JPH09261554A - Power supply control circuit for video equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To interrupt a power supply circuit when no video signal nor audio signal is in existence even in the case of the video equipment receiving an invalid video signal such as a blue back signal or receiving only an audio signal and reproducing it. SOLUTION: A video image presence discrimination circuit 5 hecks the presence of a video signal from an input signal and when a state of non video image keeps for a prescribed time, a non video image time measurement circuit 6 outputs a signal to a control circuit 13A, and the control circuit 13A interrupts a power supply circuit 15. A video signal converted into a digital signal by a D/A converter circuit 7 and a preceding video signal stored in a memory circuit 8 are compared by a video comparator circuit 9, and a non change time measurement circuit 10 discriminates no change or a specific pattern and measures the continuity of the state for a prescribed time, then the power supply circuit 15 is interrupted similarly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video device such as a VTR or LD for processing and displaying an input signal of a video signal from an external AV device, and more particularly to a power supply control circuit.

[0002]

2. Description of the Related Art Conventionally, a power supply control circuit of this kind controls the power supply circuit by judging the presence or absence of a synchronizing signal in an input signal, that is, a video signal.

FIG. 4 is a block diagram of a television receiver (Japanese Unexamined Patent Publication No. 5-236394) equipped with this kind of power supply control circuit.

The external input terminal 21 is an external input terminal for a video signal from an external AV device, and usually two or more are provided. The tuner circuit 22 selects a broadcast video signal with the antenna 20. The input switching circuit 23 has an external input terminal 2
The video signal from 1 and the video signal from the tuner circuit 22 are switched. The video processing circuit 24 processes the video signal from the input switching circuit 23, and the synchronous system circuit 25 and the picture tube 26.
The video signal is sent to and. The control circuit 27 outputs a switching command signal to the input switching circuit 23. Power supply circuit 2
Reference numeral 9 is a power supply circuit of the apparatus main body. Image presence / absence detection circuit 28
Is connected to the output of the input switching circuit 23 to determine the presence or absence of an input video signal, and when the absence of video is detected, the power supply circuit 29 is turned off via the control circuit 27. Next, the operation of this conventional example will be described. The input video signal is processed by the video processing circuit 24, and the video is displayed on the screen of the picture tube 26. In such an operation, the video signal output from the input switching circuit 23 is also input to the video presence / absence detection circuit 28, in which the presence / absence of the video signal is determined by the synchronization signal, and the control signal of the presence / absence is determined by the control circuit 27. Entered in. Control circuit 27
Then, when the input switching circuit 23 is switched to the side of the external input terminal 21 and receives the information signal of no image, an off control signal is output to the power supply circuit 29 to automatically turn off the power supply circuit 29. Further, even when the input switching circuit 23 is switched to the tuner circuit 22 side, when a control signal indicating no image is received, an off control signal is output to the power supply circuit 29 to automatically turn off the power supply circuit 29. by this,
Forgetting to turn off the power supply circuit 29 is prevented.

In the above-mentioned conventional example, when the image presence / absence detection circuit 28 detects the absence of an image, the power supply circuit 29 is immediately turned off. However, the image presence / absence detection circuit 28 detects the absence of an image. From the power supply circuit 2 after a predetermined time
By providing the control circuit 27 with a delay timer function for turning off 9, the power supply circuit 29 is unnecessarily turned off when the cassette tape is replaced in the middle of watching a video signal from the VTR. It is possible to avoid inconveniences such as being lost.

[0006]

The conventional power supply control circuit described above has the following problems.

(1) Since the presence / absence of a video signal is detected only by the presence / absence of a sync signal in the video signal, control in a device in which the sync signal is always included only in the effective video signal can be realized. However, it is difficult to control the power supply circuit in the device in which the synchronization signal is always output.

The reason for this is that a synchronizing signal is always inserted in a signal during a broadcasting period such as a normal TV (broadcasting) signal, and since the signal is not transmitted after the end of broadcasting, there is no synchronizing signal, so that determination can be made. , VTR (LD), etc., have some devices that send out invalid video signals (blue back, etc.) when the power is turned on, and such devices cannot judge the presence or absence of video. In other words, this is because there is a problem in application to a device in which a sync signal is always output even if the video signal is not reproduced.

