JPH11164228A - Power supply circuit for television receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain a standby state in the case an AC power supply falls down and then rises when the television receiver is in the standby state and to reduce power consumption when a main power switch is open by turning on the main power switch from the off state to activate the television receiver. SOLUTION: In the case a voltage applies to a power input terminal falls down and then rises, and in the case that a detection result stored in a nonvolatile memory before the voltage falls down indicates an off-state of a main power switch 13, a microcomputer 17 gives a control signal a1 to set a deflection and signal circuit 16 to an on-state from its on/off terminal 18. In the case that the detection result stored in the nonvolatile memory before the voltage falls down indicates an on-state of the main power switch 13, the microcomputer 17 applies the control signal a1 to set the deflection and signal circuit 16 to an off-state from its on/off terminal 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply circuit of a television receiver for controlling an operation state and a standby state using a microcomputer.

[0002]

2. Description of the Related Art In recent years, in television receivers and the like, an operating state and a standby state are controlled using a microcomputer.

FIG. 3 is a block diagram showing a power supply circuit of a television receiver using a conventional microcomputer.

In FIG. 3, reference numerals 61 and 62 denote AC power supply input terminals of a television receiver connected to one and the other output terminals of a commercial AC power supply. The AC power supply input terminal 61 is connected to one input terminal of the first rectifier circuit 63, and is connected to the primary winding L11 of the standby transformer 71.
To one end.

The AC power input terminal 62 is connected to a relay 70
Is connected to the other input terminal of the first rectifier circuit 63 via the switch SW21, and to the other end of the primary winding L11 of the standby transformer 71.

The first rectifier circuit 63 has positive and negative output terminals connected to the positive and negative input terminals of the operating state power supply circuit 64.
When an AC power supply voltage is supplied from the power supply circuits 1 and 62, the supplied AC power supply voltage is rectified and supplied to the operating state power supply circuit 64 as a DC power supply voltage. Power supply circuit 6 for operating state
4 connects the negative output terminal of the first rectifier circuit 63 to the reference potential point, stabilizes the DC power supply voltage from the first rectifier circuit 63, and deflects and signals as the DC voltage V21 with respect to the reference potential point. It is supplied to the circuit 65. The deflection and signal circuit 65 performs deflection of the picture tube and signal processing of a television broadcast signal by using the DC power supply voltage V21 from the power supply circuit for operation state 64.

On the other hand, the secondary winding L12 of the standby transformer 71
Are connected to one end and the other end of the second rectifier circuit 72.

The second rectifier circuit 72 has a positive output terminal connected to a positive input terminal of the microcomputer power circuit 73 and an input terminal of the first switch SW22 of the main power switch 76, and a negative output terminal. Terminal is power supply circuit 73 for microcomputer
Of the secondary winding L12
, The supplied AC power supply voltage is rectified and supplied to the microcomputer power supply circuit 73 as a DC power supply voltage.

The microcomputer power supply circuit 73 connects the negative output terminal of the second rectifier circuit 72 to a reference potential point. Thus, the DC voltage V22 with respect to the reference potential point is obtained from the output terminal on the positive electrode side of the second rectifier circuit 72.

A microcomputer power supply circuit 73 stabilizes the DC power supply voltage from the second rectifier circuit 72 and supplies it to the microcomputer 74 as a voltage V22. The microcomputer power supply circuit 73 connects the input terminal of the second switch SW23 of the main power supply switch 76 to the input terminal. Lead.

The output terminal of the switch SW22 is connected to the relay 7
It is connected to the on / off terminal 75 of the microcomputer 74 via the zero coil L13. The output terminal of the switch SW23 is connected to the voltage detection terminal of the microcomputer 74.

The relay 70 turns on the switch SW21 when a current flows through the coil L13, and turns on the coil L1.
When no current flows through the switch 3, the switch SW21 is turned off.

