JP2000004547A - Power supply circuit and ac adapter thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce power consumption during standby waiting to as closely to zero as possible. SOLUTION: A switch 11 and a backup capacitor C11 are provided respectively between an AC power supply 1 and a transformer 12 for connecting or disconnecting the AC power feeding path to the transformer 12 from the AC power supply depending on the on or off condition, and moreover a supply means 131 for supplying the operating power to a microprocessor unit(MPU) 16 is also provided, and the MPU 16 is also provided to decide whether or not the backup capacitor C11 should be charged when the switch 11 is turned off, then is turned on the switch 11, when it is decided that the backup capacitor C11 should be charged, and thereafter to decide whether or not the backup capacitor C11 has completed the charging and then to turn off the switch 11 when it is decided that the backup capacitor C11 has completed the charging.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply circuit for supplying power to, for example, a microprocessor unit and an AC circuit.
It is about the adapter.

2. Description of the Related Art Conventionally, in electronic equipment such as television receivers, stationary VTRs, and audio equipment, a power supply circuit capable of supplying electricity to a timer circuit, a remote control start-up circuit, and the like, even when the main power supply is off, has been employed. (199
No. 23, February 8, 2008; 710 or April 2, 1998
On day 0, No. 714, see Nikkei Electronics). FIG. FIG. 710 illustrates an example of a conventional power supply circuit described on page 150 of Nikkei Electronics. This power supply circuit includes an auxiliary transformer 92a in addition to the main transformer 92, and is interposed between the AC power supply 1 and the
A switch 91 for connecting or disconnecting an AC power supply path from the power supply to the main transformer 92;
MPU (microprocessor unit) 96 for turning off
And On the secondary winding side above the main transformer 92, a rectifying circuit D
Rectification and smoothing are performed by B92 and smoothing capacitors C92 and C93, respectively, and the resulting DC power is supplied to a power amplifier (not shown). On the lower secondary winding side, rectification and smoothing are performed on the AC power generated in this winding by the rectifier circuit DB93 and the smoothing capacitors C94 and C95, respectively, and the resulting DC power is not shown. Is supplied to each functional block. On the other hand, on the secondary winding side of the auxiliary transformer 92a, the rectifying circuit DB91 and the smoothing capacitor C
Rectification and smoothing are performed by the respective components 91, and the obtained DC power is further stabilized by the regulator 95 before being supplied to the MPU 96. As described above, the MPU 96 is supplied with the stabilized DC power by the auxiliary transformer 92a and the like which is always on, so that the switch 91 can be turned on / off and the main transformer 92 is on standby. Even at this time, it becomes possible to drive a timer circuit and a remote control starting circuit (not shown). In addition, by using the auxiliary transformer 92a only at the time of standby, power loss due to the excitation current is reduced.
The standby power consumption of about 15 W is reduced to about 3 W.

However, in the above-described conventional power supply circuit, although the power consumption during standby can be reduced, it still consumes about 3 W of power. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a power supply circuit and an AC adapter capable of reducing power consumption during standby to zero as much as possible.