(2) Since the presence / absence of a video signal is detected only by the presence / absence of a sync signal in the video signal, only an audio signal is input from an external input terminal for reproduction (use without inputting a video signal. In this case, the control operation of the power supply circuit is difficult.

The reason for this is that when there is only an audio signal input, there is no synchronization signal in the video signal that serves as a criterion for turning off the power supply circuit. Therefore, in the conventional configuration, the power supply circuit is turned off during audio listening. This is because the normal operation in the reproduction of only the audio becomes impossible because the operation of switching to another input source such as TV broadcasting is performed.

(3) Since the presence / absence of a video signal is detected only by the presence / absence of a sync signal in the video signal, when an audio signal and a video signal are separately input from an external input terminal for reproduction, When there is no video signal, the power supply circuit is turned off (or switched to TV) regardless of the presence or absence of an audio signal.

The reason is that the synchronizing signal, which is the reference for determining whether to turn off the power supply circuit, is included only in the video signal. Therefore, when the audio signal and the video signal are separately input, the conventional configuration is used. This is because, when the video signal disappears, the power supply circuit is turned off or the operation is switched to TV broadcasting even while the audio is being viewed, and the normal operation in the reproduction of only the audio becomes impossible.

(4) Criteria for controlling the power supply circuit (conditions,
Since the conditions such as time) and the switching of the input source are uniform, there is a possibility that the case may not be suitable for the usage condition (environment).

The reason is that the circuit for controlling the power supply always performs the same operation when the connection condition of the externally connected device is different depending on the user and the purpose of use is sometimes different. (Non-optimal behavior) occurs.

An object of the present invention is to send an invalid video signal (blue back, etc.) by turning on the power, VTR, LD.
It is an object of the present invention to provide a power supply control circuit for a video device that determines the presence or absence of a video image and turns off the power supply circuit when it determines that there is no video. Another object of the present invention is VT
Provided is a power supply control circuit for video equipment such as R and LD, which judges the presence or absence of audio when inputting and reproducing only an audio signal from an external input terminal, and turns off the power supply circuit when it is judged to be absent. To do.

Still another object of the present invention is to provide a VT for separately inputting and reproducing an audio signal and a video signal from an external input terminal.
It is an object of the present invention to provide a power supply control circuit for a video device such as an R or LD that can continuously reproduce only the audio signal even when the video signal is lost during the reproduction of the video signal and the audio signal.

Still another object of the present invention is to turn off the power supply circuit according to various usage conditions and purposes of the user.
It is to provide a power supply control circuit for a video device.

[0018]

The power supply control circuit of the video equipment of the present invention is connected to the output of the input switching circuit, and checks for the presence of an input video signal. Connected to the output of the input switching circuit and the image presence / absence determining means for determining
When the invalid state of the input signal continues for a predetermined time or longer, the input signal valid / invalid determination means for determining the input signal is invalid, and the power supply circuit is turned off when it is determined that there is no image and when the input signal is invalid. Or the power supply circuit is turned off only when it is determined that there is no video or input invalid corresponding to a predetermined input signal to the input switching circuit, or it is determined that there is no video and the input signal is invalid. At this time, it has a control circuit for controlling the input switching circuit to switch to another input signal.

In addition to the control by the synchronizing signal included in the video signal, the power supply circuit is turned off even when an invalid video signal is continuously input for a certain period of time or more, so that the blue output to the standby state of the external device is performed. There is no restriction on the control of the power supply circuit, which occurs when processing an invalid video signal such as a back signal.

In addition to the control by the detection of the synchronizing signal included in the video signal, the presence / absence of an audio signal is determined, and the power supply circuit is turned off when the absence of audio continues for a certain period of time. As a result, there is no restriction on the control of the power supply circuit that occurs in the processing of the connection state of only the audio input signal in the external device.

Further, there is no restriction on the control of the power supply circuit which is generated in regard to the input state from the separate equipment of the video signal and the audio signal in the connection form of the external equipment.

According to the embodiment of the present invention, the input valid / invalid determination means converts the video signal output from the memory circuit and the input switching circuit into a digital signal and stores it in the D / A conversion circuit. The A conversion circuit, the video comparison circuit that compares the data stored in the memory circuit with the output signal of the D / A conversion circuit, and the state where the video comparison circuit determines that the video signal is unchanged or has a specific pattern is predetermined. It includes a non-change time measuring circuit for measuring whether or not the video signal has continued for a predetermined time or more and determining that the video signal is invalid when it is judged that the video signal has continued for a predetermined time or longer.

