KR100956377B1 - Low power communication system and communication method thereof - Google Patents

Abstract

The present invention relates to a low power communication system and method thereof for reducing power consumption.

A low power communication system according to the present invention includes a detector for detecting a received signal received through an antenna; A comparator operated by a first clock and comparing the detected received signal with a preset reference voltage to output a comparison signal; And when the comparison signal is output, is operated by a second clock corrected in response to the first clock, and compares the comparison signal with a preset wake-up signal to determine an operation mode. It includes; wake-up determination unit for outputting.

Power Consumption, Low Power, Wake-up, Communication, Zigbee

Description

LOW POWER COMMUNICATION SYSTEM AND COMMUNICATION METHOD THEREOF

The present invention relates to a low power communication system and method for use in a wireless communication device, and more particularly, when a signal received in a deep sleep mode is the same as a preset wake-up signal, the operation mode is switched to an operation mode. Accordingly, the present invention relates to a low-power communication system and method for reducing power consumption and improving demodulation accuracy of a received signal by correcting a frequency of an operation clock based on a frequency of a reference clock.

In general, a radio frequency identification tag is a tag attached to a product or an object instead of a conventional bar code, and is a device having a small chip in which various kinds of information of the object are stored.

The information stored in the radio wave identification tag is used in the management system by interworking with various communication lines such as wired as well as satellite communication through a radio wave reader.

At this time, IC tag and antenna are embedded in the RFID tag, and auxiliary memory for storing ID code and other data is stored in the chip, and a signal is sent from the reader to send data in the tag. There is a main memory for it.

The radio wave identification tag does not always operate to transmit information of the object, but operates only at a time selected by the user and needs to be used for a long time, so that power consumption should be reduced.

Accordingly, the system to which the radio wave identification tag is currently attached is driven in the deep sleep mode in which only minimal operation is performed when no signal is transmitted from the outside, thereby reducing power consumption and operating mode only when a predetermined signal is transmitted. By driving to, the operation corresponding to the received signal is performed.

However, in the system to which the radio wave identification tag is attached, even if a signal transmitted from the outside is not a signal for operating the radio wave identification tag, the radio wave identification tag does not determine this and switches from the deep sleep mode to the operation mode. As a result, unnecessary power is consumed.

In addition, the system with the radio wave identification tag uses a clock having a different frequency between the deep sleep mode and the operation mode, but when switching from the deep sleep mode to the operation mode, the frequencies of the respective modes are not synchronized correctly. There is a problem that the demodulation of the received signal is not precise.

The present invention has been made to solve the above problem, and when the received signal in the deep sleep mode (deep sleep mode) is the same as the preset wake-up signal can be switched to the operation mode to reduce power consumption, operation It is an object of the present invention to provide a low-power communication system and method for improving the demodulation accuracy of a received signal by correcting the frequency of a clock based on the frequency of a reference clock.

A low power communication system according to the present invention for achieving the above object, the detector for detecting a received signal received through the antenna; A comparator operated by a first clock and comparing the detected received signal with a preset reference voltage to output a comparison signal; And when the comparison signal is output, is operated by a second clock corrected in response to the first clock, and compares the comparison signal with a preset wake-up signal to determine an operation mode. It includes; wake-up determination unit for outputting.

In this case, the detector may include a diode having an anode connected to the antenna; And a capacitor having one end connected to the cathode of the diode and the other end grounded.

The low power communication system may further include a main SOC driven by an enable signal output from the wakeup determination unit.

The comparator includes: a comparator configured to compare the detected received signal with a preset reference voltage and output a comparison signal; And a first clock generator for generating the first clock.

The wakeup determiner may include: a second clock generator configured to generate a second clock having a frequency faster than a frequency of the first clock when the comparison signal is output; A frequency corrector for correcting the second clock generator based on a first clock; And a wake-up discriminator configured to receive and operate the second clock to compare the comparison signal with a preset wake-up signal, and to generate an enable signal when the comparison signal and the wake-up signal coincide with each other. It is characterized by.

In this case, the frequency corrector counts a section having a high level of the second clock and compares it with a preset reference counting value. When the counting value is equal to a preset reference counting value, the resistance value of the second clock generator is measured. Alternatively, the capacitance may be adjusted to correct the frequency of the second clock.

