JP3158450B2 - Power supply control method for AV equipment and AV equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television receiver.
Power control method by a control microcomputer in AV equipment such as audio and audio sets , and the power control
The present invention relates to an AV device using a control method .

[0002]

2. Description of the Related Art A microcomputer such as a television receiver or an audio stereo set is generally equipped with a microcomputer as a control means, and performs operation control and power control associated with various operation switches. By the way, the processing contents related to the power control include control of power supply from the power supply circuit unit to each circuit unit or stop thereof based on on / off operation of the power switch, mute processing of audio output at the time of on / off, and Further, there is a process of detecting an instantaneous interruption of the power supply at the time of a power failure or when the AC outlet is suddenly unplugged, and muting an impulsive sound (hereinafter referred to as an off-buzz sound) generated in such a case. Of the above processes, the muting process at the moment of a momentary power failure is implemented by providing a relay circuit in the audio processing circuit, for example, so that the audio signal system can be disconnected.

[0003]

However, there is a problem in that the use of the relay circuit requires a considerable board area, and the performance of the audio signal circuit system deteriorates due to aging of the relay contact. It is desirable that the microcomputer can perform the operation related to the power supply control even when the power supply is momentarily interrupted.

Here, in order to respond to the momentary interruption of the power supply by the control of the microcomputer, a power supply line whose voltage drops before the power supply to the microcomputer at the momentary interruption is provided, and the voltage state thereof is set. To detect an instantaneous interruption, and input the detection signal to the input port of the microcomputer where interrupt processing is given the highest priority. The microcomputer must supply a mute control signal to the audio signal processing circuit based on the instantaneous interruption detection. There is. Therefore,
In addition to the input port for inputting a signal for detecting the operation of the normal power switch, one additional input port is allocated to enable the highest priority interrupt processing of the microcomputer for instantaneous interruption detection. And there is a problem that efficient use of the input port is hindered.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has been made in consideration of the above circumstances.
One input port of a microcomputer can detect the power-off due to a momentary power interruption. That is, a first power state detection signal for detecting that the power switch of the AV device is turned on, and a second power state detection signal output as a down-edge waveform when the power is turned off are controlled. Input to a predetermined input port of the microcomputer. This input port is designed to be able to perform the highest priority interrupt processing based on the detection of the down edge of the input signal. Then, the control microcomputer detects the input signal of the input port with a binary signal of H or L for a predetermined period after the energization is started, thereby setting the level of the first power supply state detection signal. Detecting the ON operation of the power switch on the basis of the power switch, and detecting the down-edge waveform for the input signal of the input port after the ON of the power switch is detected, thereby detecting the second power state detection signal. It is intended to make it possible to determine that the power has been turned off upon detection. Further, based on the detection of the power ON / OFF, a mute control signal is supplied to the audio signal processing circuit to perform a sound output silencing process.

[0006]

When the power is turned on, the signal level of one input port is determined by the binary value of H or L, and it is detected that the power switch has been turned on. If the operation mode on the software in the control microcomputer is switched so as to detect the down-edge waveform for the input signal of, the power-off at the momentary interruption and the operation of the power switch can be detected, Input ports can be used efficiently.

[0007]

FIG. 1 is a block diagram showing an embodiment for realizing a power supply control method according to the present invention. For example, in a television receiver, a monitor device, an audio stereo set, etc.
It is applied as a circuit block for power on / off control of AV equipment .

1 is an AC outlet, 2 is an AC outlet from the AC outlet, and obtains a DC output of, for example, 5 V or 12 V to be supplied to a digital IC circuit, and a device such as a voltage for an analog signal (analog 5 V, analog 12 V). A power supply circuit unit for converting to a required DC power supply voltage and supplying it to each circuit unit; 3, an audio signal processing unit for performing processing such as volume adjustment and mute on the L and R audio signals;
Indicates a speaker output unit. Power is supplied to the audio signal processing unit 3 from the power supply circuit unit 2 through a power supply line (X).

Reference numeral 5 denotes a microcomputer for supplying various control signals to at least the power supply circuit unit 2 and the audio signal processing unit 3, and reference numeral 6 denotes a clock oscillation circuit. Also, 7a,
Reference numeral 7b denotes a switch circuit that is switched by a user performing, for example, an on / off operation of a power switch provided on the device main body. When the power switch is off, the switch circuit 7a has a B contact, that is, a switch circuit 7a. It is grounded, and the switch circuit 7b is disconnected. When the power switch is turned on, the power line (Y) is closed by the switch circuit 7b and the power is supplied from the power circuit unit 2 to the microcomputer 5.

Reference numeral 8 denotes an instantaneous interruption detection circuit unit, which detects that the power supply voltage introduced through the power supply line (Z) has dropped due to an AC outlet being unplugged or a power failure, and sends a power-off detection signal to the microcomputer 5. Output. That is, in the instantaneous interruption detection circuit section 8, the power supply voltage supplied from the power supply line (Z) is compared with the reference voltage _Vref by the comparator 8a to perform waveform shaping, thereby shaping a steep down-edge pulse when the voltage drops. And output it. The output down-edge pulse is supplied to a predetermined input port 5a of the microcomputer 5.