According to a first aspect of the present invention, there is provided a power supply apparatus comprising: a transformer for converting a primary voltage from an AC power supply into a predetermined secondary voltage; A rectifier circuit connected to the side and rectifying AC power to DC power, and by DC power from the rectifier circuit,
A backup power supply for storing charging power used by a computer, and an AC power supply path between the AC power supply and the transformer that is interposed between the AC power supply and the transformer and that is turned on or off in accordance with an ON or OFF control signal. And a switch for turning on the switch when a determination result indicating that the backup power supply should be charged is obtained. It is provided. In this configuration, since the computer operates on the power from the backup power supply, the switch can be turned off during that time, and the power consumption in the standby mode approaches zero as much as possible. In addition, the backup power supply is automatically charged even if the charging power of the backup power consumption consumed by the computer during standby is used. Therefore, even when the switch is not turned on by operation for a long time, the standby using the charging power of the backup power supply can be performed. Will be possible. Note that, after the switch is turned on by the ON unit, a charge completion determination unit that determines whether the charging of the backup power supply is completed, and a determination result that the charging of the backup power supply is completed are obtained. And off means for turning off the switch may be provided (claim 2). In this configuration, the switch is turned off when the automatic charging is completed, so that the power consumption during standby is further reduced. In addition, a configuration may be provided in which a measurement unit that measures the amount of charging power of the backup power supply is provided, and the determination unit determines whether to charge the backup power supply using the measurement result (claim 3). . With this configuration, the backup power supply is automatically charged at more accurate timing. Further, the determination unit measures an elapsed time from a point in time when the AC power supply path is cut off by the switch, and charges the backup power supply when the elapsed time exceeds a predetermined reference time. A configuration for judging power should be adopted (claim 4). In this configuration,
In addition to the automatic charging of the backup power supply, the frequent automatic charging operation of the backup power supply due to the failure of the backup power supply is prevented. further,
A configuration may be provided in which the computer is provided, and the on means and the off means are provided by the computer. According to this configuration, the power consumption in the standby state when the switch is turned off approaches zero as much as possible. An AC adapter according to a sixth aspect of the present invention includes the power supply circuit, a cable including a power supply line and a control line, and the backup to a predetermined device having the computer via the power supply line of the cable. The switch supplies power from a power supply, and the switch connects an AC power supply path from the AC power supply to the transformer via a control line of the cable according to an ON or OFF control signal from a computer of the predetermined device. Alternatively, each of them is cut off. In this configuration, since the computer operates on the power from the backup power supply, the switch can be turned off during that time, and the power consumption in the standby mode approaches zero as much as possible. In addition, the backup power supply is automatically charged even if the charging power of the backup power consumption consumed by the computer during standby is used. Therefore, even when the switch is not turned on by operation for a long time, the standby using the charging power of the backup power supply can be performed. Will be possible.