The frequency corrector may be further configured to recalibrate the frequency of the second clock after increasing or decreasing the resistance value or capacitance of the second clock generator when the counting value and the reference counting value are different from each other. The wakeup determination unit may stop the operation when the comparison signal and the wakeup signal are different from each other.

In addition, the low-power communication method according to the present invention for achieving the above object, a) detecting the received signal, and comparing with a preset reference voltage; b) when the detected received signal is greater than the reference voltage, outputting a comparison signal to switch the deep sleep mode to the sleep mode, and correcting the frequency of the second clock corresponding to the first clock as the reference clock; c) comparing the comparison signal with a preset wakeup signal; And d) outputting an enable signal to switch the sleep mode to an operation mode when the comparison signal is the same as the preset wakeup signal.

At this time, the step of correcting the frequency of the second clock in step b), b-1) initializing the correction value of the second clock generator for generating the second clock; b-2) counting a section having a high level of the second clock; And b-3) determining whether the counting value is the same as a preset reference counting value, and if the counting value is the same, controlling the second clock generator to correct a frequency of the second clock.

In particular, in step b-3, the second clock generator is controlled by increasing or decreasing the resistance value and the capacitance corresponding to the correction value of the second clock generator.

When the comparison signal is different from the preset wake-up signal in step c), the feedback signal is fed back to step a), and when the comparison signal is fed back to step a), the sleep signal is switched from the sleep mode to the deep sleep mode. .

The low power communication system and method thereof according to the present invention can reduce power consumption by switching to the operation mode when the received signal is the same as the preset wake-up signal in the deep sleep mode. .

In addition, the present invention has the effect of improving the demodulation accuracy of the received signal by correcting the operation clock frequency of the operation mode on the basis of the reference clock frequency of the deep sleep mode.

Details of the configuration and effects of the low power communication system according to the present invention will be clearly understood by the following detailed description with reference to the drawings showing preferred embodiments of the present invention.

Hereinafter, a communication method in a low power communication system and a low power communication system according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a low power communication system according to the present invention, FIG. 2 is a block diagram showing a detector and a comparison unit of FIG. 1, FIGS. 3A and 3B are charts showing symbols of a received signal, and FIG. A timing diagram showing a second clock, and FIGS. 5A and 5B are graphs showing current consumption of the present invention.

First, as shown in FIG. 1, the low power communication system 100 according to the present invention includes a detector 110 that detects a received signal received through an antenna, and a predetermined set of the detected received signal Vd. Comparing unit 120 to compare the reference voltage and output the comparison signal (Swake), and wake-up determination by determining the wake-up (wake-up) by the comparison signal (Swake) to determine the wake-up signal The main unit 130 includes a main SOC 140 driven by the enable signal Sen output from the wake-up determination unit 130.

As illustrated in FIG. 2, the detector 110 includes a diode D1 and a capacitor C1 and detects a received signal transmitted through the antenna ANT.

In this case, an anode of the diode D1 is connected to the antenna ANT, and a cathode of the diode D1 is connected to the capacitor C1. In addition, the capacitor C1 is connected between the cathode of the diode D1 and ground. The diode D1 may be a schottky diode capable of detecting a 1 W received signal.

The comparator 120 includes a comparator 121 and a first clock generator 122, and receives the received signal Vd detected by the detector 110 and compares it with a preset reference voltage Vref. Output a comparison signal (Swake).

Here, the first clock generator 122 of the comparator 120 may include a first clock having a minimum frequency to drive a memory (not shown) that may be included in the comparator 120 in addition to the comparator 121. Produce and supply F1).

In this case, when the preset reference voltage Vref includes a wakeup signal, which is a signal for operating the main SOC 140, the received reference signal Vref is somewhat different from when the wakeup signal is not included in the received signal. Since it has a signal power of, it can be set to a voltage size for detecting whether or not the power of the wake-up signal is included in the received signal.

For example, the comparator 121 outputs a low level comparison signal Swake when the detected reception signal Vd has a voltage lower than the reference voltage Vref, and detects the detected signal Vd. When the received signal Vd has a voltage higher than the reference voltage Vref, a high level comparison signal Swake is output. At this time, the comparator 121 is preferably made of a comparison means (121a).