According to another embodiment of the present invention, the input validity / invalidity determining means determines the level of the voice signal output from the input switching circuit and determines the presence / absence of a voice signal, It includes a voiceless time measuring circuit that determines whether or not the voiceless state determined by the voice presence / absence determination circuit has continued for a predetermined time or more, and determines that the voice signal is invalid if the voiceless state continues for a predetermined time or more.

According to another embodiment of the present invention, the image presence / absence determining means sets a predetermined time for the user to determine that there is no image and a predetermined time for determining that the input signal is invalid, respectively.
It further has a setting circuit for setting the input signal validity / invalidity determination means and setting the condition for turning off the power supply circuit and the input switching condition of the input switching circuit in the control circuit.

Therefore, the user can use the video equipment according to the purpose (environment).

[0026]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a video equipment (television receiver) including a power supply control circuit according to a first embodiment of the present invention.

The video equipment of FIG. 1 includes an external input terminal 1, a tuner circuit 2, an input switching circuit 3, a video processing circuit 4, a video presence / absence determination circuit 5, a no-video time measuring circuit 6, a D / A conversion circuit 7, and a memory. The circuit 8, the video comparison circuit 9, the no change time measuring circuit 10, the control circuit 13A, the setting circuit 14A, and the power supply circuit 1
And 5.

The external input terminal 1 is an input terminal for a video signal and an audio signal from an external AV device, and it is assumed that at least one system is installed. The tuner circuit 2 selects a broadcast signal received by an antenna input. The input switching circuit 3 is a circuit for switching between the signal from the tuner circuit 2 and the signal from the external input terminal. The video processing circuit 4 outputs the video signal selected by the input switching circuit 3 to the CRT.
It is a circuit that performs processing for displaying (not shown).

Image presence / absence determining circuit 5, non-image time measuring circuit 6, D / A converting circuit 7, memory circuit 8 and image comparing circuit 9
The non-change time measuring circuit 10, the control circuit 13A, and the setting circuit 14A constitute a power supply control circuit.

The video presence / absence determining circuit 5 and the no-video time measuring circuit 6 constitute a video presence / absence determining means for determining the presence / absence of a video signal. The video presence / absence determination circuit 5 determines the presence / absence of a video signal by detecting the synchronization signal from an integration circuit or the like after separating the synchronization signal from the video signal output from the input switching circuit 3. That is, the presence / absence of the video signal is determined by the presence / absence of the sync signal. The no-image time measuring circuit 6 measures the state in which the image presence / absence determination circuit 5 determines that there is no image, and outputs the no-image determination signal to the control circuit 13A when the state has continued for a predetermined time or longer.

The D / A conversion circuit 7, the memory circuit 8, the video comparison circuit 9, and the no-change time measuring circuit 10 constitute a video valid / invalid judging means for judging the validity / invalidity of the video signal. The D / A conversion circuit 7 converts the video signal from an analog signal to a digital signal and stores it in the memory circuit 8. The video comparison circuit 9 compares the data stored in the memory circuit 8 with D /
The output signals of the A conversion circuit 7 are compared. The no-change measurement time determination circuit 10 measures the state when the video comparison circuit 9 determines that there is no change (same) or a specific pattern (blue background, etc.), and when the video comparison circuit 9 continues for a predetermined time or more, the non-change measurement time determination circuit 10 judges an invalid video. The signal is output to the control circuit 13A, and when the image comparison circuit 9 determines that the image is different from the previous image, the content of the memory circuit 8 is updated.

The control circuit 13A is a non-video time measuring circuit 6,
No-picture determination signal from the no-change time measuring circuit 10,
The following method can be considered as a control method in a circuit that controls the power supply circuit 15 and the input switching circuit 3 when the invalid video determination signal is output. (1) The power supply circuit 15 is turned off when the no-image determination signal or the invalid image determination signal is output.

