JP3200258B2 - Power supply - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an externally controllable switching power supply, and more particularly to a power supply suitable for a facsimile apparatus having a low power consumption and having a standby state.

[0002]

2. Description of the Related Art Conventionally, in a device having a standby state such as a facsimile device, a switching power supply or the like is generally used as a power supply. This power is always on during standby or during operation. In addition to the main power supply, some devices have a separate sub power supply for standby. This type of device is
At the time of standby, only the sub power supply rises, and the main power supply rises only during operation, so that power consumption is reduced.

[0003] Also, an entirely new system has been proposed for the purpose of reducing power consumption during standby.
That is, the start and stop of the main power supply (switching power supply) are controlled by the main power supply control unit, and the power supply to the main power supply control unit is performed by the secondary battery during standby and by the main power supply during operation. In a system where the main power supply is stopped during standby, only the main power control unit operates (standby), and during operation, the main power supply rises while a control signal from the main power control unit is supplied to the main power supply. is there. As a result, power consumption can be further reduced as compared with the related art.

[0004]

When the power is supplied from the secondary battery to the main power controller for controlling the main power as described above, the power is not supplied during the standby mode because the main power is stopped. Although the power can be reduced, the following problem arises because the main power controller controls the main power.

In other words, if the main power supply is always turned on when AC input is started, the main power supply is stopped during standby, so that the main power supply control unit continuously outputs a control signal for stopping the main power supply. In addition, the consumption of the secondary battery is accelerated, and it is impossible to reduce the power consumption.

In addition, the main power supply does not rise when the AC input is started, and the main power supply rises when a control signal for starting the main power supply is supplied from the main power supply control unit to the main power supply in this state. Then, there is no problem when the secondary battery is charged, but when the secondary battery is completely discharged, the main power control unit cannot supply a control signal for starting the main power to the main power.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and is capable of reducing power consumption and starting up a main power supply even when a secondary battery is completely discharged. The purpose is to get.

[0008]

According to the present invention, there is provided a power supply device comprising:
An output transformer for generating AC power on the secondary side by secondary side oscillation, switch means for turning on and off the primary side oscillation, a switching control unit capable of controlling the switch means from the outside, a delay A switching circuit, wherein when the power supply from the power supply source is started, the switching control section turns on the switch means only for a certain period of time by the delay circuit and causes the primary side of the output transformer to oscillate. It is what was constituted.

Further, the switching control section oscillates (turns on and off) the switch means in accordance with an external ON signal before a predetermined time elapses by the delay circuit.

The delay circuit is constituted by a resistor and a capacitor.

[0011]

According to the present invention, by providing the delay circuit, when the supply of the electric power from the power supply source is started, the main power supply rises only for a predetermined time by the delay circuit. Further, by causing the switching control to be performed externally before the fixed time elapses, the switching power supply can be handled in the same manner as a conventional switching power supply.

[0012]

FIG. 1 is a circuit diagram showing a configuration of a power supply device according to an embodiment of the present invention. In the figure, reference numeral 39 denotes an insulating transformer (output transformer) for generating AC power to the secondary winding 38 by the oscillation of the primary winding 36, and the AC input to the power supply device includes a filter circuit 40, a rectifying circuit. 41, a smoothing circuit 42 is supplied to the primary and secondary insulating transformers 39, and the primary side of the insulating transformer 39 is switched (ON, OFF) by an FET 43 as a switch means.

Reference numeral 44 denotes an IC for controlling the oscillation of the primary side of the insulating transformer 39. The output port OUT1 keeps oscillating while the input port IN1 is at the Low level, during which the primary side of the insulating transformer 39 oscillates. IN1 is Hig
During the h level, the output port OUT1 maintains the Low level, and during that time, the primary side of the insulating transformer 39 stops oscillating. The power supply (Vdd) of the IC 44 is
9 is provided by an auxiliary winding 37 wound around. Also, from the secondary side of the insulating transformer 39, the secondary winding 38
+ 24V, +5 through the rectifying / smoothing circuits 52 and 53
V power is supplied to each unit of the apparatus main body 1 of the facsimile apparatus of FIG.

Reference numeral 54 denotes a current detection circuit, and 55 denotes an overvoltage detection circuit.
The signal is fed back to the IC 44 through 57. Further, the IC 44 performs PWM control using the current on the secondary side, and shuts down the entire system when an overvoltage is detected.

