JP3717668B2 - Power supply circuit and electrical equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power supply circuit including a standby power supply circuit that includes a power transformer and supplies power regardless of whether a power switch is on or off, and an improvement in an electric device including the power supply circuit.
[0002]
[Prior art]
FIG. 3 is a circuit diagram showing a configuration example of a conventional power supply circuit of an audio device which is an electric device. This power supply circuit includes a primary winding 25 wound around an iron core 26 of a power transformer 24 and supplied with AC power, secondary windings 27, 28 and 29 wound around the iron core 26, and a secondary winding 27. In addition, a rectifier circuit 30 made of a diode connected via a relay contact ry5 interlocked with a power switch (not shown), a rectifier circuit 32 made of a diode connected to the secondary winding 28, and a positive polarity of the rectifier circuit 32. A 5V stabilization circuit 33 connected to the side output terminal and a -30V stabilization circuit 34 connected to the negative output terminal of the rectifier circuit 32 are provided.
[0003]
The rectifier circuit 30 is used as a power amplifier power supply, the rectifier circuit 32 is used as various other power supplies, the 5V stabilization circuit 33 is used as a 5V power supply for microcomputers, and the -30V stabilization circuit 34 is used as a grid voltage power supply for fluorescent display tubes. The line 29 is directly used for the filament voltage power source for the fluorescent display tube.
In such a power supply circuit, when the power switch is turned off, the relay contact ry5 is turned off, and the rectifier circuit 30 that is a power amplifier power supply is turned off. However, the rectifier circuit 32 of the other various power supplies, the 5V stabilization circuit 33, The -30V stabilization circuit 34 and the secondary winding 29 are supplied with power. That is, the power consumption during standby is reduced by not energizing the power supply circuits other than those necessary for standby such as a microcomputer, a liquid crystal display, and a fluorescent display tube.
[0004]
FIG. 4 is a circuit diagram showing another configuration example of a conventional power supply circuit of an audio device which is an electric device. The power supply circuit includes a primary winding 40 wound around an iron core 41 of a power transformer 38 and supplied with AC power via a relay contact ry6 that is linked to a power switch (not shown), and a secondary winding wound around the iron core 41. The rectifier circuit 44 made of a diode connected to the wires 42 and 43, the secondary winding 42, the rectifier circuit 45 made of a diode connected to the secondary winding 43, and the iron core of the small power transformer 39 47, a primary winding 46 to which an AC power is applied, secondary windings 48, 51, 54 wound around an iron core 47, and a rectifier circuit 49 made of a diode connected to the secondary winding 48. And a rectifier circuit 52 composed of a diode connected to the secondary winding 51, a 5V stabilization circuit 50 connected to the positive output terminal of the rectifier circuit 49, and a negative output terminal of the rectifier circuit 52. -30V stabilization circuit 5 It is equipped with a door.
[0005]
The rectifier circuit 44 is the power amplifier power supply, the rectifier circuit 45 is the other various power supplies, the 5V stabilization circuit 50 is the microcomputer 5V power supply, the -30V stabilization circuit 53 is the grid voltage power supply for the fluorescent display tube, and the secondary winding. The line 54 is directly used for the filament voltage power source for the fluorescent display tube.
[0006]
In such a power supply circuit, when the power switch is off, the relay contact ry6 is turned off, and no current flows through the primary winding 40. The rectifier circuit 44 that is a power amplifier power supply and the rectifier circuits 45 of other various power supplies Although turned off, current flows through the primary winding 46 of the small power transformer 39, and power is supplied to the 5V stabilization circuit 50, the -30V stabilization circuit 53, and the secondary winding 54. That is, the power consumption during standby is reduced by providing a small power transformer 39 that supplies only the power required during standby separately from the power transformer 38 for supplying power required during normal use. .
[0007]
[Problems to be solved by the invention]
As described above, in conventional electrical equipment, only the power circuit required for standby is not energized, or only the power required for standby is supplied separately from the power transformer for supplying power required for normal use. Power consumption during standby is reduced by providing a small power transformer.
