KR20110092375A - Circuit for the wake-up control and its controlling method to extend usable battery life time on battery assisted rfid tags - Google Patents

Abstract

PURPOSE: A circuit for a wake-up control and its controlling method to extend usable battery life time on battery assisted RFID tags are provided to reduce the power consumption due to an unnecessary operation. CONSTITUTION: A wake-up controller(380) turns on or off the power of a power supplier(350). The wake-up controller supplies or cuts off the power for a microprocessor(360). The wake-up controller offers an interrupt to the microprocessor by controlling the on/off controller. The wake-up controller converts the microprocessor into an operation of a standby state.

Description

JP-GP control circuit and its control method for extending battery life of RDF tag using battery {circuit for the WAKE-UP control and its controlling method to extend usable battery life time on battery assisted RFID Tags}

The present invention relates to a WAKE-UP circuit for extending the battery life of a battery-operated RFID TAG and a control method thereof, and more particularly, to minimize current consumption in a standby state and to generate a radio wave source other than an RFID reader signal. Minimizes power consumption caused by unnecessary start of the tag microprocessor due to interference signal or noise from EMI and analyzes the baseband signal components input to the WAKE-UP control unit after starting the microprocessor by the WAKE-UP signal. WAKE-UP control circuit of battery operated RFID tag that can extend the battery life by minimizing the current consumption by unnecessary start of the tag microprocessor by maintaining or shutting off the power supply to the microprocessor at proper timing. It relates to a control method thereof.

Typically, Battery Assisted Semi-Passive TAGs (BAPs) or Active TAGs (BAPs) use battery power such as lithium coin cells for internal microprocessor startup and memory backup, built-in sensor operation or response data transfer to an RFID reader. In order to improve the battery life of a tag to which primary cells are applied, it is important to maintain low standby current consumption. To do this, when there is no RFID reader signal, the battery power including the microprocessor and memory inside the tag When powering off the devices that require the device and receiving the RFID reader signal, it must be WAKE-UP (in a few milliseconds) to receive, read and respond to the signal from the reader. Tag that can be generated even when noise is introduced by interference signal or EMI from radio wave source Wake-up control circuit that allows the microprocessor to minimize current consumption due to unnecessary startup of the microprocessor and to enter standby after an appropriate time has elapsed when the input signal from the outside is extinguished or turned out to be an invalid signal. Is needed.

Looking at a conventional WAKE-UP circuit configuration as follows. 1 is a configuration diagram of a WAKE-UP circuit according to the prior art. As shown in FIG. 1, a conventional WAKE-UP circuit includes a diode detector 110 and a microprocessor that separate an ASK (Amplitude Shift Keying) component from a radio signal (RF _in ) from an RFID reader input from the outside. A / D conversion unit 120 for digitizing and outputting the detected ASK signal to be recognized by the microprocessor, the microprocessor itself and the interrupt control unit 130 and the baseband signal of the microprocessor itself to wake up the microprocessor (WAKE-UP) It is composed of a combination of a battery and a reception data processing unit 140 and a microprocessor built-in or external type read and read by the device.

Looking at the role and operation of each component of the tag according to the prior art as follows. The diode detector 110 includes a schottky diode (ZBD), a smoothing capacitor (C1) and an impedance matching resistor (R1), and the ZBD is an ASK modulated radio signal (RF _in) And detects and demodulates the envelope, and the smoothing capacitor and the resistor are output matching circuits of the ZBD. In addition, the ASK demodulated signal (Vs) restored by the diode detector 110 is an interrupt control unit of the microprocessor via the A / D conversion unit 120 for converting the digital signal to be recognized by the microprocessor Is applied to 130.

The interrupt controller 130 may have a rising edge or a falling edge of a baseband signal Vd outputted from the A / D converter 120 (high or low) or an applied baseband signal waveform. (Falling Edge) is detected and started, and after starting, it analyzes the pattern of bits input by the microprocessor's computing device and detects the preamble or frame-sync signal to see if it is a signal from the RFID reader. Will be judged.

In the conventional WAKE-UP control circuit configured as described above, the microprocessor interrupt control method using the A / D conversion unit 120 output signal has the following problems.

