KR20020033328A - Card reader of contactless type - Google Patents

Abstract

PURPOSE: A contactless card terminal is provided to reduce the probability of error generating by providing power to a contactless card, by transmitting data with 106Kbps in case that a data level '0' is transmitted, by detecting the 106Kbps data of a BPSK, and by classifying the data into the level '0' and the level '1'. CONSTITUTION: An SIM card(60) stores keys for analyzing and processing data. An oscillation unit(20) oscillates a frequency of 13.56MHz. A power data transmitting unit(30) adjusts output waveforms of the oscillation unit(20) according to data values and transmits data through an antenna(10). A data receiving unit(40) receives a signal transmitted from a contactless type card and performs a filtering of the signal. A control unit(50) transmits power and data through a power data transmitting unit(30) with the frequency generated from the oscillation unit(20). In addition, the control unit(50) analyzes and controls the data received from the data receiving unit(40) based on contents stored in the SIM card(60). An asynchronous connection unit(70) transmits the data to external devices.

Description

Non-contact Card Terminal {CARD READER OF CONTACTLESS TYPE}

The present invention relates to a contactless card terminal, and more particularly, to generate an electric field of 13.56MHz to supply power to a contactless card, and to distinguish between '1' and '0' during data transmission by adjusting the amplitude of the electromagnetic field and transmitting the ISO. / Contactless card terminal that satisfies Type B of IEC 14443 standard.

Data transmission and power supply methods between 13.56 MHz card terminals and contactless IC cards are carried out in accordance with ISO / IEC 14443, and are divided into Type A and Type B according to the data transmission method.

In Type A, when the signal is sent from the terminal (PCD) to the card (PICC), the ASK (Amplitude Shift Keying) 100% modulation causes the power to be turned off momentarily. Capacitors must be used.

That is, as shown in FIG. 1, since the power supply is momentarily interrupted due to the ASK 100% modulation scheme, which may cause a malfunction of the CPU in the card, there is a high probability that data bits will not be recognized, thus significantly affecting the transmission and reception of data.

In addition, since Type A is 100% modulation, the high frequency is completely turned on and off, resulting in noise due to ON / OFF, which emits considerable electromagnetic waves.

On the other hand, when transmitting from a non-contact card (PICC) to a card terminal (PCD) it transmits 106Kbit / s data by OOK (On Off Keying) modulation method according to Manchester coding method.

On the other hand, Type B transmits data from the card terminal to the contactless card by ASK 10% modulation, so the power is not turned off, and there is no need for a capacitor in the contactless card.

That is, when the data is '0', the power is not turned off because the amplitude is attenuated by 10% than the '1' so that the data can be distinguished.

As Type B transmits data using ASK 10% modulation, the probability of error in recognition between bits is relatively lower than that of Type A, enabling stable data transmission and reception.

In addition, since Type B transmits data using the ASK 10% modulation method, a switch-like phenomenon does not occur during data transmission, and thus emits less electromagnetic waves than Type A.

The object of the present invention is to continuously generate an electric field of 13.56 MHz based on the communication standard of ISO / IEC 14443 Type B as described above to supply power to a contactless card, and to transmit data level "0", when transmitting "1". It transmits data at 10% ASK and 106Kbps, which reduces the electric field of 13.56MHz by 10%, and detects 106Kbps data of BPSK (Binary Phase Shift Keying) using Manchester coding method to level "0" and level "1". A contactless card terminal is provided for sorting.

1 is a graph showing Type A and Type B according to ISO / IEC 14443 regulation data transmission method.

Figure 2 is a block diagram showing a contactless card terminal according to the present invention.

3 is a circuit diagram illustrating in detail the power data transmitter of FIG. 2.

4 is a circuit diagram illustrating in detail the data receiver of FIG. 2.

5 is a circuit diagram showing in detail the data detection unit of the data receiving unit according to the present invention.

6 is a circuit diagram showing in detail the data detection unit of the data receiving unit according to the present invention.

7 is a graph showing the data state of each point in the data receiving unit according to the present invention. (A) is a graph showing the case where data starts with '1', and (B) is a case where the data starts with '0'. The graph shown.

-Explanation of symbols for the main parts of the drawings-

10 antenna 20 oscillator

30: power data transmitter 40: data receiver

50: control unit 60: SIM card

70: asynchronous connection

The present invention for realizing the above object is to adjust the amplitude according to the input data value of the SIM card, the oscillator for oscillating the frequency of 13.56MHz, and the oscillation unit for storing the SIM card, the key for data analysis and processing, etc. A power data transmitter for transmitting power and data to the contactless card through an antenna, a data receiver for receiving data from the contactless card through an antenna, filtering the signal, amplifying the signal, and synchronizing the detection point of the data to detect the data; The controller controls power and data to be transmitted through the power data transmitter at the frequency generated by the oscillator, and analyzes and controls the data received through the data receiver based on the contents stored in the SIM card. Consisting of an asynchronous connection for transmitting the signal to an external device It shall be.