In this case, with respect to both the input signal input from the external input terminal 1 and the input signal from the tuner circuit 2, the power supply circuit 15 is turned on when the no-video determination signal or the invalid video determination signal is output. For example, the method of turning off the power supply circuit 15 is turned off when the no-picture judgment signal or the invalid picture judgment signal is output for the input signal input from the external input terminal 1, and the input signal from the tuner circuit 2 On the other hand, a method of turning off the power supply circuit 15 only when the invalid video determination signal is output can be considered.

(2) When the no-picture judgment signal or the invalid picture judgment signal is output, the power supply circuit 15 is not turned off, but the input switching circuit 3 is controlled to automatically switch to another input signal. The order of this switching can be arbitrarily set by the user using the setting circuit 14A. For example, tuner circuit 2 → external input terminal 1 or external input terminal 1
→ There may be an order such as the tuner circuit 2. If the external input terminal 1 has two or more systems, the external input terminal 1 (external device 1) → tuner circuit 2 → external input terminal 1
It is also possible to further finely set the order like (external device 2).

The setting circuit 14A is a reference time for the non-video time measuring circuit 6 and the no-change time measuring circuit 10 to determine the non-video and the invalid video, respectively, and the input when the non-video or the invalid video is determined. This is a circuit for the user to set the input switching condition of the switching circuit 3 and the control condition of the power supply circuit 15 described above.

In this setting circuit 14A, no video,
The reference time for determining the invalid video can be arbitrarily set to different values. That is, it is possible to separately set the reference time of the video time measuring circuit 6 to 5 minutes and the reference time of the unchanged video time measuring circuit 10 to 1 hour, for example. Therefore, when the power supply is unnecessary, the on-state time of the power supply circuit 15 can be shortened, and the power consumption can be reduced.

FIG. 2 is a block diagram of a video equipment (television receiver) including a power supply control circuit according to a second embodiment of the present invention. The same reference numerals as those in FIG. 1 indicate the same components.

The video device of FIG. 2 has an external input terminal 1, a tuner circuit 2, an input switching circuit 3, a video processing circuit 4, a video presence / absence determination circuit 5, a no-video time measuring circuit 6, an audio presence / absence determination circuit 11, and no audio. It is composed of a time measuring circuit 12, a control circuit 13B, a setting circuit 14B, and a power supply circuit 15.

The video presence / absence determining circuit 5, the non-video time measuring circuit 6, the voice presence / absence determining circuit 11, the non-voice time measuring circuit 12, the control circuit 13B and the setting circuit 14B constitute a power supply control circuit.

The voice presence / absence determining circuit 11 and the voiceless time measuring circuit 12 constitute voice presence / absence determining means for determining the presence / absence of a voice signal. The voice presence / absence determination circuit 11 is the input switching circuit 3
The presence or absence of voice is determined by the level detection operation of the voice signal which is the output of. That is, a threshold is set for the voice level, and by comparing this level with the voice input signal, it is determined that there is no voice when the voice signal is below a certain level. The voice time measuring circuit 12 is a voice presence / absence determining circuit 11
Is measured by the setting circuit 14
When it continues for a predetermined time or longer defined by B, the non-voice determination signal is output. The control circuit 13B supplies power to the power supply circuit 1 when the no-video time measuring circuit 6 and the no-audio time measuring circuit 12 output a no-video determination signal and a no-audio determination signal, respectively.
The following method is conceivable as a control method in a circuit for controlling the input voltage switching circuit 5 and the input switching circuit 3.

(1) When the no-picture judgment signal or the no-sound judgment signal is output, the power supply circuit 15 is turned off.

In this case, the power supply circuit 15 is turned off when the no-picture judgment signal or the no-sound judgment signal is output for both the input signal input from the external input terminal 1 and the input signal from the tuner circuit 2. Method, for example, the power supply circuit 15 is turned off only when a soundless judgment signal is output for an input signal input from the external input terminal 1, and an invalid video judgment is performed for an input signal from the tuner circuit 2. A method is conceivable in which the power supply circuit 15 is turned off only when a signal is output.

(2) When the no-picture decision signal or the no-voice decision signal is output, the power supply circuit 15 is not turned off, but the input switching circuit 3 is controlled to automatically switch to another input signal. The order of this switching can be arbitrarily set by the user using the setting circuit 14B. For example, tuner circuit 2 → external input terminal 1 or external input terminal 1 →
There may be an order of the tuner circuit 2 and the like. If the external input terminal 1 has two or more systems, the external input terminal 1 (external device 1) → tuner circuit 2 → external input terminal 1
It is also possible to further finely set the order like (external device 2).

