JP2007095127A - Electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic device which has a function of turning off the main power source of the device when the illumination of a room where the device is installed is put out. <P>SOLUTION: While the main power source is on and the device is turned to an operation state, when the illumination of the room is put out, since the optical sensor 301 of an illumination detection circuit 30 is not exposed to light and a current does not flow to the optical sensor 301, put-out detection signals suddenly changed from a high level to a low level for instance are outputted from an optical change detection means 302 and supplied to a power source control means 303. The power source control means 303 turns off a main power source switch circuit 28 by the put-out detection signals and turns off the main power source 31. Thus, the device is turned to a standby state, power is saved and the service life of the device is not affected. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to an audio device such as a CD player or a stereo device that reproduces and outputs an audio signal, or a video cassette recorder or DV that reproduces and outputs an audio signal and a video signal.
The present invention relates to an electronic device such as an AV device such as a D player or a DVD recorder, and more particularly to an electronic device having a function of turning off the main power supply of the device when the room illumination is turned off.

Conventionally, many home electronic devices that are operated by a remote controller have been widely used. For example, as for audio equipment, there are a CD player that reproduces an audio signal recorded on a CD and outputs sound, a stereo device that outputs an audio signal recorded on a magnetic tape or CD in stereo through a stereo amplifier, and the like. . As for AV equipment, a video cassette recorder that reproduces a video / audio signal recorded in a video cassette, inputs it to a monitor device such as a television receiver, displays video on a display device, and outputs audio from a speaker. Or
There is a DVD player or a DVD recorder that reproduces a video / audio signal recorded on a DVD, and inputs the video / audio signal to a monitor device such as a television receiver to display the video on a display device and output audio from a speaker.

These electronic devices have a main power source and a standby power source. When the power key of the remote control is pressed to turn on the main power source, the main power source is turned on to enable each operation, and the remote control device is used to shut off the main power source. When the power key is pressed again, the main power supply is turned off, the voltage from the standby power supply is applied only to a specific component (system controller or the like), and the specific component enables the standby operation.
JP 2005-25409 A Japanese Patent Laid-Open No. 11-3144 JP-A-9-311597 Japanese Patent Laid-Open No. 5-119874

Such an electronic device is operated by a remote controller. For example, an audio / video signal recorded on a DVD is reproduced by a DVD recorder so that an image is displayed on a display device of a television receiver and audio is output from a speaker. When the playback ends, the television receiver may be switched from the video side to the television side by operating the remote control to watch the television program and enjoy the television program. For example, the user turns off the main power supply of the television receiver by operating the remote controller at the time of going to sleep, but may forget to turn off the main power supply of the DVD recorder.

Normally, when you go to sleep at night, if you have forgotten to turn off the main power supply, such as a television receiver display device, you can forget to turn off the main power. Therefore, the main power supply is turned off when it is noticed at that time, but the main power supply is turned on even if the lights are turned off for those that only have a front panel display unit such as a DVD recorder. Is hard to notice.

Therefore, an audio device such as a CD player or a stereo device, a video cassette recorder, a DVD player, or a DVD that reproduces and outputs audio signals and video signals.
In a conventional electronic device such as an AV device such as a recorder, the main power source cannot be automatically turned off even if the illumination of the room where the device is installed is turned off. If it exists, power consumption will be wasted and the subject that the lifetime of an apparatus is affected will arise.

In the prior art of Patent Document 1, when a predetermined illuminance value is stored, the detected illuminance is compared with the stored illuminance value, and it is determined that the detected illuminance is smaller than the illuminance value, the electronic device By cutting off the power supply of the main unit, power consumption can be controlled according to the surrounding brightness, but it does not shut off the power supply by a sudden change in brightness like when the light is turned off. The above problems cannot be solved.

In the prior art of Patent Document 2, the brightness of the information processing apparatus is appropriately controlled according to the ambient brightness by detecting the brightness of the surroundings and performing the power saving control according to the brightness information. However, this prior art also cannot solve the above-mentioned problems because the power supply is not shut down by a sudden change in brightness unlike when the illumination is turned off.

In the prior art of Patent Document 3, when it is determined that the brightness around the printer body is darker than a preset brightness, part or all of the power output of the power supply circuit is cut off. This prior art also cannot solve the above-mentioned problems because the power supply is not shut off by a sudden change in brightness as when the illumination is turned off.

