JPH07298612A - Power source - Google Patents

Abstract

PURPOSE:To supply power to a secondary side of an insulating transformer for a predetermined time even if short power interruption occurs by discharging an electric storage element for delaying a control signal to a switching controller when a power supply from a power supply source is interrupted. CONSTITUTION:An AC input is supplied to primary, secondary insulating transformers 39 via a filter 40, a rectifier 41 and a smoothing circuit 42, and switched by an FET 43. A delay circuit 35 for delaying a control signal of this switching is provided. The circuit 35 has a time constant between resistors 48, 61 and a capacitor 62 of an electric storage element, and sets the constant by altering resistance values of the resistors 48, 61 and an electric capacity of the capacitor 62. A discharge circuit 64 is provided, charge stored in the capacitor 62 is immediately discharged even when a short interruption of an AC input occurs, and when the AC input is again recovered, the constant is altered to supply power to the secondary side. Accordingly, an erroneous operation of the system can be prevented.

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 device, and more particularly to a power supply device used in a facsimile machine or the like which has a low power consumption and is capable of standby.

[0002]

2. Description of the Related Art Conventionally, a switching power supply or the like is generally used as a power supply in a device having a standby state such as a facsimile device. This power supply is always on during standby or during operation. In addition to the main power supply, there are also devices that have a sub power supply for standby separately, and this type of device has a configuration in which only the sub power supply rises during standby and the main power supply rises only during operation. Low power consumption is achieved.

A completely new system has also been proposed for the purpose of reducing power consumption during standby (Japanese Patent Application No. 5-230259). That is, the main source control unit controls the start and stop of the main power source (switching power source),
The secondary battery supplies power to the main power supply control unit during standby, and the main power supply performs operation during operation. The main power supply is stopped during standby, and only the main power supply control unit operates (standby). However, the system is a system in which a control signal from the main power supply control unit is given to the main power supply during operation, so that the main power supply starts up. The main power supply in this system is configured to rise while the control signal is being input from the main power supply control unit and to be stopped when the control signal is not input from the main power supply control unit. As a result, it is possible to further reduce power consumption as compared with the conventional case.

As a main power supply for this new system, a power supply device incorporating a delay circuit has been newly proposed (Applicant Canon, Japanese Patent Application No. 5-230259). This power supply device is provided with a delay circuit, so that when the power supply from the power supply source (commercial AC power supply) is started (when the power switch of the device is turned on), the delay circuit automatically performs the secondary operation for a predetermined time. Power is supplied to the power supply side, and by controlling the switching to the outside during this fixed time, it can be handled like a conventional switching power supply, and is a power supply device indispensable for the new system.

[0005]

However, in the power supply device newly proposed for the new system of the above-mentioned conventional example, when the power supply from the power supply source is started, the delay circuit automatically performs the fixed time. Power is supplied to the secondary side. In the new system, the main power supply control unit controls the main power supply by using the power supply to the secondary side for a certain period of time. Storage element (capacitor, etc.)
In the case of using, there were the following drawbacks when the power supplied from the power supply source was cut off instantaneously.

(1) If the power supplied from the power supply source is momentarily cut off for a short time, if the power supply is restored before the electric charge stored in the storage element (capacitor, etc.) is completely discharged, You can't spend a certain amount of time, 2 of the above certain amount of time
It may happen that power cannot be supplied to the secondary side.

(2) When a situation such as (1) occurs,
The system may malfunction. In addition, not only that, there are cases where the main power supply cannot be turned on.

In view of the above-mentioned drawbacks, an object of the present invention is to allow the secondary side to be supplied with electric power for a certain period of time even if the electric power supplied from the electric power source is instantaneously interrupted, and the instantaneous interruption occurs. It is an object of the present invention to provide a power supply device that can avoid a malfunction and a situation where the main power supply cannot be turned on at times.

[0009]

SUMMARY OF THE INVENTION A power supply device of the present invention includes an output transformer which is supplied with power from a power supply source and which generates AC power on the secondary side by oscillation of the primary side, and a primary of the output transformer. Side switching means, a switching control part capable of controlling the switching means from the outside, and a delay circuit using a storage element for delaying a control signal from the outside to the switching control part. And a discharge circuit for discharging the electric charge stored in the storage element when the power supply from the power supply source is interrupted.

Also, the power supply device of the present invention is supplied with power from a power supply source and supplies power to the device body.
Power supply control means for turning on and off the power supply, a storage element for delaying an instruction input for instructing the power supply control means to turn on and off the power supply, and power supply from the power supply source are interrupted. And means for discharging the electric storage element according to the detection.

