JPH04220093A - Mute system for av equipment - Google Patents

Abstract

PURPOSE:To apply mute processing to a shock sound noise at momentary interrupt of power supply of an AV equipment by using a software means. CONSTITUTION:The relation of time constants of lines (A),(B),(C) at power supply voltage drop is set to be (C)<(A)<(B) as to a 1st power supply line (A) through which a power supply is supplied from a power supply circuit section 2 receiving power from an AC power socket to an audio signal processing section, a 2nd power supply line (B) supplying power from the power supply circuit section 2 to a control means 5 outputting a silencing processing control signal to an audio signal processing section 3, and a 3rd power supply line (C) supplying power from the power supply circuit section 2 to a power supply momentary interrupt detection means 6 detecting the loss of power supply from the AC power socket, and when the power supply momentary interrupt detection means 6 detects the supply stop of the power, the control means 5 outputs a silencing processing control signal to the audio signal processing circuit section to apply silencing processing of an audio output.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention deals with the impact sound (hereinafter referred to as off-boo sound) that occurs when AC power supply is suddenly cut off.
The present invention relates to a muting method for AV equipment that causes noise.

0002

[Prior Art] In AV equipment such as television receivers and audio stereo sets, it has been a challenge to mute the buzzing sound that occurs when the power goes out or when the AC outlet is suddenly pulled out. There is a system in which a relay circuit is placed in series with the signal circuit system, and when a power failure occurs, the relay circuit cuts off the audio signal path and mutes the audio.

0003

However, the use of a relay circuit requires a considerable board area, which is undesirable, and there is a problem in that the performance of the audio signal circuit system deteriorates due to aging of the relay contacts. Therefore, if the AV device is equipped with a control function using a microcomputer, it is possible to execute the audio muting process using software, so it is preferable to execute the muting of the off-voice sound using this process. However, although it is possible to perform audio mute control as a software process when the power is turned off by normal power switch operation, it is of course not possible to respond to power abnormalities in which the power suddenly stops supplying power, so it cannot be used during power outages or when the outlet is unplugged. It could not be used as a means to mute the off-beat sound.

0004

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention provides a muting method for AV equipment that enables muting of off-beat sounds using software. That is, it has a power supply circuit section that receives power from an AC outlet, and outputs a silencing processing control signal to the first power supply line that supplies power from the power supply circuit section to the audio signal processing section and the audio signal processing section. a second power supply line that supplies power from the power supply circuit to the control means that can control the AC outlet; Regarding the power supply line No. 3, the time constant of the power supply voltage drop is set so that (third power supply line) < (first power supply line) < (second power supply line), and the instantaneous power interruption detection means When the stoppage of the voltage supply is detected, the control means outputs a silencing control signal to the audio signal processing circuit section, so that the audio output is muted.

[0005]

[Operation] With the above configuration, the power supply voltage of the third power line introduced into the instantaneous power interruption detection means drops the earliest.
If the instantaneous power interruption detection means detects a drop in power supply voltage and then supplies a detection signal to the control means energized by the second power supply line, the control means performs the second supplying a mute control signal to an audio signal processing unit energized by a first power supply line whose power supply voltage has not yet dropped similarly to the power supply line;
Audio signals can be muted. Furthermore, since the power supply voltage of the second power supply line drops later than that of the first power supply line, the muting process is reliably performed until the audio signal circuit system is turned off.

[0006]

Embodiment FIG. 1 is a block diagram showing an embodiment of the off-boo sound muting method of the present invention, which is applied as an audio signal circuit system and its control system in, for example, a television receiver, a monitor device, an audio stereo set, etc. It is something that

[0007] 1 is an AC outlet, and 2 is an AC outlet 5 that supplies AC power from the AC outlet to, for example, a digital IC circuit.
3 is the power supply circuit section that obtains DC output of V, 12V, converts the voltage for analog signals (analog 5V, analog 12V) into the DC power supply voltage necessary for the equipment, and supplies it to each circuit section. An audio signal processing section performs processing such as volume adjustment and muting on an audio signal using an external control signal, and 4 indicates a speaker output section.

Reference numeral 5 denotes a CPU that supplies various control signals to at least the audio signal processing section 3, and the audio signal processing section 3 is supplied with power from the power supply circuit section 2 through a power line (A). On the other hand, power is supplied to the CPU 5 from the power supply circuit section 2 via a power supply line (B). Reference numeral 6 denotes a momentary power outage detection circuit section, which detects a drop in the power supply voltage introduced through the power line (C) due to unplugging of an AC outlet, power outage, etc., and outputs a power off detection signal to the CPU 5.

[0009] Here, the power supply circuit section 2 is connected to the AC outlet 1.
When the AC power input from the ). That is, as shown in FIG. 2, for example, t0
If the AC outlet 1 is suddenly pulled out at a certain time, the power supply voltage [power line (C)] introduced into the momentary interruption detection circuit section 6 is designed to drop first, and then when T1 time has elapsed. After that, the power supply voltage [power line (A)] supplied to the audio signal processing section 3 is turned off,
Then, after a further time T2 has elapsed, the power supply voltage [power line (B)] supplied to the CPU 5 is turned off.

In the instantaneous power failure detection circuit section 6, the power supply voltage supplied from the power supply line (C) is compared with a reference voltage using, for example, a comparator and waveform shaping is performed, thereby generating a power-off detection signal as shown in FIG. Since it can be obtained, it is supplied to the power on/off detection port of the CPU 5. The CPU 5 performs processing based on the input from the power on/off detection port when the power is turned on and when the power switch is turned off (when the power switch is manually turned off rather than when the AC outlet 1 is pulled out). The software is structured as follows.

