JP2002112456A - Power circuit for electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power circuit which reduces the power consumption at standby time. SOLUTION: An electric charge is charged at a condenser 5a by a direct current which is got by rectifying an AC current of a secondary side of the transformer of a main power circuit, and a direct current which is got by rectifying an AC current of a secondary side of the transformer of a standby power circuit. The power consumption of the standby power circuit is reduced by driving a relay 6, which turns on/off the AC current of the primary side of the main power circuit, by the electric charge charged at the condenser 5a.

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 for electronic equipment having a standby function, such as video and audio equipment, and more particularly to a power supply circuit for electronic equipment in which power consumption during standby is reduced.

[0002]

2. Description of the Related Art In recent years, electronic equipment such as home video equipment and audio equipment has been enhanced in function, so that even when the electronic equipment is in a standby state in a non-operating state (during stop), power is always supplied from a commercial power supply to a remote controller. (Hereinafter referred to as remote control.)
Electronic devices having a standby function of quickly starting a part of a power supply circuit of the electronic device in response to a start instruction from a user due to the above-mentioned operation are frequently used. In this case, since a large amount of power is consumed in the standby state, regulation by the government is being implemented due to problems such as energy saving.

In such a power supply circuit for an electronic device having a standby function, the most common power supply circuit for an electronic device for saving energy is configured as shown in FIG. The conventional power supply circuit of FIG. 5 controls the main power supply circuit 2 that supplies a power supply voltage to an electronic device 10 such as an audio device and a video device via a plug 7 connected to a commercial AC power supply, and controls the electronic device 10 in a standby state. It comprises a standby power supply circuit 1 for supplying a drive voltage to the means 3 and the relay 6 and the like.

The main power supply circuit 2 is supplied with a commercial AC voltage from a plug 7 inserted into a commercial AC power supply via a relay 6.

The standby power supply circuit 1 comprises an auxiliary power supply transformer 1a comprising a primary winding to which a commercial AC voltage is supplied, a secondary winding to which a rectifier diode 1b and a smoothing capacitor 1c are connected, and a voltage stabilizing circuit 1d. You.

[0006] Voltage stabilization circuit 1 of standby power supply circuit 1
The output of d is supplied to control means 3 such as a microcomputer (hereinafter referred to as CPU). The CPU 3 is connected to a display section 8 such as a light-emitting element and a remote control light-receiving section 4 composed of a light-receiving element for receiving infrared light from a remote controller 11 and also includes an electronic device 10 and a relay drive transistor 5 b constituting a relay drive circuit 5. Control the base.

The emitter of the relay driving transistor 5b is grounded, the collector is connected to one end of the relay driving coil 6a, the other end is connected to the output terminal of the rectifier diode 1b of the standby power supply circuit 1, and the contact of the relay 6a is driven. The coil 6a is turned on by the excitation of the coil 6a. 6b is an arc-extinguishing diode.

A contact of a relay 6 is connected to a primary winding of a main power transformer 2h provided in the main power circuit 2, and rectifier diodes 2d and 2e and a smoothing capacitor 2f are connected to a secondary winding. 2g is connected to form a normal power supply circuit, the output of which is supplied as a power supply voltage of various circuits of the electronic device 10.

In the power supply circuit for electronic equipment having the above-described configuration, the remote controller 11 or the main body start switch (from the plug 7 to the CPU 3)
(It is not shown in the figure)
In the standby state, the relay 6 is in the "off" state, the main power supply circuit 2 is not operating, and the standby power supply circuit 1
The CPU 3 supplies a voltage to the PU 3 and the remote control light receiving unit 4 and the display unit 8 around the PU 3.
Waiting for an activation instruction to the remote control light receiving unit 4 by the user or an activation instruction of the operator by the main body activation switch. Upon receiving the operator's activation instruction, the CPU 3 activates the relay driving transistor 5b of the relay driving circuit 5 and causes the relay 6 to operate.
Is turned on, the main power supply circuit 2 is operated, and the electronic device 1
A voltage is supplied to 0 to activate various electronic circuits.