In addition, the wakeup determiner 130 includes a wakeup determiner 131, a second clock generator 132, and a frequency corrector 133, and receives the detected signal by receiving a comparison signal. The enable signal Sen is output by determining whether the wake-up signal is included in Vd.

In this case, the wakeup discriminator 131 receives a comparison signal Swake output from the comparator 121 and determines whether the wakeup signal is included in the applied comparison signal Swake.

In the wakeup discriminator 131, the wakeup signal is included in the wakeup discriminator 131 when the comparison signal Swake is applied in a predetermined pattern, as shown in FIGS. 3A and 3B. The signal is discriminated by any one of "," 1 "," SOF "or" EOF ".

The "Start Of Frame" indicates that the detected reception signal Vd includes a wake-up signal for operating the main SOC 140, and the "End Of Frame" denotes a main SOC ( It indicates that the transmission of data for operating the 140 is completed.

That is, suppose that the reception signal Vd including the wake-up signal for operating the main SOC 140 is transmitted while the reception signal Vd has a voltage lower than the reference voltage Vref. .

First, when the voltage of the reception signal Vd is lower than the voltage of the reference voltage Vref, the wakeup determination unit 130 operates in a deep sleep mode in which the first clock generator does not operate. Only 122 will operate.

During operation in the deep sleep mode, when the voltage of the reception signal Vd is higher than the voltage of the reference voltage Vref, the comparator 121 wakes up the comparison signal Swake ( In operation 131, the wakeup determining unit 130 is operated to switch from the deep sleep mode to the sleep mode.

At this time, the wakeup discriminator 131 receiving the comparison signal Swake compares the comparison signal Swake with a preset wakeup signal. In particular, the wake-up discriminator 131 defines the comparison signal (Swake) as shown in FIG. 3B to determine the data signal transmitted after the "SOF" signal is transmitted as actual data, and to determine the actual data. The transmission end time is determined as the time at which the "EOF" signal is transmitted.

Accordingly, the wakeup discriminator 131 compares the data signal data among the signals included in the comparison signal Swake with a preset wakeup signal, so that the data signal data is the main SOC 140. It is determined whether the information is included or the information can be executed without operating the main SOC 140.

If the data signal data includes information for operating the main SOC 140, that is, when the data signal data coincides with a preset wake-up signal, the main SOC 140. Outputs an enable signal (Sen) for operating.

In addition, when the data signal data does not include information for operating the main SOC 140, that is, when the data signal data does not coincide with a preset wake-up signal, the enable signal is enabled. After executing the corresponding command without outputting the signal Sen, the device enters deep sleep mode again.

In particular, the frequency corrector 133 operates when the comparison signal Swake is output to generate a second clock F2 for operating the wakeup discriminator 130. By adjusting, the frequency of the second clock F2 is corrected.

In this case, in the deep sleep mode, the second clock generator 132 is stopped to stop all components of the wake-up determination unit 130, and when the switch is to sleep mode, the second clock generator 132 operates. As a result, the second clock F2 does not always have a constant frequency, and a predetermined frequency may be changed at every mode change.

Accordingly, the frequency corrector 133 corrects the second clock F2 based on the first clock F1 having a constant frequency as a reference, thereby synchronizing the wakeup discriminator 131 to wake up the comparison signal (Swake). Can demodulate correctly.

In detail, as shown in FIGS. 4A and 4B, the frequency corrector 133 operates at the output point of the comparison signal Swake to initialize the correction value of the second clock generator 132, and then The high level section of the second clock F2 output from the two clock generators 132 is counted during the high level sections t0 to t1 of the first clock F1. In this case, the correction value of the second clock generator 132 refers to resistance values and capacitances of the resistors and capacitors (not shown) included in the second clock generator 132.

When the counted value is equal to the preset reference counting value, the second clock generator 132 is not corrected by determining that the second clock F2 operates at the preset frequency.

However, when the counted value and the preset reference counting value are not the same, it is determined that the second clock F2 does not operate at the preset frequency and corrects the correction value of the second clock generator 132. .

In particular, correction of the correction value of the second clock generator 132 changes the frequency of the second clock F2 by increasing or decreasing the resistance value or capacitance of the second clock generator 132.