[0011]

According to the present invention, by providing the discharge circuit, even when the power supply from the power supply source is interrupted due to a momentary interruption or the like, the electric charge stored in the storage element (capacitor or the like) forming the delay circuit is stored. Can be forcibly discharged. Also,
By configuring the discharge circuit using high-speed switching elements such as transistors, even if the power supply from the power supply source is interrupted due to a momentary interruption, etc., it is stored in the storage element (capacitor, etc.) that constitutes the delay circuit. The electric charge can be discharged immediately.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments shown in the drawings.

FIG. 1 is a simplified circuit diagram of the main power supply 16 shown in FIG. 2, and is a drawing that best represents the features of the present invention.

In the figure, the AC input is the filter circuit 4
After passing through 0, the rectifying circuit 41, and the smoothing circuit 42, it is supplied to the primary and secondary insulating transformers 39, and is switched by the FET 43.

Here, 36 is a primary winding, and 38 is a secondary winding.

Reference numeral 44 denotes an IC for controlling the oscillation of the primary side of the isolation transformer 39, which is OUT while IN1 is at Low level.
1 continues to oscillate, while the primary side of the isolation transformer 39 oscillates, OUT1 maintains the Low level while IN1 is at the High level, and the primary side of the isolation transformer 39 stops oscillating during that period.

The power source Vdd of the IC 44 is the insulating transformer 39.
Is provided by an auxiliary winding 37 wound on the. The secondary side of the insulation transformer 39 is a power source of + 24V and + 5V from the secondary winding 38 via the rectifying / smoothing circuits 52 and 53.
To each part of the facsimile machine 1.

Reference numeral 54 is a current detection circuit, and 55 is an overvoltage detection circuit.
Feedback to IC44 through 57.

Further, the IC44 is set to P by the current value on the secondary side.
WM control is performed, and when an overvoltage is detected, the whole system is shut down.

Further, P for controlling the main power supply 16 from the outside
The S signal is input to the IC 44 through the photocoupler 45, and when the PS signal is at the high level, the transistor 46 is turned on and a current flows through the photocoupler 45, and the photocoupler 45 performs current-voltage conversion to input the input port IN of the IC 44.
1, the output port OUT1 of the IC 44 oscillates in response to this, and the primary side oscillates via the FET 43 to supply power to the secondary side, and the main power supply 16 rises and operates.

When the PS signal is low level, 46 is OF
F becomes 44, and IN1 of 44 becomes High level. In response to this, the output port OUT1 of IC44 becomes Low level, FET43 becomes OFF, oscillation of the primary side is stopped, power supply to the secondary side is stopped, and main power supply 16 Stops working.

The main power supply 16 is activated when the PS signal is at the high level and stopped when the PS signal is at the low level by the light emitting element in the photocoupler 45 during standby. This is to prevent power consumption, reduce the consumption of the secondary battery during standby, and reduce power consumption.

Reference numerals 47, 49, 50 and 51 are current limiting resistors.

The photocoupler 45 also insulates the primary side and the secondary side.

A delay circuit 35 has a time constant between the resistors 48 and 61 and the capacitor 62, and this time constant can be set by changing the resistance value of the resistors 48 and 61 and the electric capacitance of 62.

Thanks to this delay circuit, power is always supplied to the secondary side for a moment (about 500 ms in this embodiment) at the start of AC input (see the operation flow described later).

Reference numeral 63 is an IC 44 and photo couplers 45 and 46.
Is a switching control unit configured to control ON / OFF of the FET 43 by a signal from the outside.

Reference numeral 64 is a discharge circuit for immediately discharging the electric charge stored in the capacitor 62 when the AC input is cut off.

In order to immediately discharge the capacitor 62,
The discharge circuit 64 is configured by using a high speed switching element such as a transistor.

As described above, about 50 at the start of AC input.
In order to supply electric power to the secondary side for 0 ms, the capacitor 62
Needs to be large capacity.

However, when the capacitor 62 has a large capacity, it takes a very long time until the capacitor 62 is completely discharged when the AC input is cut off, for example, when a short interruption of the AC input occurs. If the AC input is restored before the capacitor 62 is completely discharged, the time constant cannot be reduced, and it may be difficult to supply power to the secondary side for about 500 ms.