A P for externally controlling this power supply
The S signal is input to the IC 44 via the photocoupler 45. When the PS signal is at a high level, the transistor 4
6 turns on, and a current flows through the photocoupler 45. Then, the photocoupler 45 performs current-voltage conversion, and
The input port IN1 of the IC 4 goes low, and the output port OUT1 of the IC 44 oscillates accordingly,
The primary side of the transformer 39 oscillates via 3 to supply power to the secondary side. As a result, the power supply rises and starts operating. When the PS signal is low, the transistor 46 is turned off, and the input port I of the IC 44 is turned off.
N1 becomes High level, and accordingly, the output port OUT1 of the IC 44 becomes Low level and the FET 43
Is turned off. As a result, oscillation on the primary side of the transformer 39 stops, power supply to the secondary side stops, and the operation of this power supply stops.

Reference numerals 47, 49, 50 and 51 denote current limiting resistors, 58 denotes a diode for preventing backflow, and 59 denotes a current limiting resistor. The photocoupler 45 also insulates the primary side and the secondary side.

Reference numeral 35 denotes a delay circuit composed of resistors 48 and 72 and a capacitor 73. The delay circuit 35 has a time constant between the resistors 48 and 72 and the capacitor 73, and determines the value of the resistors 48 and 72 and the capacitance of the capacitor 73. By changing the time constant, the time constant can be set. Reference numeral 74 denotes a switching control unit including the IC 44, the photocoupler 45, and the transistor 46, which can control on / off of the FET 43 by an external signal.

Note that the switching control unit 74 starts the delay circuit 35 when the power supply from the power supply source is started.
, The FET 43 is oscillated (on / off) only for a certain period of time to oscillate the primary side of the insulating transformer 39. Further, before the predetermined time elapses, the control of the switching control unit 74 is performed to the outside, and the switching control unit 74 switches the FET 43 according to an instruction (signal) from the outside.
Is controlled so that the oscillation of the primary side of the insulating transformer 39 is controlled.

Further, the FET 43 is turned off to stop the oscillation on the primary side of the insulation transformer 39, and the insulation transformer 3 is turned off.
The off signal for stopping power supply to the secondary side of No. 9 does not consume power.

FIG. 2 is a block diagram showing the configuration of a facsimile apparatus using the above-described power supply as the main power supply 16. In the figure, reference numeral 1 denotes an apparatus main body of the facsimile apparatus, and 2 denotes a CPU constituted by a microprocessor and the like.
The system of the entire apparatus is controlled in accordance with a program stored in a ROM 3, and a data read / write RAM 4, a nonvolatile RAM 5, a character generator (CG) 6, a document reading unit 7, a recording unit 8, a modem unit 9, the network control unit (NCU) 10, the operation unit 13, and the display unit 14 are controlled.

The RAM 4 stores the binarized image data read by the reading unit 7 or the binarized image data recorded by the recording unit 8 and transmits a signal modulated by the modem unit 9 to the network control unit 10. And stores the binarized image data to be output to the telephone line 11 via the. Also this RAM4
Stores binary image data obtained by demodulating an analog waveform signal input from the telephone line 11 via the network control unit 10 and the modem unit 9.

The nonvolatile RAM 5 is provided in the main unit 1.
Even if the power of the device is turned off, data to be stored such as speed dial numbers is securely stored. ROM3 is J
Characters such as an IS code and an ASCII code are stored, and character data corresponding to a predetermined code is extracted as required by 2-byte data under the control of the CPU 2.

The reading section 7 is composed of a DMA controller, an image processing IC, an image sensor, a CMOS logic IC, etc., binarizes data read using a contact sensor (CS) under the control of the CPU 2,
The binarized data is sequentially sent to the RAM 4. The setting state of the original on the reading unit 7 can be detected by a mechanical original detection sensor provided on the original conveyance path. The original detection signal is a main power supply control for controlling the main power supply 16. It is input to the unit 15 and the CPU 2.

The recording section 8 is composed of a DMA controller, an ink jet recording apparatus, a CMOS logic IC, and the like. The recording section 8 takes out recording data stored in the RAM 4 under the control of the CPU 2 and records and outputs it as a hard copy. The modem unit 9 includes G3 and G2 modems and a clock generation circuit connected to these modems.
The transmission data stored in the RAM 4 is modulated based on the control of the PU 2 and output to the telephone line 11 via the network control unit 10. The modem unit 9 is provided with a telephone line 11
Is introduced via the network control unit 10,
The binarized data obtained by modulating the signal is stored in the RAM 4.

