# US 2017/0288729 A1 · Communication system and transmission apparatus

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- Number: US 2017/0288729 A1
- Document ID: US20170288729A1
- Status: Published application
- Kind: A1
- Application number: 15/508,948
- Filed: 2014-10-28
- Published: 2017-10-05
- Earliest claimed: 2014-10-28
- Assignees: Mitsubishi Electric Corporation
- Applicants: Mitsubishi Electric Corporation
- Inventors: Hiroaki KOTAKE; Yoshiaki KOIZUMI; Takuya MUKAI; Masahiro ISHIHARA
- Web page: https://patentgrep.com/patent/US20170288729A1

## CPC

- H04B 3/56: Circuits for coupling, blocking, or by-passing of signals
- H04B 3/542: {the information being in digital form}
- H04L 25/02: Details {; arrangements for supplying electrical power along data transmission lines (systems for transmitting signals via power distribution lines H04B3/54)}
- H10F 30/245: {Bipolar phototransistors}
- H10F 39/103: {the at least one element covered by H10F30/00 having potential barriers, e.g. integrated devices comprising photodiodes or phototransistors}
- H04B 2203/5466: using three phases conductors
- H04B 2203/5483: using coupling circuits
- H04B: TRANSMISSION
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION

## Abstract

A transmission circuit includes a photocoupler, a conductive/non-conductive state of which is controlled in accordance with data to be transmitted to a communication device. A reception circuit includes a photocoupler, a conductive/non-conductive state of which is controlled in accordance with the conductive/non-conductive state of the transmission path. A transmission circuit includes a photocoupler, a conductive/non-conductive state of which is controlled in accordance with data to be transmitted to a communication device. A reception circuit includes a photocoupler, a conductive/non-conductive state of which is controlled in accordance with the conductive/non-conductive state of the transmission path. The photocoupler is included in the transmission path. The photocoupler and the photocoupler are in opposite conductive/non-conductive states.

## Claims

### Claim 1

A communication system comprising a first communication device and a second communication device that are configured to perform serial communication with each other, either one device of the first communication device and the second communication device including a direct-current power source, the first communication device and the second communication device being connected to each other via a communication line that allows electric current supplied from the direct-current power source to flow therethrough from the one device to another device and via a reference line that allows the electric current passed through the communication line to flow therethrough from the other device to the one device, wherein
the first communication device comprises:
a first transmission circuit comprising a first transmission photocoupler, a conductive/non-conductive state of the first transmission photocoupler being controlled in accordance with data to be transmitted to the second communication device, the first transmission circuit being configured to control a conductive/non-conductive state of a transmission path including the communication line and the reference line in accordance with the conductive/non-conductive state of the first transmission photocoupler; and
a first reception circuit comprising a first reception photocoupler, a conductive/non-conductive state of the first reception photocoupler being controlled in accordance with the conductive/non-conductive state of the transmission path, the first reception circuit being configured to detect the conductive/non-conductive state of the first reception photocoupler, thereby receiving data transmitted by the second communication device,
the second communication device comprises:
a second transmission circuit comprising a second transmission photocoupler, a conductive/non-conductive state of the second transmission photocoupler being controlled in accordance with data to be transmitted to the first communication device, the second transmission circuit being configured to control the conductive/non-conductive state of the transmission path in accordance with the conductive/non-conductive state of the second transmission photocoupler; and
a second reception circuit comprising a second reception photocoupler, a conductive/non-conductive state of the second reception photocoupler being controlled in accordance with the conductive/non-conductive state of the transmission path, the second reception circuit being configured to detect the conductive/non-conductive state of the second reception photocoupler, thereby receiving data transmitted by the first communication device,
the second reception photocoupler is included in the transmission path, and
the first transmission photocoupler and the second reception photocoupler are in opposite conductive/non-conductive states.

### Claim 2 (depends on 1)

The communication system according to claim 1, wherein
the first transmission circuit further comprises a first PNP transistor including a current path included in the transmission path, and a first resistance including one end connected to a base of the first PNP transistor and another end connected to the reference line,
the first transmission photocoupler includes a collector connected to an emitter of the first PNP transistor, and
the first transmission photocoupler includes an emitter connected to the base of the first PNP transistor.

### Claim 3 (depends on 1)

The communication system according to claim 1, wherein
the second reception circuit further comprises a first NPN transistor, a second resistance including one end connected to a collector of the first NPN transistor and another end connected to a first power source terminal, and a third resistance including one end connected to a base of the first NPN transistor and another end connected to the first power source terminal,
the second reception photocoupler includes a collector connected to the base of the first NPN transistor, and
the second reception photocoupler includes an emitter connected to a first ground terminal and to an emitter of the first NPN transistor.

### Claim 4 (depends on 1)

The communication system according to claim 1, wherein
the first reception photocoupler is included in the transmission path, and
the second transmission photocoupler and the first reception photocoupler are in opposite conductive/non-conductive states.

### Claim 5 (depends on 4)

The communication system according to claim 4, wherein
the second transmission circuit further comprises a second PNP transistor including a current path included in the transmission path, and a fourth resistance including one end connected to a base of the second PNP transistor and another end connected to the reference line,
the second transmission photocoupler includes a collector connected to an emitter of the second PNP transistor, and
the second transmission photocoupler includes an emitter connected to the base of the second PNP transistor.

### Claim 6 (depends on 4)

The communication system according to claim 4, wherein
the first reception circuit further comprises a second NPN transistor, a fifth resistance including one end connected to a collector of the second NPN transistor and another end connected to a second power source terminal, and a sixth resistance including one end connected to a base of the second NPN transistor and another end connected to the second power source terminal,
the first reception photocoupler includes a collector connected to the base of the second NPN transistor, and
the first reception photocoupler includes an emitter connected to a second ground terminal and to an emitter of the second NPN transistor.

### Claim 7

A transmission device for data transmission by control of a conductive/non-conductive state of a transmission path including a communication line and a reference line, the transmission device being connected via the communication line and the reference line to a reception device comprising a reception photocoupler, a conductive/non-conductive state of the reception photocoupler being controlled in accordance with the conductive/non-conductive state of the transmission path, the reception device being configured to receive data by detection of the conductive/non-conductive of the reception photocoupler,
either one device of the transmission device and the reception device including a direct-current power source for supply of electric current on the transmission path,
the electric current, supplied by the direct-current power source, flowing from the one device via the communication line to another device and flowing from the other device via the reference line to the one device,
the transmission device comprising:
a transmission circuit comprising a transmission photocoupler, a conductive/non-conductive state of the transmission photocoupler being controlled in accordance with data to be transmitted to the reception device, the transmission circuit being configured to control the conductive/non-conductive state of the transmission path in accordance with the conductive/non-conductive state of the transmission photocoupler,
wherein
the reception photocoupler is included in the transmission path, and
the transmission photocoupler and the reception photocoupler are in opposite conductive/non-conductive states.

### Claim 8 (depends on 7)

The transmission device according to claim 7, wherein
the transmission circuit further comprises a first PNP transistor including a current path included in the transmission path, and a first resistance including one end connected to a base of the first PNP transistor and another end connected to the reference line,
the transmission photocoupler includes a collector connected to an emitter of the first PNP transistor, and
the transmission photocoupler includes an emitter connected to the base of the first PNP transistor.