In the prior art of Patent Document 4, all or a part of the circuits of the information processing apparatus are turned off according to the ambient brightness. Since the power supply is not shut down by a sudden change in brightness, the above problems cannot be solved.

The present invention has been made to solve the above problems, and provides an electronic device having a function of turning off the main power of the device when the illumination of the room in which the device is installed is turned off. The purpose is to do.

In order to achieve the above object, according to the first aspect of the present invention, in an electronic device that reproduces and outputs an audio signal, or reproduces and outputs an audio signal and a video signal, the brightness of the room in which the device is installed An optical sensor that outputs a detection signal corresponding to the optical signal, an amplification circuit that inputs the detection signal from the optical sensor and amplifies the detection signal, and a detection signal amplified by the amplification circuit when the level of the signal suddenly changes A coupling capacitor that allows only the detection signal to pass through, a Schmitt trigger circuit that shapes the detection signal that has passed through this coupling capacitor into a pulse shape, and the level of the pulsed detection signal from the Schmitt trigger circuit and an adjustable reference When the level of the detection signal is compared with the reference level, a turn-off detection signal is output and the level of the detection signal exceeds the reference level. And a comparison circuit that outputs a lighting detection signal when the room light is turned on, and when the lighting in the room changes from the lighting state to the light-off state, the light-off detection signal is output due to a change in the level of the detection signal from the light sensor. A light change detecting means for outputting a lighting detection signal according to a level change of a detection signal from the light sensor when the lighting state is changed from a light-off state;
When the turn-off detection signal is input, the main power switch circuit is turned off to turn off the main power supply. When the turn-on detection signal is input within the set time, the main power switch circuit is turned on. An electronic device is provided that includes an illumination detection circuit having a power supply control means for turning on a power supply.

In this configuration, when the room power is turned off when the main power supply is turned on and the device is in an operating state, the light sensor of the illumination detection circuit will not be exposed to light, and current will flow through the light sensor. Since the electric current does not flow, the potential of the output terminal of the amplifier circuit drops rapidly, for example. That is,
From the output terminal of the amplifier circuit, a detection signal that suddenly changes from high level to low level is output. This detection signal passes through the coupling capacitor due to an excessive phenomenon, and is further shaped into a pulse shape by a Schmitt trigger circuit.

The level of the low pulse detection signal that has been shaped into a pulse shape by the Schmitt trigger circuit is compared with the reference level by the comparison circuit. If the level is below the reference level, a high level signal is output as the extinction detection signal. When the light extinction detection signal is output from the light change detection means, it is detected that the lighting in the room has been extinguished, and the light extinction detection signal is supplied from the comparison circuit to the power supply control means. The power control means turns off the main power switch circuit by turning off the main power switch circuit by the high level extinction detection signal. Thereby, the said apparatus will be in a standby state.

In this way, when the room illumination is turned off and the device is in the standby state, if the room illumination is turned on, the light hits the optical sensor and the detection signal flows, so the potential of the output terminal of the amplifier circuit For example rises rapidly. That is, a detection signal that suddenly changes from a low level to a high level is output from the output terminal of the amplifier circuit. And this detection signal is
It passes through the coupling capacitor due to an excessive phenomenon, and is further shaped into a pulse shape by a Schmitt trigger circuit.

The level of the high-pulse detection signal shaped into a pulse shape by the Schmitt trigger circuit is compared with the reference level of the comparison circuit. When the level exceeds the reference level, a low-level signal is output as the lighting detection signal. When the lighting detection signal is output from the light change detection means, it is detected that the lighting in the room is turned on, and the turn-off detection signal is supplied from the comparison circuit to the power control means. The power supply control means turns on the main power supply switch circuit and turns on the main power supply when there is a low level lighting detection signal inputted within the set time.

According to this configuration, when the illumination of the room in which the device is installed is turned off, the main power supply of the device can be automatically turned off, so that power saving can be achieved and the life of the device can be increased. Will no longer affect. In addition, when the lighting is turned on, the main power supply of the device can be automatically turned on within the set time. Therefore, when the user turns off the lighting once when leaving the room, the main power of the device is turned off. Even if the power is turned off, within the set time,
When you return to the room again and turn on the light, the main power of the device is automatically turned on, which eliminates the need for remote control operation to turn the main power of the device back on, and also turns off the light. The main power of the device is off while
Power saving can also be achieved.