The CPU 3 detects a stop signal instruction of the remote controller light-receiving unit 4 or a stop instruction of the main body start switch by the remote controller 11 and issues a stop instruction to the electronic device 10, and a relay drive circuit 5 By turning off the transistor 5b, the relay 6 is turned off, the main power supply circuit 2 is stopped, and the state is shifted to the standby state to reduce power consumption.

Japanese Unexamined Patent Application Publication No. 11-69261 discloses, for the purpose of use in electronic equipment such as a television receiver, without reducing the voltage of the commercial AC power supplied to the main power supply circuit 2 as shown in FIG. Rectifying diode 2 bridged as shown
a, and is smoothed by the smoothing capacitor 2b. The switching element 2c is connected to the primary winding of the switching transformer 2k in series and the switching control unit 2j drives the switching element 2c.
The switching power supply circuit supplies a predetermined voltage to a television receiver as the electronic device 10 via a plurality of rectifier diodes 2d and 2e and a plurality of smoothing capacitors 2f and 2g on the next winding side.

Furthermore, a plug 7 connected to a commercial AC power supply
A standby power supply relay 12 is provided between the primary winding of the auxiliary power supply transformer 1a of the standby power supply circuit 1 and the CPU 3 controls the relay drive coil 12a to be "on" or "off" so that the remote controller 11 is instructed. The standby power supply relay 12 is turned "on" in the standby state to operate the standby power supply circuit 1, and the standby power supply relay 12 is turned "off" when the television receiver is being received.
By turning off the standby power supply circuit 1 and turning on all the necessary power supply by turning on the relay 6 via the main power supply circuit 2, the auxiliary power supply transformer 1 a that operates in the conventional manner at the time of remote control standby is provided. The generated crosstalk magnetic field does not adversely affect the CRT of the television receiver.

In the electronic device 10 having the standby function as described above, the remote controller 11 can perform an external electronic "on" and "off" operation, which is convenient for the user.
In order to reduce power consumption during standby, it is common to provide a standby power supply circuit 1 that supplies power only to the above-mentioned constantly energized portion. When the standby power supply circuit 1 is connected to a commercial AC power supply, it is the most reliable in terms of reliability and safety to constitute a transformer of a commercial frequency.

[0014]

As described above, in the conventional circuit configuration, the standby power supply circuit 1 supplies current to the CPU 3 and its peripheral circuits, and particularly turns on the relay 6 when the electronic device 10 operates. It is necessary to supply a current to the relay drive circuit 5, which is one of the factors that determine the size of the standby power supply circuit 1.

If a specific example is shown by numerical values, the CPU 3, the remote control light-receiving unit 4, and the display unit 8 have a total of 5 VDC, 1
0 mA to 15 mA, and the relay drive circuit 5 is DC 12 V and about 45 mA including the relay itself. Therefore, the auxiliary transformer 1a of the standby power supply circuit 1 needs to have a capacity of about 12V, 60mA or more in rectified DC output, and has a capacity of 2-3VA including iron loss and copper loss of the auxiliary transformer 1a itself. Is used. Therefore, the power consumption in the standby state is a value of about 1 to 2 W in the entire electronic device 10 even though the net power consumption around the CPU 3 is extremely small, which is a limit for future energy saving.

As described above, the main power supply circuit 2 starts from standby.
Until the standby power supply is operated, the standby power supply circuit 1 must receive a relatively large amount of power for driving the relay 6 for inputting the commercial AC power supply voltage of the main power supply circuit 2. This causes the power consumption of the circuit 1 during standby to be reduced.

The present invention has been made in order to solve the above-mentioned problem, and it is possible to operate the relay 6 without supplying the relay driving current consumed when operating the main power supply circuit 2 from the standby power supply circuit 1. It is an object of the present invention to provide a power supply circuit for electronic equipment that can be driven and that can reduce power consumption during standby of the standby power supply circuit 1.