By providing the discharge circuit 64, the electric charge stored in the capacitor 62 is immediately discharged even when the AC input is instantaneously cut off, and when the AC input is restored again, the electric charge is always kept on the secondary side for about 500 ms. Power is supplied.

The time of about 500 ms is A
This is a time sufficiently longer than the time required to bring the PS signal to the high level after the microcomputer 17 (see FIG. 3) is initialized (initialized) when the C input is input.

FIG. 2 is a block diagram of a facsimile machine using the power supply device embodying the present invention as its main power supply. In FIG. 2, 1 is a facsimile machine.

Reference numeral 2 denotes a CPU composed of a microprocessor and the like, and RAM4, a non-volatile RAM5, a character generator (CG) 6, a reading section 7, a recording section 8, a modem section 9, in accordance with a program stored in the ROM3.
Network control unit (NCU) 10, operation unit 13, display unit 1
Control 4

The RAM 4 stores the binarized image data read by the reading unit 7 or the binarized image data recorded in the recording unit 8.

The binarized image data stored in the RAM 4 is modulated by the modem unit 9 and output to the telephone line 11 via the NCU 10.

The analog waveform signal input from the telephone line 11 is demodulated via the NCU 10 and the modem unit 9,
The demodulated binary image data is stored in the RAM 4.

The non-volatile RAM 5 surely stores data (for example, abbreviated dial number) to be stored even when the power of the facsimile apparatus 1 is cut off.

The character generator 6 is an RO for storing characters such as JIS code and ASCII code.
The character data is M, and character data corresponding to a predetermined code is extracted with 2-byte data as needed under the control of the CPU 2.

The reading unit 7 is composed of a DMA controller, an image processing IC, an image sensor, a CMOS logic IC, etc., and binarizes the data read using the contact sensor (CS) under the control of the CPU 2, and then The digitized data is sequentially sent to the RAM 4.

The setting state of the original document on the reading unit 7 can be detected by a mechanical original document sensor (included in the operation unit 13) provided on the original conveyance path. It is input to the main power supply controller 15.

Here, the reason why the mechanical original sensor (mechanical switch) is used without using a photo interrupter using a light emitting element for the original sensor is that power is not consumed during standby for inserting the original.

The recording unit 8 is composed of a DMA controller, an ink jet recording device, a CMOS logic IC, etc., and takes out the recording data stored in the RAM 4 under the control of the CPU 2 and outputs it as a hard copy.

The modem section 9 is composed of G3 and G2 modems and a clock generation circuit connected to these modems, and modulates the transmission data stored in the RAM 4 under the control of the CPU 2 and makes a call via the NCU 10. Line 1
Output to 1.

Further, the modem 9 introduces the analog signal of the telephone line 11 through the NCU 10 and modulates the signal to 2
The data is binarized and the binarized data is stored in the RAM 4.

Under the control of the CPU 2, the NCU 10 switches the telephone line 11 to either the modem section 9 or the telephone 12 and connects it.

Further, the NCU 10 has means for detecting a call signal (CI), and when the call signal is detected, the NCU 10 sends an incoming signal to the main power supply controller 15.

The telephone 12 is integrated with the facsimile apparatus 1.

Specifically, the telephone 12 comprises a handset, a speech network, a dialer, a ten-key pad or a one-touch key.

The operation unit 13 has a key for starting image transmission and reception, a mode selection key for designating an operation mode such as fine, standard, and automatic reception during transmission and reception,
It consists of a numeric keypad for dialing or a one-touch key.

When these keys are pressed, an ON signal is input to the main power supply 15. The display unit 14 is an LCD module in which a pictogram LCD for displaying 7-segment for clock display and various modes and a dot matrix LCD capable of displaying 5 × 7 dots 16 digits × 1 line are combined, and L
It is composed of an ED and the like, and the pictogram LCD and the dot matrix LCD are independent of each other.

The main power supply control unit 15 is used for the facsimile apparatus 1
It controls energization (power supply) to each part (block) of the whole, and is composed of a one-chip microcomputer, a capacitor-type secondary battery, etc., and can be driven only by the power supplied from this secondary battery. .

When the incoming signal from the NCU 10, the document detection signal from the operation unit 13 or the ON signal from the operation unit 13 is input, the main power source control unit 15 receives a start signal (High signal).
and sends an h level PS signal) to the main power supply 16.

The display of the pictogram LCD of the display unit 14 is controlled by the microcomputer of the main power supply control unit 15, and the display of the dot matrix LCD of the display unit 14 is C.
It is controlled by PU2.