According to the second aspect of the present invention, in an electronic device that reproduces and outputs an audio signal or reproduces and outputs an audio signal and a video signal, a detection signal corresponding to the brightness of a room in which the device is installed is output. When the light from the light sensor and the lighting in the room is changed from the lighting state to the lighting-off state, a light-off detection signal is output due to a change in the level of the detection signal from the light sensor. A light change detecting means for outputting a lighting detection signal according to a level change of a detection signal from the light sensor, and when the light extinction detection signal is inputted, the main power switch circuit is turned off to turn off the main power supply and set time Power supply control means for turning on the main power supply by turning on the main power supply switch circuit when the lighting detection signal is inputted in Further comprising a lighting detection circuit to provide the characteristics and electronic equipment.

In this configuration, when the room power is turned off when the main power supply is turned on and the device is in an operating state, the light sensor of the illumination detection circuit will not be exposed to light, and current will flow through the light sensor. Since it does not flow, a light extinction detection signal that suddenly changes from, for example, a high level to a low level is output from the light change detection means and supplied to the power supply control means. Power control means
The main power switch circuit is turned off by the turn-off detection signal to turn off the main power.
Thereby, the said apparatus will be in a standby state.

In this way, when the room illumination is turned off and the device is in the standby state, when the room illumination is turned on, the light hits the light sensor and the lighting detection signal flows. It is output from the change detection means and supplied to the power supply control means. If there is a lighting detection signal input within the set time, the power control means turns on the main power switch circuit by turning on the main power switch circuit by this lighting detection signal.

According to this configuration, when the illumination of the room in which the device is installed is turned off, the main power supply of the device can be automatically turned off, so that power saving can be achieved and the life of the device can be increased. Will no longer affect. In addition, when the lighting is turned on, the main power supply of the device can be automatically turned on within the set time. Therefore, when the user turns off the lighting once when leaving the room, the main power of the device is turned off. Even if the power is turned off, within the set time,
When you return to the room again and turn on the light, the main power of the device is automatically turned on, which eliminates the need for remote control operations to turn the main power of the device back on, and also turns off the light. Since the main power supply of the device is off during the operation, power saving can be achieved.

According to a third aspect of the present invention, in the second aspect of the invention, the light change detecting means receives the detection signal from the optical sensor and amplifies the detection signal, and the detection signal amplified by the amplification circuit. A coupling capacitor that passes only the detection signal when there is a sudden level change;
The Schmitt trigger circuit that shapes the detection signal that has passed through the coupling capacitor into a pulse shape, and the level of the detection signal by comparing the level of the pulse detection signal from the Schmitt trigger circuit with an adjustable reference level And a comparison circuit that outputs a turn-off detection signal when the signal level is below the reference level and outputs a turn-on detection signal when the level of the detection signal exceeds the reference level.

Therefore, the light change detection means outputs a detection signal generated by a sudden change in brightness (a state in which it suddenly becomes dark) as a turn-off detection signal when the lighting in the room changes from a lighting state to a turning-off state. In addition, when the lighting in the room changes from the off state to the on state, it is possible to output a detection signal generated by a sudden change in brightness (a state of suddenly brightening) as a lighting detection signal. become.

As described above, according to the present invention, in an electronic device that reproduces and outputs an audio signal, or reproduces and outputs an audio signal and a video signal, a detection signal corresponding to the brightness of the room in which the device is installed An optical sensor that outputs a detection signal, an amplification circuit that receives the detection signal from the optical sensor and amplifies the detection signal, and passes only the detection signal when the detection signal amplified by the amplification circuit undergoes a sudden level change. And a Schmitt trigger circuit that shapes the detection signal that has passed through the coupling capacitor into a pulse shape, and the level of the pulsed detection signal from the Schmitt trigger circuit is compared with an adjustable reference level. When the detection signal level is below the reference level, a turn-off detection signal is output, and when the detection signal level exceeds the reference level, lighting detection is performed. The comparator circuit outputs a signal, and when the room illumination changes from the on state to the off state, it outputs a turn-off detection signal due to the level change of the detection signal from the light sensor, and the room illumination turns on from the off state. A light change detecting means for outputting a lighting detection signal according to a change in a level of a detection signal from the photosensor when a state is reached, and turning off a main power switch circuit when the extinction detection signal is input to turn off the main power supply. When the lighting detection signal is input within a set time, the illumination detection circuit has power control means for turning on the main power by turning on the main power switch circuit. When the room is turned off, the main power of the equipment can be turned off automatically. Can be, it is no longer affects the life of the equipment. In addition, when the lighting is turned on, the main power supply of the device can be automatically turned on within the set time. Therefore, when the user turns off the lighting once when leaving the room, the main power of the device is turned off. Even if the power is turned off, the main power of the device is automatically turned on when the lighting is turned on again after returning to the room within the set time. Since the main power supply of the device is turned off while the illumination is turned off, the power can be saved.