The switches SW22 and SW23 are turned on and off in an interlocked manner by manual operation. In this case, when the switch SW22 is on, the switch SW22 is turned on.
When the switch 23 is turned on and the switch SW22 is turned off,
The switch SW23 turns off.

The microcomputer 74 changes the detection result of the voltage detection terminal from a low level (0 V) to a high level (V).
When the mode is switched to 22), it is confirmed that the power has been turned on, so that the current flows into the on / off terminal 75, the current flows through the coil L13 of the relay 70, and the switch SW21 is turned on. Thus, the deflection and signal circuit 65
Is supplied with the DC voltage V21, and the television receiver enters an operating state.

When the detection result of the voltage detection terminal is at a high level, the microcomputer 74 switches the operation / standby state in a standby state (for example, a power button provided separately from a main power switch in a cabinet of a television receiver). Or a power button provided on a remote control transmitter), the on / off terminal 75 is set to a state in which a current flows, a current flows through the coil L13 of the relay 70, and a video display operation state of a television broadcast is performed. And
When the switching operation is performed by the operation / standby state switching key in the operating state, the microcomputer 74 sets the on / off terminal 75 to a state in which no current flows, so that the current cannot flow through the coil L13 of the relay 70, The switch SW21 is turned off. Thus, the deflection and signal circuit 65
Is no longer supplied with the DC voltage V21, and the television receiver enters a standby state.

The operation of such a conventional apparatus will be described.

When the AC power supply voltage is supplied to the input terminals 61 and 62, the power supply voltage V22 is always supplied to the microcomputer 74.

In this state, when the main power switch 76 is turned off, the microcomputer 74 makes it impossible to supply current to the coil L13 of the relay 70, and turns off the switch SW21. Thereby, the DC voltage V is applied to the deflection and signal circuit 65.
21 is no longer supplied, and the television receiver enters a standby state.

When the main power switch 76 is switched from OFF to ON while the AC power supply voltage is being supplied to the input terminals 61 and 62, the microcomputer 74 causes the relay 7 to operate.
0, the switch SW21 is turned on, and the DC voltage V is applied to the deflection and signal circuit 65.
21 to supply a television broadcast image display operation state. Thereafter, the microcomputer 74 operates the switch S by a switching operation using the operation / standby state switching key.
W21 is switched on and off, and the television receiver is switched between the standby state and the operating state.

According to such a conventional apparatus, even if the main power switch 76 is turned off while the television receiver is in the operation state or the standby state, the operation state is established by turning on the main power switch 76. Can be.

However, when the AC power supply voltage is supplied to the input terminals 61 and 62, the main power switch 7
Even when the power supply 6 is off, the power supply voltage V22 is supplied to the microcomputer 74, so that there is a disadvantage that power is consumed as long as the input terminals 61 and 62 are connected to an AC power supply.

In response to this, a circuit shown in FIG. 4 has been developed.

FIG. 4 is a block diagram showing a conventional power supply circuit of a television receiver for suppressing power consumption.

In FIG. 4, reference numerals 81 and 82 are AC power supply input terminals of a television receiver connected to one and the other output terminals of a commercial AC power supply. The AC power input terminals 81 and 82 are connected to the input terminals of the first and second switches SW31 and SW32 of the main power switch 83, respectively. First and second switches SW of main power switch 83
Output terminals of 31 and SW32 are connected to one and the other input terminals of the rectifier circuit 84.

The switches SW31 and SW32 are turned on and off in conjunction with each other by manual operation. In this case, when the switch SW31 is on, the switch SW31 is turned on.
32 is turned on and the switch SW31 is turned off,
The switch SW32 is turned off.