If the radio signal RFin applied to the diode detector 110 is greater than or equal to a threshold intensity, the envelope is detected and input to the A / D converter 120, and then converted to a digital signal level to be converted into a digital signal level. ), The microprocessor starts up and consumes a lot of current. In addition, the tag reads the presence or absence of a preamble or frame-sync signal from the applied baseband signal waveform. As a result, the A / D is not only affected by the RFID reader signal but also by EMI interference having a fast peak voltage component. Since the converter applies the AC signal to the rising edge and the falling edge to the interrupt control unit 130, this leads to unnecessary starting and operation of the microprocessor, thereby causing frequent current consumption. To shorten the battery life. In particular, the 860MHz to 960MHz band and the 2.4GHz band are allotted frequency bands for use in wireless LAN, ZigBee, and mobile devices. Can be discharged prematurely, losing valuable information stored on the tag.

In order to detect the pattern of the preamble or frame synchronization signal, the microprocessor must be in a running state. Since the operation is performed to detect the preamble or frame synchronization signal even by the interference signal, unnecessary consumption of the battery may occur. do.

The present invention has been made to solve the above problems, in order to minimize the battery current consumption, in the standby state without a valid baseband signal (Vd) the main part power supply (OFF) while the signal from the RFID reader It wakes up quickly at the time of reception (WAKE-UP), minimizes unnecessary startup (WAKE-UP) due to interference signals, and optimizes the startup time after startup to reduce the power loss caused by unnecessary startup, effectively extending the battery life. It is an object of the present invention to provide a WAKE-UP control circuit of an RFID tag and a control method thereof.

WAKE-UP control circuit 200 of the tag according to the present invention for achieving the above object is a high pass filtering from the baseband signal (Vd) applied from the A / D conversion unit 120 The data input unit 210 and the rectifier 220 rectifying it, the low pass filter 230 and the power supply 150 are turned on, and the interrupt control unit 130 is controlled to start the microprocessor 160 and the baseband signal disappears. Characterized in that the on / off control unit 240 for switching the microprocessor to the standby state,

The control method of the WAKE-UP control circuit according to the present invention is composed of a combination of an initial starting process, a late starting process, and a post-starting process. The initial starting process does not have an RFin signal input to the diode detector 110. A / D conversion from the diode detector 110 due to the application of the RFin signal while the D converter 120, the WAKE-UP controller 200, the power supply 150, and the microprocessor 160 are turned off. The baseband signal Vd starts to be supplied through the data input unit 210 of the WAKE-UP control unit 200 via the unit 120, and the data input unit 210 performs high pass filtering. The rectifier 220 and the low pass filter 230 perform a rectification and a low pass filtering process for the signal passing through the data input unit 210 and the power supply unit by the on / off control unit 240. 150) is turned on to provide battery power to the microprocessor. At the same time it is performed by the path for controlling the interrupt control unit 130 of the microprocessor to start the microprocessor.

The late start process is a baseband signal output from the A / D converter 120 on the path while the power supply 150 is turned on by the control of the on / off control unit 240 and the microprocessor is started. The receiving data processor 140 reads the received data from Vd and performs a necessary command therefrom.

In the post-start process, when the reading in the reception data processing unit 140 is completed and the microprocessor completes the required instruction execution, the microprocessor switches to the standby state or the RFin signal disappears or the A / D conversion unit When the baseband signal Vd output from 120 is a signal out of a valid voltage-frequency pattern, the on / off controller 240 is turned on because the signal is blocked or extinguished by the WAKE-UP controller 200. The state is changed to the OFF (OFF) state is a microprocessor is switched to the standby state is characterized in that the power supply 150 is off

The WAKE-UP control circuit and its control method for extending the battery life of the RFID tag using the battery according to the present invention has the following effects.

By selectively blocking, delaying, or attenuating the baseband signal Vd outputted from the A / D converter 120 according to the waveform thereof, reducing unnecessary WAKE-UP of the tag, and applying a valid baseband signal Vd to the micro Quickly start up the processor and maintain a stable start-up state.When the effective signal component disappears, the microprocessor enters the standby state according to the normal termination procedure to reduce unnecessary loss of power by optimizing unnecessary wake-up and start duration of the tag. By doing so, the battery life of the battery-operated RFID tag can be extended.

1 is a block diagram of a receiver and a WAKE-UP of an RFID TAG according to the prior art.
2 is a block diagram of a WAKE-UP control circuit of the RFID TAG according to an embodiment
3 is a block diagram illustrating a receiver and a wake-up circuit of an RFID TAG according to an embodiment.