Further, according to the present invention, in an electronic device that reproduces and outputs an audio signal, or reproduces and outputs an audio signal and a video signal, a detection signal corresponding to the brightness of the room in which the device is installed is output. When the lighting of the room changes from the on state to the off state, the light detection signal is output by the change in the level of the detection signal from the photo sensor, and the lighting of the room changes from the off state to the on state. Light change detection means for outputting a lighting detection signal according to a level change of a detection signal from the light sensor, and when the light extinction detection signal is input, the main power switch circuit is turned off and the main power supply is turned off and set. Power supply control means for turning on the main power supply by turning on the main power switch circuit when the lighting detection signal is inputted within the time; Since an illumination detection circuit, when turned off illumination of the room in which the device is installed, it can be automatically turned off the main power of the device,
As a result, power saving can be achieved and the life of the device is not affected.
In addition, when the lighting is turned on, the main power supply of the device can be automatically turned on within the set time. Therefore, when the user turns off the lighting once when leaving the room, the main power of the device is turned off. Even if the power is turned off, the main power of the device is automatically turned on when the lighting is turned on again after returning to the room within the set time. Since the main power supply of the device is turned off while the illumination is turned off, the power can be saved.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram showing a configuration of a DVD recorder as an electronic apparatus according to an embodiment of the present invention. Here, the configuration of the DVD recorder will be described. However, the illumination detection circuit that is a feature of the present embodiment is not limited to the DVD recorder, but can be applied to electronic devices such as a DVD player, a CD player, a stereo device, and a video cassette recorder. Needless to say.

This DVD recorder has a spindle motor 5 that rotates a DVD or CD optical disk 1.
And an optical pickup 2 for emitting laser light for recording / reproducing information on the optical disc 1 and receiving reflected light from the optical disc 1, and for moving the optical pickup 2 in the radial direction of the optical disc 1. The spindle motor 5 and the thread 3 are driven in accordance with an instruction from the system controller 22 and the objective lens (not shown) built in the optical pickup 2 is moved to change the focal position of the laser light on the optical disk 1. And a servo control unit 4 that performs control to move the recording surface in the vertical and horizontal directions.

The DVD recorder also includes an RF amplifier 6 that amplifies an RF signal that is a read signal from the optical pickup 2 during reproduction of the optical disc 1, and an optical disc 1 that converts the RF signal output from the RF amplifier 6 into digital data. A digital signal processing unit 8 that stores data generated by performing signal demodulation processing and ECC error correction processing in accordance with the data format in RAM 7 and data output from the digital signal processing unit 8 in response to an instruction from the system controller 22 A stream separation unit 9 is provided for separating audio data, sub-picture data, and video data from the stream.

The DVD recorder also receives audio data output from the stream separation unit 9 and performs a predetermined decoding process, and temporarily stores data for performing the decoding process by the audio decoder 11. The RAM 10, the sub-picture decoder 13 that inputs the sub-picture data output from the stream separation unit 9 and performs a predetermined decoding process, and temporarily stores the data to perform the decoding process by the sub-picture decoder 13 A RAM 12, a video decoder 15 that receives the video data output from the stream separation unit 9 and performs a predetermined decoding process, and a RAM 14 that temporarily stores data to perform the decoding process in the video decoder 15. It has.

The DVD recorder also synthesizes the data output from the video decoder 15 and the data output from the sub-picture decoder 13 in response to an instruction from the system controller 22, and the video processor 17 outputs the video processor 17. For example, the video encoder 18 converts the synthesized data into a video signal for display and displays the image on the display device 20, and converts the data output from the audio decoder 11 into an analog audio signal, for example, via an audio circuit (not shown). And a D / A converter 16 to be supplied to the speaker 19.