FIG. 1 shows a first embodiment of the present invention.
Power supply circuit for audio equipment.
FIG. 3 is a schematic configuration diagram of the first embodiment.
Give an explanation. The power supply circuit 10 according to the first embodiment includes a switch
11, transformer 12, DC power supply unit 13, voltage detection unit 1
4. Regulator 15 and MPU (computer) 1
6. The switch 11 is connected to the AC power supply 1
Between the MPU 16 and the transformer 12
AC power supply 1 according to (closed) or off (open) control signal
Connecting or blocking the AC power supply path from
This is to make a disconnection. This switch 11 is
Ray switch or semiconductor switch, etc., provided on the primary side
Therefore, relays that comply with safety standards are usually used.
Used. However, in this case, the AC power supply 1
Power outlet and power circuit 10
Connection to the power supply via a power cord with a plug
It is done. The transformer 12 has a winding n1 on the primary side,
An AC power supply having windings n21, n22, and n23 on the secondary side;
1 to convert the primary voltage V1 from the windings n21, n22,
A predetermined secondary voltage V21, V2 is applied to both ends of n23.
2, V23. The DC power supply unit 13
Supply unit 131 for supplying operating power to U16,
-Supply unit 132 for supplying drive power to amplifier and illustration omitted
Supply unit 133 for supplying power to each functional block of
It is configured. The supply unit 131 has two inputs to the winding n21.
Terminal is connected and the AC power from the winding n21 is
Rectifier circuit (rectifier) DB11 for rectifying to power and
Charging power by DC power from the output of the flow circuit DB11
Backup capacitor (backup
Source) C11. The supply unit 132 is wound
Both input terminals are connected to the line n22, and the
A rectifier circuit DB12 for rectifying AC power to DC power; and
A smoothing capacitor for smoothing the output voltage of this rectifier circuit DB12.
It is composed of sensors C12 and C13. These smooth
Capacitors C12 and C13 are connected to both ends of rectifier circuit DB12.
The smoothing capacitors C12 and C1 are connected in series between the power terminals.
The connection point 3 is grounded. The supply unit 133 includes a winding n
23 are connected to both input terminals.
A rectifier circuit DB13 for rectifying power to DC power and
Smoothing capacitor for smoothing the output voltage of rectifier circuit DB13
It is composed of C14 and C15. These smoothing capacitors
The capacitors C14 and C15 are both output terminals of the rectifier circuit DB13.
Are connected in series between the terminals of the smoothing capacitors C14 and C15.
The connection point is grounded. Voltage detector (measuring means) 14
Is the measurement of the amount of power charged in the backup capacitor C11
In the first embodiment, the target of the charging power amount is
The voltage across the backup capacitor C11
And a D / A converter. Note that this configuration is
Instead, the voltage detector is, for example, a backup capacitor
The voltage across C11 is compared with a predetermined charging start reference voltage.
A configuration including a comparator may be used. Regulator 1
5 is the DC voltage from the backup capacitor C11.
To obtain a stable DC voltage by suppressing fluctuations.
Any voltage stabilizing circuit (constant voltage circuit) may be used. MPU16
Uses the power from the backup capacitor C11
Operates in addition to the power supply circuit 10 and a circuit (not shown)
Controls audio equipment in general.
Turn the power on or off for audio equipment.
Monitor and switch on or off when performed
11 is turned on or off. Ma
The MPU 16 operates when the switch 11 is off.
If the backup capacitor C11 should be charged
Is determined, and the backup capacitor C11 is charged.
When it is determined that the power should be turned on, the control for turning on the switch 11 is performed.
Do. In the first embodiment, the output voltage value of the voltage detection unit 14
And compare it with the specified charging start reference voltage value.
If the output voltage value is lower than the charge start reference voltage value,
It is determined that the backup capacitor C11 should be charged.
Done. Note that the voltage detection unit is
In this configuration, the comparator
The voltage across the capacitor C11 is a predetermined charging start reference
If a comparison result indicating lower than voltage is obtained,
It is determined that the top capacitor C11 should be charged.
You. However, the MPU 16 operates with the charge start reference voltage.
A valid backup capacitor C
11 is decided at the design stage which is a guide to start charging.
This is the voltage to be applied. In addition, the MPU 16
Switch 1 to charge up capacitor C11
Before turning on 1, the voice cut processing is performed. 1st real
In the embodiment, make sure that no audio signal is input to the power amplifier.
Short-circuit the input of a power amplifier (not shown)
Processing is performed. The power is not limited to this configuration.
-Shut off the input of the amplifier and input the audio signal to the power amplifier.
A configuration in which no force is applied may be used. Alternatively, the winding n2
Between the winding n22 and the rectifier circuit DB12 between the rectifier circuit DB2 and the rectifier circuit DB12.
Connects or cuts off the AC power supply path to the road DB12
Switch, and this switch is operated by MPU16.
The above-mentioned voice cut processing is performed by being turned off.
A configuration may be used. Also, after the audio cut, the MPU 16
If an ON operation is performed, a sound output process is performed. 1st real
In the embodiment, the short circuit of the input of the power amplifier is released.
In the configuration where the input of the power amplifier is cut off,
The disconnection connection is made. Alternatively, the winding n22 and the rectifying circuit
