JPH1013347A - Infrared-ray data communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To highten substantial communication speed by preventing the saturation of an amplifier for amplifying the output of a light receiving element to shorten a time required to turn a transmission state to the receivable state. SOLUTION: An infrared-ray data communication equipment is provided with a switch 12 for controlling connection between the output terminal 17 of the light receiving element D2 and the input terminal 18 of the amplifier 13 which amplifies the output of the light receiving element D2 and by controlling the operation of the switch 12, the output from the output terminal 17 is prevented from being guided to the input terminal 18 when a light emitting element D1 emits light and is guided to the input terminal 18 when at least data is received.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention performs data communication with information equipment such as a personal computer, an electronic organizer, and an electronic still camera having an infrared data communication function for performing infrared data communication, and other general home appliances. The present invention relates to an infrared data communication device.

[0002]

2. Description of the Related Art FIG. 6 is a block diagram showing a prior art of an infrared data communication apparatus for performing data communication with a personal computer having an infrared data communication function. This device is roughly divided into a transmitting unit 21 and a receiving unit 8
1 and a communication controller 15.

[0003] Specifically, a transmission section 21 transmits a transmission data signal 23 output from the communication controller 15 to the infrared signal 2 by the light emitting element drive circuit 11 and the light emitting element D1.
7 and emits the converted infrared signal 27 toward another infrared data communication device.

[0004] A receiving section 81 receives an infrared signal 28 radiated from another infrared data communication device and converts the infrared signal 28 into a light receiving element D2.
After that, the current signal is converted into a current signal, and then amplified by the amplifier 13 to a predetermined level. The data demodulator 14 demodulates received data from the signal amplified to a predetermined level, and sends out the demodulated received data to the communication controller 15 as a received data signal 24.

[0005] The infrared data communication device having the above configuration is a miniaturized device when applied to wireless data communication means of a portable information device. FIG. 7 shows the appearance of a miniaturized infrared data communication device, in which a light emitting element D1 is provided behind a light emitting window 85 and a light receiving window 86 is provided.
, A light receiving element D2 is provided. For this reason, when the size of the infrared data communication device is reduced in accordance with a request to make the shape as small as possible, the light emitting element D1 and the light receiving element D2 are provided at positions closer to each other in response to the size reduction. .

When the light emitting element D1 and the light receiving element D2 are provided close to each other, the following problems have occurred.

That is, since the light emitting element D1 and the light receiving element D2 are close to each other, a part (indicated by 29) of the infrared ray emitted from the light emitting element D1 at the time of data transmission goes around the light receiving element D2, Received. The infrared ray 29 received by the light receiving element D2 is converted into a current signal, and then converted into a data demodulator 14 via the amplifier 13.
Sent to The data demodulator 14 demodulates data based on the output of the amplifier 13 and outputs the data to the communication controller 15 as a received data signal 24. However, since the demodulated data is random data, there has been a problem that a reception error occurs in the communication controller 15.

In order to prevent the occurrence of this reception error, a conventional technique disclosed in Japanese Patent Laid-Open No. 14979/1993 has been proposed.

FIG. 8 is a block diagram showing the prior art, in which a switch 82 for opening and closing the connection of the received data signal 24 is provided. The switching operation of the switch 82 is controlled by the control signal 25 that is output from the communication controller 15a and switches between data transmission and reception.

That is, at the time of data transmission, a part 29 of the infrared light radiated from the light emitting element D1 wraps around the light receiving element D2, and random data is output from the data demodulator 14 by the wrapped infrared light 29. However, when transmitting data, the connection of the switch 82 is opened. As a result, random data is not guided to the communication controller 15, so that occurrence of a reception error is prevented.

[0011]

However, even when the above configuration is used, the following problems have arisen as the communication speed of infrared data communication increases.

That is, a current corresponding to the intensity of the received infrared light is output from the light receiving element D2. Further, since the distance between the light emitting element D1 and the light receiving element D2 is short, the light intensity of the infrared light circulating to the light receiving element D2 is much stronger than the intensity of the infrared light radiated from another infrared data communication device.

