JPH01176123A - Communication system - Google Patents

Abstract

PURPOSE:To reduce the system cost and to make the size of the system small by using one line in time division and sending an electric energy and a signal from a 1st equipment to a 2nd equipment. CONSTITUTION:A controller 1 brings the level of a terminal P1 to LO level at a period T1 and a transistor(TR) 2 is turned on, then the power energy is fed to an external device through a terminal PDLIN and a capacitor 3 of the external device stores the power energy. On the other hand, the controller 1 brings the level of the terminal P1 to LO level at a period T2 and the TR 2 is turned off, then the communication between the controller 1 and the external device is attained from a terminal P2 via a terminal PDLIN. Thus, the system main body and the external device are connected by two lines in total, that is, ground line and a line sending the electric energy and signal in the time division and the system is miniaturized.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a communication system for communicating between, for example, a system body equipped with a power source and an external device not equipped with a power source. Regarding.

(Prior Art) Generally, when exchanging data between a system main body and an external device, some kind of communication means is required.

There are various methods of communication means, but there is a method in which power is supplied from the system main body side without providing a power source on the external device side.

By the way, three systems of communication lines are required in this case: a power supply line, a ground line, and a signal line, but as the number of lines increases, the connectors etc. become larger and the system cost increases.

Also, on the sending side, such as in telephones, DC is used as power energy.
A method is also known in which the AC component is combined with the AC component that becomes the signal, and the receiving side separates both components using a filter circuit, etc., but this method requires a transformer, etc., making it difficult to miniaturize the system. There is a problem.

(Problems to be Solved by the Invention) The present invention has been made in view of the above circumstances, and aims to reduce system costs and reduce system costs when communicating between an external device that does not have a power source and a system body that has a power source. The purpose is to make the system more compact.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a method for communicating via a predetermined line between a first device equipped with a power source and a second device not equipped with a power source. , the second device is provided with a capacitive element that stores electrical energy, and one line is time-divided to send electrical energy from the first device to the second device in the first period, and in the second period. The second device performs communication using electrical energy stored in the capacitive element.

(Function) In the communication system of the present invention, a capacitive element for storing electrical energy is provided in the second device, and one line is time-divisionally transferred from the first device to the second device in the first period. Electrical energy is sent, and the second device performs communication using the electrical energy stored in the capacitive element during the second period, so the line to be installed between the first device and the second device is The number of lines can be reduced to two, the above-mentioned line and the ground line.

(Example) Hereinafter, details of an example of the present invention will be described based on the drawings.

FIG. 1 is a diagram illustrating the configuration of the system main body side in an embodiment of the present invention, and FIG. 2 is a diagram not showing the configuration of the external device side in an embodiment of the present invention.

In FIG. 1, 1 is a controller (microcomputer) that controls communication, and 2 is a transistor that switches between supplying electrical energy and transmitting and receiving signals. Furthermore, R1 is a resistor that sets the base voltage of transistor 2, R2 is a resistor that sets the emitter-to-base current of transistor 2,
R3 and R4 are resistors that set the current of signals to be transmitted and received, and R5 is a resistor that pulls up the signals to be transmitted and received.

Note that PDLIN is a terminal for inputting and outputting power or signals,
ND is a ground terminal.

In Fig. 2, 3 is a capacitor for storing power supply energy, 4 is a diode for preventing backflow of electrical energy, and 5 is a capacitor for storing power supply energy.
is a reset circuit that outputs a clear signal to a device on the external device side when the potential at the Δ point decreases, and R6 is a resistor that sets the current of the signal to be transmitted and received.

FIG. 3 is a diagram showing the operation of the circuit shown in FIGS. 1 and 2.

In the figure, T1 is a period during which the system main body side supplies electrical energy to an external device. During this period T1, the controller 1 sets the terminal P1 to LO level, and the transistor 2
becomes ON.

Therefore, the power supply energy is sent to the external device through the terminal PDLIN, and the capacitor 3 stores this power energy on the external device side.

- In Figure 3, T2 is a period during which the system main body and an external device communicate. During this period T2, the controller 1 sets the terminal P1 to HI level, and the transistor 2 turns OFF.
Becomes F state. Therefore, from terminal P2 to terminal PDL[N
Communication between the controller 1 and external devices is possible via the .

At this time, as shown by Ml, the controller 1
is set to LO level for period T3. This becomes a communication request from the controller 1 and is sent to the external device. The external device waits for receiving this communication request and transmits a signal to the system main body, and thereafter communication data M2 is exchanged between the system main body and the external device within a period T2.

Then, during period T2, electrical energy for the external device is supplied from capacitor 3, which has been charged during period T3. During this period, if the voltage at point A in the external device becomes low, the reset circuit 5 resets the device on the external device side.

Thus, according to this embodiment, the sum of the ground line and the line for transmitting electrical energy and signals in a time division manner is
Since the system main body and an external device can be connected with two lines, the configuration of the connection part is simplified.

In addition, unlike a telephone, the system does not involve adding electric energy to the signal by m, so the system can be made smaller and is resistant to external factors such as noise.

Although this embodiment describes the case where communication is performed between the system main body and an external device, the present invention can be widely applied to cases where communication is performed between a device with a power source and a device without a power source. can.

[Effects of the Invention] As explained above, in the system of the present invention, electric energy and signals are sent from the first device to the second device using one line in a time-division manner. The number of lines between the device and the device can be reduced to two including the ground line, thereby reducing system cost and downsizing the system.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the configuration of the system main body side in an embodiment of the present invention, FIG. 2 is a circuit diagram showing the configuration of the external device side in an embodiment of the present invention, and FIG. 3 is a circuit diagram of the same embodiment. FIG. 3 is a diagram for explaining the operation. 1... Controller, 2... Transistor, 3...
・Capacitor, 4...Diode, 5...Reset circuit. Applicant Toshiba Corporation Patent Attorney Sasa Suyama - Figure 2 Figure 3

Claims (1)

[Claims] (1) When communicating via a predetermined line between a first device equipped with a power source and a second device not equipped with a power source, the second device is provided with a capacitive element that stores electrical energy. , one line is time-divided to send electrical energy from the first device to the second device in the first period, and in the second period, the second device uses the electrical energy stored in the capacitive element. A communication system characterized by being configured to perform communication.