KR0151046B1 - Television power off circuit at the time of no-signal - Google Patents

Abstract

A power cut-off circuit of a television receiver is disclosed so that power is not cut off even under weak electric field conditions.

The power cutoff circuit according to the present invention comprises: a time information generator for setting a predetermined time period and generating state information indicating the set time period; And a logic calculator configured to determine whether a valid broadcast signal is not introduced in a predetermined time period with reference to the result of determining the level of the broadcast signal and the state information generated by the time information generator.

The power cutoff device according to the present invention has the effect of eliminating inconvenience in viewing by not interrupting the power of the television receiver during the broadcast time even when the level of the incoming broadcast signal is weak.

Description

Power Shutdown Circuit at No Signal

1 is a block diagram showing a conventional power interruption device.

2 is a blurred view showing a power cut device according to the present invention.

3 is a block diagram showing a preferred embodiment of the apparatus shown in FIG.

4 is a waveform diagram showing the operation of the apparatus shown in FIG.

The present invention relates to a power cut-off circuit that cuts off the power of a television receiver when a broadcast signal is hardly received. More particularly, the present invention relates to a power cut-off circuit of a television receiver that does not cut off power even under a weak electric field condition during a normal broadcast time. It is about.

The power cut-off circuit of the television receiver has no broadcast signal for a predetermined time and automatically cuts off the power of the television receiver to prevent unnecessary power consumption and prevents the TV receiver from running in the air. It is a circuit to protect from.

Such a circuit compares the level of the broadcast signal of the tuned channel, particularly the level of the synchronization signal, with the reference level to determine the presence or absence of the broadcast signal.

However, in the weak electric field area, although a broadcast signal is received, its size may appear smaller than a normal level. In this case, the conventional power cut-off circuit judges that there is no broadcast signal because it is simply determined by the level of the broadcast signal. do.

As a result, there is a problem in that the television becomes impossible at all in the weak electric field, which causes the claim.

The present invention has been made to solve the above problems, and an object thereof is to provide a power cutoff device whose operation is limited within a regular broadcast time.

A power cut-off device of a television receiver according to the present invention for achieving the above object is effective by comparing a level of a broadcast signal detected by the level detector with a predetermined level by detecting a level of a broadcast signal of a tuned channel. A power cut-off circuit of a television receiver having a determination unit for determining whether to receive a broadcast signal and a switch for shutting off power provided to the television receiver with reference to the determination result of the determination unit, a predetermined time interval is set, A time information generator for generating state information indicating a set time period; And a logic calculator configured to determine whether a valid broadcast signal is not introduced in a predetermined time period by referring to the judgment result of the determination unit and the state information generated by the time information generator. The switch includes a determination result of the logic calculator. According to the present invention, the power supply to the television receiver is cut off. Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram showing a conventional power interruption device. The operation of the apparatus shown in FIG. 1 will be briefly described. The broadcast signal introduced through the antenna 10 is tuned by the tuner 12 and demodulated by the demodulator 14 into an audio signal AUDIO and a video signal VIDEO signal. The audio signal is provided to an audio processor (not shown), and the video signal is provided to an image processor (not shown) and output to a speaker and a CRT, respectively. On the other hand, the video signal is also provided to the sync separator 16, the sync separator 16 separates the horizontal / vertical sync signal included in the video signal and provides it to the comparator 18.

The comparison unit 18 compares the horizontal / vertical synchronization signal and the reference signal Vref provided by the synchronization separation unit 16. The comparing unit 18 outputs a valid comparison determination signal, for example, a high level logic signal, when the magnitude of the horizontal / vertical synchronization signal is smaller than the reference signal Vref.

The microcomputer 20 recognizes when a high level logic signal is applied through the input port connected to the comparator 18, and applies the low level logic signal to the base terminal of the transistor 22 through the output port. .

The transistor 22 is cut off when a low-level logic signal is applied to its base terminal, and as a result, the power switch 26 is cut off through the relay 24. Therefore, no power is applied to the power switch 26 of the television receiver.

2 is a block diagram showing the configuration of a power interruption device according to the present invention. The apparatus shown in FIG. 2 includes a level detector 100, a determiner 120, a visual information generator 140, a logic operator 160, and a switch 180.

The level detector 100 detects the level of the broadcast signal of the tuned channel, and the determination unit 120 compares the level of the broadcast signal detected by the level detector 100 with a predetermined level to determine whether to receive a valid broadcast signal. To judge.

The time information generation unit 140 sets a predetermined time period and generates state information indicating the set time period. Here, the state information may be, for example, a logic signal that maintains a high level for a period from midnight to 4 am.

The logic operation unit 160 determines whether a valid broadcast signal is not introduced in a predetermined time period by referring to the determination result of the determination unit 120 and the state information generated by the time information generation unit 140.

The switch 180 cuts off the power provided to the television receiver according to the determination result of the logic operation unit 160.

3 is a block diagram showing a preferred embodiment of the apparatus shown in FIG. The operation of the apparatus shown in FIG. 3 will be briefly described.

The broadcast signal introduced through the antenna 30 is tuned by the tuner 32 and demodulated by the demodulator 34 into an audio signal and an video signal. The audio signal is provided to an audio processor (not shown), and the video signal is provided to an image processor (not shown) and output to a speaker and a CRT, respectively. On the other hand, the video signal is also provided to the synchronization separator 36, which separates the horizontal / vertical synchronization signal included in the video signal and provides it to the comparator 38.

The comparison unit 38 compares the horizontal / vertical synchronization signal and the reference signal Vref provided by the synchronization separation unit 36. The comparator 38 outputs a valid comparison determination signal, for example, a high level logic signal, when the magnitude of the horizontal / vertical synchronization signal is smaller than the reference signal Vref.

The timer 40 generates a status signal indicating a time zone during which it is not broadcast. The status signal may be, for example, a logic signal that maintains a high level in the time zone from midnight to 4 am.

The AND gate 42 performs a logical operation on the determination signal output from the comparator 38 and the status signal output from the timer 40, and provides the result to the microcomputer 44.

The microcomputer 44 recognizes when a high level logic signal is applied through an input port connected to the AND gate 42 and applies a low level logic signal to the base terminal of the transistor 46 through its output port. .

The transistor 46 is cut off when a low-level logic signal is applied to its base terminal, and as a result, the power switch 48 is cut off. Therefore, power is not applied to the power supply circuit 50 of the television receiver.

4 is a waveform diagram showing the operation of the apparatus shown in FIG. FIG. 4A shows the determination signal output from the comparator 38, FIG. 4B shows the status signal output from the timer 40, and FIG. 4C shows the output of the AND gate 42. FIG.

As described above, the power cutoff device according to the present invention has the effect of eliminating inconvenience in viewing by not interrupting the power of the television receiver during the broadcast time even when the level of the incoming broadcast signal is weak.

Claims (1)

A level detecting unit detecting a level of a broadcast signal of a tuned channel, a determining unit determining whether to receive a valid broadcast signal by comparing the level of the broadcasting signal detected by the level detecting unit with a predetermined level, and a determination result of the determining unit. A power cut-off circuit of a television receiver having a switch to cut off power supplied to the television receiver, the power cut-off circuit comprising: a time information generator for setting a predetermined time period and generating status information indicating the set time period; And a logic calculator configured to determine whether a valid broadcast signal is not introduced in a predetermined time period by referring to the judgment result of the determination unit and the state information generated by the time information generator. The switch includes a determination result of the logic calculator. Power cutoff device characterized in that for cutting off the power provided to the television receiver.