JP2008028906A - Optical communication device, and electronics - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical communication device which has low power consumption, can communicate at high speed, is miniaturized, is light-weighted, and accordingly is suitable for being incorporated in a mobile product. <P>SOLUTION: The optical communication device comprises a light emitter 1 for emitting a light, a light receiver 2 for performing a photoelectric conversion of an incident light, a transmission circuit 11 that receives a transmission signal SS and drives the light emitter 1, a reception circuit 21 that processes a signal generated by the light receiver 2 and outputs a reception signal SR, a first power supply route 18 for supplying a power to the transmission circuit 11, and a second power supply route for supplying a power to the reception circuit 21 on a common member integrally. An electric power shutoff for reception circuit for shutting off a power supply to the reception circuit 21 in synchronization with the transmission signal SS is provided in the second power supply route. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical communication device, and more particularly to an optical communication device that includes a light emitting unit and a light receiving unit and performs optical communication with another electronic device. Typically, the present invention relates to an infrared communication device that performs data communication using infrared rays.

  The present invention also relates to an electronic apparatus provided with such an optical communication device.

FIG. 9A shows a configuration of a conventional infrared communication device incorporated in a mobile product. 2 shows a block configuration of an infrared communication device. The infrared communication device includes a light emitting chip 101, a transmission circuit 111 that drives the light emitting chip 101, a light receiving chip 102, and a receiving circuit 121 that processes a signal from the light receiving chip 102 on a substrate 190. Yes. The transmission circuit 111 and the reception circuit 121 are configured by an IC (integrated circuit) chip. A transmission signal SS (see FIG. 9B) is input to the input unit 112 of the transmission circuit 111 from the outside through an input terminal 191 on the substrate 190. The light emitting chip 101 is caused to emit light. The reception circuit 121 is configured to keep the reception signal SR at the L (low) level while the transmission signal SS is at the H level. The reception signal SR is output from the output unit 123 of the reception circuit 121 to the outside through the output terminal 192 on the substrate 190. On the substrate 190, a Vcc terminal 193 that receives supply of power (potential Vcc) from the outside and a GND terminal 194 that is maintained at the ground potential are provided. The transmission circuit 111 and the reception circuit 121 operate by receiving power from the power supply receiving units 113 and 122 through wirings 118 and 128 connected to the Vcc terminal 193, respectively (Icc indicates current consumption of the infrared communication device). The transmission circuit 111 and the reception circuit 121 are grounded to the GND terminal 194 through wirings 119 and 129, respectively.
Japanese Patent Laid-Open No. 11-205239 JP-A-9-326800

  This type of infrared communication device is used for various applications such as mobile phones, mobile personal computers, PDAs (Personal Digital Assistants), printers, etc., and in recent years it has been used for data communication with other electronic devices (such as parent devices). More and more applications are built into mobile products. In mobile products, there are strong demands such as low power consumption (reducing battery burden), small size and light weight, and high communication speed, and the same specifications are required for infrared communication devices incorporated therein.

  Correspondingly, the optical lens (not shown) used in such mobile products is also reduced in size, so that the directivity of light emission becomes narrow in the light emitting part of the infrared communication device, and the light emission intensity when the lens angle is shifted. Tends to decrease, and the light receiving section of the infrared communication device has a tendency to deteriorate the light condensing property and decrease the receiving sensitivity.

  Here, if a high-power type light-emitting chip is used to increase the light emission intensity, or if the light-emitting output is increased by passing a high drive current through the light-emitting chip, the light-emitting chip is expensive and the cost is increased. Therefore, it is not preferable. Similarly, if a high-sensitivity type light receiving chip is used to increase the sensitivity of reception, or if a circuit for increasing the sensitivity is added to the IC chip, the IC chip is expensive and the cost is increased. Therefore, it is not preferable.

  In particular, if a high drive current is applied using a high-power type light-emitting chip in the light-emitting section, heat is generated beyond the package loss due to the drive current, and the light emission intensity decreases instead of increasing as designed. Or a malfunction or a short life. In addition, the IC chip may malfunction due to the heat generation. If the circuit for malfunction prevention is built in the IC chip, the circuit scale becomes enormous, the size of the IC chip increases, it becomes difficult to reduce the size, and the cost of the member increases.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an optical communication device that satisfies the demands for low power consumption, high communication speed, and small size and light weight and is suitable for being incorporated into a mobile product.

  Moreover, this invention is providing the electronic device provided with such an optical communication device.