In the rectifier circuit 84, the positive and negative output terminals are connected to the positive and negative input terminals of the power supply circuit 85, and the first and second switches SW31 and SW are connected.
When an AC power supply voltage is supplied from the output terminal 32, the supplied AC power supply voltage is rectified and supplied to the power supply circuit 85 as a DC power supply voltage. The power supply circuit 85 connects the output terminal on the negative side from the rectifier circuit 84 to the reference potential point, stabilizes and transforms the DC power supply voltage from the rectifier circuit 84, and outputs it as DC voltages V31 and V32 for the reference potential point. . The DC voltage V31 is supplied to the deflection and signal circuit 86, and the DC voltage V32 is supplied to the microcomputer 87.

The microcomputer 87 has a DC voltage V
When the DC voltage V32 is supplied from a state where the signal 32 is not supplied, first, a control signal a4 for turning off the deflection and signal circuit 86 is supplied from the on / off terminal 88. Thereafter, the microcomputer 87 supplies a control signal a4 that is turned on to the deflection and signal circuit 86 when a switching operation is performed by an operation / standby state switching key (power button). Microcomputer 87
Supplies a control signal for turning off the television receiver to the deflection and signal circuit 86 when the switching operation is performed by the operation / standby state switching key in the operating state.

The deflection and signal circuit 86 has a DC voltage V31
Is turned on and off based on a control signal a4 from the microcomputer 87 to perform deflection of the picture tube and signal processing of a television broadcast signal.

According to such a conventional apparatus, the microcomputer 8 is turned off by turning off the main power switch 83.
7, the power consumption can be reduced to zero. However, each time the main power switch 83 is switched from off to on, the standby state is established, and the operation / standby state switching key must be operated again, which is troublesome. Here, when the microcomputer 87 is configured to supply the control signal a4 for turning on the deflection and signal circuit 86 by supplying the DC voltage V32 from a state where the DC voltage V32 is not supplied. Can be activated every time the main power switch 83 is turned on. However, if the main power switch 83 is turned on and the standby state is set, a power failure occurs and the operation is resumed when the power is restored. However, there is a problem that the display is in a video display and audio output state in an unattended state, and power is wasted.

[0030]

In the above-mentioned power supply circuit of the conventional television receiver, the operation of the microcomputer can be stopped by turning off the main power supply switch, and the power consumption can be reduced to zero. However, each time the main power switch is switched from off to on, the standby state is established, and the operation / standby state switching key must be operated again, which is troublesome.

Therefore, according to the present invention, the television receiver is set in an operating state by turning on a main power switch from off, and the standby state is maintained when the television receiver is in a standby state and the AC power is turned on and then turned on. It is another object of the present invention to provide a power supply circuit of a television receiver that can reduce power consumed when a main power switch is turned off.

[0032]

A power supply circuit for a television receiver according to claim 1, wherein the power supply circuit rectifies a power supply voltage from an AC power supply and outputs the rectified power supply voltage as first and second DC power supply voltages; A deflection and signal circuit for deflecting a picture tube of a television receiver and processing a television broadcast signal using the first power supply voltage from the DC power supply circuit, and a second DC power supply from the DC power supply circuit. A capacitor charged by a power supply voltage, a main power switch provided on a path for supplying a power supply voltage from the AC power supply to the DC power supply circuit, and on / off detection means for detecting on / off of the main power switch. A nonvolatile memory for storing a detection result of the on / off detection means, wherein a second DC power supply voltage from the DC power supply circuit and a voltage from the capacitor are supplied to a power supply input thereof. When the detection result stored in the nonvolatile memory before the voltage falls indicates that the voltage has been turned off when the voltage supplied to the power supply input terminal and the voltage supplied to the power supply input terminal falls, the deflection is performed. And a microcomputer that turns on the signal circuit, turns off the deflection and signal circuit when indicating on, or turns the deflection and signal circuit into a state before the voltage supplied to the power supply input terminal falls, It is characterized by having.

[0033]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit diagram showing an embodiment of a power supply circuit of a television receiver according to the present invention.