In a configuration in which a switch is provided between the
Control for turning on the switch is performed. Also, MPU1
6 is when the backup capacitor C11 should be charged
After turning on switch 11, the backup capacitor
It is determined whether or not the charging of the battery C11 has been completed.
It is determined that the charging of the up capacitor C11 has been completed.
Then, control to turn off the switch 11 is performed. First implementation
In the embodiment, the output voltage value of the voltage
Output voltage value obtained by comparing with the fixed full charge reference voltage value
Is higher than the full charge reference voltage.
It is determined that the charging of the capacitor C11 has been completed.
Note that in a configuration in which the voltage detection unit includes a comparator,
From this comparator, the backup capacitor C11
Comparison that the voltage between both ends is higher than the specified full charge reference voltage
When the result is obtained, the backup capacitor C11
It is determined that the charging has been completed. However, fully charged
The reference voltage is the voltage of the normal backup capacitor C11.
A voltage that should be determined at the design stage, which is a guide to full charge.
And FIG. 2 shows the operation of “automatic charging” by the MPU 16.
In the following flowchart, referring to FIG.
The operation of “automatic charging” will be described. Audio equipment
When the switch is turned off, the switch 11 is turned off.
As a result, the backup capacitor C11 is charged.
The operation shifts to the standby operation using only electric power. After this, `` Auto charge
The subroutine "den" is called repeatedly. This sub
When the routine is called, the backup capacitor C
It is determined whether or not 11 should be charged (S5). Ba
It is determined that the backup capacitor C11 should be charged.
If not (NO in S5), return
On the other hand, it is determined that the backup capacitor C11 should be charged.
If the voice cut is performed (YES in S5),
The process is performed (S10), and the switch 11 is turned on.
(S15). Thereby, the backup capacitor C1
The standby operation using only the charging power of 1 is interrupted and the backup
Automatic charging is performed on the top capacitor C11. Next
Then, it is confirmed whether or not the ON operation has been performed (S2).
0), if the ON operation is not performed (NO in S20),
It is determined whether or not the charging has been completed (S25). charging
Is determined to have been completed (YE in S25).
S), the switch 11 is turned off (S30). to this
Therefore, only the charging power of the backup capacitor C11 is
To a standby operation. After that, it returns. one
On the other hand, when it is not determined that the charging is completed (S
(NO at 25), and returns to step S20. Step S20
If the ON operation is performed (YES), the sound is output
Is performed (S35), and thereafter, the process returns. This
In the case of, repeat call of the "auto charge" subroutine
Is canceled. As described above, according to the first embodiment, for example,
Backup capacitor C11 keeps MPU16 for several days.
Or charge power that can be operated continuously for several weeks.
In the meantime, switch 11 is continuously turned off during that time.
The backup capacitor C
Switch 11 is operated before the charging power of
And the backup capacitor C11 is charged.
It is. In this case, the power consumption during standby can be reduced to zero.
Will be possible. On the other hand, charging the backup capacitor C11
Switch 11 is turned on by operation before electric power runs out.
Even if the power is not
When the switch 11 is turned on, the backup capacitor C
11 is automatically charged, in this case, power consumption during standby
The force can be brought to zero as much as possible. Figure 3
A power supply circuit according to a second embodiment of the
Schematic diagram applied to the power supply circuit of the
Hereinafter, the second embodiment will be described. Power supply of the second embodiment
As in the first embodiment, the circuit 20 includes the switch 11 and the
Lance 12, DC power supply 13, voltage detector 14,
In addition to having the regulator 15, the MP of the first embodiment
An MPU 26 that operates differently from U16 is provided. this
The MPU 26 controls the AC power supply path by the switch 11.
A predetermined charging start reference time has passed since the
After that, the subroutine of the "automatic charging" of the first embodiment is
Call repeatedly. In this way, "automatic charging"
The subroutine call will not be made at the charging start reference time
By doing so, the failure of the backup capacitor C11
Frequent automatic charging operation due to such factors can be prevented.
However, the above charging start reference time is
Ensure MPU16 only with charging power of capacitor C11
The time is set to be equal to or less than the time during which continuous operation is possible. Above, the second actual
According to the embodiment, the failure of the backup capacitor C11
For example, frequent automatic charging operations can be prevented. Figure
4 is a power supply circuit according to a third embodiment of the present invention,
This is a schematic configuration diagram applied to the power supply circuit of audio equipment.
The third embodiment will be described below with reference to FIG. Third embodiment
The power supply circuit 30 is in the same state as the first embodiment.
11, transformer 12, DC power supply unit 13 and regulation
In addition to the MPU 16 of the first embodiment,
Has an MPU 36 that operates differently. This MPU3
6 is based on the power from the backup capacitor C11.
The power supply circuit 30 operates in addition to the power supply circuit 30 and includes an unshown circuit.
It controls the overall audio equipment.
Monitor the power on / off operation of audio equipment.
Switch, if the on or off operation is performed,