Therefore, during data transmission, an extremely large current is sent from the light receiving element D2 to the amplifier 13. The amplifier 13 that amplifies the current signal from the light receiving element D2 becomes saturated when a signal having an extremely large current value is output from the light receiving element D2, and cannot perform normal amplification.

In order to recover from such a saturated state due to a large current until a normal amplification operation becomes possible, a relatively long period is required because the current value at the time of saturation is large.

This will be described with reference to FIG. 9. In the data transmission periods t11 and t12, the amplifier 13 is in a saturated state. When the data transmission ends, a certain recovery period t13
Has elapsed (time T11, T12), data reception becomes possible.

More specifically, the recovery period t13
10 ms is required, and the communication speed is 4 Mbp
Assuming that s, during the 10 ms period required for recovery at this time,

[0017]

## EQU00001 ## It is possible to transmit a data amount of (4 Mbps.times.10 mS) / 8 = 5000 bytes. This means that since the amplifier 13 was saturated, a time in which communication of a data amount of 5 kbytes was possible wasted. That is, when the data communication speed is increased, there has been a problem that the recovery period required for the amplifier 13 to be operable prevents substantial improvement in the communication speed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to prevent an amplifier for amplifying an output of a light receiving element from being saturated, and to enable reception from a transmission state. By reducing the time it takes to become
An object of the present invention is to provide an infrared data communication device capable of substantially increasing the communication speed.

Another object of the present invention is to provide an infrared data communication apparatus which can simplify control for preventing saturation of an amplifier in addition to the object of the present invention. is there.

The object of the invention described in claim 3 is, in addition to the object of the invention described in claim 1, in addition to the existing signal only,
It is an object of the present invention to provide an infrared data communication device capable of performing control for preventing saturation of an amplifier.

It is another object of the present invention to provide an infrared data communication apparatus capable of simplifying the configuration of an additional circuit for preventing saturation of an amplifier in addition to the above objects. .

[0022]

According to the present invention, there is provided an infrared data communication apparatus comprising a light receiving element for receiving infrared light and a light emitting element for emitting infrared light. The present invention is applied to an infrared data communication device that transmits and receives data, and includes a switch that controls connection between an output terminal of the light receiving element and an input terminal of an amplifier that amplifies an output of the light receiving element, and controls a switching operation of the switch. Thereby, when the light emitting element emits light, the output from the output terminal is prevented from being guided to the input terminal, and at least when the data is received, the output from the output terminal is guided to the input terminal. And

That is, when the light emitting element emits infrared light, a large current is output from the light receiving element due to the infrared light that has entered. However, when the light emitting element emits light, the output from the output terminal is not guided to the input terminal. Therefore, the amplifier does not saturate. Further, when data is received, the output from the output terminal is guided to the input terminal, so that the output converted into an electrical signal by the light receiving element is output after being amplified by the amplifier.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, the infrared data communication apparatus further comprises a control signal indicating whether or not the data is transmitted.
When the control signal indicates that the data is being transmitted, the output from the output terminal is prevented from being guided to the input terminal, and the transmission of the data is performed. When the control signal indicates that the operation is not performed, the output from the output terminal is guided to the input terminal.

That is, the time when the control signal indicates that data transmission is being performed is when infrared light is radiated from the light emitting element. At this time, the output from the output terminal of the light receiving element is equal to the input of the amplifier. Not guided to terminal. Therefore, the amplifier does not saturate. When data is received, data is not transmitted. At this time, the output of the output terminal of the light receiving element is guided to the input terminal of the amplifier.

According to a third aspect of the present invention, in addition to the configuration of the first aspect of the present invention, the infrared data communication apparatus further comprises a light emitting element driving circuit for causing the light emitting element to emit light in accordance with a signal level of a transmission data signal. Transmit data signal
A signal for controlling a switching operation is guided to the switch, and when a signal level of the transmission data signal is a level at which light emission is instructed, an output from the output terminal is prevented from being guided to the input terminal, and the transmission data signal is transmitted. When the signal level is a level at which light emission is not instructed, the output from the output terminal is guided to the input terminal.