In addition, this DVD recorder uses an infrared signal to the system controller 22,
A remote controller 21 having various operation keys such as a reproduction key for giving a reproduction instruction, a recording key for giving a recording instruction, a stop key for instructing reproduction stop or recording stop, and a power key.
And the system controller 22 for controlling the entire apparatus.

The DVD recorder also includes a flash ROM 23 that stores programs and data for controlling each component of the device and for controlling the entire device, and the flash R
A CPU 24 that performs arithmetic processing according to the program and data of the OM 23 and controls the system controller 22, and a RAM 27 that temporarily stores data necessary for the processing of the CPU 24
And.

The DVD recorder also includes a recording data modulation circuit 25 that modulates video / audio data sent from a television receiver (not shown) or a personal computer to record on the optical disc 1, and the recording data modulation circuit 25. And a laser modulation circuit 26 for outputting a laser modulation signal for modulating the laser beam emitted from the optical pickup 2 to the optical pickup 2 based on the modulated data.

The DVD recorder also has a standby power supply 29 for supplying power to specific components during standby.
A main power supply 31 for supplying power to each component during operation, a main power switch circuit 28 for turning on or off the main power supply 31 by a power control signal of the system controller 22 in response to pressing of the power key of the remote controller 21; Illumination detection circuit 3 as a feature of the present embodiment
0. The system controller 22, the main power switch circuit 28, and the illumination detection circuit 30 can be operated by the standby power supply 29 even when the main power supply 31 is off.

FIG. 2 is a block diagram for explaining the configuration of the illumination detection circuit 30. In FIG. 2, an illumination detection circuit 30 includes an optical sensor 301 that outputs a detection signal corresponding to the brightness of the room in which the DVD recorder is installed, and an optical sensor when the illumination of the room changes from the on state to the off state. A light change detection that outputs a turn-off detection signal according to a change in the level of the detection signal from 301 and outputs a turn-on detection signal according to a change in the level of the detection signal from the light sensor 301 when the room illumination changes from a light-off state to a light-on state. When the means 302 and the extinction detection signal are input, the main power switch circuit 28 is turned off to turn off the main power supply 31, and when the lighting detection signal is input within a set time, the main power switch circuit 28 Power supply control means 303 for turning on the main power supply 31 by turning on the power supply.

FIG. 3 is a circuit diagram for explaining an example of a circuit constituting the light change detecting means 302. Note that the circuit of the light change detecting means 302 is not limited to the one shown below, and any circuit that can perform the same operation may be used.

In FIG. 3, the light change detection means 302 receives the detection signal from the photodiode D of the optical sensor 301 and amplifies the detection signal (an inverting amplifier) A, and the detection signal amplified by the amplification circuit A From the coupling capacitor C that passes only the detection signal when the level changes suddenly, the Schmitt trigger circuit S that shapes the detection signal that has passed through the coupling capacitor C into a pulse shape, and the Schmitt trigger circuit S Compares the level of the pulse-shaped detection signal with an adjustable reference level, and outputs a turn-off detection signal when the level of the detection signal is lower than the reference level, and detects lighting when the level of the detection signal exceeds the reference level And a comparison circuit B for outputting a signal.

The inverting input terminal (−terminal) of the amplifier circuit A is connected to the cathode of the photodiode D and the resistor R1.
And one end of the resistor R2 are connected. The anode of the photodiode D and the other end of the resistor R1 are grounded. The non-inverting input terminal (+ terminal) of the amplifier circuit A is grounded,
The output terminal is connected to the other end of the resistor R2 and one end of the coupling capacitor C. The other end of the coupling capacitor C is connected to the input terminal of the Schmitt trigger circuit S, and the output terminal of the Schmitt trigger circuit S is connected to the inverting input terminal (− of the comparison circuit B via the resistor R4.
Terminal).

The non-inverting input terminal (+ terminal) of the comparison circuit B is connected to the connection point between the resistor R5 and the variable resistor R6, and its output terminal is connected to the input terminal of the power supply control means 303. The other end of the variable resistor R6 is grounded, and the other end of the resistor R5 is connected to the cathode of the Zener diode Z and one end of the resistor R3. The anode of the Zener diode Z is grounded, and the voltage + V is supplied to the other end of the resistor R3.

FIG. 4 is a flowchart for explaining the operation of the illumination detection circuit 30 in the present embodiment. The operation of the illumination detection circuit 30 will be described with reference to this flowchart and FIGS.