1 is turned on or off. Also,
When the switch 11 is in the off state, the MPU 36
Of whether or not the backup capacitor C11 should be charged
And charge the backup capacitor C11.
Is determined, the switch 11 is turned on.
In the third embodiment, the switch 11 supplies AC power.
Measures the elapsed time T1 since the route was interrupted
The elapsed time T1 is equal to the predetermined charging start reference time T2.
If it exceeds, charge the backup capacitor C11.
A determination that power is to be made is made. However, the charging start reference time T
2 is the charging power of the normal backup capacitor C11
Less than the time that the MPU 16 can be operated continuously with only
It is set and predetermined in the design stage. Ma
In addition, the MPU 36 has a backup as in the first embodiment.
When the capacitor C11 should be charged, the switch 11 is turned off.
Audio cut processing before turning on
After that, if an ON operation is performed, a sound output process is performed.
Also, the MPU 36 connects the backup capacitor C11
After turning on switch 11 when charging is required,
Determination of whether or not charging of the up capacitor C11 is completed
And the backup capacitor C11 is completely charged.
When it is determined that the switch 11 has been
Do. In the third embodiment, the backup capacitor C1
From when the switch 11 was turned on for charging
The charging time T3 is measured, and the charging time T3
When the reference time T4 or more, the backup capacitor
It is determined that the charging of C11 has been completed. However,
The full charge reference time T4 is equal to the backup capacitor C11.
Required to charge to the specified full charge reference voltage level
The time is determined in advance in the design stage. FIG.
Is a flowchart showing the operation of "automatic charging" by the MPU 36.
In the chart below, refer to
The operation will be described. The audio device is turned off.
After the elapsed time T1 is initialized, the off operation is performed.
The elapsed time T1 from the time of the crop is measured, and thereafter, FIG.
"Auto charge" subroutine is called repeatedly
You. When this subroutine is called, the backup
Determination of whether to charge the capacitor C11, that is,
Whether the elapsed time T1 has exceeded the charging start reference time T2
A determination is made (S50). Backup capacitor C
If it is not determined that 11 should be charged,
(NO in S50), while returning, the elapsed time T1
Exceeded charging start reference time T2, backup capacitor
If it is determined that C11 should be charged (S5
0, YES), a voice cut process is performed (S55),
The switch 11 is turned on (S60). Then charge
Time T3 is initialized and switch 11 is turned on
The charging time T3 from is measured (S65).
A confirmation is made as to whether or not an operation has been performed (S70).
If the ON operation is not performed (NO in S70), the charging is completed.
The charging time T3 is equal to the full charge
It is determined whether or not the time is equal to or longer than the quasi-time T4 (S7).
5). The charging time T3 becomes longer than the full charging reference time T4,
If it is determined that charging has been completed (S75:
YES), the switch 11 is turned off (S80), and
Time T1 is initialized. After that, it returns. one
On the other hand, when it is not determined that the charging is completed (S
(NO at 75), and returns to step S70. Step S70
If the ON operation is performed (YES), the sound is output
Is performed (S85), and thereafter, the process returns. This
In the case of, repeat call of the "auto charge" subroutine
Is canceled. As described above, according to the third embodiment, the backup
It becomes possible to automatically charge the top capacitor C11
In addition, due to failure of the backup capacitor C11, etc.
Frequent automatic charging operation can be prevented. What
In the first to third embodiments, the backup
It is determined whether or not the sensor C11 should be charged.
If it is determined that the top capacitor C11 should be charged,
In this case, means for turning on the switch 11 is configured by the MPU.
However, the circuit is not limited to this,
It may be composed of This configuration is described in the following fourth example.
This will be described in detail in an embodiment. FIG. 6 shows a fourth embodiment of the present invention.
An outline showing an example of application to an AC adapter as a power supply circuit.
FIG. 14 is a schematic configuration diagram, and a description of the fourth embodiment will be given below using this diagram.
I do. The AC adapter 40 shown in FIG.
1, transformer 42, DC power supply unit 43, constant voltage circuit 44
a, a comparator 44b, an OR circuit 44c, and a regulator
And an electrical connection with the AC power supply 1
Plug connector (not shown) on the input side
The power supply connected to the output terminal of the regulator 15 is
Output cable C including feed line and control line
Have. However, the switch 11 and the regular
The filter 15 is the same as in the previous embodiment. Also, Sui
Switch 11 has a control terminal (not shown) whose signal level is Hi.
gh, the contact closes, and when it goes low, the contact opens.
It is like. The transformer 42 has a winding n1 on the primary side.
Have a winding n2 on the secondary side, and
The voltage V1 is converted to a predetermined secondary voltage V2 across the winding n2.
Is what you get. The DC power supply 43 is connected to both ends of the winding n2.
A power terminal is connected and the AC power from the winding n2 is
Rectifier circuit DB11 for rectifying power and rectifier circuit DB
Stores charging power with DC power from output of 11
It is composed of a backup capacitor C11.
The constant voltage circuit 44a is, for example, a backup capacitor
A resistor R44 having one end connected to the positive terminal of C11,
The other end of the resistor R44 and the backup capacitor C