That is, the time when the signal level of the transmission data signal is a level at which light emission is instructed is when infrared light is emitted from the light emitting element. In this case, the output from the output terminal of the light receiving element is the input of the amplifier. Not guided to terminal. Therefore, the amplifier does not saturate. When data is received, the signal level of the transmission data signal is at a level at which light emission is not instructed, and the output from the output terminal of the light receiving element is guided to the input terminal of the amplifier.

According to a fourth aspect of the present invention, in addition to the above configuration, the infrared data communication apparatus further comprises an NPN switch.
In the NPN transistor, a signal line for connecting the output terminal and the input terminal is connected to a collector, and a signal for controlling connection between the output terminal and the input terminal is guided to a base of the NPN transistor. The emitter is grounded.

That is, when the NPN transistor is turned on, the output terminal of the light receiving element is grounded, and the output from the output terminal of the light receiving element is not guided to the input terminal of the amplifier. When the NPN transistor is off, the output terminal of the light receiving element is not grounded, so that the output from the output terminal of the light receiving element is guided to the input terminal of the amplifier.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below.
This will be described with reference to the drawings.

FIG. 1 is a block diagram showing an electric configuration of a first embodiment of an infrared data communication apparatus according to the present invention, and shows a configuration corresponding to the first and second aspects of the present invention. . FIG. 2 is a block diagram more specifically showing the embodiment shown in FIG. 1, and shows a configuration corresponding to the invention described in claim 4. In FIGS. 1 and 2, the same reference numerals as in FIGS. 6 and 8 are assigned to blocks having the same configuration as that of the conventional technology.

In the figure, a light emitting element D1 that emits an infrared signal 27 to another infrared data communication device is a light emitting diode that emits infrared light. The light emitting element driving circuit 11 also controls the light emitting element D1 according to the signal level of the transmission data signal 23 output from the communication controller 15a.
Is a switching circuit that emits light.

The light receiving element D2 for receiving the infrared signal 28 emitted from another infrared data communication device is a pin photodiode.

The switch 12 controls the connection between the output terminal 17 of the light receiving element D2 and the input terminal 18 of the amplifier 13 in accordance with the control signal 25. Specifically, when the signal level of the control signal 25 is H level, the connection is opened to prevent the output from the output terminal 17 from being guided to the input terminal 18. When the signal level of the control signal 25 is L level, the connection is closed, and the output from the output terminal 17 is led to the input terminal 18.

This switch 12, as shown in FIG.
The collector is constituted by an NPN transistor Q (hereinafter simply referred to as a transistor Q) connected to the output terminal 17. Also, the base of the transistor Q
The control signal 25 is led via the resistor R, and the emitter is grounded.

The amplifier 13 is connected to the output terminal 1 of the light receiving element D2.
7 is a block that amplifies a weak current signal output from the data demodulator 7 and outputs it to the data demodulator 14 as a TTL level signal. The data demodulator 14 performs data demodulation based on the signal output from the amplifier 13 and outputs the demodulated data as a received data signal 24 to the communication controller 15a.

The communication controller 15a is a block that mainly controls the operation of the infrared data communication device, and is specifically constituted by a microcomputer. Further, a control signal 25 for switching between transmission and reception of data is output. The signal level of the control signal 25 is set to H level during transmission, and is set to L level when transmission is not performed.

The appearance of this embodiment is the same as the shape shown in FIG.

FIG. 5 is a timing chart showing main signal timings. The operation of the present embodiment will be described with reference to FIG.

When transmitting data, the communication controller 15a transmits a signal 2 indicating data to the transmission data signal 23.
31 is output. The light emitting element driving circuit 11 outputs a signal 231
Is at the H level, the light emitting element D1 emits light. Therefore, in the period t2, the infrared signal 2 is output from the light emitting element D1.
7 is emitted.