The main power supply 16 is an AC-input switching power supply, which can control ON / OFF of switching from the outside, and has a start signal (High level PS signal) and a stop signal (Low level PS) from the main power supply control unit 15. Signals) may or may not be supplied with power.

FIG. 3 is a circuit diagram showing a simplified structure of the main power supply controller 15 and its peripheral structure, and FIG. 4 is a part of the NCU 10 and C.
It is a circuit diagram showing a simplified configuration around PU2.

In these figures, Vcc connects the power supply sources of the three systems via the DC-DC converter 22 (FIG. 3), one is +5 V from the main power source 16, the second is the solar cell 23, Third is a capacitor-type secondary battery 19
Is. The priority of these three power supplies is determined by the respective voltages, the state of charge of the secondary battery 19, the Schottky barrier diode 20 for backflow prevention, and the backflow prevention diode 29, and those from the main power supply 16 are Schottky barriers. 4.8V due to the diode 20, 4.6V due to the diode 29 from the solar cell 23, secondary battery 19
The voltage from the above is the voltage depending on the state of charge.

The Schottky barrier diode 20,
Due to the direction of the diode 29, the power supply becomes the most dominant when the main power supply 16 is up, charging the secondary battery 19 through the resistor 21 and supplying power to Vcc through the converter 22. At this time, the output from the solar cell 23 has a low potential due to the diode 29, and the current does not flow into the converter 22 from the solar cell 23.

The main power source 16 is not operating and the solar cell 23
If the secondary battery 19 is higher in electric potential than the solar battery 23, the secondary battery 19 is converted into the converter 22 when the main battery 16 is not operating but the light energy is supplied. Power is supplied to Vcc through the solar cell 23, and no power is supplied from the solar cell 23.

When the potential of the secondary battery 19 is lower than that of the solar cell 23, V is supplied from the solar cell 23 via the converter 22.
Power is supplied to cc, and at the same time, the solar cell 19 also has a resistor 21.
Be charged through.

The main power source 16 is not operating, and the solar cell 2
When 3 is also not supplying power, the secondary battery 19 supplies power to Vcc via the converter 22.

In FIG. 3, reference numeral 17 is an 8-bit 1-chip microcomputer (hereinafter referred to as a microcomputer), which can operate with an extremely low power consumption and has a timer means for a clock built therein.

The microcomputer 17 can exchange data with the CPU 2 through the serial interface sI / O.

Whether or not the solar cell 23 is supplying electric power is detected by the voltage detecting circuit 27, and when the voltage is larger than 2.5 V, the OUT of the voltage detecting circuit 27 is detected.
Becomes High level, and when the voltage is below 2.5V, 27 O
UT becomes Low level.

The output from OUT of the voltage detection circuit 27 is input to IN8 of the microcomputer 17.

The discharged voltage of the secondary battery 19 is detected by the voltage detection circuit 24. When the voltage is larger than 1.2V, OUT of the voltage detection circuit 24 becomes High level, and when the voltage is 1.2V or less, the voltage is detected. OUT of the detection circuit 24 becomes low level.

The output from OUT of the voltage detection circuit 24 is input to IN9 of the microcomputer 17.

The voltage of the fully charged state of the secondary battery 19 is detected by the voltage detection circuit 28. When the voltage is higher than 4.8V, OUT of the voltage detection circuit 28 becomes High level and when it is 4.8V or lower. OUT of the voltage detection circuit 28
Becomes the Low level.

The output from OUT of the voltage detection circuit 28 is input to IN13 of the microcomputer 17.

The converter 22 is a DC-DC converter, and operates as a series regulator when the input voltage is higher than the output voltage and as a step-up switching regulator + series regulator when the input voltage is low.

The output voltage can be selected from 5V and 3V, and 5V is output when the input port SEL is at high level, and 3V is output when the input port SEL is at low level.

The converter 22 has an input Vin of 0.9.
When the voltage is V or higher, 5V or 3V is always output from the output Vout. Reference numeral 18 is a voltage detection circuit for resetting the microcomputer 17, and its output RE is RES of the microcomputer 17.
Input to ET.

The voltage of Vout of the converter 22 is 2.7.
When the voltage RE is V or less, RE of the voltage detection circuit 18 is at the low level, and when it becomes larger than 2.7 V, the microcomputer 17 is reset by delaying the time required for resetting the microcomputer 17 and maintaining the low level, and then changing to the high level. Become.

Reference numeral 25 is the pictogram LCD described above, which is controlled by the microcomputer 17.