11 negative terminals and cathode and anode respectively
A constant-voltage diode D44 connected thereto.
Is generated. Comparing
The input terminal 44b has a non-inverting input terminal and an inverting input terminal.
The cathode and back-up of the constant voltage diode D44, respectively.
Connected to the positive terminal of the top capacitor C11. I
Accordingly, the signal level of the output terminal of the comparator 44b
Indicates that the charging voltage of the backup capacitor C11 is
If it is higher than the initial reference voltage, it becomes LOW while it is lower.
If it becomes High. The OR circuit 44c has two input terminals.
The output terminal of the comparator 44b and the cable C
Output terminal is connected to the switch 11
Is connected to the control terminal. AC configured in this way
The adapter 40 is connected via a cable C to, for example, a game machine.
Connected to a predetermined device D such as a container. In the example shown in FIG.
Power from the backup capacitor C11
MPU (Computer) via the power supply line of Bull C
) Is supplied to the device D having the
Power on / off performed for the controller (not shown)
High or Low depending on the operation
The signal is transmitted from the MPU 46 via the control line of the cable C.
To be sent to one input terminal of the OR circuit 44c
Has become. Next, the AC adapter 40 and the MPU 46
The operation of will be outlined. However, switch 11 is off
It is assumed to be in the state. When the on operation is performed on the device D side,
OR times from the MPU 46 via the control line of the cable C
A high-level signal is sent to one input terminal of the path 44c.
Will be issued. Thus, the high level is output from the OR circuit 44c.
Since the bell signal is transmitted, the switch 11 is turned on.
You. When the switch 11 is turned on, the AC power supply 1
To the specified voltage level, rectification,
Smoothing and stabilizing, resulting in DC power
Is the MPU of the device D via the power supply line of the cable C
46 and the like. Also, at this time,
Capacitor C11 converts DC current from rectifier circuit DB11
More charged. Thereafter, the device D is turned off.
Then, from the MPU 46 via the control line of the cable C
A low-level signal is applied to one input terminal of the OR circuit 44c.
Is sent. At this time, the backup capacitor C1
Assuming that 1 is sufficiently charged, the charging voltage is
Higher than the initial reference voltage and the output of the comparator 44b
From the terminal to the other input terminal of the OR circuit 44c.
Is transmitted. As a result, the switch 11 is turned off.
become. After that, for a while, turn on the device D
Is not performed, the backup capacitor C11
The charging voltage level gradually decreases. And charge
When the charging voltage becomes lower than the charging start reference voltage, the comparator
Data from the output terminal of the OR circuit 44c to the other input of the OR circuit 44c.
A high-level signal is sent to the terminal. This
Switch 11 is turned on, and the AC
The power is converted to a predetermined voltage level and rectified.
The backup capacitor C11 is a rectifier circuit
It is charged by the direct current from DB11. After this,
The backup capacitor C11 is sufficiently charged,
When the voltage becomes higher than the charge start reference voltage, the comparator
From the output terminal of 44b to the other input terminal of OR circuit 44c
, A low-level signal is transmitted. With this,
Switch 11 is turned off and the backup capacitor C11
To supply power to the MPU 46. No.
According to the fourth embodiment, the timer function or the controller
Provide the device with a remote control activation function etc.
AC adapter connected to the device
Power plug on the equipment
If the source is off, the backup capacitor C11 and
Switch 11 is almost off with automatic charging function
State, so that standby power is reduced to zero as much as possible
You can also connect the AC adapter to the power
The trouble of connecting and disconnecting
It becomes possible. FIG. 7 shows a power supply circuit according to a fifth embodiment of the present invention.
Road showing an example of application to AC adapters and equipment
FIG. 14 is a schematic configuration diagram, and the fifth embodiment will be described below with reference to FIG.
I do. The AC adapter 50 shown in FIG.
1, transformer 42, DC power supply unit 43 and regulator
15 as in the fourth embodiment.
Plug connector (not shown) for electrical connection of
And connected to the output terminal of regulator 15
Power supply lines and cables including control lines
On the output side. AC configured in this way
The adapter 50 is connected via a cable C to a game machine, for example.
Connected to a predetermined device E such as a container. In the example shown in FIG.
Is connected to the MPU via the power supply line of cable C.
Computer E) having the backup condition
Power is supplied from the
Power on / off performed on rollers (not shown)
Depending on the operation, each of the High or Low level
The signal is transmitted from the MPU 56 via the control line of the cable C.
Is sent to the control terminal of the switch 11
You. The MPU 56 is a type of the AC adapter 50 and the device E.
It performs various processes, for example, when set in the device E
A program stored on a cassette or CDROM
Load the ram, and the player
The main process is to output image information according to an instruction to a TV or the like.
To do. The MPU 56 is a controller or a device.
ON / OFF of the power switch provided in any of 41
To monitor when an on or off operation is performed
The signal which becomes High or Low respectively is controlled by the cable C.
Processing for sending to the control terminal of the switch 11 via the control line
Work. In the MPU 56, the switch 11 is turned off.
, The charging start reference time as in the third embodiment.
Should be used to charge backup capacitor C11
Is determined. However, the charging start reference time is