In order to solve the above-described problems, an optical communication device of the present invention includes:
Integrally on a common member,
A light emitting unit for emitting light;
A light receiving unit that photoelectrically converts incident light; and
A transmission circuit that receives the transmission signal and drives the light emitting unit;
A receiving circuit that processes a signal generated by the light receiving unit and outputs a received signal;
A first power supply path for supplying power to the transmission circuit;
A second power supply path for supplying power to the receiving circuit,
The second power supply path is provided with a power interrupting unit for receiving circuit that shuts off power supply to the receiving circuit in synchronization with the transmission signal.

  In the optical communication device according to the present invention, the power cutoff unit for the reception circuit cuts off the power supply to the reception circuit in synchronization with the transmission signal, so that the reception is performed during the transmission period in which the transmission circuit drives the light emitting unit. The power supply to the circuit is interrupted. Therefore, it is possible to reduce wasteful current consumption flowing in the receiving circuit. Since the current consumption flowing in the receiving circuit during the transmission period can be reduced in this way, the burden on the battery is reduced when the optical communication device is incorporated into a mobile product.

  In addition, since the current consumption flowing in the receiving circuit can be reduced during the transmission period, that is, during the heat generation of the light emitting unit, the heat generation (package temperature rise) as the entire optical communication device can be effectively suppressed. Therefore, the failure rate of the light emitting unit (for example, the light emitting chip) can be reduced, and the life of the light emitting unit can be improved. That is, reliability can be improved.

  In addition, since heat generation can be effectively suppressed, stable communication can be performed without passing an extra driving current to the light emitting unit during the transmission period, and communication speed can be increased and long-distance communication can be performed.

  Further, since the heat generation can be effectively suppressed, a circuit for preventing malfunction (for example, malfunction due to heat generation or malfunction when ambient light is incident) can be omitted in the IC chip constituting the transmission circuit or the reception circuit. . Therefore, it is possible to reduce the size of the IC chip, thereby reducing the size and weight and reducing the cost.

  The light emitting unit, the light receiving unit, the transmitting circuit, the receiving circuit, the first power supply path, the second power supply path, and the receiving circuit power cut-off unit are integrally mounted on a common member. Is desirable. The common member widely refers to a member on which each component can be mounted, such as a printed wiring board and a lead frame (copper material).

  In the optical communication device according to an embodiment, the reception circuit power cut-off unit cuts off power supply to the reception circuit for a certain period from a timing at which the transmission signal transitions.

In the optical communication device according to this embodiment, the reception circuit power cut-off unit cuts off the power supply to the reception circuit for a certain period from the timing at which the transmission signal transitions. That is, the receiving circuit power cut-off unit has a timer function. Therefore, it is possible to reliably cut off the power supply to the receiving circuit during the transmission period, and it is possible to appropriately suppress wasteful current consumption flowing through the receiving circuit. The receiving circuit power cut-off section can be provided with a timer function by adding a small circuit without increasing the circuit scale of the IC chip constituting the optical communication device. Therefore, this optical communication device is small and light, and in another aspect, the optical communication device of the present invention is
Integrally on a common member,
A light emitting unit for emitting light;
A light receiving unit that photoelectrically converts incident light; and
A transmission circuit that receives the transmission signal and drives the light emitting unit;
A receiving circuit that processes a signal generated by the light receiving unit and outputs a received signal;
A first power supply path for supplying power to the transmission circuit;
A second power supply path for supplying power to the receiving circuit,
A transmission circuit power cut-off unit that cuts off power supply to the transmission circuit in synchronization with the reception signal is provided in the first power supply path.

  In the optical communication device of the present invention, the transmission circuit power cut-off unit cuts off the power supply to the transmission circuit in synchronization with the reception signal, so that the reception circuit processes the output of the light receiving unit during the reception period. The power supply to the receiving circuit is cut off. Accordingly, it is possible to reduce useless current consumption flowing in the transmission circuit. As described above, since the current consumption flowing in the transmission circuit during the reception period can be reduced, the burden on the battery is reduced when the optical communication device is incorporated in a mobile product.

  In addition, since the current consumption flowing in the transmission circuit during the reception period can be reduced, heat generation (temperature rise of the package) as the entire optical communication device can be effectively suppressed. Therefore, the failure rate of the light emitting unit (for example, the light emitting chip) can be reduced, and the life of the light emitting unit can be improved. That is, reliability can be improved.

  In addition, since heat generation can be effectively suppressed, stable communication can be performed without passing an extra driving current to the light emitting unit during the transmission period, and communication speed can be increased and long-distance communication can be performed.

  Further, since the heat generation can be effectively suppressed, a circuit for preventing malfunction (for example, malfunction due to heat generation or malfunction when ambient light is incident) can be omitted in the IC chip constituting the transmission circuit or the reception circuit. . Therefore, it is possible to reduce the size of the IC chip, thereby reducing the size and weight and reducing the cost.