The network control unit 10 switches and connects the telephone line 11 to either the modem unit 9 or the telephone 12 under the control of the CPU 2. Further, the network control unit 10 has a detecting means for detecting a call signal (CI).
And to both CPU2.

The telephone 12 is integrated with the apparatus main body 1, and specifically includes a handset, a speech network, a dialer, a numeric keypad, a one-touch key, and the like. The operation unit 13 includes a start key for starting image transmission and reception, a mode selection key for designating operation modes such as “fine”, “standard”, and “automatic reception” during transmission and reception, and a ten-key for dialing or It consists of one-touch keys. Then, when these keys are pressed, an ON signal is input to the main power supply control unit 15 and the CPU 2.

The display unit 14 has a liquid crystal display for displaying 16 digits, and displays predetermined characters under the control of the CPU 2. The main power supply control unit 15 controls the energization (power supply) to each unit (block) of the apparatus main body 1 and includes a one-chip microcomputer, a capacitor type secondary battery, and the like. It can be driven only by electric power. The main power supply control unit 15 receives a document detection signal from the reading unit 7, an incoming signal from the network control unit 10, or the operation unit 13.
When the ON signal is input from the CPU, the main power supply 16 is started by outputting a start signal. The main power supply 16 is configured by an AC input switching power supply, and can control switching on and off from the outside. The main power supply 16 supplies power by a start signal and a stop signal from the main power supply control unit 15, respectively.
Or stop supplying power.

FIG. 3 is a circuit diagram showing the internal configuration of the main power supply control unit 15, and FIG.
FIG. 2 is a diagram showing a circuit configuration around 2;

In these figures, the power supply line of Vcc connects three power supply sources.
The second is the solar cell 23, and the third is the capacitor type secondary battery 19 described above. The priority of these three power supplies is determined by the respective voltages, the charging of the secondary battery 19, the Schottky barrier diode 22 for backflow prevention, and the diode 26 for backflow prevention. Is Zener diode 1
4.8 V, solar cell 2 by 8 and barrier diode 22
The voltage from the battery 3 is 4.6 V, and the voltage from the secondary battery 19 is 4.5 V (when fully charged).

Also, depending on the orientation of the diodes 22 and 26, when the main power supply 16 is turned on, the power supply becomes the dominant, and the secondary battery 19 is charged and V
Supply power to the cc line. At this time, the solar cell 23
Becomes low potential, and no current flows from the solar cell 23. When the main power supply 16 is not operating and the solar cell 23 is supplying power, that is, when the main power supply 16 is not operating but light energy is being supplied,
If the potential of the secondary battery 19 is higher than that of the solar battery 23, power is supplied from the secondary battery 19 to the Vcc line, and no power is supplied from the solar battery 23. When the potential of the secondary battery 19 is lower than that of the solar battery 23, power is supplied from the solar battery 23 to the Vcc line, and at the same time, the secondary battery 19
Is also charged through the resistor 20. When the main power supply 16 is not operating and the solar cell 23 is not supplying power, the secondary battery 19 supplies power to the Vcc line.

In FIG. 3, reference numeral 17 denotes a 4-bit one-chip microcomputer which can operate with very low power consumption and has a built-in timer means. Whether or not the solar cell 23 supplies power is determined by the potential of the resistor 2.
The voltage is divided by 4 and 25, and the divided voltage is input to the input port IN2 of the computer 17. Rechargeable battery 1
9 is a primary battery 2 for backing up the RAM 5 by the comparator 27 via the voltage stabilizing resistor 21.
The output of the comparator 27 is input to the input port IN4 of the microcomputer 17 which is a voltage detecting means. In addition, 2
Reference numerals 9 and 30 denote resistors for dividing the voltage of the primary battery 28.

Reference numeral 31 denotes a voltage Vac on the secondary side of the main power supply 16.
And an IC for comparing the voltage Vcc1 of +5 V from the main power supply 16 with the voltage Vcc2 of the secondary battery 19.
When 1 becomes greater than 2V, the CE output port goes high, and when Vac falls below about 2V, the CE output port goes low. This output is input to the input port IN1 of the microcomputer 17. Also Vcc
When 2 becomes 3 V or less, the RE output port changes from the High level to the Low level, and the reset signal is continuously output. When Vcc2 exceeds 3 V, the RE output port maintains the High level. This output is connected to inverter I
The signal is input to the RESET port of the microcomputer 17 through the C32 and the OR gate IC34. This output is also input to the RESET port of the CPU 2 through the AND gate IC 71 in FIG.