[0018]

According to the first aspect of the present invention, a standby power supply circuit connected to a commercial AC power supply for controlling a control circuit and a voltage of the commercial AC power supply is relayed through a relay. A main power supply circuit 2 for inputting and supplying a power supply voltage to the electronic device 10, and capacitors 5a and 1c for driving the relay 6 based on control from the control circuit 3.
A first current supply circuit 13 for supplying current from the main power supply circuit 2 to the capacitors 5a and 1c, and a second current supply circuit 13 for supplying current from the standby power supply circuit 1 to the capacitors 5a and 1c.
And a power supply circuit for electronic equipment.

The power supply transformer 2h or the switching transformer 2k in the main power supply circuit 2 according to the present invention.
The relay 6 is connected to the primary winding side of the power transformer 2h.
Or rectification on the secondary winding side of the switching transformer 2k,
The smoothed current is supplied to the capacitors 5a and 1c via the first current supply circuit 13 and the standby power supply circuit 1
2. A power supply circuit for electronic equipment according to claim 1, wherein a current obtained by rectifying and smoothing the current is supplied to capacitors 5a and 1c via a second current supply circuit 14.

According to a third aspect of the present invention, there is provided a capacitor 5a
3. A power supply circuit for an electronic device according to claim 2, wherein the power supply circuit is disposed in a relay drive circuit 5 for driving the relay 6 or is also used as a smoothing capacitor 1c in the standby power supply circuit 1. It is.

According to a fourth aspect of the present invention, the control circuit 3 comprises a microcomputer, monitors the charging voltages of the capacitors 5a and 1c for driving the relay 6, and shifts the electronic device 10 from the standby state to the operating state. If the charging voltage of the capacitors 5a and 1c does not exceed the predetermined value when the start instruction is received, the charging voltage of the capacitors 5a and 1a exceeds the predetermined value after waiting for a certain time without driving the relay 6. 4. A power supply circuit for an electronic device according to claim 1, further comprising a process for outputting a control instruction for driving the relay when the power supply circuit is turned on.

According to the electronic device power supply circuit of the present invention described above, in the standby state, the capacitor 5a, 1c is charged with enough electric charge to flow through the relay 6 for a sufficient time to drive the relay 6 from the standby state to "ON". After charging, once the relay 6 is turned on, the relay 6 continues to be turned on by the current from the first current supply circuit 13 connected to the main power supply circuit 1. Therefore, the standby power supply circuit 1 does not need a current supply capability necessary to keep the relay 6 driven.

According to the present invention, the power supplied to the standby power supply circuit 1 in the operation state of the electronic device 10 can be reduced, and the transformer 1a of the standby power supply circuit 1 can be made smaller to reduce the iron loss of the transformer 1a. It is also possible to reduce copper loss and to reduce power consumption during standby.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a video device as an electronic device,
Alternatively, a power supply circuit for an electronic device for supplying a power supply voltage to various circuits of an audio device will be described with reference to FIGS.

FIG. 1 is a circuit diagram of a power supply circuit for electronic equipment showing one embodiment of the present invention, FIG. 2 is a circuit diagram of a power supply circuit for electronic equipment showing another embodiment of the present invention, and FIG. FIG. 4 is a flowchart showing the transition of the power supply circuit for electronic equipment from the standby state to the operation state according to the present invention, and FIG. 4 is an explanatory diagram showing the relationship between the voltage of the relay driving capacitor and the voltage of the smoothing capacitor of the power supply circuit. Parts corresponding to those in FIGS. 5 and 6 showing the conventional configuration are denoted by the same reference numerals, and redundant description is omitted.

FIG. 1 corresponds to FIG. In FIG. 1, reference numeral 1 denotes an auxiliary power transformer 1a, a rectifier diode 1b,
A standby power supply circuit including a smoothing capacitor 1c and a voltage stabilizing circuit 1d, a main power supply circuit 2 including a main power supply transformer 2k, rectifier diodes 2d and 2e, and smoothing capacitors 2f and 2g, and a control for controlling a standby state and an operation state. A circuit (CPU), 4 is a light receiving section for receiving a standby or activation instruction from the remote controller 11 and transmitting it to the CPU 3, 6 is a relay coil 6a, a surge absorbing diode 6
A relay drive circuit 5 drives a relay 6 including a relay drive transistor (hereinafter, referred to as a relay drive element) 5b and a capacitor 5a serving as a current source for relay drive. It is grounded and the other end is connected to one end of the drive coil 6a of the relay 6.

