respectively turned on or off so that the on/off control result appears as a specific light pattern. In addition, each illumination lamp may be controlled to have a desired brightness, or a certain illumination lamp arranged at a desired position may be separately controlled. 
     The above-mentioned scheme for controlling the illumination lamp may remotely control the illumination lamp using the RFID device. In other words, if an RFID tag is attached to each LED and a desired RF signal is transmitted to each RFID tag through an external reader, the RFID tag attached to the LED recognizes the transmitted RF signal and receives an additional command according to a unique ID. In this way, the number and brightness of the LEDs can be controller as desired. The RFID tag is relatively cheaper than a general wireless remote controller. Accordingly, if the RFID tag is applied to the illumination lamp, the implementation cost can be reduced and more options can be provided to the users. 
     As apparent from the above description, the RFID system according to the above-mentioned embodiments of the present invention have the following effects. 
     First, the embodiment of the present invention relates to an RFID technology for allocating an identification (ID) code to a driving device using an RFID device such that each driving device can be wirelessly controlled at a remote site. 
     Second, the embodiment of the present invention relates to an RFID technology for allocating an ID code to each driving device using an RFID device including an internal or external sensor, and transmitting a specific driving command to each RFID device using an RF signal, thus establishing a specific output level. 
     Third, the embodiment of the present invention relates to an RFID technology for allocating an ID code to each driving device using an RFID device including an internal MCU or an external MCU, and transmitting a specific driving command to each RFID device using an RF signal, thus establishing a specific output level. 
     Fourth, the embodiment of the present invention relates to an RFID device for predetermining handle values to a plurality of RFID devices using a fixed handle mode, and allowing each RFID device to be arbitrarily selected and controlled using the corresponding predetermined handle value, thus increasing the operational efficiency. 
     Although a number of illustrative embodiments consistent with the invention have been described, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. Particularly, numerous variations and modifications are possible in the component parts and/or arrangements which are within the scope of the disclosure, the drawings and the accompanying claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.