In FIG. 1, reference numerals 11 and 12 are AC power supply input terminals of a television receiver connected to one and the other output terminals of a commercial AC power supply. The AC power input terminals 11 and 12 are connected to input terminals of first and second switches SW1 and SW2 of the main power switch 13, respectively.
The first and second switches SW1, SW1 of the main power switch 13
The output terminal of SW2 is connected to one and the other input terminals of the rectifier circuit 14.

The switches SW1 and SW2 are turned on and off in conjunction with each other by manual operation. In this case, when the switch SW1 is on, the switch SW2 is on, and when the switch SW1 is off, the switch SW2 is on.
2 turns off.

The rectifier circuit 14 has the positive and negative output terminals connected to the positive and negative input terminals of the power supply circuit 15, and the first and second switches SW1 and SW2.
When the AC power supply voltage is supplied from the output terminal of the power supply circuit 15, the supplied AC power supply voltage is rectified and supplied to the power supply circuit 15 as a DC voltage. The power supply circuit 15 connects the negative output terminal of the rectifier circuit 14 to a reference potential point, and
The DC power supply voltage from the DC power supply 4 is stabilized and transformed, and the DC power supply voltage is output from the first and second output terminals as first and second DC power supply voltages V1 and V2 with respect to a reference potential point, respectively. The rectifier circuit 14 and the power supply circuit 15 are DC power supply circuits that rectify a power supply voltage from an AC power supply and output the rectified power supply voltage as first and second DC power supply voltages V1 and V2. The main power switch 13 is provided on a path for supplying a power supply voltage from the AC power supply to the DC power supply circuit.

The DC voltage V1 is supplied to a deflection and signal circuit 16, and the DC voltage V2 is supplied to a microcomputer 17
And is guided to the input terminal of the detection switch 18. The second output terminal of the power supply circuit 15 is connected to a reference potential point via the capacitor C1. Capacitor C
1 is the second DC power supply voltage V2 from the power supply circuit 15
Will be charged by.

The detection switch SW3 is connected to the main power switch 1
The on / off detecting means for detecting the on / off state of the switch 3 is turned on / off by inverting the switches SW1 and SW2 of the main power switch 13 between the input terminal and the output terminal. The output terminal of the detection switch SW3 is connected to the voltage detection terminal of the microcomputer 17.

The microcomputer 17 determines that the main power switch 13 is off when the voltage applied to the voltage detection terminal is at a high level (V2), and determines when the voltage applied to the voltage detection terminal is at a low level (0 V). Main power switch 1
By determining that 3 is on, the detection result of the above-described on / off detection means is determined. The microcomputer 17 has a non-volatile memory for storing the detection result of the on / off detection means, and the second DC power supply voltage V2 from the power supply circuit 15 and the voltage from the capacitor C1 are supplied to the power supply input terminal thereof. Supplied, and when the voltage supplied to the power input terminal rises after falling, when the detection result stored in the nonvolatile memory indicates that the main power switch 13 is off before the voltage falls. A control signal a1 for turning on the deflection and signal circuit 16 is supplied from the on / off terminal 18, and if the detection result stored in the nonvolatile memory before the voltage falls indicates that the main power switch 13 is on, the on / off terminal A control signal a1 for turning off the deflection and signal circuit 16 is supplied from the control circuit. The microcomputer 17 is turned off when the deflection / signal circuit 16 is on when the switching operation is performed by the operation / standby state switching key (power button), and is turned on when the switching circuit is off. Is supplied.

The deflection and signal circuit 16 turns on and off the operation based on a control signal a1 from the microcomputer 17 using the DC voltage V1 as a power supply voltage, and performs deflection of the picture tube and signal processing of a television broadcast signal. Do.

With such a configuration, the microcomputer 17 has a non-volatile memory for storing the detection result of the on / off detection means, the second DC power supply voltage V2 from the DC power supply circuit and the capacitor C1. Is supplied to the power input terminal thereof, and when the voltage supplied to the power input terminal rises after falling, the detection result stored in the non-volatile memory before the voltage falls, The deflection and signal circuit is turned on when the signal is off, and the deflection and signal circuit is turned off when the signal is on.