The power data transmitter includes a class C tuning amplifier for amplifying the power supply voltage by the output waveform of the oscillator, an amplitude adjusting unit for adjusting the amplitude of the output waveform of the class C tuning amplifier according to the input data value, and a class C tuning amplifier. Characterized in that it consists of a matching circuit unit for matching the output terminal and the antenna with each other.

The data receiver may further include a filtering unit for filtering the signal received through the antenna at 847 kHz, a level matching unit for maintaining the signal passing through the filtering unit at a constant level, and amplifying the signal passing through the filtering unit according to the bias of the level matching unit. An amplifying section, a data sensing section for synchronizing the detection time of data in the signal amplified by the amplifying section, a first low pass filter for removing noise in an output value of the data sensing section, and a first low pass filter. And a second low pass filter for removing data in the data detected by the data detector, and a second low pass filter for detecting data in the signal amplified by the amplifier according to the signal.

The present invention made as described above is to output the data by adjusting the amplitude of the power frequency in accordance with the data to meet the Type B standard of ISO 14443, and after receiving the data of the BPSK method to synchronize the data detection time through the data detection unit It is operated to receive data from and output to external device.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings. In addition, this embodiment is not intended to limit the scope of the present invention, but is presented by way of example only.

Figure 2 is a block diagram showing a contactless card terminal according to the present invention.

As shown here, the SIM card 60, which stores keys for data analysis and processing, the oscillator 20 oscillating a frequency of 13.56 MHz, and the output waveform of the oscillator 20 according to input data values. The power data transmitter 30 transmits power and data to the contactless card (PICC) through the antenna 10 by adjusting the amplitude, and receives and filters the signal transmitted from the contactless card (PICC) through the antenna 10. The data receiver 40 detects the data by synchronizing the data at the time of detection and then transmits power and data through the power data transmitter 30 at the frequency generated by the oscillator 20. The data receiver 40 Control unit 50 for analyzing and controlling the data received through the information stored in the SIM card 60, and for transmitting the operating state and the received data of the control unit 50 to an external device (not shown) Nasal sinus It comprises a connecting portion (70).

3 is a circuit diagram illustrating in detail the power data transmitter of FIG. 2.

As shown here, the class C tuning amplifier 310 amplifies the power supply voltage by the output waveform of the oscillator 20 and the amplitude of the output waveform of the class C tuning amplifier 310 is adjusted according to the input data value. The amplitude adjusting unit 330, and the matching circuit unit 320 for matching the output terminal of the C-class tuning amplifier 310 and the antenna 10 is characterized in that it is made of.

The oscillator at 13.56 MHz of the oscillator 20 is oscillated at the same time as the power is applied, and is differentiated by the differential circuit 340 composed of R31 and L2 and input to the base of the transistor Q6.

In the class C tuning amplifier 310 including the transistor Q6, the inductor L3, and the capacitors C31 and C32, 9V of the power supply voltage applied to the collector of the transistor Q6 is the waveform of the oscillator 20 applied to the base. It is amplified by twice the power supply and outputs a 13.56MHz waveform of about 18V _{peak to peak} .

The waveform of the collector of the transistor Q6 of the class C tuning amplifier 310 is transmitted to the resistor R34 while the transistor Q7 of the amplitude adjusting unit 330 is turned on and off in accordance with the TX signal output from the controller 50. This results in a 10% difference in amplitude.

That is, when the TX signal is '1', the collector waveform of the transistor Q6 is not attenuated because Q7 is turned off while passing through the inverter INV1 and becomes '0', but when the TX signal is '0', the inverter ( Since the transistor Q7 is turned on by passing through INV1 and becomes '1', the collector waveform of the transistor Q6 outputs a low amplitude waveform of about 10% by the resistor R34.

The output waveform is output through the antenna 10 via a matching circuit unit 320 formed of an inductor L4, a capacitor C33, an inductor L5, and a capacitor C34, and supplied to a non-contact card PICC.

The C-class tuning amplifier 310 is biased so that it can be conducted at less than 180 °, the efficiency is much higher than the class A, class B push-pull, class AB push-pull amplifier, it is possible to obtain a larger output power.

In addition, since the output waveform is severely distorted, the C-class tuning amplifier 310 is usually applied only to a radio frequency (high frequency) tuning amplifier.