  The light emitting unit, the light receiving unit, the transmission circuit, the reception circuit, the first power supply path, the second power supply path, and the transmission circuit power cut-off unit are integrally mounted on a common member. Is desirable. The common member widely refers to a member on which each component can be mounted, such as a printed wiring board and a lead frame (copper material).

  In the optical communication device according to an embodiment, the transmission circuit power cut-off unit cuts off power supply to the transmission circuit for a certain period from a timing at which the reception signal transitions.

  In the optical communication device according to this embodiment, the transmission circuit power cut-off unit cuts off the power supply to the transmission circuit for a certain period from the timing at which the reception signal transitions. That is, the transmission circuit power cut-off unit has a timer function. Therefore, power supply to the transmission circuit can be reliably cut off during the reception period, and wasteful current consumption flowing through the transmission circuit can be appropriately suppressed.

  In the optical communication device according to an embodiment, the transmission circuit drives the light emitting unit after the transmission period in which the transmission circuit drives the light emitting unit or the reception period in which the reception circuit processes the output of the light receiving unit. The transmission circuit power cut-off unit cuts off the power supply to the transmission circuit when a standby state in which the transmission operation is not performed and the reception circuit does not perform the reception operation for processing the output of the light receiving unit continues for a certain period. In addition, the receiving circuit power cut-off unit cuts off the power supply to the receiving circuit.

  In the optical communication device of this embodiment, when the standby state continues for a certain period, the power cutoff unit for the transmission circuit cuts off the power supply to the transmission circuit, and the power cutoff unit for the reception circuit Since the power supply to is cut off, the current consumption can be further suppressed.

  In addition, although power is supplied to the transmission circuit and the reception circuit, the transmission circuit does not perform a transmission operation for driving the light emitting unit, and the reception circuit performs a reception operation for processing the output of the light receiving unit. The state where there is no is called “standby state”.

  In addition, a state in which the transmission circuit power cut-off unit cuts off power supply to the transmission circuit and the reception circuit power cut-off unit cuts off power supply to the reception circuit is referred to as a “shutdown state”. .

  In the optical communication device of one embodiment, the transmission circuit power cutoff unit shuts off the power supply to the transmission circuit and the reception circuit power cutoff unit receives the reception when the standby state continues for a certain period. After a transition to a shutdown state that cuts off the power supply to the circuit, when a certain period of time has elapsed, the power cutoff unit for the transmission circuit and the power cutoff unit for the reception circuit are respectively supplied with power to the transmission circuit and the reception circuit. The supply is started.

  In the optical communication device of this embodiment, after the transition to the shutdown state because the standby state has continued for a certain period, when the certain period has passed, the transmission circuit power cutoff unit and the reception circuit power cutoff unit are The power supply to the transmission circuit and the reception circuit is restarted. Therefore, the optical communication device can be returned to the standby state or the operating state.

  In the optical communication device of one embodiment, the transmission circuit power cutoff unit shuts off the power supply to the transmission circuit and the reception circuit power cutoff unit receives the reception when the standby state continues for a certain period. After shifting to a shutdown state that cuts off the power supply to the circuit, the transmission circuit power cutoff unit and the reception circuit power cutoff unit supply power to the transmission circuit and the reception circuit, respectively, in synchronization with the transmission signal. It is characterized by starting.

  In the optical communication device of this embodiment, after the standby state has shifted to the shutdown state due to a certain period of time, the transmission circuit power cutoff unit and the reception circuit power cutoff unit are respectively synchronized with the transmission signal. The power supply to the transmission circuit and the reception circuit is resumed. Therefore, the optical communication device can be returned from the shutdown state to the operation state (particularly, the transmission operation state) in synchronization with the transmission signal.

  In the optical communication device of one embodiment, the transmission circuit power cutoff unit shuts off the power supply to the transmission circuit and the reception circuit power cutoff unit receives the reception when the standby state continues for a certain period. After the power supply to the circuit is cut off, the transmission circuit power cutoff unit and the reception circuit power cutoff unit start supplying power to the transmission circuit and the reception circuit, respectively, in synchronization with the reception signal. Features.

  In the optical communication device according to this embodiment, after the standby state has shifted to the shutdown state due to a certain period of time, the transmission circuit power cutoff unit and the reception circuit power cutoff unit are respectively synchronized with the reception signal. The power supply to the transmission circuit and the reception circuit is resumed. Therefore, the optical communication device can be returned from the shutdown state to the operating state (particularly, the receiving operation state) in synchronization with the received signal.

  An electronic apparatus of the present invention is an electronic apparatus provided with the optical communication device.