The operation of the embodiment of the present invention will be described below.

First, the case where the AC power supply is normal will be described.

When the main power switch 13 (switches SW1 and SW2) is turned off while the television receiver is operating (deflection and signal circuit 16 is on) or in a standby state (deflection and signal circuit 16 is off), rectification occurs. Since the AC power supply voltage is not supplied to the circuit 14 and the DC power supply voltage is no longer output from the first and second output terminals of the power supply circuit 15, the deflection and signal circuit 16 is stopped. 18 has a capacitor C
A power supply voltage is supplied from 1 for a predetermined time (for example, 1 minute),
The operation is performed for a predetermined time. In this state, the detection switch SW
3 is turned on, so that the microcomputer 18
Determines that the main power switch 13 is off, and records this in a non-volatile memory. After this, the capacitor C
The electric charge is released from 1 and the microcomputer 18
It will be stopped. Thereafter, when the main power supply switch 13 is turned on, the AC power supply voltage is supplied to the rectifier circuit 14, and the DC power supply voltage V is supplied from the first and second output terminals of the power supply circuit 15.
1 and V2 are output, and the microcomputer 18 starts operation, and the detection result stored in the nonvolatile memory indicates that the main power switch 13 has been turned off. Turn on.
Thus, the television receiver can be brought into the operating state only by turning on the power switch 13.

Next, a case where the AC power supply returns after a power failure will be described.

When the television receiver is in operation (deflection and signal circuit 16 is on) or in a standby state (deflection and signal circuit 16 is off), the main power switch SW1 is turned on when the AC power is cut off. Rectifier circuit 14
And the DC power supply voltage is not output from the first and second output terminals of the power supply circuit 15. As a result, the deflection and signal circuit 16 is stopped.
, A power supply voltage is supplied for a predetermined time (for example, one minute), and operation is performed for a predetermined time. In this state, the detection switch SW3
Is turned off, the main power switch 13 is determined to be on, and this is recorded in the nonvolatile memory.
Thereafter, the electric charge is discharged from the capacitor C1, and the microcomputer 18 is stopped. Thereafter, when the AC power supply is restored, the AC power supply voltage is supplied to the rectifier circuit 14, and the DC power supply voltages V1 and V2 are output from the first and second output terminals of the power supply circuit 15, whereby the microcomputer 18 , And the detection result stored in the nonvolatile memory indicates that the main power switch 13 has been turned on, so that the deflection and signal circuit 16 is turned off. Thereby, the television receiver can maintain the standby state when the AC power is turned on after the fall.

Since the power consumed when the main power switch SW1 is turned off is the power for operating the microcomputer 18 for a predetermined time, when the main power switch SW1 is turned off as in the conventional example of FIG. This is a sufficiently small value, not just power consumption.

As described above, in the embodiment of the present invention shown in FIG. 1, the television receiver is set to the operating state by turning on the main power switch from off, and the AC power supply is turned on while the television receiver is in the standby state. Since the standby state is maintained when the power supply rises and the power supply is turned off when the main power switch is turned off, the operability of the television receiver and the reduction in power consumption are both achieved. be able to.

The microcomputer 17 shown in FIG.
When the voltage supplied to the power supply input terminal rises after falling, the deflection and signal circuit is turned off when the detection result stored in the nonvolatile memory before the voltage falls indicates that the main power supply switch 13 is turned on. The power supply input terminal may be configured to be in a state before the voltage supplied to the power supply input terminal falls.

FIG. 2 is a circuit diagram showing a power supply circuit of a television receiver according to a second embodiment of the present invention.

In FIG. 2, reference numerals 21 and 22 are AC power supply input terminals of a television receiver connected to one and the other output terminals of a commercial AC power supply. The AC power input terminal 21 is connected to one input terminal of the first rectifier circuit 23 and to one end of the primary winding L1 of the standby transformer 31.

