Electrical transmission or interconnection systems – Plural supply circuits or sources – Substitute or emergency source
Reexamination Certificate
1999-09-10
2001-05-01
Jackson, Stephen W. (Department: 2836)
Electrical transmission or interconnection systems
Plural supply circuits or sources
Substitute or emergency source
C307S116000
Reexamination Certificate
active
06225709
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a power supply circuit for an electric device such as a television set which is provided with at least a main power supply switch and controls the operation status and the stand-by status of the electric device according to the turning ON/OFF operation of the main power supply switch and the control operation of a controlling means.
2. Description of the Related Art
Some conventional electric devices such as television sets are designed to supply the power fed from the commercial AC power source to a stand-by power supply circuit, and at the same time, to a main power supply circuit via a stand-by switch. Such an electric device usually supplies the power to a stand-by power supply circuit to make at least a controlling means, such as a microcomputer, operable so that it can be controlled by a remote control transmitter (stand-by status). To actually operate the main circuit of a device, the user manually turns on the stand-by switch or operates the power key on the remote control transmitter to turn on the stand-by switch so that the output of the main power supply circuit is supplied to the main circuit to put the device into the operation status.
FIG. 11
is a block diagram showing a power supply circuit for a conventional television set.
In
FIG. 11
, an AC plug
1
is connected with the commercial alternating current power source (AC), with one line of the AC plug
1
being connected with one input terminal of a first rectifier circuit
2
and the other line being connected with the other input terminal of the first rectifier circuit
2
via a switch
7
-
1
of a relay
7
. The rectified voltage in which the commercial AC voltage is rectified and smoothed is outputted from the first rectifier circuit
2
. The rectified voltage is turned into a stabilized DC voltage at a main power supply circuit
3
which is configured with a stabilized power supply circuit, such as a switching type power supply circuit, and supplied to a signal and deflection processing circuit
4
which is the main circuit of a television (TV) set. Video signals and deflection signals from the signal and deflection processing circuit
4
are supplied to a picture tube (CRT)
5
.
Meanwhile, the voltage of the commercial AC power source is supplied to a primary winding
6
-
1
of a stand-by transformer
6
, and the output voltage of a secondary winding
6
-
2
thereof is supplied to a second rectifier circuit
9
. The rectified output voltage is supplied to a stand-by power supply circuit
10
which is configured with a stabilized power supply circuit. The output voltage Vcc of the stand-by power supply circuit
10
is supplied to a power supply input terminal
81
of a microcomputer
8
which is a controlling means. The second rectifier circuit
9
outputs a rectified voltage in which AC voltage obtained from the commercial AC power source is rectified and smoothed. The stand-by power supply circuit
10
stabilizes the rectified voltage, and at the same time, converts it into power supply voltage Vcc for microcomputer and outputs it.
Further, an output terminal of said second rectifier circuit
9
is connected with an end of a drive winding
7
-
2
of the relay
7
via one switch
11
-
1
of an interlocking switch
11
, and the other end of the drive winding
7
-
2
is connected with an ON/OFF terminal
12
of the microcomputer
8
. The interlocking switch
11
is a manually actuated main power supply switch provided with two switches
11
-
1
and
11
-
2
which are turned ON/OFF at the same time in an interlocked manner. That is, the turning on or off of one switch
11
-
1
is designed to be interlocked with turning on or off of the other switch
11
-
2
. The output voltage Vcc of the stand-by power supply circuit
10
is connected with an operation (ON) instruction terminal
82
of the microcomputer
8
via the switch
11
-
2
in the interlocking switch
11
.
With the configuration described above, in a status where the interlocking switch
11
is turned off while the commercial AC power is supplied to the AC plug
1
, that is, in the stand-by status, when the interlocking switch
11
is turned on, the voltage Vcc enters a terminal
82
of the microcomputer
8
as an ON signal by turning on of the switch
11
-
2
of the interlocking switch
11
. This causes the terminal
12
of the microcomputer
8
to be connected with a reference potential point in a device, and at the same time, turning on of the switch
11
-
1
lets the drive current flow from the second rectifier circuit
9
to a reference potential point via the switch
11
-
1
, the drive winding
7
-
2
and the terminal
12
. Consequently, the switch
7
-
1
of the relay is turned on and a TV set is put in the operation status. Contrarily, when the interlocking switch
11
is turned off in this operation status, the relay switch
7
-
1
is turned off and the TV set is put into the stand-by status again since the voltage Vcc is not supplied to the operation instruction terminal
82
of the microcomputer
8
and the power supply to the drive winding
7
-
2
of the relay
7
is turned off.
In order to make the TV set shown in
FIG. 11
operable by a remote control transmitter
17
, a light receiving circuit
83
is provided in the microcomputer
8
. In case of the remote control transmitter operation, when the interlocking switch
11
is turned on to keep a TV set in the operation status, if an operation stoppage (OFF) signal is transmitted from the remote control transmitter
17
, the microcomputer
8
receives and decodes this signal, and turns off the connected status (ON) of the ON/OFF terminal
12
with a reference potential point. Consequently, since the drive electric current stops flowing to the winding
7
-
2
of the relay
7
, the switch
7
-
1
is turned off, putting a TV set into the stand-by status. That is, a TV set can be turned into the stand-by status by the remote control transmitter operation while the interlocking switch
11
is kept tuned on. When it is desired to return a TV set from the stand-by status caused by this remote control transmitter operation back into the operation status through the remote control transmitter operation, the user transmits an operation instruction (ON) signal from the remote control transmitter
17
. This signal returns the ON/OFF terminal
12
back into the ON status with a reference potential point to turn on the relay
7
, putting the TV set into the operation status. When it is desired to return a TV set from the stand-by status caused by the remote control transmitter operation back into the operation status by manual operation, the user turns off the interlocking switch
11
and turns it on again manually. Then, an operation instruction (ON) signal of voltage Vcc from the stand-by power supply circuit
10
enters into the terminal
82
of the microcomputer
8
. This signal returns the terminal
12
back to the ON status to turn on the relay
7
, putting the TV set into the operation status.
As described above, so long as the power from the commercial AC power source is supplied to the AC plug
1
, a TV set can be put into the operation status by turning on the manual switch
11
no matter which status the TV set is in when the switch
11
is turned off, either in the operation status or in the stand-by status.
However, the configuration shown in
FIG. 11
has a problem that electricity is supplied from the stand-by power supply circuit
10
to the microcomputer
8
as long as a TV set is connected with the commercial power source and electric power, even in small amount, is consumed because some power is necessary to keep the microcomputer
8
working even while the switch
11
is turned off.
There is another example of conventional electric devices such as TV sets in which electric power fed from the commercial AC power source is supplied via the main power supply switch to a power supply circuit where various power source voltages are generated. One of the power source voltage is used to keep at least a
Jackson Stephen W.
Kabushiki Kaisha Toshiba
Pillsbury & Winthrop LLP
Roberto Rios
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