The frequency corrector 133 corrects the second clock generator 132, counts the high level of the second clock F2 again, and repeats the correction process until it is equal to a preset reference counting value. If it is the same, the operation is stopped by determining that correct correction has been made.

The low power communication system 100 according to the present invention having such a configuration determines whether a wake-up signal for operating the main SOC 140 is transmitted from the outside in the deep sleep mode state, and sleep mode in the deep sleep mode. By switching to, power consumption can be reduced.

That is, as shown in Figs. 5A and 5B, which are graphs showing the current consumption of the present invention, the conventional communication system (see Fig. 5A) without the wake-up signal discrimination function has a predetermined time (t0, t1, t2. The operation mode is executed every ...), and after determining whether to transmit the operation signal, the operation mode is switched to the deep sleep mode again, thereby increasing power consumption.

However, the low power communication system 100 (refer to FIG. 5B) according to the present invention operates only in a deep sleep mode when a received signal including a wake-up signal for operating the main SOC 140 is transmitted. By executing the operation mode, power consumption can be reduced.

In addition, the low power communication system 100 according to the present invention always corrects the second clock generator 132 based on the first clock F1 when the deep sleep mode is switched to the sleep mode. The second clock F2 having the same can be output.

Hereinafter, a low power communication method using the low power communication system 100 having the above configuration will be described with reference to the accompanying drawings.

6 is a flowchart illustrating a low power communication method according to the present invention, and FIG. 7 is a flowchart of frequency correction according to the present invention.

First, as shown in FIG. 6, the received signal Vd detected through the detector 110 is compared with a preset reference voltage Vref (S210).

When the voltage of the received signal Vd compared in the step S210 is higher than the voltage of the reference voltage Vref, a comparison signal Swake is output to switch from the deep sleep mode to the sleep mode (S220).

In this case, in the transition from the deep sleep mode to the sleep mode, the second clock generator 132 of the wakeup determination unit 130 is operated to set the second clock F2 to the wakeup discriminator 131 and the frequency. By supplying to the compensator 133, the wakeup determining unit 130 is operated.

Then, the frequency of the second clock (F2) is corrected based on the first clock (F1) (S230).

In particular, in the method of correcting the frequency of the second clock in step S230, as shown in FIG. 7, first, the correction value of the second clock generator 132 is initialized (S231). In this case, the correction value of the second clock generator 132 refers to resistance values and capacitances of resistors and capacitors (not shown) included in the second clock generator 132.

After initializing the correction value, the section having the high level of the second clock F2 is counted during the section having the high level of the first clock F1 (S232).

In step S232, the counted value is compared with a preset reference counting value (S233). When the counted value is not the same as the preset reference counting value in step S233, it is determined that the correction of the second clock F2 is not normally performed and the correction value of the second clock generator 132 is determined. After the change, it is fed back to the step S232.

If the counted value is equal to the preset reference counting value in step S233, it is determined that the correction of the second clock F2 is normally performed, and the comparison signal Swake is compared with the preset wakeup signal. Compare (S240).

If the comparison signal (Swake) is not the same as the preset wake-up signal, the sleep mode is switched to the deep sleep mode, and then fed back to the step S210.

In addition, when the comparison signal Swake is the same as the preset wake-up signal, the sleep mode is switched to the operation mode by outputting an enable signal Sen for operating the main SOC 140.

The low power communication system 100 operating in the above-described configuration and method may be coupled to an ESL system (Electric Self Label system), as shown in FIG. 8 showing an application example of the low power communication system 100. .

In this case, the ESL system 200 to which the low power communication system 100 is coupled may process data by waking up once every predetermined period (for example, 8 hours), and the user uses a RFID reader to perform low power at a desired time. Information may be updated through the communication system 100.

In addition, as shown in FIG. 9 showing another application example of the low power communication system 100, by combining the low power communication system 100 with a zigbee module 300, an efficient logistics management system can be realized. have.

For example, a signal transmitted through the RFID reader 400 is detected by the low power communication system 100 and transmitted to the Zigbee module 300 in a large mart such that the location of the article is changed from time to time, and the Zigbee module 300 is provided. Transmits the location of the article to a Zigbee router 310 through a Zigbee network, and the Zigbee Router 310 transmits the transmitted item location information to a Zigbee coordinator 330.