  In the electronic device of the present invention, it is possible to satisfy demands such as low power consumption (reduction of battery burden), reduction in size and weight, and increase in communication speed.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

(First embodiment)
FIG. 1A shows a block configuration of an infrared communication device according to an embodiment of the present invention incorporated in a mobile product. The infrared communication device includes a light emitting chip 1 as a light emitting unit, a transmission circuit 11 for driving the light emitting chip 1, a light receiving chip 2 as a light receiving unit, and a signal from the light receiving chip 2 on a common substrate 90. And a receiving circuit 21 for processing the above. The transmission circuit 11 and the reception circuit 21 are configured by an IC (integrated circuit) chip.

  On the substrate 90, there are provided a Vcc terminal 93 which receives supply of power (potential Vcc) from the outside, and a GND terminal 94 which is kept at the ground potential. In this example, the transmission circuit 11 operates by receiving power from the power supply receiving unit 13 through the wiring 18 serving as a first power supply path connected to the Vcc terminal 93. On the other hand, in the second power supply path between the Vcc terminal 93 and the power receiving unit 22 of the receiving circuit 21, a PNP transistor 41 is provided as a receiving circuit power cut-off unit. In this example, the base terminal B of the transistor 41 is connected to the input terminal 91 by the wiring 14. The transmission circuit 11 and the reception circuit 21 are grounded to the GND terminal 94 by wirings 19 and 29, respectively. Icc indicates the current consumption of the infrared communication device.

  A transmission signal SS (see FIG. 1B) is input to the input unit 12 of the transmission circuit 11 from the outside through the input terminal 91 on the substrate 90. When receiving power supply from the power supply receiving unit 13, the transmission circuit 11 drives the light emitting chip 1 to emit light during a period when the transmission signal SS is at the H (high) level, that is, during the transmission period. While the transmission signal SS is at the L (low) level, the light emitting chip 1 is not driven and the standby state is set. When the power supply unit 13 does not receive power supply, the transmission circuit 11 stops operating.

  As shown in FIG. 1C, during the period in which the transmission signal SS is at the H level, the input to the base terminal of the transistor 41 (shown as “B input” in the figure) is at the H level, and the transistor 41 is turned off. The emitter-collector of the transistor 41 (shown as “EC connection” in the figure) is cut off (turned off). Accordingly, during the transmission period when the transmission signal SS is at the H level, the power supply to the power supply unit 22 is cut off in synchronization with the transmission period, and the reception circuit 21 stops its operation.

  On the other hand, while the transmission signal SS is at the L level, the input to the base terminal of the transistor 41 is at the L level, the transistor 41 is turned on, and the emitter and collector of the transistor 41 are conducted (turned on). Therefore, during the period when the transmission signal SS is at the L level, the reception circuit 21 processes the signal generated by the light receiving chip 2 and outputs the reception signal SR corresponding thereto. The reception signal SR is output from the output unit 23 of the reception circuit 21 to the outside through the output terminal 92 on the substrate 90.

  As described above, in this infrared communication device, the power supply to the reception circuit 21 is interrupted during the transmission period, and the reception circuit 21 stops its operation. Accordingly, it is possible to reduce useless consumption current flowing in the receiving circuit 21. As described above, since the current consumption flowing in the receiving circuit 21 during the transmission period can be reduced, the burden on the battery is reduced in the mobile product in which the infrared communication device is incorporated.

  Further, since the current consumption flowing to the receiving circuit 21 can be reduced during the transmission period, that is, during the heat generation of the light-emitting chip 1, the heat generation (package temperature rise) as the entire infrared communication device can be effectively suppressed. Therefore, the failure rate of the light emitting chip 1 can be reduced, and the life of the light emitting chip 1 can be improved. That is, reliability can be improved.

  In addition, since heat generation can be effectively suppressed, stable communication can be performed without supplying an extra driving current to the light emitting chip 1 during the transmission period, and communication speed can be increased and long-distance communication can be performed.

  In addition, since the heat generation can be effectively suppressed, a circuit for preventing malfunction (for example, malfunction due to heat generation or malfunction when ambient light is incident) in the IC chip constituting the transmission circuit 11 or the reception circuit 21 is provided. Can be omitted. Therefore, it is possible to reduce the size of the IC chip, thereby reducing the size and weight and reducing the cost.

(Second Embodiment)
FIG. 2A shows a modification of the infrared communication device shown in FIG. 1A. In addition, the same code | symbol is attached | subjected to the component same as the component in FIG. 1A (hereinafter the same).