The smoothed voltage Vmain rectified by the rectifier diode 2e of the main power supply circuit 2 and smoothed by the smoothing capacitor 2f.
Is supplied to the anode of the diode 9b, and the cathode of the diode 9b is connected to the capacitor 5 in the relay drive circuit 5.
a of the first current supply circuit (path) 1
Form 3

The smoothing voltage Vsub of the smoothing capacitor 1c of the standby power supply circuit 1 is supplied to the anode of a diode 9c.
The second current supply circuit (path) 14 is connected to the other end of the capacitor 5a in the relay drive circuit 5 via a.

FIG. 2 corresponds to FIG. 6, and the main power supply circuit 2 constitutes a switching power supply similarly to FIG. 2
a is a primary rectifier diode that rectifies the commercial AC without stepping down, 2b is a primary smoothing capacitor, 2c is a switching element, 2h is a switching transformer, 2d and 2e are secondary rectifier diodes, 2f and 2g are 2 The secondary smoothing capacitor 2j is a switching control circuit. The first and second current supply circuits (paths) 13 and 14 have exactly the same circuit configuration as in FIG.

In the power supply circuits for electronic equipment shown in FIGS. 1 and 2, the smoothing capacitor 1 is connected to the second current supply circuit 14 in the forward direction.
Capacitor 5 serving as a current source for driving the relay by charging current c
Although the diode 9c for flowing the current 9a is provided, the resistor 9a may be simply connected to the second current supply circuit (path) 14.

Further, the series circuit of the diode 9c and the resistor 9a is short-circuited and directly connected, the diode 9c and the resistor 9a are omitted, and the smoothing capacitor 1c in the standby power supply circuit 1 is omitted.
May be used as it is for the capacitor 5a as the relay drive power supply.

Hereinafter, the operation of the power supply circuit for an electronic device in the above configuration will be described. In the standby state in which the electronic device 10 is inoperative, the CPU 3 does not output the signal to the relay driving element 5b. Therefore, the relay 6 is turned off, and the transformers 2k and 2h of the main power supply circuit 2 are disconnected from the commercial AC power supply. Has stopped. Therefore, the smoothing capacitors 2f, 2f
g is not charged. On the other hand, the transformer 1a of the standby power supply circuit 1 supplies current to the CPU 3 while being connected to the AC commercial power supply, and constantly charges the capacitor 5a serving as a relay driving current source via the diode 9c and the resistor 9a.

Next, when an instruction to start the electronic device 10 is received from the remote controller 11 via the remote controller light receiving section 4, the CP
U3 immediately turns on the relay drive element 5b, excites the relay drive coil 6a, and turns the relay 6 on. When the current for driving the relay 6 flows, the charge of the capacitor 5a serving as the current source for driving the relay decreases and the charging voltage across the terminals decreases. On the other hand, the transformers 2k and 2h of the main power supply circuit 1 are energized. When the smoothing capacitor 2f on the secondary side is charged and the voltage rises, the diode 9b
, The capacitor 5a is also charged.

When a long time elapses in the above-described standby state, the electric charge charged in the capacitor 5a is reduced by the diodes 9b provided in the first and second current supply circuits 13 and 14,
The discharge is gradually discharged by the impedance of the reverse bias state 9c and the impedance of the cutoff state of the relay driving element 5b. The electric charge at this time is small because it only compensates for the electric charge discharged from the capacitor 5a, so that the charging current requires only a small current. When there is a command from the remote controller 11 to turn on the power during standby, the drive current for turning on the relay 6 discharges the electric charge charged in the capacitor 5a and becomes the drive current. Circuit 1
There is no need to output current from

That is, when the main power supply circuit 2 is operating, a current that keeps the relay 6 in the "ON" state flows from the main power supply circuit 2, and the relay drive current source is connected until the moment when the relay 6 is turned "OFF". A current flows from the main power supply circuit 2 to the capacitors 5a and 1c, thereby charging the capacitors 5a and 1c.