Accordingly, by combining the low-power communication system 100 with the Zigbee module 300, it is possible to more efficiently use the management system for articles with frequent changes in location.

Preferred embodiments of the present invention described above are disclosed for the purpose of illustration, and various substitutions, modifications, and changes within the scope without departing from the spirit of the present invention for those skilled in the art to which the present invention pertains. It will be possible, but such substitutions, changes and the like should be regarded as belonging to the following claims.

1 is a block diagram of a low power communication system in accordance with the present invention.

FIG. 2 is a block diagram illustrating a detector and a comparison unit of FIG. 1. FIG.

3A and 3B are charts showing symbols of a received signal.

4 is a timing diagram illustrating first and second clocks.

5a and 5b are graphs showing the current consumption of the present invention.

6 is a flowchart illustrating a low power communication method according to the present invention.

7 is a flow chart of frequency correction in accordance with the present invention.

8 and 9 are block diagrams showing an application example of a low power communication system according to the present invention;

Description of the Related Art

100: low power communication system 110: detector

120: comparator 121: comparator

122: first clock generator 130: wake-up determination unit

131: wake-up discriminator 132: second clock generator

133: frequency compensator 140: main SOC

Claims (13)

A detector for detecting a received signal received through an antenna; A comparator operated by a first clock and comparing the detected received signal with a preset reference voltage to output a comparison signal; And When the comparison signal is output, the comparison signal is operated by a second clock corrected to correspond to the first clock, and the operation mode is determined by comparing the comparison signal with a preset wake-up signal. A wakeup determination unit for outputting; Low power communication system comprising a. The method of claim 1, wherein the detection unit, A diode having an anode connected to the antenna; And A capacitor having one end connected to the cathode of the diode and the other end grounded; Low power communication system comprising a. The system of claim 1, wherein the low power communication system, And a main SOC driven by an enable signal output from the wakeup determination unit. The method of claim 1, wherein the comparison unit, A comparator for comparing the detected received signal with a preset reference voltage and outputting a comparison signal; And A first clock generator for generating the first clock; Low power communication system comprising a. The wakeup determination unit of claim 1, A second clock generator configured to generate a second clock having a frequency faster than that of the first clock when the comparison signal is output; A frequency corrector for correcting the second clock generator based on a first clock; And A wake-up discriminator configured to receive and operate the second clock to compare the comparison signal with a preset wake-up signal, and generate an enable signal when the comparison signal and the wake-up signal coincide with each other; Low power communication system comprising a. The method of claim 5, wherein the frequency corrector, Counting a section having a high level of the second clock and comparing it with a preset reference counting value, and when the counting value is the same as the preset reference counting value, adjusts the resistance value or capacitance of the second clock generator to adjust the second value. A low power communication system comprising correcting the frequency of a clock. The method of claim 6, wherein the frequency corrector, And when the counting value and the reference counting value are different, increase or decrease the resistance value or capacitance of the second clock generator, and then recalibrate the frequency of the second clock. The method of claim 5, wherein the wake-up determination unit, And stop the operation when the comparison signal and the wake-up signal are different. a) detecting a received signal and comparing the received signal with a preset reference voltage; b) outputting a comparison signal to switch the deep sleep mode to the sleep mode when the detected received signal is greater than the reference voltage, and correcting a frequency of the second clock corresponding to the first clock as the reference clock; c) comparing the comparison signal with a preset wakeup signal; And d) outputting an enable signal to switch the sleep mode to an operation mode when the comparison signal is the same as a preset wakeup signal; Low power communication method comprising a. 10. The method of claim 9, wherein the step of correcting the frequency of the second clock in step b), b-1) initializing a correction value of a second clock generator that generates the second clock; b-2) counting a section having a high level of the second clock; And b-3) determining whether the counting value is equal to a preset reference counting value, and if the counting value is the same, controlling the second clock generator to correct the frequency of the second clock; Low power communication method comprising a. The method of claim 10, In the step b-3), the second clock generator is controlled by increasing or decreasing the resistance value and the capacitance corresponding to the correction value of the second clock generator. The method of claim 9, And in step c), when the comparison signal is different from a preset wake-up signal, the comparison signal is fed back to step a). The method of claim 12, When the feedback to step a), the low power communication method, characterized in that for switching from the sleep mode to the deep sleep mode.

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