Reference numeral 33 denotes a NAND gate IC, which is a hooking switch 60 shown in FIG. 4, a mechanical original detection switch (or reed switch) 61, a call signal detection switch (photocoupler) 64, or a handset off-hook detection switch ( A signal from a photocoupler 65 is input. The output of this IC 33 is
Is input to the RESET port of the microcomputer 17. 4, 62, 63, 66, 67 in FIG.
Is a resistor for voltage adjustment, and 69 and 70 are modular jacks.

When the input port IN3 of the microcomputer 17 is at a high level, it indicates that the CPU 2 is operating. The output from the output port OUT1 of the microcomputer 17 is input to the main power supply 16 through the IC. And the microcomputer 17
, A reset signal is output to the CPU 2 through the AND gate 71. 75 is a resistor for voltage adjustment.

FIGS. 4A and 4B show the circuit configuration of each part of FIG. 2. FIG. 4A shows the periphery of the CPU 2, FIG. 4B shows the inside of the operation unit 13, and FIG. 4C shows the inside of the network control unit 10. ing. In FIG. 4, reference numeral 68 denotes a delay circuit composed of a resistor and a capacitor.
Are delayed by the time required for the initialization of the CPU 2 and output to the output ports O1 to O4, respectively.

FIGS. 5, 6, 7 and 8 are flowcharts showing the operation of the present embodiment. Next, the operation will be described with reference to these drawings.

FIG. 5 shows an operation flow of the main power supply. When the AC input is started (step 101), the input port IN1 of the IC 44 is at the low level by the delay circuit 35 at this time (step 102). According to this I
The output port OUT1 of C44 oscillates (step 10).
3), the primary side of the transformer 39 oscillates via the FET 43 to supply power to the secondary side. As a result, the main power supply 16 starts up (step 104). When the power supply is started, the microcomputer 17 is initialized (step 10).
5) When the initialization is completed, the microcomputer 17 outputs a High level from the output port OUT1,
The signal is input to the main power supply 16 as a PS signal via C34 (step 106).

When the transistor 46 is turned on by the PS signal, a current flows through the photocoupler 45 and the photocoupler 45 is turned on (step 107), and the input port IN1 of the IC 44 goes low.
ow level (step 108), the output port OUT1 of the IC 44 oscillates accordingly (step 1).
09), the primary side of the transformer 39 oscillates via the FET 43, and supplies power to the secondary side. This state is maintained, and the main power supply 16 continues to supply power (step 11).
0). Here, the time constant of the delay circuit 35 is set so that the input port IN1 of the IC 44 keeps the Low level from the start of the AC input until the photocoupler 45 is turned on by the PS signal from the microcomputer 17. Set.

When the PS signal goes low (step 111), the transistor 46 is turned off.
Since the photocoupler 45 is also turned off, the input port IN1 of the IC 44 goes high (step 11).
2) According to this, the IC 44 sets the output port OUT1 to L
ow level (step 113). by this,
The FET 43 is turned off, the primary side of the transformer 39 stops oscillating, and the power supply to the secondary side is stopped.
Stops its operation (step 114). PS in this state
When the signal goes high (step 115), the transistor 46 turns on, the photocoupler 45 turns on (step 116), and the input port IN1 of the IC 44 goes low (step 117). Accordingly, the output port OUT1 of the IC 44 oscillates (step 118), the primary side of the transformer 39 oscillates via the FET 43 to supply power to the secondary side, and the main power supply 16 rises (step 119). Then, this state is maintained, and the main power supply 16 continues to supply power.

FIG. 6 shows an operation flow in the FAX standby state. When AC input is started (step 20).
1) First, the main power supply 16 is turned on to start up (step 202), the microcomputer 17 is initialized (step 203), the CPU 2 is initialized (step 204), and charging of the secondary battery 19 is started simultaneously (step 202). 205). Then, when the initialization of the microcomputer 17 is completed, the facsimile enters the standby state, and the secondary battery 19 continues to be charged while the standby state continues.