First, when the DVD recorder provided with the illumination detection circuit 30 is set to the standby state where the standby operation is maintained only by the standby power source 29 (step S1), the power key of the remote controller 21 is pressed to depress the device. The main power supply 31 is turned on. That is, when the power key of the remote controller 21 is pressed, the system controller 22 turns on the main power switch circuit 28, thereby turning on the main power supply 31 (step S2).

Thus, when the main power supply 31 is turned on and the DVD recorder is in the playback or stopped state, if the room illumination is turned off, the photodiode D of the photosensor 301 of the illumination detection circuit 30 will not be exposed to light. As a result, no current flows through the photodiode D. Therefore, in the amplifier circuit A, the potential of the inverting input terminal is rapidly increased and the potential of the output terminal is rapidly decreased. That is, a detection signal that suddenly changes from a high level to a low level is output from the output terminal of the amplifier circuit A. This detection signal passes through the coupling capacitor C due to an excessive phenomenon, and is further shaped into a pulse shape by the Schmitt trigger circuit S.

The level of the low pulse detection signal shaped into a pulse shape by the Schmitt trigger circuit S is compared with the reference level (reference voltage) given to the non-inverting input terminal of the comparison circuit B, and is below the reference level. The high level signal is output as a turn-off detection signal. The illumination detection circuit 30 detects that the room illumination has been turned off by outputting the turn-off detection signal from the light change detection means 302 (step S3), and the power supply control means 30 from the comparison circuit B.
3 supplies the extinction detection signal. The power supply control means 303 turns off the main power supply switch circuit 28 in response to the high level extinction detection signal to turn off the main power supply 31 (step S4). As a result, the DVD recorder enters a standby state (step S5).

When the room illumination is turned off in this way and the DVD recorder is in a standby state, if the room illumination is turned on, the photodiode D of the optical sensor 301 of the illumination detection circuit 30 is exposed to light, and photo Since a current flows through the diode D, in the amplifier circuit A, the potential of the inverting input terminal is rapidly lowered and the potential of the output terminal is rapidly raised. That is, a detection signal that suddenly changes from a low level to a high level is output from the output terminal of the amplifier circuit A. This detection signal passes through the coupling capacitor C due to an excessive phenomenon,
Further, the waveform is shaped into pulses by the Schmitt trigger circuit S.

The level of the high-pulse detection signal that has been shaped into a pulse by the Schmitt trigger circuit S is compared with a reference level (reference voltage) applied to the non-inverting input terminal of the comparison circuit B. A low level signal is output as a lighting detection signal. The illumination detection circuit 30 detects that the room illumination is turned on by outputting the lighting detection signal from the light change detection means 302 (step S6), and the power supply control means 303 from the comparison circuit B.
To supply the lighting detection signal. If there is a low level lighting detection signal within the set time, the power supply control means 303 turns on the main power supply switch circuit 28 and turns on the main power supply 31 (step S2).

When the set time is 0 hour, or when the elapsed time from when the illumination is turned off to when it is turned on exceeds the set time, the power control means 303 inputs a lighting detection signal. However, since the control signal for turning on the main power switch circuit 28 is not output, the main power supply 31 is not turned on. Such a setting time can be set if it can be set by remote control operation.

When the illumination is turned off and the room becomes dark, the main power supply 31 of the apparatus is turned off by the process of step S4. However, there are cases where it is desired to turn on the main power supply 31 in a dark room.
In such a case, if the power key of the remote controller 21 is pressed, the system controller 22
Can turn on the main power switch circuit 28 and turn on the main power supply 31.

In addition, when the light is turned off, the main power supply 31 of the apparatus is turned off. However, since the darkness in the room when the light is turned off varies depending on the home, the main power supply 3 of the apparatus depends on the degree of darkness when the light is turned off.
If the variable resistor R6 connected to the non-inverting input terminal of the comparison circuit B of the light change detection means 302 is adjusted so that the operation of turning off 1 can be performed, the reference level changes, so according to the degree of darkness. A turn-off detection signal can be output from the comparison circuit B, which makes it possible to turn off the main power supply 31 of the apparatus according to the degree of darkness when the light is turned off. This variable resistance R
6 can adjust the resistance value of the variable resistor R6 if, for example, the knob is protruded from the front panel of the main body or the display unit is changed by menu setting.