  This infrared communication device includes a timer circuit 42 connected to the wiring 14 connected to the input terminal 91 in addition to the transistor 41 as a power interrupting unit for the receiving circuit. That is, the transistor 41 and the timer circuit 42 constitute a reception circuit power cutoff unit. The timer circuit 42 receives the transmission signal SS and outputs an H level signal as the output BS1 only for a certain period from the timing when the transmission signal SS transits from the L level to the H level. During other periods, the output BS1 of the timer circuit 42 is at L level. The output BS1 of the timer circuit 42 is input to the base terminal B of the transistor 41 through the wiring 42BS.

  As shown in FIG. 2B, it is assumed that the transmission signal SS is initially at L level and the output BS1 of the timer circuit 42 is at L level. When the transmission signal SS transitions from the L level to the H level, the timer circuit 42 outputs an H level signal as the output BS1 for a certain period from the timing at which the transmission signal SS transitions. As shown in FIG. 2C, the transistor 41 is turned off by the output BS1 of the timer circuit 42 corresponding to the transmission signal SS. Therefore, the power supply to the receiving circuit 21 can be reliably cut off during the transmission period, and the operation of the receiving circuit 21 can be stopped. Therefore, it is possible to appropriately suppress useless consumption current flowing in the reception circuit 21.

  The provision of the timer circuit 42 on the substrate 90 is possible by adding a small scale circuit without enlarging the circuit scale of the IC chip constituting the infrared communication device.

(Third embodiment)
FIG. 3A shows a block configuration of an infrared communication device according to another embodiment of the present invention incorporated in a mobile product.

  In this infrared communication device, the receiving circuit 21 operates by receiving power from the power supply receiving unit 22 through the wiring 28 serving as the second power supply path connected to the Vcc terminal 93. On the other hand, in the first power supply path between the Vcc terminal 93 and the power supply receiving unit 13 of the transmission circuit 11, an NPN transistor 43 as a transmission circuit power cutoff unit is provided. In this example, the base terminal B of the transistor 43 is connected to the output terminal 92 by the wiring 24.

  An optical signal SP is input to the light receiving chip 2 from the outside. When receiving power supply from the power receiving unit 22, the receiving circuit 21 processes a signal generated by the light receiving chip 2 and outputs a received signal SR corresponding thereto. Specifically, as shown in FIG. 3B, when the optical signal SP is at the H level, the reception signal SR is at the L level, and when the optical signal SP is at the L level, the reception signal SR is at the H level. The reception signal SR is output from the output unit 23 of the reception circuit 21 to the outside through the output terminal 92 on the substrate 90.

  As shown in FIG. 3C, during the period in which the received signal SR is at the L level, the input to the base terminal of the transistor 43 (shown as “B input” in the figure) is at the L level, and the transistor 43 is turned off. The emitter-collector of the transistor 43 (shown as “EC connection” in the figure) is cut off (turned off). Therefore, while the reception signal SR is at the L level, the power supply to the power supply unit 13 is cut off in synchronization with the reception signal SR, and the transmission circuit 11 stops operating.

  On the other hand, while the received signal SR is at the H level, the input to the base terminal of the transistor 43 is at the H level, the transistor 43 is turned on, and the emitter and collector of the transistor 43 are conducted (turned on). Therefore, during a period in which the reception signal SR is at the H level, the transmission circuit 11 is in a transmission operation state or a standby state depending on whether the transmission signal SS is at the H level or the L level.

  As described above, in this infrared communication device, during the period in which the optical signal SP is at the H level, that is, during the period in which the reception signal SR is at the L level, the power supply to the power supply receiving unit 13 is cut off in synchronization therewith, The transmission circuit 11 stops operating. Therefore, it is possible to reduce wasteful current consumption flowing in the transmission circuit 11. As described above, since the current consumption flowing in the transmission circuit 11 during the reception period can be reduced, the battery load is reduced in the mobile product in which the infrared communication device is incorporated.

  In addition, since the current consumption flowing in the transmission circuit 11 during the reception period can be reduced, heat generation (temperature rise of the package) as the entire infrared communication device can be effectively suppressed. Therefore, the failure rate of the light emitting chip 1 can be reduced, and the life of the light emitting chip 1 can be improved. That is, reliability can be improved.

  In addition, since heat generation can be effectively suppressed, stable communication can be performed without supplying an extra driving current to the light emitting chip 1 during the transmission period, and communication speed can be increased and long-distance communication can be performed.

  In addition, since the heat generation can be effectively suppressed, a circuit for preventing malfunction (for example, malfunction due to heat generation or malfunction when ambient light is incident) in the IC chip constituting the transmission circuit 11 or the reception circuit 21 is provided. Can be omitted. Therefore, it is possible to reduce the size of the IC chip, thereby reducing the size and weight and reducing the cost.