The setting circuit 14B is used as a reference time for the no-video time measuring circuit 6 and the no-voice time measuring circuit 12 to determine the no-video and the no-voice, respectively, and switches the input when the no-video or the no-voice is determined. This is a circuit for the user to set the input switching condition of the circuit 3 and the control condition of the power supply circuit 15 described above.

In this setting circuit 14B, no video,
It is possible to arbitrarily set the time for determining the invalid video to different values. That is, it is possible to separately set the reference time of the no-video time measuring circuit 6 to 5 minutes and the reference time of the no-voice time measuring circuit 12 to 30 minutes, for example. Therefore, when the power supply is unnecessary, the on-state time of the power supply circuit 15 can be shortened, and the power consumption can be reduced.

FIG. 3 is a block diagram of a video equipment (television receiver) including a power supply control circuit according to a third embodiment of the present invention. The same reference numerals as those in FIGS. 1 and 2 denote the same components.

The video equipment of FIG. 3 has an external input terminal 1, a tuner circuit 2, an input switching circuit 3, a video processing circuit 4, a video presence / absence determining circuit 5, a no-video time measuring circuit 6, a D / A conversion circuit 7, and a memory. Circuit 8, video comparison circuit 9, no change time measuring circuit 10, sound presence / absence determination circuit 11, and no sound time measuring circuit 1
2, a control circuit 13C, a setting circuit 14C, and a power supply circuit 15.

Image presence / absence determining circuit 5, non-image time measuring circuit 6, D / A converting circuit 7, memory circuit 8 and image comparing circuit 9
A non-change time measuring circuit 10, a voice presence / absence determining circuit 11, a non-voice time measuring circuit 12, a control circuit 13C, and a setting circuit 14.
C constitutes a power supply control circuit.

That is, the power supply control circuit of this embodiment is
The control circuit 13 includes all of the video presence / absence determining means of the first and second embodiments, the video valid / invalid determining means of the first embodiment, and the audio presence / absence determining means of the second embodiment.
Only C and setting circuit 14C are different from the first and second embodiments.

The control circuit 13C is a non-video time measuring circuit 6,
A circuit that controls the power supply circuit 15 and the input switching circuit 3 when a no-video determination signal, an invalid video determination signal, and a no-audio determination signal are output from the no-change time measuring circuit 10 and the no-voice time measuring circuit 12, respectively. The following methods can be considered as control methods.

(1) The power supply circuit 15 is turned off when the no-picture judgment signal, the invalid-picture judgment signal, or the no-sound judgment signal is output.

In this case, the power supply circuit is output when the no-picture judgment signal, the invalid picture judgment signal or the no-sound judgment signal is output for both the input signal input from the external input terminal 1 and the input signal from the tuner circuit 2. 15 is turned off, and for example, the power supply circuit 15 is turned off only when the no-sound determination signal or the invalid video determination signal is output for the input signal input from the external input terminal 1 and the tuner circuit 2 A method is conceivable in which the power supply circuit 15 is turned off only when the invalid video determination signal or the non-voice determination signal is output for the input signal. In other words, regarding the input signal from the tuner circuit 2, since the audio and the video are synchronous inputs, the presence / absence of the audio is determined, and the video signal disappears at the end of the broadcast (there is no output such as blue back). It becomes possible to make an optimum (lean) judgment based on the input signal, since the judgment of is unnecessary.

(2) When the no-picture decision signal or the no-voice decision signal is output, the power supply circuit 15 is not turned off, but the input switching circuit 3 is controlled to automatically switch to another input signal. The order of this switching can be arbitrarily set by the user using the setting circuit 14C. For example, tuner circuit 2 → external input terminal 1 or external input terminal 1 →
There may be an order of the tuner circuit 2 and the like. If the external input terminal 1 has two or more systems, the external input terminal 1 (external device 1) → tuner circuit 2 → external input terminal 1
It is also possible to further finely set the order like (external device 2).