Even when the power is turned off, the CPU 5 remains energized until time t2, so that the program operation can be continued. Therefore, after time t1, the audio signal processing unit 3 enters the normal power switch-off processing mode based on the power-off detection signal supplied to the power-on/off detection port, and performs one of the processes during power-off. It is possible to output a mute control signal SM to the target. Then, until time t1, when the audio signal processing section 3 is kept energized, mute processing is performed as one of the normal power-off processings. In other words, in this embodiment, even if a sudden power-off occurs, the CPU 5 can recognize that the power-off is due to a normal switch operation and perform processing. Since the off-beat sound occurs immediately after the point t0 when the AC power supply voltage drops, the output of the off-beat sound can be eliminated by performing mute processing up to the time t1. Furthermore, there is an advantage that the operating program for the CPU 5 can be almost unchanged from the conventional one.

The instantaneous interruption detection circuit section 6 in this embodiment is configured as shown in FIG. 3, for example. 6a is a reset circuit section using a comparator, which shapes the power supply voltage supplied from the power supply line (C) into a waveform having a sharp down edge as shown in FIG. 2, and uses it as a power-off detection signal. 6b
is a 3-state buffer, with gate input G and input A
Based on this, it is possible to obtain a ternary output Y as shown in Table 1. As the gate input G, an "H" signal is supplied from the CPU 5 when the device is in a "power-on" state in which it is in operation. Note that 6c is a diode for preventing backflow.

[0013]

[Table 1]

The provision of the 3-state buffer 6b will be explained below. As described above, the output of the instantaneous power failure detection circuit section 6 is input to the power on/off detection port of the CPU 5, and when power on and power off are detected by the input to the power on/off detection port, the CPU 5 Predetermined processing is performed according to each program, but two different controls may be performed when the power is turned on. First, when the user turns on the power switch of the device while the AC outlet 1 is connected (hereinafter referred to as PS-on). Next, when the power switch of the main unit of the device is in the on state, power is automatically supplied after the AC outlet is plugged in or the power outage ends (hereinafter referred to as A
C-on).

[0015] As is well known, AV equipment such as television receivers can be operated using a remote commander, and even if the power switch of the equipment itself is turned on, the equipment does not always turn on. ”. The device is said to be "power on" when its power switch is on and the remote commander is also on. In other words, if the power switch of the device itself is in the on state, on/off control is possible using only the remote commander. If the remote commander is turned off but the power switch on the main body of the device is not operated, the device is placed in a so-called standby state (remote commander operable state).

[0016] Normally, the CPU as a control device for AV equipment always knows the current state of the equipment, and when the power switch of the equipment itself is turned off, the operating state by the remote commander immediately before it was turned off is retained. (last memory function), when the power switch is turned on again, it will return to the state immediately before the last power off operation. For example, when the power switch is turned off from the standby state, turning the power switch on again returns the device to the standby state.

By the way, in the case of AC-ON, such control using the last memory is always necessary. For example, if a power outage occurs during standby mode, and then the power outage ends, it is not appropriate to turn on the power just because the power switch of the main unit is on, but it is preferable to return to standby mode. However, PS-
If it is turned on, the user will have to operate the remote commander further if it is turned off in the standby state and then returned to the standby state as described above, which is extremely troublesome. For this reason, the CPU 5 controls the device so that it is forcibly "powered on" regardless of the last memory at the time of PS-ON.

That is, in the CPU 5 of this embodiment, signals with different waveforms are input to the power on/off detection port when AC-on and PS-on are turned on, thereby distinguishing between AC-on and PS-on. They are detected separately and processed differently. Therefore, if a power-off detection signal is output from the momentary interruption detection circuit section 6 to the power-on/off detection port when AC-on or PS-on, it will affect the AC-on and PS-on detection signals. In order to make it impossible to make a determination, the power supply is "H" or "L" only when the gate input of the 3-state buffer 6b is "H", that is, only when the device is in the "power on" state. An off detection signal is output, and other outputs are high impedance outputs to eliminate the influence of AC-on and PS-on detection signals.

[0019]

Effects of the Invention As explained above, in the muting method of the AV equipment of the present invention, the time constant of power supply voltage drop is (third power line) < (first power line) < (second power line). A momentary power interruption is detected from the third power supply line, which drops the power supply voltage earliest in the event of a momentary power interruption, and the control means is energized by the second power line, and the first power supply line is energized. Since the mute control signal is supplied to the audio signal processing unit that performs mute processing of the audio signal, it is possible to mute the off-booting sound even when the power is suddenly turned off, such as by unplugging the outlet or power outage. The advantage is that the processing can be carried out by software means.

[Brief explanation of the drawing]

FIG. 1 is a block diagram illustrating an embodiment of a muting method for AV equipment according to the present invention.

FIG. 2 is a waveform diagram for explaining the present embodiment.

FIG. 3 is a block diagram of a momentary interruption detection circuit section of the present embodiment.

[Explanation of symbols]

1 AC outlet 2 Power supply circuit section 3 Audio signal processing section 5 CPU 6 Momentary interruption detection circuit section

Claims (1)

[Claims] 1. A power supply circuit unit that obtains power from an AC outlet, a first power supply line that supplies power from the power supply circuit unit to an audio signal processing unit, and a silencing process control for the audio signal processing unit. a second power supply line for supplying power from the power supply circuit to a control means capable of outputting a signal; and a power supply circuit for detecting instantaneous power interruption detection means for detecting that power is no longer supplied from the AC outlet. With respect to the third power supply line that supplies power from the unit, the time constant of the power supply voltage drop is set so that (third power supply line) < (first power supply line) < (second power supply line), When a stop in the supply of power supply voltage is detected by the instantaneous power interruption detection means, the control means outputs a silencing processing control signal to the audio signal processing circuit unit, so that the audio output is muted. A muting method for AV equipment characterized by the following configuration.