(Fourth embodiment)
FIG. 4A shows a modification of the infrared communication device shown in FIG. 3A.

  This infrared communication device includes a timer circuit 44 connected to the wiring 24 connected to the output terminal 92 in addition to the transistor 43 as a power cutoff unit for a transmission circuit. That is, the transistor 43 and the timer circuit 44 constitute a transmission circuit power cutoff unit. The timer circuit 44 receives the reception signal SR and outputs an L level signal as the output BS2 only for a certain period from the timing when the reception signal SR transits from the H level to the L level. During other periods, the output BS2 of the timer circuit 44 is at the H level. The output BS2 of the timer circuit 44 is input to the base terminal B of the transistor 43 through the wiring 44BS.

  As shown in FIG. 4B, it is assumed that the received signal SR is initially at the H level in response to the optical signal SP being at the L level, and the output BS2 of the timer circuit 44 is at the H level. When the reception signal SR transits from the H level to the L level, the timer circuit 44 outputs an L level signal as the output BS2 for a certain period from the timing at which the reception signal SR transits. As shown in FIG. 4C, the transistor 43 is turned off by the output BS2 of the timer circuit 44 corresponding to the received signal SR. Therefore, it is possible to reliably cut off the power supply to the transmission circuit 11 during the reception period, and it is possible to appropriately suppress useless current consumption flowing through the transmission circuit 11.

  The provision of the timer circuit 44 on the substrate 90 is possible by adding a small circuit without increasing the circuit scale of the IC chip constituting the infrared communication device.

(Fifth embodiment)
FIG. 5A shows a block configuration of an infrared communication device according to another embodiment of the present invention incorporated in a mobile product.

  In this infrared communication device, the NPN transistor 46 provided in the first power supply path between the Vcc terminal 93 and the power supply unit 13 of the transmission circuit 11, the Vcc terminal 93 and the power supply unit 22 of the reception circuit 21, And an NPN transistor 47 provided in the second power supply path, and a timer circuit 45 for turning them on and off in common. The transistor 46 and the timer circuit 45 constitute a transmission circuit power cutoff unit, and the transistor 47 and the timer circuit 45 constitute a reception circuit power cutoff unit. The output of the timer circuit 45 is input in common to the base terminals B of the transistors 46 and 47 through the wiring 45BS.

  Initially, the output BS3 of the timer circuit 45 is at the H level, and the transistors 46 and 47 are turned on in response thereto (see FIG. 5B). The timer circuit 45 detects whether or not the transmission circuit 11 is performing a transmission operation for driving the light emitting chip 1 through the wiring 15 connected to the transmission circuit 11, and the reception circuit 21 processes the output of the light receiving chip 2. It is detected through the wiring 25 connected to the transmission circuit 21 whether or not the receiving operation is performed. Then, the transmission circuit 11 does not perform the transmission operation for driving the light emitting chip 1 and the reception circuit 21 does not perform the reception operation for processing the output of the light receiving chip 2 (this state is referred to as “standby state”). ) Continues for a certain period, an L level signal is output as the output BS3. Thereby, the transistors 46 and 47 are turned off (see FIG. 5B). Therefore, the emitters and collectors of the transistors 46 and 47 are cut off (off), the power supply to the transmission circuit 11 is cut off, and the power supply to the reception circuit 21 is cut off (this state is referred to as “shutdown state”). "). Therefore, current consumption can be suppressed.

(Sixth embodiment)
FIG. 6A shows a modification of the infrared communication device shown in FIG. 5A.

  In this infrared communication device, the PNP transistor 49 provided in the first power supply path between the Vcc terminal 93 and the power supply receiving unit 13 of the transmission circuit 11, the Vcc terminal 93 and the power supply receiving unit 22 of the reception circuit 21, PNP transistor 50 provided in the second power supply path between and timer circuit 48 for turning them on and off in common. The transistor 49 and the timer circuit 48 constitute a transmission circuit power cutoff unit, and the transistor 50 and the timer circuit 48 constitute a reception circuit power cutoff unit. The output of the timer circuit 48 is input in common to the base terminals B of the transistors 49 and 50 through the wiring 48BS.