When the charging of the secondary battery 19 is completed (step 206), that is, when the output of the comparator 27 becomes High level, or when one hour elapses with the timer built in the microcomputer 17, the main operation is performed. The power supply 16 stops. At this time, in the former case, the port IN4 of the microcomputer 17 becomes High level, so the microcomputer 17 resets the CPU 2 accordingly (step 20).
7) Then, the operation of the main power supply 16 is also stopped (step 2).
08), power supply by only the secondary battery 19 and the solar battery 23 is started (step 209). Similarly, in the latter case, the microcomputer 17 resets the CPU 2 accordingly,
Further, the operation of the main power supply 16 is also stopped, and power is supplied only by the secondary battery 19 and the solar battery 23 (step 2).
10). In any case, the secondary battery 19 is charged with the surplus power of the power supplied by the solar cell 23 (step 211).

The power supplied from the solar cell 23 is reduced,
When the voltage becomes 2.8 V or less (step 21)
2), the secondary battery 19 is discharged. When the voltage becomes 3 V or less (step 213), the RE port of the IC 31 becomes low level, and the PS signal becomes high.
Since it is at the high level, the photocoupler 45 is turned on,
The port IN1 of the IC 44 becomes Low level. Accordingly, the port OUT1 of the IC 44 oscillates and the FET4
The primary side of the transformer 39 oscillates via 3 to supply power to the secondary side. As a result, the main power supply 16 starts up (step 214). Then, during this operation, the CPU 2 is initialized, and charging of the secondary battery 19 is started. Thus, the secondary battery 19 is charged again while maintaining the fax standby state. Then, this cycle is repeated.

FIG. 7 shows the FA in the FAX standby state.
This is an interrupt routine for X transmission. When there is a document in the FAX standby state (step 301) or when the hooking button is pressed (step 30).
2) Or, when the receiver is off-hook (step 303), the switches 61, 60, and 65 are turned on, and the ON signals are input to the CPU 2 through the delay circuit 68, and are output as the PS signals through the ICs 33, 32, and 34 as photo signals. While turning on the coupler 45, the microcomputer 17 is reset. Thus, the interrupt operation is started (Step 304).

When the photocoupler 45 is turned on, I
C44 oscillates the primary side via the FET 43 and supplies power to the secondary side. As a result, the main power supply 16 starts up (step 305). While the main power supply 16 is turned on, the secondary battery 19 is constantly charged (step 311). In this state, a call is made to the other party's FAX (step 206), and when the line is captured (step 30).
7), a state where normal facsimile transmission can be performed (step 308). Then, the transmission is completed (step 30).
9) When the line is disconnected (step 310), the CPU
2 changes from a high level to a low level from the port OUT1 of the microcomputer 17 to the port IN3 of the microcomputer 17, the microcomputer 17 resets the CPU 2 in accordance with the signal, and sets the PS signal to a low level, thereby setting the main power supply 16 to a low level.
Is stopped (step 312.) Then, this interrupt is completed (step 313), the FAX standby state is established, and the process returns to A in FIG.

FIG. 8 shows the FA in the FAX standby state.
This is an interrupt routine at the time of X reception. When the hooking button is pressed in the FAX standby state (step 4
01) or when the receiver is hooked off (step 402), the switches 60 and 65 are turned on, respectively, and the on signals are input to the CPU 2 through the delay circuit 68, and as the PS signal through the ICs 33, 32 and 34 as the PS signal. Is turned on, and the microcomputer 17 is reset. Thus, this interrupt operation is started (step 404).

When the photocoupler 45 is turned on, I
C44 oscillates the primary side of the transformer 39 via the FET 43 and supplies power to the secondary side. As a result, the main power supply 16 starts up (step 405). Also, when the calling signal (CI) is detected (step 403), the switch 64 is turned on, the ON signal is input to the CPU 2 through the delay circuit 68, and the ICs 33, 32, 34
Similarly, the photocoupler 45 is turned on as a PS signal, and the microcomputer 17 is reset. Thereby, this interrupt operation is started (step 40).
7). When the photocoupler 45 is turned on, IC4
4 oscillates the primary side via the FET 43 and supplies power to the secondary side. As a result, the main power supply 16 starts up (step 408). In any case, the main power supply 16
While is rising, the secondary battery 19 is constantly charged (step 413).