A part 29 of the infrared rays emitted from the light emitting element D1 goes around the inside of the apparatus main body and is received by the light receiving element D2. For this reason, the signal output from the output terminal 17 of the light receiving element D2 during the period t2 is a signal having an extremely large current value.

On the other hand, when transmitting data, the communication controller 15a sets the period t to indicate that it is transmission.
In 2, the control signal 25 is set to the H level. When the control signal 25 becomes H level, the switch 12 opens the connection in the case of the configuration shown in FIG. 1 and prevents the output from the output terminal 17 from being guided to the input terminal 18. Specifically, as shown in FIG. 2, during the period t2, the transistor Q
Turns on.

Therefore, all of the current output from the light receiving element D2 flows to the ground, and the input terminal 1 of the amplifier 13
8 does not flow. That is, since an excessive output current from the light receiving element D2 does not flow through the input terminal 18 of the amplifier 13, the amplifier 13 maintains a state in which the amplification operation can be performed immediately without being saturated.

When the data to be transmitted ends at time T1, the communication controller 15a changes the control signal 25 to the L level to indicate that the data is not to be transmitted (that is, to be received). When the control signal 25 becomes L level, the switch 12 closes the connection and the light receiving element D
The output from the output terminal 17 of the amplifier 2 is connected to the input terminal 1 of the amplifier 13.
Lead to 8. Specifically, as shown in FIG. 2, the transistor Q is turned off, and the output from the light receiving element D2 is
It is led to 3.

On the other hand, the amplifier 13 during the period t2 is maintained in an operable state immediately without becoming saturated. For this reason, the control signal 25 becomes L level,
When the output of the light receiving element D2 is guided to the amplifier 13 (time T1), the amplifier 13 normally amplifies the signal output from the light receiving element D2 and sends the amplified signal to the data demodulator 14. .

That is, during the period t1 during which no data transmission is performed, as shown by 31 in FIG.
The reception of the infrared signal 28 radiated from another infrared data communication device can be immediately performed without waiting for the recovery of the third data.

FIG. 3 is a block diagram showing an electrical configuration of a second embodiment of the infrared data communication apparatus according to the present invention, and shows a configuration corresponding to the first and third aspects of the present invention. . FIG. 4 is a block diagram more specifically showing the embodiment shown in FIG. 3, and shows a configuration corresponding to the invention described in claim 4.

The configuration shown in FIGS. 3 and 4 corresponds to the configuration shown in FIG.
And the communication controller 15 shown in FIG.
a is the communication controller 15 that does not output the control signal 25
And the only difference is that the signal for controlling the operation of the switch 12 is changed from the control signal 25 to the transmission data signal 23.

That is, the light emitting element D1 that emits the infrared signal 27 is a light emitting diode for infrared light. Also,
The light emitting element driving circuit 11 is a switching circuit that causes the light emitting element D1 to emit light in accordance with the signal level of the transmission data signal 23. Specifically, when the transmission data signal 23 is at the H level, the light emitting element D1 emits light, and when the transmission data signal 23 is at the L level.
At the level, the light emitting element D1 does not emit light.

The light receiving element D2 for receiving the infrared signal 28 is a pin photodiode. Also, the switch 12
Output terminal 17 of light receiving element D2 and input terminal 1 of amplifier 13
8 is a switch for controlling the connection with the transmission data signal 8 according to the signal level of the transmission data signal 23. Specifically, when the transmission data signal 23 is at the H level, the connection is opened to prevent the output of the light receiving element D2 from being guided to the amplifier 13. When the transmission data signal 23 is at the L level, the connection is closed, and the output of the light receiving element D2 is led to the amplifier 13.

This switch 12, as shown in FIG.
A collector is an NPN transistor Q (hereinafter simply referred to as a transistor Q) connected to the output terminal 17;
The transmission data signal 23 is guided to the base via the resistor R. The emitter is grounded.