  Initially, the output BS4 of the timer circuit 48 is at L level, and the transistors 49 and 50 are turned on in response to this (see FIG. 6B). Like the timer circuit 45 in FIG. 5A, the timer circuit 48 detects whether or not the transmission circuit 11 is performing a transmission operation for driving the light emitting chip 1 through the wiring 15 connected to the transmission circuit 11, and It is detected through the wiring 25 connected to the transmission circuit 21 whether or not the reception circuit 21 is performing a reception operation for processing the output of the light receiving chip 2. When the transmission circuit 11 does not perform the transmission operation for driving the light emitting chip 1 and the reception circuit 21 does not perform the reception operation for processing the output of the light receiving chip 2, the output BS4 An H level signal is output. Thereby, the transistors 49 and 50 are turned off (see FIG. 6B). Therefore, the emitters and collectors of the transistors 49 and 50 are cut off (off) to cut off the power supply to the transmission circuit 11 and the power supply to the reception circuit 21. That is, the shutdown state is entered. Therefore, current consumption can be suppressed. Further, when a certain period of time has elapsed after shifting to the shutdown state, the timer circuit 48 outputs an L level signal as the output BS4. Thereby, the transistors 49 and 50 are turned on, and the power supply to the transmission circuit 11 and the reception circuit 21 is resumed. Therefore, the optical communication device can be returned to the standby state or the operating state.

(Seventh embodiment)
FIG. 7A shows components to be added to the infrared communication device shown in FIG. 5A.

  In this infrared communication device, an NPN transistor 51 serving as a power cutoff unit for a transmission circuit provided in a first power supply path between the Vcc terminal 93 and the power supply receiving unit 13 of the transmission circuit 11, the Vcc terminal 93, and the reception And an NPN transistor 52 as a power interrupting unit for the receiving circuit provided in a second power supply path between the circuit 21 and the power supply unit 22. The input terminal 91 and the base terminals B of these transistors 51 and 52 are connected by a wiring 14. Thereby, these transistors 51 and 52 are turned on and off by the transmission signal SS. Specifically, as shown in FIG. 7B, the transistors 51 and 52 are turned off when the transmission signal SS is at L level, and the transistors 51 and 52 are turned on when the transmission signal SS is at H level.

  These transistors 51 and 52 and wiring 14 are added to the infrared communication device shown in FIG. 5A.

  In this optical communication device, after shifting to the shutdown state due to the standby state continuing for a certain period, the transistors 51 and 52 are turned on in synchronization with the timing when the transmission signal SS transitions from the L level to the H level. Thereby, power supply to the transmission circuit 11 and the reception circuit 12 is resumed. Therefore, this optical communication device can be returned from the shutdown state to the operation state (particularly the transmission operation state) in synchronization with the transmission signal SS.

(Eighth embodiment)
FIG. 8A shows components to be added to the infrared communication device shown in FIG. 5A.

  In this infrared communication device, an NPN transistor 53 serving as a power cutoff unit for a transmission circuit provided in a first power supply path between the Vcc terminal 93 and the power supply receiving unit 13 of the transmission circuit 11, the Vcc terminal 93, and the reception And an NPN transistor 54 serving as a power interrupting unit for a receiving circuit provided in a second power supply path between the circuit 21 and the power supply unit 22. The output terminal 92 and the base terminals B of these transistors 53 and 54 are connected by a wiring 24. Thereby, these transistors 53 and 54 are turned on and off by the reception signal SR. Specifically, as shown in FIG. 8B, the transistors 53 and 54 are turned on when the received signal SR is at L level, and the transistors 53 and 54 are turned off when the received signal SR is at H level.

  These transistors 53 and 54 and wiring 24 are added to the infrared communication device shown in FIG. 5A.

  In this optical communication device, after shifting to the shutdown state because the standby state has continued for a certain period, the transistors 53 and 54 are turned on in synchronization with the timing at which the received signal SR transitions from the H level to the L level. Thereby, power supply to the transmission circuit 11 and the reception circuit 12 is resumed. Therefore, the optical communication device can be returned from the shutdown state to the operation state (particularly the reception operation state) in synchronization with the transmission signal SS.

  An electronic device such as a mobile product provided with each of the optical communication devices described above can satisfy demands such as low power consumption (reduction of battery burden), small size and light weight, and high communication speed.

  Note that a printed wiring board is typically used as the common board 90. However, the present invention is not limited to this, and any member that can mount each component such as a lead frame (copper material) may be used.

  In the above embodiment, the light for optical communication is infrared, but is not limited thereto, and may be visible light, for example.

