JPH03296889A - Contactless type magnetic connection transmitter for ic memory card - Google Patents

Abstract

PURPOSE:To improve a communication speed by discriminating the bit pattern of a data signal and inverting the bit pattern based upon the discrimination. CONSTITUTION:A deciding means 32 counts up the number of bits 1 for one byte of data and generates a decision signal indicating five or more or four or less for instance. Namely, whether a half or more of all the bits are '1' or not is decided and the bit patterns '1'/'0' for one byte of data are inverted in accordance with the decision signal. Since a half or more of the data part for power transmission/data waveforms is always '1', power transmission capac ity is not dropped due to the contents of data as compared with a convensional method and the charging time can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a contactless magnetic coupling transmitter for IC memory cards.

[Conventional technology]

Conventionally, contactless magnetic coupling transmitters that transmit data signals and power to an IC memory card using a single transmitter coil modulate the power carrier with the transmitted data, so the power transmission capacity varies depending on the data content. Resulting in.

FIGS. 2 and 3 show conventional data transmission.

In FIG. 2, 10 is a transmitter. , 11 are data buffers in which transmission data is stored.

12 is a driver that converts parallel data into serial data, modulates the power carrier with transmission data, and sends a transmission coil 13
Excite. 21 is a card, and when magnetic flux is transmitted from the transmitter 10 to the card-side receiving coil 14, the carrier component is rectified by a rectifier 15, 16 and stored in a capacitor 17, 18. - Data of the force signal component is written into the memory 20 through the control circuit 19.

[Problem to be solved by the invention]

The drive waveform at point A in FIG. 2 is shown in FIG. Figure 3 (a)
is an example in which data 4B (hexadecimal notation) is transmitted. In this example, there are four bits 1, and accordingly, the power is sent moderately, but when data 00 (hexadecimal notation) is transmitted, as shown in Figure 3(b), bit 0 is Since 8 pieces of data are output continuously, there may be a period in which the power is completely cut off depending on the data content.

In order to avoid such a situation, conventional methods have been used in which, as shown in Figure 3 (a) and (b), when one byte is sent, a power charging period is provided, during which time the capacitor is charged. However, if the charging period is one byte, the communication speed will be half of the communication speed per bit.

The present invention aims to improve the above-mentioned drawbacks, make it possible to downsize the capacitor of the card side power supply, and further improve the communication speed.

[Means for solving problems]

In order to achieve such an object, a non-contact magnetic coupling transmitter for an IC memory card is provided with determining means for determining the bit pattern of a data signal and means for inverting the bit pattern based on the determination.

[Effect]

The judgment means counts the number of bits 1 for 1 byte of data,
A determination signal is generated as to whether the number is 5 or more or 4 or less. That is, it is determined whether more than half of all bits are 1. The bit pattern inverting means inverts Ilo of the bit pattern of one byte of data in response to the judgment signal.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of the present invention.

In FIG. 1, 100 is a transmitter and 20[) is a card. 31 is a data buffer in which transmission data is stored. Reference numeral 32 denotes a judgment circuit which inverts or non-inverts the parallel data so that the number of 1's in the parallel data is always greater than the number of 0's by means of a judging means and an inverting means which constitute the judging circuit. 3
4 is a driver which converts parallel data into serial data, modulates the power carrier with transmission data, and excites the transmission coil 35.

The driving waveform at point B in FIG. 1 is shown in FIG. 4. Figure 4(a)
is an example in which data 4B (hexadecimal notation) is transmitted. Immediately after the start bit is an inversion bit where 1 means inversion and 0 means non-inversion.

In this data, since the number of 1's is 4, the inversion bit becomes 1, and the data is inverted as shown in FIG. 4(b).

When the magnetic flux is transmitted to the card side receiving coil 36, the carrier component is rectified by the rectifier 41.42 and stored in the capacitor 43.44. On the other hand, data of the signal component is written into the memory 48 through the control circuit 45.

FIG. 5 shows an example of a judgment circuit. In FIG. 5, 50 is a decoder. For example, the decoder 50 writes inverted and non-inverted data in advance in a read-only memory with a capacity of 256 bytes or more, inputs the original data to the address, and outputs the data as converted data based on the data. It also serves as a means of bit reversal.

Reference numeral 51 is a comparison element for comparing the original data and the converted data and creating an inverted bit.

FIG. 6 shows a flowchart when the determination circuit is constructed using software. In this way, the present invention can also be configured by software.

〔Effect of the invention〕

As can be seen from the above explanation and waveform diagram, according to the method according to the present invention, more than half of the bits in the data part of the power transmission/data waveform are always 1, so unlike the conventional method, the power transmission ability is significantly improved depending on the data content. There is no such thing as falling (
Therefore, since the charging period can be extremely shortened, the communication speed can be improved.

Furthermore, it is possible to downsize the power storage device built into the card, which leads to the downsizing of the card itself.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing a non-contact magnetic coupling transmitter for an IC memory card and a card according to the present invention, FIG. 2 is a circuit diagram showing a conventional non-contact magnetic coupling transmitter for an IC memory card and a card, and FIG. Figures 3(a) and 3(a)) are waveform diagrams showing the output from a conventional non-contact magnetic coupling transmitter for IC memory cards, and Figures 4(a) and (b) are waveform diagrams for IC memory cards of the present invention. FIG. 3 is a waveform diagram showing the output from the non-contact magnetic coupling transmitter. 100... Transmitter, 32... Judgment circuit. 200...Card, Figure Figure 1 L JL Figure Figure m-'' Procedural Amendment (Dragon) August 14, 1990

Claims (1)

[Claims] In a contactless magnetic coupling transmitter for an IC memory card, which is equipped with a transmitter coil for transmitting a data signal and power to the IC memory card and a receiver coil for receiving the data signal from the IC memory card, the bit pattern of the data signal is An IC characterized by comprising a judgment means for making a judgment and a means for inverting a bit pattern based on the judgment.
Contactless magnetic coupling transmitter for memory cards.