The AC power input terminal 22 is connected to the input terminal of the main power switch SW11. The output terminal of the main power switch SW11 is connected to the switch SW13 of the relay 30.
Is connected to the other input terminal of the first rectifier circuit 23 and to the other end of the primary winding L1 of the standby transformer 31.

In the first rectifier circuit 23, the positive and negative output terminals are connected to the positive and negative input terminals of the operating state power supply circuit 24.
When an AC power supply voltage is supplied from the power supply circuits 1 and 22, the supplied AC power supply voltage is rectified and supplied to the operating state power supply circuit 24 as a DC power supply voltage. Power supply circuit 2 for operating state
Reference numeral 4 denotes a first power supply circuit, and a first rectifier circuit 2
3 is connected to the reference potential point,
The DC power supply voltage from the rectifier circuit 23 is stabilized and converted into a DC voltage V11 with respect to a reference potential point.
5 The deflection and signal circuit 25 performs deflection of the picture tube and signal processing of a television broadcast signal by using the DC power supply voltage V11 of the power supply circuit 24 for operation state.

On the other hand, one end and the other end of the secondary winding L2 of the standby transformer 31 are connected to one end and the other end of the second rectifier circuit 32.

The second rectifier circuit 32 has an output terminal on the positive side connected to an input terminal on the positive side of the power supply circuit 33 for the microcomputer, and an on / off terminal of the microcomputer 34 via the coil L3 of the relay 30. 35,
The output terminal on the negative electrode side is connected to the input terminal on the negative electrode side of the power supply circuit 33 for the microcomputer, and when the AC power supply voltage is supplied from the secondary winding L2, the supplied AC power supply voltage is rectified to DC power. It is supplied to the microcomputer power supply circuit 33 as a power supply voltage.

The microcomputer power supply circuit 33 is a second power supply circuit, and connects the negative output terminal of the second rectifier circuit 32 to a reference potential point. Thereby, the second
The DC voltage V12 with respect to the reference potential point is obtained from the output terminal on the positive side of the rectifier circuit 32.

The microcomputer power supply circuit 33 stabilizes the DC power supply voltage from the second rectifier circuit 32 and supplies it to the microcomputer 34 as the voltage V12. The output terminal of the microcomputer 34 is connected to a reference potential point via a capacitor C11, and the detection switch SW1
2 input terminals. The capacitor C11 is connected to the second DC power supply voltage V1 from the microcomputer power supply circuit 33.
2 charged.

The detection switch SW12 serves as on / off detection means for detecting the on / off of the main power switch SW11. The connection between the input terminal and the output terminal of the detection switch SW12 is inverted with respect to the main power switch SW11. Turned off. The output terminal of the detection switch SW12 is a microcomputer 35
Is connected to the voltage detection terminal.

The relay 30 turns on the switch SW13 when a current flows through the coil L3, and turns off the switch SW13 when no current flows through the coil L3.

When the voltage applied to the voltage detection terminal is at a high level, the microcomputer 34 detects the detection switch SW
When the voltage applied to the voltage detection terminal is low (0 V), it is determined that the detection switch SW12 is off. The microcomputer 17
It has a nonvolatile memory for storing the detection result of the detection switch SW12, and the second DC power supply voltage V12 from the microcomputer power supply circuit 33 and the voltage from the capacitor C11 are supplied to the power supply input terminal. The microcomputer 17 is turned on when the voltage supplied to the power input terminal falls and then rises, and when the detection result stored in the nonvolatile memory indicates that the detection switch SW12 is on before the voltage falls.・ Off terminal 3
5 to a state in which current flows, the coil L3 of the relay 30
When the detection result stored in the non-volatile memory indicates that the detection switch SW12 is turned off, the on / off terminal 35 is set to a state where the current does not flow, and the current is supplied to the coil L3 of the relay 30. Then, the switch SW13 is turned off.