As described above, the electronic device 1 is switched from the standby state.
The state shifts to the operation state of 0, and the “on” state of the relay 6 is maintained. In the operation state of the electronic device 10, the standby power supply circuit 1
By setting the charging voltage Vmain between the terminals of the smoothing capacitor 2f of the main power supply circuit 2 slightly higher than the charging voltage Vsub between the terminals of the smoothing capacitor 1c, Vsub <Vmain, the standby power supply 1 to the relay driving circuit 5
Current flowing to the power supply can be eliminated.

When a standby instruction is received from the remote controller 11 in the operation state of the electronic device 10, the CPU 3
After issuing the evacuation instruction to 0, the output to the relay drive circuit 5 is stopped, and the relay 6 is turned off. Since the transformer 2k of the main power supply circuit 1 is turned off, the smoothing capacitor 2e of the main power supply circuit 2 is not charged, and the current to the capacitor 5a of the relay drive circuit 5 via the diode 9b is stopped. As described above, according to the present invention, the load of the transformer 1a of the standby power supply circuit 1 is based on the initial charge of the control circuit 3 and some circuits such as the display unit 8 and the light receiving unit 4 attached thereto and the capacitor 5a as a current source for driving the relay. Only, a relay driving current several times larger than the current required for the original standby state is not required.

Considering general constants, when a relay of the most general-purpose type having a driving voltage of 12 V is used, the rated driving current is about 44 mA. In addition, the charging rise time of the smoothing capacitor 2f of the main power supply circuit 2 reaches 90% in three to four waves when the size of the main power supply circuit transformer 2k is about 100 to 200 VA and the rectifier circuit has two waves. Therefore, even if the mechanical operation delay time of the relay 6 is taken into consideration, if the capacitance of the capacitor 5a serving as the relay driving current source is about 220 μF, the driving current to the relay 6 at the transition from the standby state to the operation state of the electronic device 10 is reduced. It is possible to switch to the current supply from the main power supply circuit 2 without interruption. FIG. 4 shows the voltage relationship at the switching timing.

In FIG. 4, at the instant t = 0 when the relay 6 is turned on, the voltage of the capacitor 5a serving as a current source for driving the relay starts decreasing, while the voltage of the smoothing capacitor 2f of the main power supply circuit 2 is charged. As a result, the charge starts rising and charges the capacitor 5a of the current source for driving the relay via the diode 9b.
The voltage for keeping driving the relay 6 is maintained.

When the switching power supply is used for the main power supply circuit 2, the basic operation of FIG. 2 is not different from that of FIG. Although there is a difference that the setting of the capacitance value of the capacitor 5a serving as the current source for driving the relay is slightly increased due to the configuration of the main power supply circuit 2 being a switching power supply, the charging rise time of the primary-side smoothing capacitor 2f of the switching transformer 2h is different. And switching control circuit 2j
By setting the capacitance value of the capacitor 5a serving as the relay driving current source in consideration of the rise time of the relay, a relay operation similar to that of FIG. 1 can be realized.

When the control circuit 3 is constituted by a CPU in the embodiment of the present invention, it is clear that the transition from the standby state to the operation state of the electronic device 10 and vice versa is extremely easy. One of the control sequences will be described with reference to the flowchart of FIG.

FIG. 3 shows a process for shifting the electronic device 10 from the standby state to the operating state.
1 receives a start instruction from the remote control light receiving unit 4 or from a main body start switch, the CPU 3 checks the voltage of the capacitor 5a of the current source for driving the relay, and determines a predetermined value sufficient to drive the relay 6. determine exceeds k _1, outputs (first step ST ₁₎ if more than relay drive signal to the relay driving circuit 5, (3 step S
T ₃₎ to proceed to the fourth step ST _4. If not, the voltage is checked again after a predetermined time, for example, 10 ms (step ST ₂ ). In the fourth step ST ₄ proceeds to the next step.

When the smoothing capacitor 1c in the standby power supply circuit 1 is substituted for the capacitor 5a as a relay drive current source in the relay drive circuit 5, FIGS.
It is obvious that the second current supply circuit 14 omits a system path including the capacitor 5a and the ground as a simple path.