If the hooking button is pressed or the receiver goes off-hook, a call is made to the other party's FAX (step 406), and when the line is seized (step 409), normal facsimile reception is performed (step 409). Step 410). When a call signal is detected, the network control unit 10 captures the line and performs facsimile reception by automatic reception.

When the reception is completed (step 411) and the line is disconnected (step 412), the signal input from the port OUT1 of the CPU 2 to the port IN3 of the microcomputer 17 changes from a high level to a low level. Resets the CPU 2 and sets the PS signal to Low level to stop the operation of the main power supply 16 (step 414). Then, the interrupt operation is completed (step 415), the FAX standby state is established, and the process returns to A in FIG.

The operation in each state of the facsimile apparatus using the main power supply 16 having the configuration shown in FIG. 1 has been described above. However, in this embodiment, the delay circuit 35 is provided in the main power supply 16 as described above. When the AC input is started, the main power supply 16 always rises, and after a certain period of time, the main power supply 16 stops operating. Therefore, it is not necessary for the main power supply control unit 15 to always output a main power supply stop control signal in order to stop the main power supply 16 during standby.
The consumption of the secondary battery 19 is suppressed, and power consumption can be reduced.

When the AC input is started, the main power supply 16 always rises. Therefore, even when the secondary battery 19 is completely discharged, the main power supply control unit 15 sends a control signal for starting the main power supply to the main power supply. 16 can be given. Further, the delay circuit 35 can be constituted only by a resistor and a capacitor, and can be realized at low cost.

[0051]

As described above , according to the present invention, the control
In response to the power ON signal supplied from the control means,
The switching of the primary side of the output transformer is externally controlled, and when the supply of power from the power supply source is started , the power ON signal
There also need not be supplied, so causing the oscillation of the primary side of the output transformer, always there is no need to output a stop signal for the main power supply during standby, that <br/> the power consumption can be reduced effective. In addition, the power ON signal is
If the configuration is powered by electricity, the secondary battery
That the main power can be turned on even if the
Has the effect.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a facsimile apparatus using the main power supply having the configuration shown in FIG. 1;

FIG. 3 is a circuit diagram showing an internal configuration of a main power control unit.

FIG. 4 is a diagram showing a circuit configuration of each unit in FIG. 2;

FIG. 5 is a flowchart showing the operation of the main power supply.

FIG. 6 is a flowchart showing an operation of the facsimile apparatus in a standby state.

FIG. 7 is a flowchart showing an interrupt routine at the time of transmission in a standby state of the facsimile apparatus;

FIG. 8 is a flowchart showing an interrupt routine at the time of reception of the facsimile apparatus in a standby state.

[Description of Signs] 1 Apparatus main body 2 CPU 15 Main power control unit 16 Main power supply 17 1-chip microcomputer 19 Secondary battery 35 Delay circuit 39 Insulation transformer (output transformer) 43 FET (switch means) 74 Switching control unit

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H02M 3/28

Claims (5)

(57) [Claims] 1. An output transformer for generating AC power on a secondary side by a primary side oscillation, a switch for controlling the primary side oscillation, and a switching control capable of controlling the switch from the outside And a delay circuit, wherein the switching control unit responds to a telephone call signal.
And control means for supplying a power ON signal, response to the supply of the supplied power ON signal from said control means
Then, the switch means is turned on and off, and the output
When the power supply is started from the power supply source, the switching control unit causes the power ON signal to be oscillated on the primary side of the power supply signal for a certain period of time by the delay circuit.
A power supply device for turning on and off the switch means to oscillate the primary side of the output transformer even when the power is not supplied . 2. The switching control section oscillates (turns on and off) switch means in accordance with an external ON signal before a predetermined time by a delay circuit elapses, and switches the switching means.
2. The power supply device according to claim 1, wherein the oscillation of the next side is continued. 3. The switching control section oscillates (turns on and off) a switch means in accordance with an external ON signal before a predetermined time by the delay circuit elapses, and switches the switching means.
The oscillation of the secondary side is continued, and thereafter the switching control unit oscillates (turns on and off) and stops the switching means in accordance with an on signal or an off signal from the outside, and thereby controls the primary side of the transformer. The power supply device according to claim 1, wherein oscillation is controlled. 4. The power supply device according to claim 1, wherein the delay circuit comprises a resistor and a capacitor. 5. The off signal for stopping the switching means to stop oscillation on the primary side of the transformer and stopping power supply to the secondary side is a signal that does not consume power. 3. The power supply device according to 3.