Also, even if the room gradually becomes brighter or darker due to natural light, the main power supply 31 of the apparatus does not turn on / off because the amount of light hitting the photodiode D in the illumination detection circuit 30 gradually increases. As a result, the output signal of the amplifier circuit A also changes gradually. Even if such a gradually changing signal is given to the coupling capacitor C, the signal is almost the same as in the steady state, so that the signal is a Schmitt trigger. It is not transmitted to the circuit S. Therefore, since the output of the comparison circuit B does not change at all, the main power supply 31 of the apparatus does not turn on / off even when the room gradually becomes brighter or darker due to natural light.

As described above, according to the present embodiment, when the illumination of the room in which the device is installed is turned off, the main power supply of the device can be automatically turned off, so that power saving can be achieved. This will not affect the life of the device. In addition, when the lighting is turned on, the main power of the device can be turned on within the set time, so when the user turns off the light, the main power of the device is turned off. However, when the lighting is turned on again after returning to the room within the set time, the main power of the device is automatically turned on, thereby eliminating the need for remote control operation to turn the main power of the device back on. This is convenient, and the main power supply of the device is turned off while the light is turned off, so that power saving can be achieved.

It is a block diagram which shows the structure of the DVD recorder as an electronic device which concerns on one Embodiment of this invention. It is a block diagram for demonstrating the structure of the illumination detection circuit in FIG. It is a circuit diagram for demonstrating an example of the circuit which comprises the light change detection means in FIG. It is a flowchart for demonstrating operation | movement of an illumination detection circuit in the said embodiment.

Explanation of symbols

28 Main power switch circuit 30 Illumination detection circuit 31 Main power supply 301 Optical sensor 302 Light change detection means 303 Power control means A Amplifying circuit B Comparison circuit C Coupling capacitor S Schmitt trigger circuit

Claims (3)

In electronic equipment that reproduces and outputs audio signals, or reproduces and outputs audio signals and video signals,
An optical sensor that outputs a detection signal corresponding to the brightness of the room in which the device is installed;
An amplification circuit that inputs a detection signal from the optical sensor and amplifies the detection signal, a coupling capacitor that passes only the detection signal when the detection signal amplified by the amplification circuit undergoes a sudden level change, and A Schmitt trigger circuit that shapes the detection signal that has passed through the coupling capacitor into a pulse shape, and the level of the detection signal from the Schmitt trigger circuit is compared with an adjustable reference level to determine the level of the detection signal. A comparison circuit that outputs a turn-off detection signal when the level is lower than the reference level and outputs a turn-on detection signal when the level of the detection signal exceeds the reference level, and the light is turned on when the lighting in the room is turned off. When a light extinction detection signal is output due to a change in the level of the detection signal from the sensor, and the room lighting changes from the off state to the on state A light change detection means for outputting a lighting detection signal by the level change of the detection signal from the light sensor,
When the turn-off detection signal is input, the main power switch circuit is turned off to turn off the main power supply. When the turn-on detection signal is input within the set time, the main power switch circuit is turned on. An electronic device comprising an illumination detection circuit having power supply control means for turning on a power supply. In electronic equipment that reproduces and outputs audio signals, or reproduces and outputs audio signals and video signals,
An optical sensor that outputs a detection signal corresponding to the brightness of the room in which the device is installed;
When the illumination of the room is changed from the on state to the off state, a light extinction detection signal is output by a change in the level of the detection signal from the optical sensor, and when the room illumination is changed from the off state to the on state, the light sensor A light change detecting means for outputting a lighting detection signal according to a level change of the detection signal;
When the turn-off detection signal is input, the main power switch circuit is turned off to turn off the main power supply. When the turn-on detection signal is input within the set time, the main power switch circuit is turned on. An electronic device comprising an illumination detection circuit having power supply control means for turning on a power supply. The light change detecting means receives only a detection signal from an optical sensor and amplifies the detection signal, and passes only the detection signal when the detection signal amplified by the amplification circuit undergoes a sudden level change. Compare the coupling capacitor, the Schmitt trigger circuit that shapes the detection signal that has passed through the coupling capacitor into a pulse shape, and the level of the pulse detection signal from the Schmitt trigger circuit and the adjustable reference level. 3. The comparison circuit according to claim 2, further comprising a comparison circuit that outputs a turn-off detection signal when the level of the detection signal is lower than a reference level and outputs a turn-on detection signal when the level of the detection signal exceeds the reference level. Electronics.

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