The current is supplied from the main power supply circuit 2 to the capacitors 5a and 1c serving as the current sources for driving the relay via the diode 9b from the smoothing capacitor 2f on the secondary side of the transformer 2k of the main power supply circuit 2 and not directly. It is also possible to perform this through some kind of voltage adjustment in a stabilized power supply circuit or the like.

[0045]

As described above, according to the present invention, the current capacity required for the standby power supply circuit 1 for supplying the current in the standby state does not include the relay driving current for driving the relay 6 and the control is performed. A sufficient power supply transformer 1a can be set by supplying only the current value of the circuit 3, so that the power supply transformer 1a can be made extremely small, the iron loss and the copper loss of the transformer itself are small, and the standby power supply with small power consumption during standby is used. The circuit 1 can be supplied, and an electronic device such as a video device or an audio device with low power consumption during standby can be provided.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a power supply circuit for electronic equipment according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of a power supply circuit for electronic equipment showing another embodiment of the present invention.

FIG. 3 is a flowchart illustrating a transition from a standby state to an electronic apparatus operating state according to the present invention.

FIG. 4 is an explanatory diagram showing a relationship between a voltage of a capacitor of a current source for driving a relay of the present invention and a voltage of a smoothing capacitor of a main power supply circuit.

FIG. 5 is a circuit diagram of a power supply circuit for a conventional electronic device.

FIG. 6 is a circuit diagram of another conventional power supply circuit for electronic equipment.

[Explanation of symbols]

1,100 ‥‥ standby power supply circuit, 1c ‥‥ auxiliary power supply smoothing capacitor, 2,200 ‥‥ main power supply circuit, 2f, 2
g Smoothing capacitor for main power supply, 2h switching transformer, 2k main power transformer, 3 control circuit (CPU), 4 remote control light receiving section, 5 relay drive circuit, 5a relay drive Current source capacitor, 6
{Relay, 8} display element, 9a resistance, 9b, 9
c ‥‥ diode, 10 ‥‥ electronic equipment

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 5C026 EA07 5C056 BA05 DA11 5G065 AA01 DA06 DA07 EA06 FA02 GA06 GA07 HA04 JA07 KA08 LA07 MA01 MA03 MA07 MA09 MA10 NA01 NA09 NA10 5H006 BB06 CA07 CB03 DB01 DB07 DC05 DA0401 EA01 EB02 HA21 HA32 HA33

Claims (4)

[Claims] 1. A standby power supply circuit connected to a commercial AC power supply for controlling a control circuit, and a main power supply circuit for inputting a voltage of the commercial AC power supply via a relay and supplying a power supply voltage to an electronic device. A capacitor for driving the relay based on the control from the control circuit, a first current supply circuit for supplying a current from the main power supply circuit to the capacitor, and a current from the standby power supply circuit. A power supply circuit for electronic equipment, comprising: a second current supply circuit that supplies the capacitor. 2. The relay connected to a primary winding of a power transformer or a switching transformer in the main power circuit, and rectifying and smoothing a current obtained by rectifying and smoothing a secondary winding of the power transformer or the switching transformer. 2. A capacitor according to claim 1, wherein said capacitor is supplied to said capacitor via a first current supply circuit, and a current obtained by rectifying and smoothing said standby power supply circuit is supplied to said capacitor via said second current supply circuit. Power supply circuit for electronic equipment. 3. The electronic device according to claim 2, wherein the capacitor is provided in a relay driving circuit for driving the relay or is used also as a smoothing capacitor in the standby power supply circuit. Power circuit. 4. The control circuit is configured by a microcomputer, monitors a charging voltage of the capacitor for driving the relay, and receives a start instruction for transitioning the electronic device from a standby state to an operation state. If the charging voltage of the capacitor does not exceed a predetermined value, after waiting for a predetermined time without driving the relay, a control instruction to drive the relay when the charging voltage of the capacitor exceeds a predetermined value. The power supply circuit for an electronic device according to any one of claims 1 to 3, further comprising a process of outputting the power supply.