In addition, the C-class tuning amplifier 310 having a resistive load has no value in linear applications because the collector voltage (output) is different from the input waveform. Therefore, a C-class tuning amplifier 310 having a parallel resonance circuit should be used.

At this time, the resonance frequency of the class C tuning amplifier 310 is Determined by

At this time, to make output sinusoidal voltage, short pulse of collector current should be made in each input period and vibration of resonant circuit should be maintained.

Resonant operation of the Class-C tuning amplifier 310 is charged to the input current pulse to the capacitor (C31, C32) to about + Vcc. Thereafter, the capacitors C31 and C32 are rapidly discharged to charge the inductor L3. After the capacitors C31 and C32 are completely discharged, the magnetic field of the inductor L3 disappears and the capacitors C31 and C32 are rapidly recharged in the opposite direction to the previous charging.

Next, after the capacitors C31 and C32 are re-discharged, the magnetic field of the inductor L3 rapidly increases. The inductor L3 recharges the capacitors C31 and C32 to a positive peak value slightly smaller than the previous peak value due to energy loss due to the winding resistance.

Therefore, the peak-to-peak output voltage of the C-class tuning amplifier 310 is about 2Vcc.

4 is a circuit diagram illustrating in detail the data receiver of FIG. 2.

As shown here, the data receiver 40 includes a filtering unit 410 for filtering a signal received through the antenna 10 at 847 kHz, and a level matching for maintaining a signal passing through the filtering unit 410 at a constant level. The detection unit 430, an amplifying unit 420 for amplifying the signal passing through the filtering unit 410 according to the bias of the level matching unit 430, and the timing of detecting data in the signal amplified by the amplifying unit 420 To the signal passing through the data detector 440, the first low pass filter 450 for removing noise in the output value of the data detector 440, and the first low pass filter 450. Accordingly, the data detector 460 detects data in the signal amplified by the amplifier 420 and a second low pass filter 470 for removing noise in the data detected by the data detector 460.

As such, the data receiver 40 correctly detects 8 bit data of the BPSK method generated by an ISO / IEC 14443 Type B type 13.56 MHz contactless card (PICC) at the card terminal to interrupt the microprocessor of the controller 50. By converting the data into binary data of '1' and '0' in hardware, it can be easily identified by the microprocessor.

In the above, the level matching unit 430 may amplify the data based on a level of about 2.5V when the amplifying unit 420 amplifies the data so that the correct value may be read when data is detected.

The amplifier 420 amplifies the 847KHz BPSK data filtered by the filter 410 to about 5Vpp. At this time, since the bias is maintained at about 2.5V by the level matching unit 430, a swing should occur at 2.5V.

5 is a circuit diagram showing in detail the data detection unit of the data receiving unit according to the present invention.

As shown here, the data detector 440 may convert the non-inverted data B1 amplified by 847 KHz by the filtering unit 410 and the data B2 inverted by the inverter INV2 into the diode D1. D2), resistors R14 and R15, and capacitors C15 and C16 are filtered to remove noise and high frequency components. Each of the sensed signals C1 and C2 is passed through AND gate AND1, which is a logical multiplication means, and a sensed signal is output to synchronize with a time point for detecting data.

The reason for synchronizing the detection time of the data by inverting the filtered data by the filtering unit 410 as described above is that the time when the data '1' and '0' of the BPSK method is detected is different so that correct data cannot be read. Because.

After the data having been synchronized, the glitch and the noise are removed by the first low pass filter 450 again and the interrupt signal INT notifies the data detection time.

6 is a circuit diagram showing in detail the data detection unit of the data receiving unit according to the present invention.

As shown here, the data detector 460 divides the 13.56 MHz oscillation signal of the oscillator 20 by an interrupt signal INT indicating the data detection time output from the data detector 440 (E1). And the BPSK signal B1 filtered and filtered at 847 KHz by the filtering unit 410 to detect data.

That is, when the interrupt signal INT of the data sensing unit 440 is recognized as the data detection enable signal and the interrupt signal INT is input, the frequency divider 465 divides the 13.56 MHz signal of the oscillator 20 into 16 divisions. The 847 kHz frequency E1 and the 847 kHz BPSK signal B1 are generated through the XOR gate XOR, which is a complementary logic means.

The detected data signal E2 is removed by the second low pass filter 470 when the synchronization is slightly changed due to the error and data delay of each device (resistance, capacitor, etc.) and various glitches appear instead of the complete waveform. do.

7 is a graph showing the data state of each point in the data receiving unit according to the present invention. (A) is a graph showing the case where data starts with '1', and (B) is a case where the data starts with '0'. The graph shown.