In the fifth embodiment, the MPU 56 can be operated for about one day or more.
Power is set to remain. Also, the MPU 56
When it is determined that the battery should be charged, the switch 11 is turned on.
A predetermined time calculation process is performed. For example, using random numbers,
Processing to calculate the time within a time zone such as a power peak
Is performed. Also, the MPU 56 starts scanning at a predetermined time.
A process of sending a high-level signal to the switch 11
Do. Further, the MPU 56 has a backup capacitor.
It is determined that C11 should be charged, and the high level is determined.
After sending the signal to the switch 11, the backup
It is determined whether or not charging of the capacitor C11 has been completed, and
That the charging of the backup capacitor C11 is completed
Is performed, the Low level signal is transmitted to the control line of the cable C.
To the control terminal of the switch 11 via the
Turn 11 off. FIG.
Flowchart showing the operation of
The operation of “automatic charging” will be described. However
It is assumed that the switch 11 is on. Power on equipment E side
When the off operation is performed, the switch 11 is turned off,
After the elapsed time T1 has been initialized,
The elapsed time T1 is measured, and thereafter, “automatic charging” in FIG.
The subroutine "den" is called repeatedly. This sub
When the routine is called, the backup capacitor C
11 is to be charged or not, that is, the elapsed time T1
It is determined whether or not the time has exceeded the charging start reference time.
(S100). Elapsed time T1 is longer than the reference charging start time
Short, the backup capacitor C11 should be charged
If no determination has been made (NO in S100),
While turning, the elapsed time T1 exceeds the charging start reference time.
It is determined that the backup capacitor C11 should be charged.
If the setting is performed (YES in S100), the predetermined time
Is calculated (S105). Next, the current time
It is determined whether or not the fixed time has come (S110).
If the predetermined time has not come (NO in S110), the ON operation
It is confirmed whether or not has been performed (S115). on
If no operation is performed (NO in S115), step S1
05, if an ON operation is performed (Y in S115)
ES), return. In this case, the sub-
The repetition call of the routine is released. At S110
When the fixed time comes (YES), the switch 11 is set to High.
A level signal is sent. This allows, for example, power
The switch 11 is turned on outside the working hours. Next,
The charging time T3 is initialized, and thereafter, the switch 11 is turned on.
The charging time T3 from the time when the charging time is set is measured (S12).
5). Thereafter, it is determined whether or not charging has been completed, that is,
Whether the charging time T3 is longer than the full charging reference time T4
A determination is made (S130). If charging is not completed
(NO in S130), Check whether or not ON operation has been performed
Is performed (S135). If no ON operation is performed (S
(NO at 135), while returning to step S130,
If the operation is performed (YES in S135), the process returns.
In this case, the repetition
Is released. When charging is completed (YE in S130)
S), a low-level signal is sent to the switch 11 side
(S140). As a result, the switch 11 is turned off.
You. Thereafter, the elapsed time T1 is initialized and the process returns.
You. As described above, according to the fifth embodiment, the backup
In addition to being able to automatically charge the sensor C11,
The charging switch-on operation is performed outside the peak power hours.
And it is possible to use multiple devices E
Switch for automatic charging of those devices E
The ON operation can be dispersed. Note that the first to first
In the fifth embodiment, a backup power supply
The configuration is such that a top capacitor C11 is used.
But lead battery, Ni-Cd battery or Li-ion battery
May be used. Also, secondary batteries
Can charge the MPU for a long period of time (for example, half a year or
(About one year) It may be one that enables continuous operation, or
It may be detachable. As a result,
Even if the product to which the source circuit is applied is in stock for a long time,
The remaining charge power in the battery or a new rechargeable battery
Replaceable, so relay 11 can be turned on / off
Become. The relay 11 is a so-called NC (normally
(Closed) contacts. This allows
Long-term stock of backup capacitor C11 charging power
Switch 11 is turned on even if the
And the backup capacitor C11 can be charged.
Accordingly, the operations of the above embodiments can be performed. Or figure
As shown in FIG. 9, another switch S is connected in parallel with the switch 11.
A configuration in which W1 is provided may be used. This allows backup
The charging power of the capacitor C11 becomes empty due to long-term inventory, etc.
Even if you turn on the switch SW1,
The up capacitor C11 can be charged. Also,
The switch SW1 turns on and off according to the depression.
A normal mechanical switch that holds alternately may be used.
Up capacitor C11 is empty due to long-term stock etc.
Is turned on when pressed with a finger.
Alternatively, a mechanical switch that is turned off when the finger is released may be used. this
Thereby, forgetting to turn off the switch SW1 is prevented.
In addition, a means for detecting a power failure is provided.
Configuration in which the switch 11 is turned off immediately upon detection of
May be. Also, as shown in FIG.
Alternatively, a configuration may be provided in which a separate resistor is provided. Furthermore, the first to third real
In the embodiment, the power supply circuit is suitable for a power supply circuit of an audio device.
Say, but not limited to
Not even. In short, the power supply circuit of the present invention, for example,
TV receiver, VTR, air conditioner, refrigerator, PC
And monitors.