When the detection result of the voltage detection terminal is at a low level, the microcomputer 34 switches the operation / standby state in a standby state (for example, a power button provided separately from a main power switch in a cabinet of a television receiver). Or a power switch provided on a remote control transmitter), the on / off terminal 35 is set to a state in which a current flows, a current flows through the coil L3 of the relay 30, and a video display operation state of a television broadcast is performed. When the switching operation is performed by the operation / standby state switching key in the operating state, the on / off terminal 35 is set in a state where no current flows, so that the current cannot flow through the coil L3 of the relay 30 and the switch SW13 is turned off. Turn off. As a result, the DC voltage V11 is not supplied to the deflection and signal circuit 25, and the television receiver enters a standby state.

The operation of the apparatus according to the embodiment of the present invention will be described.

First, the case where the AC power supply is normal will be described.

The television receiver is in an operation state (a state in which a power supply voltage is supplied to the deflection and signal circuit 25) or a standby state (a power supply voltage is supplied to the microcomputer 34, but the power supply voltage is not supplied to the deflection and signal circuit 25). When the main power switch SW11 is turned off in a state where power is not supplied, the AC power supply voltage is not supplied to the first and second rectifier circuits 23 and 32, and the DC power is supplied from the power supply circuit 24 for operation state and the power supply circuit 33 for microcomputer. Since the power supply voltage is no longer output, the deflection and signal circuit 25 is stopped. However, the microcomputer 34 is supplied with the power supply voltage for a predetermined time (for example, one minute) from the capacitor C11 and operates for a predetermined time. In this state, the detection switch SW12 is
Since this is turned on, this is recorded in the nonvolatile memory. Thereafter, electric charge is released from the capacitor C11,
The microcomputer 34 is stopped. Thereafter, when the main power switch SW11 is turned on, the AC power supply voltage is supplied to the first and second rectifier circuits 23 and 32, and the DC power supply voltages V11 and V12 are supplied from the power supply circuit for operating state 24 and the power supply circuit 33 for the microcomputer. Output, which
The microcomputer 34 starts the operation, and the detection result stored in the nonvolatile memory indicates that the detection switch SW12 is on. Therefore, the microcomputer 34 turns on the switch SW13 of the relay 30 to turn on the deflection and signal circuit 25. Thus, the television receiver can be brought into the operating state only by turning on the power switch SW11.

Next, a case where the AC power supply returns after a power failure will be described.

When the television receiver is in the operation state or the standby state and the AC power supply is cut off, the main power switch SW1
1 is turned on, but the first and second rectifier circuits 23,
Since the AC power supply voltage is not supplied to the power supply circuit 32 and the DC power supply voltage is not output from the power supply circuit 24 for the operation state and the power supply circuit 33 for the microcomputer, the deflection and signal circuit 25 is stopped. The power supply voltage is supplied from the capacitor C11 for a predetermined time (for example, one minute), and the operation is performed for a predetermined time. In this state, the detection switch SW12 is turned off, and the microcomputer 34 records this in the nonvolatile memory. Thereafter, electric charges are discharged from the capacitor C11, and the microcomputer 34 is stopped. Thereafter, when the AC power supply is restored, the AC power supply voltage is supplied to the rectifier circuit 14, and the DC power supply voltages V1 and V2 are output from the first and second output terminals of the power supply circuit 15, whereby the microcomputer 34 The operation is started, and the detection result stored in the non-volatile memory indicates that the detection switch SW12 is off. Therefore, the switch SW13 of the relay 30 is turned off, and the deflection and signal circuit 25 is turned off. Thereby, the television receiver can maintain the standby state when the AC power is turned on after the fall.

With the above operation, the same effect as that of the embodiment of the invention of FIG. 1 can be obtained in the embodiment of the invention of FIG.