Here, data '1' and '0' are BPSK data in 8-bit units. When data is transmitted according to ISO / IEC 14443 standard, the transmission unit is 1 byte, so it is transmitted in 64 bits at once.

Accordingly, the signal received through the antenna 10 is filtered at 847 KHz by the filtering unit 410, and then the amplified signal is maintained at a constant level by the level matching unit 430. The non-inverted signal ( When B1) is input, the sensing signal C1 is output thereto, and the inverted signal B2 of the non-inverting signal B1 output from the amplifier 420 is input and the sensing signal C2 is output thereto. do.

When the two detection signals C1 and C2 output as described above are inputted to the input of the AND gate AND1, the output of the AND gate AND1 is detected after 1/2 of the interrupt signal INT after data starts to be input. do.

After the interrupt signal INT is detected, a frequency of 847 kHz is output from the data detector 460 after 1/2 clock, and then passes through the non-inverted signal B1 and the XOR gate (XOR) output from the amplifier 420. If the data is '1', '1' is detected at the output terminal E2 of the XOR gate (XOR) because the phase of the 847KHz and the non-inverting signal B1 are 180 degrees different as shown in (a). Is 0, the phase of the non-inverting signal B1 is equal to 847 KHz, and '0' is detected at the output terminal E2 of the XOR gate XOR.

In the above graph, since the first 1 bit of the 64 bit BPSK data is used to synchronize data detection, the first data input from the controller 50 constitutes one data through 7 bits.

When data is detected by the data detector 440 of the data receiver 40, an interrupt signal INT is immediately generated to interrupt the microprocessor of the controller 50. The data is detected to convert binary data to the processor. By inputting, smooth transmission is achieved.

As described above, after communication is performed while the data is processed in the contactless card (PICC) and the card terminal period, the asynchronous connection unit 70 is collectively processed after processing the data with key values for analyzing and processing the data stored in the SIM card 60. It transmits to an external device (not shown) through.

As described above, the present invention continuously generates an electric field of 13.56 MHz according to ISO / IEC 14443 Type B communication standard to supply power to a contactless card, and transmits data level "0", rather than "1". It transmits data at 10%, 106Kbps of ASK, which reduces the electric field of 13.56MHz by 10%, and detects 106Kbps data of binary phase shift keying (BPSK) using Manchester coding method and classifies it into level "0" and level "1". It is possible to do not turn off the power instantaneously like Type A, so there is no need to install a capacitor for the momentary power off, and because the momentary power off does not occur, the probability of error occurrence and the generation of harmful electromagnetic waves This has the benefit of shrinking.

Claims (5)

A SIM card that stores keys for data analysis and processing, An oscillator for oscillating a frequency of 13.56 MHz, A power data transmitter for transmitting power and data to the contactless card through the antenna by adjusting the amplitude of the output waveform of the oscillator according to the input data value; A data receiving unit for receiving the signal transmitted from the contactless card through the antenna, filtering and amplifying the signal, and detecting the data in synchronization with the detection point of the data; A control unit for transmitting power and data through the power data transmitter at a frequency generated by the oscillator, and analyzing and controlling the data received through the data receiver based on contents stored in the SIM card; Asynchronous connection for transferring the operation status and received data to the external device Contactless card terminal, characterized in that consisting of. The method of claim 1, wherein the power data transmission unit A class-C tuning amplifier that amplifies the supply voltage by the output waveform of the oscillator, An amplitude adjusting unit for adjusting the amplitude of the output waveform of the C-class tuning amplifier according to the input data value; Matching circuit part for matching output terminal and antenna of Class C tuning amplifier Contactless card terminal, characterized in that consisting of. The method of claim 1, wherein the data receiving unit A filtering unit for filtering the signal received through the antenna to 847 kHz, A level matching unit for maintaining a signal passing through the filtering unit at a constant level; An amplifier for amplifying the signal passing through the filtering unit according to the bias of the level matching unit; A data detector for synchronizing the detection time of data in the signal amplified by the amplifier; A first low pass filter for removing noise in an output value of the data detector; A data detector for detecting data in the signal amplified by the amplifier according to the signal passing through the first low pass filter; Second low pass filter for removing noise in the data detected by the data detector Contactless card terminal, characterized in that consisting of. The method of claim 3, wherein the data detection unit And a logical multiplication means for receiving a signal output through the amplifying unit and an inverted signal of the signal output through the amplifying unit as an input. The method of claim 3, wherein the data detection unit A divider for dividing the output frequency of the oscillator by 16 using the output signal of the data detector; Complementary logic means for receiving the output frequency of the divider and the signal output through the amplifier as an input Contactless card terminal, characterized in that consisting of.