[0008]
However, when the power supply circuit other than the power supply circuit necessary for standby is not energized, since the power consumed in the power transformer is large due to the excitation current flowing through the power transformer, the effect of reducing power consumption is small. In addition to the power transformer for supplying power necessary for normal use, if a small power transformer that supplies only the power required for standby is provided, the power consumption is greatly reduced, but two power transformers are provided. Since this is necessary, the cost of parts is increased and space is also required.
The present invention has been made in view of the circumstances as described above, and provides an electric device capable of reducing power consumption without adding expensive components such as a power transformer and complicated circuits. Objective.
[0009]
[Means for Solving the Problems]
A power supply circuit according to a first aspect of the present invention includes a power supply transformer, a standby power supply circuit that supplies power to the rest of the electric device regardless of whether or not some of the power switches of the electric device to be supplied with power are on / off. comprising a該待machine power supply circuit, the power supply circuit that have a secondary winding of the power transformer, the power transformer in response to on / off the power switch, switches the number of turns of the primary winding And the standby power supply circuit includes a resistor connected in series to the secondary winding and a relay contact connected in parallel to the resistor and turned off / on in response to on / off of the power switch. It is characterized by.
[0010]
In this power supply circuit, a standby power supply circuit having a secondary winding of a power transformer supplies power to the rest of the electric device regardless of whether some power switches of the electric device are on or off. In the power transformer, the switching means switches the number of turns on the primary winding side according to on / off of the power switch, and the standby power circuit is connected in parallel to the resistor connected in series to the secondary winding. The relay contact that is turned off / on in response to the on / off of the power switch switches the supplied voltage in accordance with the on / off of the power switch. As a result, power consumption can be reduced without adding expensive components such as a power transformer and complicated circuits, and the voltage supplied from the power transformer by switching the number of turns on the primary winding side. Can compensate for changes.
[0013]
Electrical apparatus according to a second invention is characterized in that it comprises a power supply circuit according to claim 1.
[0014]
This electrical device, since a power supply circuit of claim 1, without adding expensive components and complex circuitry such as a power transformer, it is possible to reduce power consumption.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described with reference to the drawings illustrating embodiments thereof.
FIG. 1 is a circuit diagram showing a configuration of an embodiment of a power supply circuit of an audio device which is an electric device according to the present invention. The power supply circuit and the electrical device include a primary winding 10 that is wound around an iron core 11 of a power transformer 9 and is supplied with AC power via a relay contact ry1 (means for switching the number of turns) interlocked with a power switch (not shown). The secondary windings 12, 13, and 14 wound around the iron core 11, the rectifier circuit 15 made of a diode connected to the secondary winding 12 via the relay contact ry2, and the secondary winding 13 A rectifier circuit 16 (standby power supply circuit) composed of a diode, a 5V stabilization circuit 17 connected to the positive output terminal of the rectifier circuit 16, and a resistor R1 and a relay contact ry3 at the negative output terminal of the rectifier circuit 16. And a -30V stabilization circuit 18 connected via a parallel circuit (means for switching voltage).
[0016]
The primary winding 10 of the power transformer 9 has a tap 8 (means for switching the number of turns) whose number of turns is halved, for example. The relay contact ry1 is switched to the tap 8 side when the power switch is on and in normal use, and to the side where the total number of turns of the primary winding 10 is on standby when the power switch is off.
The output terminal of the secondary winding 14 (standby power supply circuit) is connected to a parallel circuit (means for switching voltage) of the resistor R2 and the relay contact ry4.
The relay contacts ry2, ry3, ry4 are interlocked with a power switch (not shown).
[0017]
The rectifier circuit 15 is a power amplifier power source, the rectifier circuit 16 is a variety of other power sources, the 5V stabilization circuit 17 is a 5V power source for microcomputers, the −30V stabilization circuit 18 is a grid voltage power source for fluorescent display tubes, and the secondary winding. The line 14 is used for a filament voltage power source for a fluorescent display tube.
[0018]
Hereinafter, operations of such a power supply circuit and electrical equipment will be described.