The microcomputer 34 shown in FIG.
In the case where the voltage supplied to the power supply input terminal rises after the fall, when the detection result stored in the nonvolatile memory before the voltage falls indicates that the detection switch SW12 is off, the deflection and signal circuit is turned on by the power supply. The configuration may be such that the state before the voltage supplied to the input terminal falls.

[0070]

As described above, according to the present invention, the television receiver is set to the operating state by turning on the main power switch from off, and after the AC power supply falls while the television receiver is in the standby state. Since the standby state can be maintained when the apparatus starts up and the power consumed when the main power switch is turned off can be reduced, the operability of the television receiver and the reduction in power consumption can both be achieved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a power supply circuit of a television receiver according to a first embodiment of the present invention;

FIG. 2 is an exemplary block diagram showing a power supply circuit of a television receiver according to a second embodiment of the present invention;

FIG. 3 is a circuit diagram showing a first example of a power supply circuit of a conventional television receiver.

FIG. 4 is a circuit diagram showing a second example of a power supply circuit of a conventional television receiver.

[Explanation of symbols]

 13 Main power switch 14 Rectifier circuit 15 Power circuit 16 Deflection and signal circuit 17 Microcomputer SW3 Detection switch

Claims (2)

[Claims] 1. A power supply voltage from an AC power supply is rectified to
A DC power supply circuit for outputting as a second DC power supply voltage; and a deflection unit for performing deflection of a picture tube of a television receiver and signal processing of a television broadcast signal using the first power supply voltage from the DC power supply circuit. And a signal circuit; a capacitor charged by a second DC power supply voltage from the DC power supply circuit; a main power supply switch provided in a path for supplying a power supply voltage from the AC power supply to the DC power supply circuit; On / off detection means for detecting on / off of a power switch, and a nonvolatile memory for storing a detection result of the on / off detection means, a second DC power supply voltage from the DC power supply circuit and the capacitor Is supplied to the power supply input terminal, and the voltage supplied to the power supply input terminal falls and then rises. When the detection result stored in the non-volatile memory before falling, the deflection and signal circuit is turned on when the detection result indicates off, and the deflection and signal circuit is turned off or when the detection result indicates on, And a microcomputer for setting a state before the voltage supplied to the power supply input terminal falls, and a power supply circuit for a television receiver. 2. A first and a second rectifier circuit for rectifying a power supply voltage from an AC power supply and outputting the rectified power supply voltage as first and second DC voltages, respectively; And a main power switch provided in a path for supplying to the rectifier circuit, and stabilizing the first and second DC power supply voltages from the first and second rectifier circuits as first and second DC power supply voltages, respectively. A first and a second power supply circuit for outputting, a deflection of a picture tube of a television receiver and a signal processing of a television broadcast signal using the first DC power supply voltage from the first power supply circuit; A signal circuit, connected to an output terminal of the second power supply circuit, charged by a second DC power supply voltage from the second power supply circuit, and output from the output terminal of the second power supply circuit decreased. A capacitor that discharges when An input terminal is connected to an output terminal of the second power supply circuit, and a detection switch in which the input terminal and the output terminal are turned on / off in reverse to the main power switch; Connection point of the second rectifier circuit and the first
A relay provided with a switch in a path between the rectifier circuit and a non-volatile memory, wherein a second DC power supply voltage from the second DC power supply circuit and a voltage from the capacitor are supplied to a power supply input terminal thereof. The output terminal of the detection switch is connected to the voltage detection terminal, and the ON / OFF state of the detection switch is determined by the voltage applied to the voltage detection terminal.
In the case where the off state is detected and stored in the non-volatile memory, and when the voltage supplied to the power input terminal rises after falling, the detection result stored in the non-volatile memory before the voltage falls is turned on. The switch of the relay is turned on when indicating, and the switch of the relay is turned off when indicating the off, or the switch of the relay is set to a state before the voltage supplied to the power input terminal falls. A power supply circuit for a television receiver, comprising: a microcomputer.