Reference numeral 26 is a key matrix circuit for scanning various keys in the operation unit 13 (identification of pressed keys), and the pressed keys can be identified by software control of the microcomputer 17.

Reference numeral 30 denotes a mechanical document detection switch (DS) (or reed switch) provided on the document conveyance path.
Is.

Here, the reason why the mechanical original detecting switch is used without using the photo interrupter using the light emitting element for the original sensor is that power is not consumed during the standby for inserting the original.

As a result, it is possible to prevent the secondary battery 19 from being consumed.

Reference numeral 31 is a hooking switch (FS) for performing off-hook or on-hook.

In FIG. 4, reference numeral 60 is a voltage detection circuit for resetting the CPU 2, and its output RE is input to RESET of the CPU 2.

The voltage of + 5V from the main power source 16 is 4.5V.
In the following cases, RE of the voltage detection circuit 60 is at the low level, and when it becomes higher than 4.5 V, it is delayed by the time required for resetting the CPU 2 and maintained at the low level to keep the CPU at the low level.
2 is reset and then becomes High level.

The output from RE is the I of microcomputer 17.
It is also input to N10 and monitored.

Reference numeral 32 is a photocoupler for detecting a calling signal (CI signal). When the calling signal comes through the telephone line 11, the incoming signal (Low level) is inputted to IN12 of the microcomputer 17. There is.

When a call signal comes in during standby, an incoming signal (Low level) is input to the microcomputer 17, and the microcomputer 17 recognizes it and sets OUT5 to High level, that is, sets the PS signal to High level to start the main power source and serialize. CPU through interface sI / O
2 sends the information to CPU 2, and CPU 2 controls each block accordingly.

The telephone 33 is a photocoupler for detecting the off-hook of the telephone 12, and when the telephone 12 is off-hook, the Low level is input to IN11 of the microcomputer 17.

When the telephone 12 is off-hooked in the standby mode, the Low level is input to the microcomputer 17, and the microcomputer 17 recognizes this and sets OUT5 to the High level, that is, sets the PS signal to the High level to activate the main power source, and the serial interface sI CPU through / O
2 sends the information to CPU 2, and CPU 2 controls each block accordingly.

Reference numerals 58 and 59 denote current limiting resistors, and 34 and 3 respectively.
5 is a modular jack.

FIG. 5, FIG. 6, FIG. 7, FIG. 8 and FIG. 9 are flow charts showing the operation of this embodiment, and the operation will be described with reference to these drawings.

FIG. 5 is a flow chart showing the operation of the main power supply 16 at the time of AC input.

When AC input is started (step S10)
1), then IN1 of IC44 is L because of the delay circuit 35
Since it is at the ow level (step S102), OUT1 of the IC44 oscillates accordingly (step S1).
03), the primary side oscillates through the FET 43 to supply power to the secondary side, and the main power supply 16 starts up (step S1).
04).

When the power supply to the secondary side is started, a high level is output from OUT5 of the microcomputer 17 and PS
The signal is input to the main power supply 16 as a signal (step S10).
5).

This PS signal causes the transistor 46 to turn off.
Then, the photo coupler 45 is turned on and the photo coupler 45 is turned on (step S106).
Goes low (step S107), and accordingly OUT1 of the IC44 oscillates (step S10).
8), the primary side oscillates through the FET 43 to supply power to the secondary side (step S109).

Then, maintaining this state, the main power supply 16 continues to supply electric power. The time constant of the delay circuit 35 is set so that IN1 maintains a low level from the time when the AC input is started until the photo coupler 45 is turned on by the PS signal from the microcomputer 17.

When the PS signal becomes low level (step S110), the transistor 46 is turned off and the photocoupler 45 is also turned off, so that IN1 of the IC44 is high.
It becomes the h level (step S111), and accordingly I
C44 sets OUT1 to Low level (step S11
2) As a result, the FET 43 is turned off, the primary side stops oscillating, the power supply to the secondary side is stopped, and the main power supply 16 stops operating (step S113).

When the PS signal becomes High level in this state (step S114), the transistor 46 is turned on and the photocoupler 45 is also turned on (step S115).
IN1 of C44 becomes Low level (step S11)
6).

In accordance with this, OUT1 of 44 oscillates (step S117), the primary side oscillates via the FET 43 to supply power to the secondary side, and the main power supply 16 rises (step S118).

Then, maintaining this state, the main power supply 16 continues to supply electric power.