It is a figure which shows the block configuration of the optical communication device of one Embodiment of this invention. It is a figure which shows the signal waveform in the optical communication device of FIG. 1A. It is a figure which shows the operation state of the component in the optical communication device of FIG. 1A. It is a figure which shows the block configuration of the optical communication device of one Embodiment of this invention. It is a figure which shows the signal waveform in the optical communication device of FIG. 2A. It is a figure which shows the operation state of the component in the optical communication device of FIG. 2A. It is a figure which shows the block configuration of the optical communication device of one Embodiment of this invention. It is a figure which shows the signal waveform in the optical communication device of FIG. 3A. It is a figure which shows the operation state of the component in the optical communication device of FIG. 3A. It is a figure which shows the block configuration of the optical communication device of one Embodiment of this invention. It is a figure which shows the signal waveform in the optical communication device of FIG. 4A. It is a figure which shows the operation state of the component in the optical communication device of FIG. A. It is a figure which shows the block configuration of the optical communication device of one Embodiment of this invention. It is a figure which shows the operation state of the component in the optical communication device of FIG. 5A. It is a figure which shows the block configuration of the optical communication device of one Embodiment of this invention. It is a figure which shows the operation state of the component in the optical communication device of FIG. 6A. It is a figure which shows the block configuration of the optical communication device of one Embodiment of this invention. It is a figure which shows the operation state of the component in the optical communication device of FIG. 7A. It is a figure which shows the block configuration of the optical communication device of one Embodiment of this invention. It is a figure which shows the operation state of the component in the optical communication device of FIG. 8A. It is a figure which shows the block configuration of the conventional optical communication device. It is a figure which shows the signal waveform in the optical communication device of FIG. 9A.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light emitting chip 2 Light receiving chip 41, 49, 50, 53, 54 PNP transistor 43, 46, 47, 51, 52 NPN transistor 91 Input terminal 92 Output terminal

Claims (9)

Integrally on a common member,
A light emitting unit for emitting light;
A light receiving unit that photoelectrically converts incident light;
A transmission circuit that receives the transmission signal and drives the light emitting unit;
A receiving circuit that processes a signal generated by the light receiving unit and outputs a received signal;
A first power supply path for supplying power to the transmission circuit;
A second power supply path for supplying power to the receiving circuit,
An optical communication device, wherein a power interrupting unit for a receiving circuit that interrupts power supply to the receiving circuit in synchronization with the transmission signal is provided in the second power supply path. The optical communication device according to claim 1.
The receiving circuit power cut-off unit cuts off the power supply to the receiving circuit for a certain period from the timing at which the transmission signal transitions. Integrally on a common member,
A light emitting unit for emitting light;
A light receiving unit that photoelectrically converts incident light; and
A transmission circuit that receives the transmission signal and drives the light emitting unit;
A receiving circuit that processes a signal generated by the light receiving unit and outputs a received signal;
A first power supply path for supplying power to the transmission circuit;
A second power supply path for supplying power to the receiving circuit,
An optical communication device, wherein a transmission circuit power cut-off unit that cuts off power supply to the transmission circuit in synchronization with the reception signal is provided in the first power supply path. The optical communication device according to claim 3.
The transmission circuit power cut-off unit cuts off power supply to the transmission circuit for a certain period from the timing at which the received signal transitions. The optical communication device according to any one of claims 1 to 4,
After the transmission period in which the transmission circuit drives the light emitting unit or the reception period in which the reception circuit processes the output of the light receiving unit, the transmission circuit does not perform the transmission operation to drive the light emitting unit, and the reception When the standby state in which the circuit does not perform the reception operation for processing the output of the light receiving unit continues for a certain period, the power cutoff unit for the transmission circuit cuts off the power supply to the transmission circuit and the power cutoff for the reception circuit An optical communication device, wherein the unit cuts off power supply to the receiving circuit. The optical communication device according to claim 5.
Shutdown in which the transmission circuit power cut-off unit cuts off power supply to the transmission circuit and the reception circuit power cut-off unit cuts off power supply to the reception circuit when the standby state continues for a certain period of time When a certain period of time elapses after the transition to the state, the transmission circuit power cutoff unit and the reception circuit power cutoff unit start supplying power to the transmission circuit and the reception circuit, respectively. Optical communication device. The optical communication device according to claim 5.
Shutdown in which the transmission circuit power cut-off unit cuts off power supply to the transmission circuit and the reception circuit power cut-off unit cuts off power supply to the reception circuit when the standby state continues for a certain period of time After the transition to the state, the transmission circuit power cutoff unit and the reception circuit power cutoff unit start supplying power to the transmission circuit and the reception circuit, respectively, in synchronization with the transmission signal. Communication device. The optical communication device according to claim 5.
After the transmission circuit power cut-off unit cuts off the power supply to the transmission circuit and the reception circuit power cut-off unit cuts off the power supply to the reception circuit because the standby state has continued for a certain period of time. The optical communication device, wherein the transmission circuit power cutoff unit and the reception circuit power cutoff unit start supplying power to the transmission circuit and the reception circuit, respectively, in synchronization with the received signal. An electronic apparatus comprising the optical communication device according to claim 1.

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