The setting circuit 14C includes a no-video time measuring circuit 6, a no-change time measuring circuit 10, and a no-voice time measuring circuit 12.
, The reference time for determining no video, invalid video, and no sound, the input switching condition of the input switching circuit 3 when it is determined to be no video, invalid video, or no sound, and the control condition of the power supply circuit 15 described above. Is a circuit for the user to set.

In the setting circuit 14C, no video,
It is possible to arbitrarily set the determination time of invalid video and silence to different values. That is, the reference time of the video time measuring circuit 6 is, for example, 5 minutes, and the no change time measuring circuit 1
The reference time of 0 is, for example, 1 hour, and the silent time measuring circuit 12
It is possible to separately set the reference time of 30 minutes, for example. Therefore, when the power supply is unnecessary, the power supply circuit 15
The on-state time of can be shortened and power consumption can be reduced.

[0057]

As described above, the present invention has the following effects. (1) It is possible to control the power supply circuit even in a video device which inputs an invalid video signal such as a blue back signal output in the standby state. (2) The power supply circuit can be controlled even when only the audio signal is input and reproduced. (3) The power supply circuit can be controlled even when the video signal and the audio signal are separately input and reproduced. (4) The user can arbitrarily set the control conditions of the power supply circuit.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a power supply control circuit according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a power supply control circuit according to a second embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a power supply control circuit according to a third embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a conventional power supply control circuit.

[Explanation of symbols]

 1 External Input Terminal 2 Tuner Circuit 3 Input Switching Circuit 4 Video Processing Circuit 5 Video Presence / Absence Judgment Circuit 6 Video No-Time Measurement Circuit 7 D / A Conversion Circuit 8 Memory Circuit 9 Video Comparison Circuit 10 No Change Time Measurement Circuit 11 Audio Presence / Absence Judgment Circuit 12 silent time measuring circuit 13A, 13B, 13C control circuit 14A, 14B, 14C setting circuit 15 power supply circuit

Claims (4)

[Claims] 1. An external input terminal for inputting a video signal from an external device, a tuner circuit, an input switching circuit for switching a video signal from the external input terminal and a video signal from the tuner circuit, and a video processing circuit. A video power supply control circuit for a video device having: a video presence determination means that is connected to the output of the input switching circuit, checks the presence of an input video signal, and determines that there is no video when the non-video state continues for a predetermined time or more. Is connected to the output of the input switching circuit to enable / disable the input signal.
Input signal valid / invalid judging means for judging invalidity of the input signal when the invalidity is checked and the invalid state of the input signal continues for a predetermined time or longer, and when it is judged that there is no image and when the input signal is invalid, The power supply circuit is turned off, or the power supply circuit is turned off only when it is determined that there is no video or a predetermined one of input invalidity corresponding to a predetermined input signal to the input switching circuit, or no video, A power supply control circuit for video equipment, comprising a control circuit for controlling the input switching circuit to switch to another input signal when it is determined that the input signal is invalid. 2. The input valid / invalid judging means includes: a memory circuit; and a D / A conversion circuit for converting a video signal output from the input switching circuit into a digital signal and storing the digital signal in the D / A conversion circuit. A video comparison circuit for comparing the data stored in the memory circuit with the output signal of the D / A conversion circuit, and a state in which the video comparison circuit determines that the video signal is unchanged or has a specific pattern for a predetermined time or more. The power supply control circuit for a video device according to claim 1, further comprising a non-change time measurement circuit for measuring whether or not the video signal has continued and determining that the video signal is invalid when it is determined that the video signal has continued for a predetermined time or more. 3. An audio presence / absence determining circuit for determining the presence / absence of an audio signal, wherein the input signal validity / invalidity determining means determines the level of the audio signal output from the input switching circuit.
The video according to claim 1, further comprising: a voiceless time measuring circuit that determines whether or not the voiceless state determined by the voice presence / absence determining circuit has continued for a predetermined time or more, and determines that the voice signal is invalid if the voiceless state continues for a predetermined time or more. Equipment power control circuit. 4. A user sets a predetermined time for determining that there is no video and a predetermined time for determining that an input signal is invalid in the video presence / absence determining means and the input signal valid / invalid determining means, respectively. 2. The power supply control circuit for video equipment according to claim 1, further comprising a setting circuit for setting conditions for turning off the power supply circuit and input switching conditions for the input switching circuit in the control circuit.