Here, the power supply lines (X) and (Y)
As for (Z), the time constant of the power supply voltage drop is (Z) <
(X) <(Y). That is, as shown in FIG. 2, AC outlet 1, for example, t ₀ point
After There is a case that suddenly withdrawn, being as a power supply voltage which has been introduced into the momentary interruption detecting circuit 8 (power supply line (Z)) is earliest drop, which then has passed time T _1,
Audio signal processor power supply voltage supplied to the 3 (the power supply line (X)) is turned off, and further T ₂ hours elapsed power supply voltage supplied to the microcomputer 5 after (power supply line (Y)) is turned off It is what becomes.

Reference numeral 9 denotes a time constant circuit, and a switch circuit 7b
Is closed, the power supply voltage supplied from the power supply line (Y ') is shaped into a waveform that rises with a time constant as shown in FIG. 3, and an input of the microcomputer 5 is provided as a signal for detecting that the power switch has been operated. Supply to port 5.

The input port 5a of the microcomputer 5
Is configured, for example, as shown in FIG. 4. That is, an interrupt control circuit operates based on an input signal (down-edge pulse), interrupt processing is enabled, and terminal levels (H, L) of the input signal are read. Then, the data is supplied to an internal data bus so that predetermined processing based on software can be performed. In other words, the microcomputer 5 not only processes the signal input from the input port 5a as a binary signal of H and L by switching the mode on software, but also, for example, once rises to the H level, sets the down edge pulse. Interrupt control may be performed when is input.

In the embodiment thus constructed, the processing of the microcomputer relating to the power supply state is shown in the flowchart of FIG. The steps in the flowchart are F1
Indicated by 00 to F110. FIG. 6 shows a signal waveform supplied to the input port 5a when the power is turned on / off. First, Figure by constant circuit 9 when the signal waveform supplied to the input port 5a for the case (F100), the power state detection power switch microcomputer 5 is turned on is energized at t ₁₀ the time of FIG. 6 6 Get up slowly as shown. Thus the microcomputer waits until period determined by the time constant circuit 9 (t ₁₀ ~t ₁₁ point, for example, several 100mm sec) (F101), and determines the terminal level of the input port 5a at t ₁₁ the time (F102) .

At this time, the microcomputer 5 is in an operation mode in which predetermined processing is performed by power-on detection based on the terminal level of the input port 5a. That is, if it is determined from the detected terminal level that the power is on, first, a mute control signal is supplied to the audio signal processing unit 3 to make the audio output mute (F10
4) Then, a power supply control signal is supplied to the power supply circuit section 2 to supply operation power to the audio signal processing section 3 and other circuit sections (F105). Then, after the device is turned on, for the input of the input port 5a, a down-edge pulse is detected instead of detecting the terminal level, and the mode is switched to a mode of waiting for an interrupt process based on the detection (F10).
6). Incidentally, when it is determined that the power supply off at t ₁₁ the time to wait in a standby state (F107).

[0016] After being powered on, for example, when an instantaneous interruption, such that the power outlet is withdrawn at t ₁₂ the time is detected,
A down-edge pulse is output from the instantaneous interruption detection circuit unit 8,
It is input to the input port 5a. Also, when the power supply switch is turned off, a similar down-edge pulse is generated because the switch circuit 7a is grounded. When such a down-edge pulse is input to the input port 5a (F108), the microcomputer 5 is set to a mode in which the input of the input port 5a performs the highest priority interrupt processing based on the down-edge pulse. Therefore, even while another operation control is being executed, a mute control signal is first supplied to the audio signal processing unit 3 as interrupt processing (F109), and then the power supply circuit unit 2 is controlled to turn off the power. The state is set (F110).

As described above, since a time constant is added to each power supply line so that the power supply voltage of the power supply line (Z) drops at the earliest at the time of the power supply interruption, even after the power supply interruption is detected. During a predetermined period, the microcomputer 5 and the audio signal processing unit 3 are kept energized, so that the audio output can be muted by the processing on the software of the microcomputer 5 at the moment of an instantaneous interruption, so that the off-buzz sound can be cut off. Become. Therefore, it is not necessary to provide a relay circuit in the audio signal processing unit, and the reliability of the mute process at the moment of interruption and the reduction in manufacturing cost are promoted.

As described above, in this embodiment, the microcomputer detects the power supply state by using the input port 5a which can perform both the interrupt processing based on the down-edge pulse and the terminal level detection. A dedicated input port is not required, and the input port can be used effectively.

The reason why the time constant circuit 9 is provided will be described below. As described above, the power-on detection is performed based on the terminal level of the input port 5a.
At power-on, two different controls may be performed. First, when the user turns on the power switch of the device main body while the AC outlet 1 is connected (hereinafter referred to as PS-ON). Next, there is a case where an AC outlet is plugged in while the power switch of the device main body is in an ON state, or power is supplied after a power failure ends (hereinafter, referred to as AC-ON).