The amplifier 13 is a block that amplifies a weak current signal output from the light receiving element D2 and outputs the signal to the data demodulator 14 as a TTL level signal. Further, the data demodulator 14 performs data demodulation based on the output of the amplifier 13 and sends out the demodulated data to the communication controller 15 as a received data signal 24.

The communication controller 15 is a block for mainly controlling the operation as an infrared data communication device, and is constituted by a microcomputer in detail. The appearance of the present embodiment is the same as the shape shown in FIG.

The operation of this embodiment will be described with reference to FIG. 5 as needed.

When transmitting data, the communication controller 15 adds a signal 23 indicating data to the transmission data signal 23.
Outputs 1. The light emitting element drive circuit 11 causes the light emitting element D1 to emit light during a period t3 when the signal 231 is at the H level. Therefore, in the period t3, the infrared signal 27 is emitted from the light emitting element D1, and a part 2 of the emitted infrared light is emitted.
9 goes around the inside of the apparatus main body and is received by the light receiving element D2. Therefore, the light receiving element D during the period t3
The signal output from the second output terminal 17 is a signal having an extremely large current value.

On the other hand, the switch 12
When the signal level of No. 3 becomes H level, the connection is opened to prevent the output of the light receiving element D2 from being guided to the amplifier 13. Specifically, as shown in FIG.
Then, the transistor Q is turned on.

Therefore, all of the current output from the light receiving element D2 flows to the ground, and the input terminal 1 of the amplifier 13
8 does not flow. That is, since an excessive output current from the light receiving element D2 does not flow through the input terminal 18 of the amplifier 13, the amplifier 13 maintains a state in which the amplification operation can be performed immediately without being saturated.

When the signal level of the transmission data signal 23 becomes L level and the light emitting element D1 does not emit light, the switch 12 closes the connection and leads the output of the light receiving element D2 to the input terminal 18 of the amplifier 13. . Specifically, FIG.
, The transistor Q is turned off, and the output from the light receiving element D2 is guided to the amplifier 13.

On the other hand, the amplifier 13 in the period t3 is maintained in a state where it can be operated immediately without becoming saturated. For this reason, when the transmission data signal 23 becomes L level and the output of the light receiving element D2 is led to the amplifier 13, the amplifier 13 normally amplifies the signal output from the light receiving element D2 and converts the amplified signal into data. Demodulator 14
To send to.

That is, during a period in which the light emitting element D1 is not emitting light (a period indicated by hatching in 32), the reception of the infrared signal 28 radiated from another infrared data communication device is immediately performed without waiting for the recovery of the amplifier 13. Becomes possible.
Therefore, when the transmission is switched from the transmission to the reception at the time T1, the infrared signal 28 radiated from another infrared data communication device can be immediately received.

[0061]

According to the first aspect of the present invention, there is provided an infrared data communication apparatus including a light receiving element for receiving infrared rays and a light emitting element for emitting infrared rays, and transmitting and receiving data using infrared rays. A switch for controlling connection between an output terminal of the light receiving element and an input terminal of an amplifier for amplifying an output of the light receiving element, and the light emitting element emits light by controlling a switching operation of the switch. Sometimes, the output from the output terminal is prevented from being led to the input terminal, and at least when the data is received, the output from the output terminal is led to the input terminal. That is, when the light emitting element emits light, a large current is output from the light receiving element due to the wrapped infrared light. However, when the light emitting element emits light, the output from the output terminal is not guided to the input terminal, and the amplifier is not saturated. Therefore, the receiving operation is started immediately after the transmission is completed, so that the substantial communication speed can be increased.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, the infrared data communication apparatus further comprises a control signal indicating whether or not the data is transmitted.
When the control signal indicates that the data is being transmitted, the output from the output terminal is prevented from being guided to the input terminal, and the transmission of the data is performed. When the control signal indicates that the operation is not performed, the output from the output terminal is guided to the input terminal. That is, since the saturation of the amplifier is prevented by a simple timing signal indicating the data transmission timing,
The control for preventing the saturation of the amplifier can be simplified.