FIG. 6 is an operation flow of the main power supply controller 15 in the FAX standby state. In FIG. 6, when the AC input is started (step S201), the main power supply 16 first rises (step S202), and the microcomputer 17 is started. Is initialized (step S203) and the CPU 2
Is initialized (step S204), and at the same time, charging of the secondary battery 19 is started (step S205).

When the initialization of the microcomputer 17 is completed, the FAX goes into a standby state.

While the standby state continues, the secondary battery 19 is continuously charged.

If the charging is completed, that is, if the output of the voltage detection circuit 28 becomes High level, or if the timer built into the microcomputer 17 has elapsed for 1 hour, IN13 of the microcomputer 17 is set in the former case. Hig
Since it becomes the h level, the microcomputer 17 outputs OUT accordingly.
5, that is, the PS signal is set to low level and the main power supply 16
Is stopped (step S207), and accordingly, RE of the voltage detection circuit 60 becomes Low level, and the CPU 2
Are reset (step S208).

Then, power supply by only the secondary battery 19 and the solar battery 23 is started (step S209).

In the latter case, an interrupt occurs and accordingly the microcomputer 17 outputs OUT5, that is, the PS signal at L level.
The operation of the main power supply 16 is stopped at the ow level (step S207), and accordingly, the RE of the voltage detection circuit 60 becomes L.
It becomes the ow level and the CPU 2 is reset (step S208).

Then, power supply by only the secondary battery 19 and the solar battery 23 is started (step S209).

In either case, at this time, the secondary battery 19 is also charged with the surplus power of the power supplied by the solar cell 23.

Further, in any case, an extremely low power consumption FAX standby state is entered (step S210).

In the case where the power supplied from the solar cell 23 decreases and the potential becomes lower than that of the secondary battery (step S2
11), the secondary battery 19 is discharged and its voltage is 1.2.
When it becomes V or less (step S212), OUT of the voltage detection circuit 24 becomes Low level and IN of the microcomputer 17
9 becomes Low level, so the ultra-low power consumption FAX standby state is released, and the microcomputer 17 sets OUT5 to H level.
High level, that is, the PS signal is set to High level.

As a result, the transistor 46 is turned on, the photocoupler 45 is turned on, and IN1 of the IC 44 is set to L.
Since it becomes the ow level, according to this, OUT1 of IC44
Oscillates, the primary side oscillates through the FET 43 to supply power to the secondary side, and the main power supply 16 starts up (step S
213).

When the main power supply 16 is turned on, the voltage detection circuit 6
The CPU 2 is initialized by 0, and at the same time, the charging of the secondary battery 19 is started.

As a result, the secondary battery 19 is charged again while the FAX standby state is maintained.

This cycle is repeated.

FIG. 7 shows the FA in the FAX standby state.
This is an interrupt routine at the time of X transmission, and in the figure, F
When a document is inserted in the AX standby state (step S301), the hooking button is pressed (step S302), or the receiver is off-hook (step S303), the document detection switch 3
0, the hooking switch 31, and the photocoupler 33 are turned on, and this ON signal is input to the microcomputer 17 to start an interrupt (step S304), and accordingly, the microcomputer 17 sets OUT5 to the high level, that is, the PS signal to the high level. Photo coupler 45
Turn on.

When the photo coupler 45 is turned on, the IC 44
Causes the primary side to oscillate through the FET 43 and power is supplied to the secondary side to start up the main power source 16 (step S30).
5).

The charging of the secondary battery 19 is started when the main power supply 16 is started (step S306), and the secondary battery 19 is always charged while the main power supply 16 is started (step S306).

Then, this information is sent to the CPU 2 through the serial interface, and thereafter, the operation of the facsimile apparatus 1 is mainly controlled by the CPU 2.

In this state, when the other party's FAX is called (step S307) and the line is captured (step S30)
8) Normal facsimile transmission can be performed (step S3)
09).

When the transmission is completed (step S310) and the line is disconnected (step S311), the information is sent to the microcomputer 17 through the serial interface, and accordingly the microcomputer 17 sets the PS signal to the Low level to operate the main power supply 16. Stop (step S31
2).

Then, the charging of the secondary battery 19 by the main power source 16 is completed (step S313), and the interruption is completed (step S314).