Here, as is well known, an AV device such as a television receiver can be operated by a remote commander, and if the power switch of the device body is simply turned on, the device is not necessarily "power". It does not turn on. When the power switch of the device main body is on and the operation state by the remote commander is on, the power is turned on. That is, when the power switch of the device body is in the on state, on / off control can be performed only by the remote commander. When the remote commander is turned off but the power switch of the device is not operated, a so-called standby state (a state in which the remote commander can be operated) is set.

Normally, the microcomputer as the control device of the AV equipment always keeps track of the current state of the equipment, and when the power switch of the equipment body is turned off, the operation state by the remote commander immediately before the power switch is turned off is maintained. When the power switch is turned on again (a so-called last memory), the power switch is set to a state immediately before the previous off operation.
For example, when the power switch is turned off from the standby state, the standby state is set again by turning on the power switch again.

Incidentally, in the case of the above-mentioned AC-ON, control by such a last memory is indispensable. For example, when a power failure occurs in the standby state, and when the power failure ends thereafter, it is not appropriate to “power on” just because the power switch of the main body is on, and it is preferable to return to the standby state. However, in the case of PS-ON, if the user is turned off in the standby state and returned to the standby state again as described above, the user must further operate the remote commander, which is very complicated. For this reason, the microcomputer 5 controls so that the device is forcibly "powered on" regardless of the last memory at the time of PS-on.

That is, in the microcomputer 5 of the present embodiment, it is necessary to distinguish between AC-ON and PS-ON. Input port 5a
In this case, a signal having a different waveform is input to the controller.

Although the embodiment of the present invention has been described with respect to an example in which mute control is performed as the highest priority interrupt processing at the moment of a power interruption, a down edge signal input to the same input port after the power is turned on is interrupted by a power interruption. A detection signal other than the above may be used, and a necessary interrupt process may be performed based on the detection signal.

[0025]

As described above, according to the present invention, the microcomputer uses the input port capable of performing both the interrupt processing based on the predetermined input pulse and the terminal level detection, and uses the input port for a predetermined period from the energization. The power on state is detected from the level, and after the power is turned on, the instantaneous power interruption and power off operation can be detected by the input pulse.
By switching the operation mode, only one input port of the microcomputer is required for detecting the power ON / OFF state, and there is an effect that the use efficiency of the input port of the microcomputer can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an embodiment of the present invention.

FIG. 2 is a waveform diagram for explaining a time constant of a power supply line according to the present embodiment.

FIG. 3 is a diagram illustrating an input waveform to an input port when power is turned on in the present embodiment.

FIG. 4 is a configuration diagram of an input port 5a of the present embodiment.

FIG. 5 is a flowchart illustrating the operation of the present embodiment.

FIG. 6 is an input waveform diagram to the input port when the power is turned on and off in the present embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 AC outlet 2 Power supply circuit part 3 Audio signal processing part 5 Microcomputer 8 Instantaneous interruption detection circuit part

Claims (2)

(57) [Claims] 1. A power supply circuit for converting a commercial AC power supply into a DC voltage for driving an AV device and outputting the DC voltage, and a control capable of supplying an output voltage of the power supply circuit and controlling an operation of the AV device Device comprising: a first power supply state detection signal for detecting that a power switch of the AV device is turned on or off; and a control microcomputer when commercial power is cut off. A second power supply state detection signal that detects a voltage set to perform a voltage drop before a drive voltage supplied to the computer and outputs the voltage as a down-edge waveform; enter the highest priority interrupt processing possible input ports, the control microcomputer, the input port from the start energized when a predetermined time period has elapsed In response to the input signal of the above, the on / off operation of the power switch is detected based on the binary signal of H or L, and after the on operation of the power switch is detected, the input signal of the input port is detected. On the other hand, by switching to an operation mode for detecting a down edge waveform and detecting the down edge waveform,
A power control method for an AV device, wherein a priority process interrupt process based on the second power status detection signal is performed, and the AV device is turned off. 2. A commercial AC power supply for driving AV equipment.
A power supply circuit that converts the output voltage into a DC voltage and outputs the DC voltage, and an output voltage of the power supply circuit is supplied,
And a control device capable of controlling the operation of the AV equipment.
For on / off operation of microcomputer and power switch
A first power supply control signal generated on the basis of a second as a down edge waveform by detecting a voltage voltage before the voltage drop of the supply voltage of the control microcomputer drops when the commercial power supply is interruption microcode for the control power supply control signal
Supplied to the input terminal of the computer that can process the highest priority interrupt
A power control circuit that, the microcomputer for the control in the AV apparatus is provided with a on the basis of the binary signal of H or L of the first power supply control signal supplied to said input port, said AV
Performs various signal processing of the device, and then controls the AV device to be turned on or off. After it is determined that the AV device is in the on state, the second device supplied to the input terminal is When a down edge of the second power control signal is detected, power-off control by the first power control signal is performed before the voltage supplied to the control microcomputer drops. AV equipment.