According to a third aspect of the present invention, in addition to the configuration of the first aspect of the present invention, the infrared data communication apparatus further includes a light emitting element driving circuit for causing the light emitting element to emit light in accordance with a signal level of a transmission data signal. A transmission data signal is guided to the switch as a signal for controlling a switching operation, and when a signal level of the transmission data signal is a level indicating light emission, an output from the output terminal is prevented from being guided to the input terminal, When the signal level of the transmission data signal is a level at which light emission is not instructed, an output from the output terminal is guided to the input terminal. That is, since the saturation of the amplifier is prevented by the timing signal indicating the timing of light emission of the light emitting element, which is indispensable for data transmission, the control for preventing the saturation of the amplifier is performed only by the existing signal. It is possible to do.

According to a fourth aspect of the present invention, in addition to the above configuration, the infrared data communication apparatus further comprises an NPN switch.
In the NPN transistor, a signal line for connecting the output terminal and the input terminal is connected to a collector, and a signal for controlling connection between the output terminal and the input terminal is guided to a base of the NPN transistor. The emitter is grounded. That is, the switch is composed of a circuit having one transistor as a main component,
It is possible to simplify the configuration of an additional circuit for preventing the saturation of the amplifier.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electrical configuration of an embodiment of an infrared data communication device according to the first and second aspects of the present invention.

FIG. 2 is a block diagram showing the configuration shown in FIG. 1 more specifically and showing a configuration corresponding to the invention described in claim 4;

FIG. 3 is a block diagram showing an electrical configuration of an embodiment of the infrared data communication device according to the first and third aspects of the present invention.

FIG. 4 is a block diagram showing the configuration shown in FIG. 3 more specifically and showing a configuration corresponding to the invention described in claim 4;

FIG. 5 is a timing chart showing timings of main signals.

FIG. 6 is a block diagram showing an electrical configuration of the related art.

FIG. 7 is a perspective view showing an appearance of a conventional technique.

FIG. 8 is a block diagram showing an electrical configuration of the related art.

FIG. 9 is an explanatory diagram showing a change in operation in the related art.

[Explanation of symbols]

 Reference Signs List 11 light emitting element drive circuit 12 switch 13 amplifier 17 output terminal 18 input terminal 23 transmission data signal 24 reception data signal 25 control signal D1 light emitting element D2 light receiving element Q NPN transistor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location H04B 10/26 10/14 10/04 10/06

Claims (4)

[Claims] 1. An infrared data communication device comprising a light receiving element for receiving infrared light and a light emitting element for emitting infrared light, and transmitting and receiving data using infrared light, comprising: an output terminal of the light receiving element and an output of the light receiving element. A switch for controlling connection with an input terminal of an amplifier for amplification is provided.By controlling a switching operation of the switch, an output from the output terminal is guided to the input terminal when the light emitting element emits light. An infrared data communication device, wherein at least when the data is received, an output from the output terminal is led to the input terminal. 2. A control signal indicating whether or not the data is being transmitted is guided to the switch as a signal for controlling a switching operation. When the control signal indicates that the data is being transmitted, the output is performed. An output from a terminal is prevented from being guided to the input terminal, and an output from the output terminal is guided to the input terminal when the control signal indicates that the data is not transmitted. Item 7. The infrared data communication device according to Item 1. 3. A light emitting element driving circuit for causing the light emitting element to emit light according to a signal level of a transmission data signal, wherein the transmission data signal is guided to the switch as a signal for controlling a switching operation, and a signal level of the transmission data signal is provided. Prevents the output from the output terminal from being guided to the input terminal when is the level at which light emission is instructed, and outputs the output from the output terminal when the signal level of the transmission data signal is at a level not instructing light emission. The infrared data communication device according to claim 1, wherein the infrared data communication device is guided to the input terminal. 4. The switch comprises an NPN transistor. The NPN transistor has a collector connected to a signal line connecting the output terminal and the input terminal, and a base connected to the output terminal and the input terminal. 4. The infrared data communication device according to claim 1, wherein a signal for controlling connection is guided, and the emitter is grounded.