Hereinafter, a WAKE-UP control circuit of an RFID tag according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. 3 is a circuit diagram of an RFID tag according to an embodiment of the present invention, and FIG. 2 is a circuit diagram of a WAKE-UP control circuit according to an embodiment of the present invention.

First, as shown in FIG. 3, the RFID tag receiving circuit according to an exemplary embodiment of the present invention is basically the diode detector 310 and the A / D like the RFID tag circuit according to the prior art as shown in FIG. 1. The converter 320, an interrupt controller 330, a reception data processor 340, a power supply 350, and a microprocessor 360 are included. In addition, the RFID tag receiving circuit according to an embodiment of the present invention further includes a WAKE-UP control unit 380.

The WAKE-UP control unit 380 is demodulated by the diode detector 310 (Vs) and the baseband signal Vd output from the A / D converter 320 is applied to the control in the baseband signal waveform. By converting into a suitable form to control the power supply 350 and the microprocessor interrupt control unit 330, the noise compared to the conventional method to directly control using the output of the diode detector 310 or the output of the A / D converter 320 And prevents starting of the microprocessor and unnecessary computation due to the invalid baseband signal Vd.

The WAKE-UP controller 380 will be described in detail later. First, the roles of the diode detector 310, the A / D converter 320, the interrupt controller 330, and the received data processor 340 The summary of the operation is as follows.

The diode detector 310 is a radio signal which is applied from the outside (RF _in) by envelope detection (Envelop Detect) demodulates as to play a role in (Demodulation), Schottky diodes (Zero Bias Schottky Diode = ZBD) and smoothing The analog demodulation data Vs composed of the capacitor C1 and the matching resistor R1 and demodulated by the diode detector 310 is applied to the A / D converter 320.

The A / D converter 320 converts the signal Vs demodulated by the diode detector 310 into a digital signal (= baseband signal Vd) that can be recognized by a microprocessor. The interrupt controller 330 receives the output of the A / D converter 320 to turn on the power supply 350 and start the microprocessor to be applied through the reception data processor 340. The baseband signal Vd is read and a necessary command is executed therefrom. The readout of the baseband signal Vd starts with detecting a preamble or frame-sync signal from a bit string of input data, including a microprocessor and a memory. The tag major elements must be powered from the battery directly or through the power supply 350 for normal operation. If the baseband signal Vd applied as a result of the reading in the reception data processor 340 is not valid, the power is turned on until the microprocessor enters the standby state or until the applied baseband signal Vd disappears. In the ON state, the reception data is monitored. However, since the receiver of the tag is an envelope detection method by ZBD, an electromagnetic signal (EMI) or an invalid signal (RFin) by other radio wave sources other than the valid signal (RFin) from the RFID reader is also described. Demodulated by the diode detector 310 and may be output as a baseband signal (Vd) via the A / D converter 320, the interrupt control unit 330 is triggered by the signal to start the microprocessor to receive the received data Since the operation of reading the baseband signal Vd applied to the processor 340 is performed, battery power is unnecessarily consumed.

 Now, the WAKE-UP control circuit of the RFID TAG according to an embodiment of the present invention will be described in earnest. First, as shown in FIG. 2, the WAKE-UP control circuit of the RFID tag according to the exemplary embodiment of the present invention has a data input unit 210, a rectifier 220, a low pass filter 230, and an on / off controller. 240 is made.

The data input unit 210 serves to receive the baseband signal Vd from the A / D converter 320 and serves as a high pass filter HPF. The rectifier 220 rectifies the signal applied from the data input unit 210, and the low pass filter 230 performs low pass filtering on the signal component passed through the rectifier 220 and is configured as Q1. The on / off controller 240 turns on the power supply 350 and starts the microprocessor.

In the above, the control method of the WAKE-UP control circuit according to an embodiment of the present invention has been described.

Claims (1)

WAKE-UP control circuit of battery operated RFID TAG,
The power supply is turned on or off by controlling the on / off control unit by performing high pass filtering, rectifying, and low pass filtering of the demodulated baseband signal applied from the A / D converter. To power on or off the microprocessor
A circuit for providing an interrupt to the microprocessor under control of the on / off control unit or switching the microprocessor to start or standby state by a method such as turning on or off the power supply of the microprocessor.

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