Then, the FAX standby state is set (step S315), 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, and in the figure, F
When the hooking button is pressed in the AX standby state (step S401) or the handset is off-hook (step S402), the hooking switch 3
1, photo coupler 33 is turned on, and this is turned on
A signal is input to the microcomputer 17 and an interrupt is started (step S403), and the microcomputer 17 turns on according to this.
UT5 is High level, that is, PS signal is High
As a level, the photo coupler 45 is turned on.

When the photo coupler 45 is turned on, the IC 44
Causes the primary side to oscillate via the FET 43, power is supplied to the secondary side, and the main power supply 16 starts up (step S40).
4).

When a calling signal is detected (step S405), the photocoupler 32 is turned on, this ON signal is input to the microcomputer 17 to start an interrupt (step S406), and the microcomputer 17 outputs OUT accordingly.
5 is set to the high level, that is, the PS signal is set to the high level, and the photocoupler 45 is turned on.

When the photo coupler 45 is turned on, the IC 44
Causes the primary side to oscillate via the FET 43, power is supplied to the secondary side, and the main power supply 16 starts up (step S40).
7).

In any case, when the main power supply 16 is turned on, the charging of the secondary battery 19 is started (steps S408, S
409), the secondary battery 19 is constantly charged by the main power source 16 while the main power source 16 is on.

Then, this information is sent to the CPU 2 through the serial interface, and thereafter, the CPU 2 mainly controls the operation of the facsimile apparatus 1.

If the hooking button is pressed or the handset is off-hook, a call is made to the other party's FAX (step S410) and the line is captured (step S411), normal facsimile reception is performed (step S412). .

When the ringing signal is detected, the NCU 10 seizes the line (step S411), and the facsimile reception is performed by the automatic reception (step S412).

When the reception is completed (step S413) and the line is disconnected (step S414), the information is sent to the microcomputer 17 through the serial interface, and accordingly the microcomputer 17 sets the PS signal to the Low level to operate the main power supply 16. Stop (step S41)
5).

Then, the charging of the secondary battery 19 by the main power source 16 is completed (step S416), and the interruption ends (step S417).

Then, the FAX standby state is set (step S418), and the process returns to A in FIG.

FIG. 9 is a flow chart showing the operation of the main power source when the AC input is interrupted.

In the same figure, when the AC input is present (step S501), if the AC input is interrupted (step S502), the discharge circuit 64 operates and the capacitor 62
The electric charge stored in is immediately discharged (step S
503).

When the AC input is restored again (step S
504), the IN1 of the IC44 becomes the Low level (step S505), the OUT1 of the IC44 oscillates accordingly (step S506), the primary side of the isolation transformer 39 oscillates through the FET43, and the power is supplied to the secondary side. The main power supply 16 is turned on.

At this time, in the case of the extremely low power consumption FAX standby state, after about 500 ms has elapsed (step S
509) IN1 of IC44 becomes High level (step S510), and accordingly OUT1 of IC44 becomes Low level (step S511), and main power supply 16
Stops its operation (step S512).

[0136] Then, even after the AC input is restored, the ultra low power consumption FA
The X standby state is maintained.

When the FAX is not in the ultra-low power consumption FAX standby state, OUT5 of the microcomputer 17 becomes High level, that is, the PS signal becomes High level, and the photocoupler 45 is turned on (step S514).
Goes low (step S515), and OUT1 of the IC44 oscillates accordingly (step S51).
6), the primary side of the insulating transformer 39 oscillates via the FET 43 and power is supplied to the secondary side.

As a result, the power supply of the main power source 16 is maintained even after the AC input is restored (step S517).

As described above, the discharge circuit 64 is provided, and the discharge circuit operates when the AC input is cut off, so that the capacitor 62 can be immediately operated even when the AC input is interrupted for a short time.
Is discharged and the AC input is restored again, the above 500
The main power supply 16 is always started for ms (time set by the time constant).

By utilizing the rise of the main power supply 16 for about 500 ms, ON / OFF of the main power supply 16 can be freely controlled.

As described above, by providing the discharge circuit, the following effects can be obtained.

(1) When the power supplied from the power supply source is interrupted due to a momentary interruption or the like, the discharge circuit is activated to forcibly be stored in the storage element (capacitor, etc.) that constitutes the delay circuit. The charge can be discharged.

(2) By configuring a discharge circuit using a high-speed switching element such as a transistor, even when power supply from a power supply source is interrupted due to a momentary interruption or the like, a storage element (a capacitor, etc.) that constitutes a delay circuit. ), The electric charge stored in can be discharged immediately.

(3) From (1) and (2), even when a short interruption occurs, the secondary circuit is always used for the fixed time by the delay circuit when the power supply from the power supply source is restored again. Power is supplied to the side.