In this power supply circuit, when the power switch is on, the relay contact ry1 is connected to the tap 8 side, the relay contact ry2 is turned on, and the relay contacts ry3 and ry4 are turned off. As a result, the rectifier circuit 15 supplies power to the power amplifier, the rectifier circuit 16 supplies power to various other circuits, and the 5V stabilization circuit 17 supplies power to the microcomputer. The −30V stabilization circuit 18 is supplied with the voltage from the rectifier circuit 16 that has been boosted to 1/2 (for example, −70V → −35V) by the resistor R1, and supplies power to the fluorescent display tube grid. The secondary winding 14 supplies a voltage power source that is stepped down to 1/2 (for example, 60 V → 30 V) by the resistor R2 to the filament for the fluorescent display tube.
[0019]
In this power supply circuit, when the power switch is off, the relay contact ry1 is connected to the side of the primary winding 10 where all the turns are made, the relay contact ry2 is turned off, and the relay contacts ry3 and ry4 are turned on. As a result, the rectifier circuit 15 is turned off and the power amplifier is turned off, but the rectifier circuit 16 is still on.
At this time, the number of turns of the primary winding 10 is twice that when the power switch is on, so that the voltage generated in the secondary winding 13 is halved, but the 5V stabilization circuit 17 Since the voltage applied to is only changed from 20V to 10V, no countermeasures need to be taken. However, in the -30V stabilization circuit 18, the voltage from the rectifier circuit 16 boosted by the resistor R1 becomes 1/2 (for example, -35V → -17.5V), so the relay contact ry3 is turned on and the resistor R1 is turned on. The voltage from the rectifier circuit 16 is directly applied by short-circuiting, and the same voltage as when the power switch is on is applied.
[0020]
Since the voltage generated in the secondary winding 14 is also ½ (for example, 60 V → 30 V), the relay contact ry4 is turned on, the resistor R4 is short-circuited, and the voltage generated in the secondary winding 14 (for example, 30 V) ) Is directly supplied to the filament for the fluorescent display tube, and the same voltage as when the power switch is on is supplied.
In this audio device, when the power switch is off, the power consumption, which was conventionally about 15 W, can be reduced to about 6 W.
[0021]
As shown in FIG. 2, the power transformer 9 is connected to, for example, two primary windings 20 and 21 having the same number of turns in series instead of the primary winding 10, and the relay contact ry1 has a power switch When the power switch is off, the two primary windings 20 and 21 may be switched to the side connected in series when the power switch is off.
[0022]
【The invention's effect】
According to the power supply circuit according to a first shot bright, due to the fact that without adding expensive components and complex circuitry such as a power transformer, it is possible to reduce power consumption, it is switched number of turns of the primary winding The change in the voltage supplied from the power transformer can be compensated.
[0024]
According to the electrical device according to the second aspect of the present invention, power consumption can be reduced without adding expensive parts such as a power transformer and complicated circuits.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing a configuration of an embodiment of a power supply circuit of an audio device which is an electric device according to the present invention.
FIG. 2 is a circuit diagram showing another configuration example of the primary winding of the power supply circuit according to the present invention.
FIG. 3 is a circuit diagram illustrating a configuration example of a power supply circuit of a conventional audio device.
FIG. 4 is a circuit diagram illustrating a configuration example of a power supply circuit of a conventional audio device.
[Explanation of symbols]
8 taps (means to switch the number of turns)
9 Power Transformer 10 Primary Winding 11 Iron Core 12 Secondary Winding 13, 14 Secondary Winding (Standby Power Supply Circuit)
15 Rectifier circuit 16 Rectifier circuit (standby power supply circuit)
17 5V stabilization circuit (standby power supply circuit)
18-30V stabilization circuit (standby power supply circuit)
ry1 relay contact (means for switching the number of turns)
ry2 relay contact ry3, ry4 relay contact (voltage switching means)
R1, R2 resistance (means to switch voltage)

Claims (2)

A power supply transformer, and a standby power supply circuit that supplies power to the rest of the electrical device regardless of whether a power switch of a part of the electrical device to which power is supplied is turned on or off. In a power supply circuit having a secondary winding of the power transformer,
The power transformer includes means for switching the number of turns on the primary winding side according to on / off of the power switch, and the standby power circuit includes a resistor connected in series to the secondary winding, and the resistor And a relay contact that is turned on / off in response to turning on / off of the power switch. An electric apparatus comprising the power supply circuit according to claim 1 .

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