As is apparent from the above description, according to the first, fifth and sixth aspects of the present invention, it is possible to make the power consumption in the standby state almost zero. Claim 2
According to the described invention, it is possible to further reduce power consumption during standby. According to the third aspect of the present invention, the backup power supply can be automatically charged with more accurate timing. According to the fourth aspect of the present invention, the power consumption during standby can be made as close to zero as possible, and frequent automatic charging operation of the backup power supply due to a failure of the backup power supply can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a power supply circuit according to a first embodiment of the present invention, which is applied to a power supply circuit of an audio device.

FIG. 2 is a flowchart showing an operation of “automatic charging” by the MPU shown in FIG.

FIG. 3 is a schematic configuration diagram of a power supply circuit according to a second embodiment of the present invention applied to a power supply circuit of an audio device.

FIG. 4 is a schematic configuration diagram of a power supply circuit according to a third embodiment of the present invention, which is applied to a power supply circuit of an audio device.

FIG. 5 is a flowchart showing an operation of “automatic charging” by the MPU shown in FIG. 4;

FIG. 6 is a schematic configuration diagram showing a power supply circuit according to a fourth embodiment of the present invention and mainly showing an application example to an AC adapter.

FIG. 7 is a schematic configuration diagram showing a power supply circuit according to a fifth embodiment of the present invention and showing an application example to an AC adapter and a device.

FIG. 8 is a flowchart showing an operation of “automatic charging” by the MPU shown in FIG. 7;

FIG. 9 is a diagram when another switch is provided in parallel with the switch of FIG. 1;

FIG. 10 is a diagram illustrating an example of a conventional power supply circuit.

[Explanation of symbols]

 1 AC power supply 10, 20, 30, 50, 60 Power supply circuit 11 Switch 12, 42 Transformer 13, 43 DC power supply unit 14 Voltage detection unit 15 Regulator 16, 26, 36, 46, 56 MPU 131, 132, 133 Supply unit DB11 Rectifier circuit C11 Backup capacitor SW1 Switch 40, 50 AC adapter D, E Equipment

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H02J 9/06 505 G06F 1/00 333C H02M 7/06 335A

Claims (6)

[Claims] A transformer for converting a primary voltage from an AC power supply to a predetermined secondary voltage; a rectifier circuit connected to a secondary side of the transformer for rectifying AC power to DC power; A backup power supply that accumulates charging power used by a computer by power; interposed between the AC power supply and the transformer, and configured to supply an AC power supply path from the AC power supply to the transformer according to an ON or OFF control signal. A switch for performing connection or disconnection, a determination unit for determining whether to charge the backup power supply, and an on switch for turning on the switch when a determination result that the backup power supply should be charged is obtained. Power supply circuit comprising: 2. A charging completion determining unit that determines whether charging of the backup power supply is completed after the switch is turned on by the ON unit, and a determination result that the charging of the backup power supply is completed. 2. An off-state means for turning off the switch when the condition is obtained.
Power supply circuit as described. 3. A measuring means for measuring a charging power amount of the backup power supply, wherein the determining means determines whether or not the backup power supply should be charged using the measurement result. Power supply circuit as described. 4. The backup power supply according to claim 1, wherein the determination unit measures an elapsed time from a point in time when the AC power supply path is cut off by the switch, and when the elapsed time exceeds a predetermined reference time. The power supply circuit according to claim 1, wherein it is determined that the battery should be charged. 5. The power supply circuit according to claim 1, further comprising the computer, wherein the on means and the off means are provided by the computer. 6. A power supply circuit according to claim 1, further comprising a cable including a power supply line and a control line, said predetermined circuit having said computer via a power supply line of said cable. The power of the backup power supply is supplied to a device, and the switch is connected to the AC power supply from the AC power supply to the transformer via a control line of the cable in accordance with an ON or OFF control signal from a computer of the predetermined device. An AC adapter that connects or disconnects the supply path.