(4) As shown in (3), when the power supply is started from the power supply source including the recovery from the momentary interruption, the delay circuit always sends the power to the secondary side for a certain time. Since power is supplied, there is no need to worry about the system malfunctioning.
The main power supply can always be controlled accurately.

(5) Since the delay circuit can be composed of only a resistor and a storage element (capacitor, etc.), it can be realized at low cost.

[0147]

According to the first and eighth aspects of the invention, when the power supply from the power supply source is interrupted, the storage element for delaying the control signal to the switching control section is discharged. You can prevent accidental electric shock during inspection.

According to the second aspect, after the power supply from the power supply source is started, the power is automatically supplied for a fixed time, so that the power can be automatically supplied for the time required for starting the apparatus.

According to the third and fourth aspects, the power source is turned on or off by an on signal or an off signal from the outside after a lapse of a certain period of time. Can be turned on or off.

According to the fifth aspect, since the delay circuit is the resistor and the capacitor, the delay circuit can be constructed at low cost.

According to the sixth aspect, since the off signal does not consume power, the power consumption is further reduced during the off period.

According to the seventh aspect of the invention, since the discharging circuit uses the high speed switching element, the electricity accumulating element can be discharged in a short time, and the electricity accumulating element can be sufficiently discharged even if the power supply source is momentarily cut off. Can be discharged.

[Brief description of drawings]

FIG. 1 is a simplified circuit diagram of a power supply device according to an embodiment.

FIG. 2 is a block diagram of a facsimile apparatus of this embodiment.

FIG. 3 is a simplified circuit diagram of a main power supply control unit of this embodiment.

FIG. 4 is a simplified configuration diagram of a network control unit (NCU) and its periphery, and a simplified circuit diagram of a CPU and its periphery.

FIG. 5 is a flowchart showing the operation of the power supply device of this embodiment.

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

FIG. 7 is a flowchart showing an interrupt routine at the time of FAX reception in the standby state of the facsimile apparatus of this embodiment.

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

FIG. 9 is a flowchart showing the operation of the main power supply when an AC input is interrupted.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Facsimile device 2 CPU 15 Main power supply control unit 16 Main power supply 17 8-bit one-chip microcomputer 19 Capacitor type secondary battery 23 Solar cell 35 Delay circuit 39 composed of resistor and capacitor 39 Primary and secondary insulation transformers (Output transformer) 43 FET (Switch means) 63 Switching controller 64 Discharge circuit

Claims (8)

[Claims] 1. An output transformer that is supplied with power from a power supply source and that generates AC power on the secondary side by oscillation of the primary side, switch means for controlling oscillation of the primary side of the output transformer, and an external device. A switching control unit capable of controlling the switch means, a delay circuit using a storage element for delaying a control signal from the outside to the switching control unit, and power supply from a power supply source being interrupted. And a discharge circuit for discharging the electric charge stored in the storage element. 2. The switching control unit according to claim 1, wherein the delay circuit automatically controls the switch means for a certain period of time after the power supply from the power supply source is started. A power supply device characterized in that it oscillates on the primary side. 3. The primary of the output transformer according to claim 2, wherein the switching control unit oscillates the switch means in response to an ON signal from the outside during the fixed time and the fixed time elapses. Power supply device characterized by continuing oscillation on the side. 4. The primary of the output transformer according to claim 2, wherein the switching control unit oscillates the switch means in response to an ON signal from the outside during the fixed time and the fixed time elapses. Oscillation of the primary side of the output transformer is continued by oscillating or stopping the switching means in accordance with an ON signal or an OFF signal from the outside after the predetermined time has elapsed. A power supply device characterized by controlling. 5. The power supply device according to claim 1, wherein the delay circuit is configured by using a resistor and a capacitor. 6. The off signal according to claim 4, wherein the switch signal is stopped to stop the oscillation of the primary side of the output transformer and to stop the power supply to the secondary side of the output transformer. A power supply device characterized by being a signal that does not consume power. 7. The power supply device according to claim 1, wherein the discharge circuit is configured by using a high speed switch element. 8. A power supply which is supplied with power from a power supply source and supplies power to the apparatus main body, power supply control means for turning on and off the power supply, and power on for the power supply control means.
A storage element for delaying an instruction input for instructing to turn off,
A power supply device, comprising: means for detecting that power supply from the power supply source is interrupted and discharging the power storage element in response to the detection.