JP5280234B2 - Electronic equipment power supply - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure supply of DC power supply to another load even if a fault occurs in a part of a plurality of loads connected to a DC power supply part that converts an AC voltage from an AC power supply into a DC voltage. <P>SOLUTION: A first DC power supply part 1 converts an AC voltage from an AC power supply into a first DC power supply voltage so as to output the first DC power supply voltage. A second DC power supply part 5 converts an AC voltage from the AC power supply into a second DC power supply voltage so as to output the second DC power supply voltage. First load parts 3, 7 are supplied with the first/second DC power supply voltages from the first/second DC power supply parts 1, 5. A third load part 13 is connected to a power supply line 15 connecting from the first DC power supply part 1 to the first load part 3. A detecting part 17 detects an abnormality of the power supply line 15. A switch part SW switches the first DC power supply voltage to the second DC power supply voltage on the basis of the detection result of the detecting part 17 and supplies the second DC power supply voltage to the third load part. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a power supply device for an electronic apparatus, and more particularly to an improvement of a power supply apparatus that is suitable for being mounted in an electronic apparatus such as an image forming apparatus, for example, a copying machine, a facsimile machine, or a multi-function peripheral (MFP).

  In this type of image forming apparatus, in addition to a sheet conveying roller, a motor for driving an image forming drum, a solenoid for displacing these rollers, a high-voltage DC power source of about 24 V applied to a mechanism unit driven by a high-voltage power source, a CPU, In general, two power sources are required, such as a 3.3V or 5V low-voltage DC power source applied to an electronic circuit board on which various semiconductor elements, sensors, and the like are mounted. The high-voltage DC power supply is a power system, and the low-voltage DC power supply is a signal system.

  Conventionally, the power system high-voltage DC power supply and the signal system low-voltage DC power supply are separated, and a power converter high-voltage DC power supply is adopted by adopting a two-converter configuration in which each AC power supply is obtained from an AC power supply by an AC / DC converter. This makes it possible to protect signal systems that are important for device control from power supply fluctuations and sudden shutdowns.

  However, from the viewpoint of device cost constraints and miniaturization, a configuration that forms a signal low voltage DC power source based on a DC power source from a power high voltage DC power source, that is, one converter in which a power system and a signal system are mixed. There is a request to adopt the method.

  For example, as shown in FIG. 2, a first DC power supply unit 1 is formed from an AC / DC converter that converts an AC power supply of AC100V into a DC power supply voltage of 24V, and the first DC power supply unit 1 has a voltage of 24V. A DC / DC converter 3 for converting a DC power supply voltage to a DC power supply voltage of 5V is connected. If necessary, the DC / DC converter 3 is connected to a second DC power supply unit 5 similar to the first DC power supply unit 1. A configuration for connecting the same DC / DC converter 7 is provided. Reference numerals 9 and 11 in FIG. 2 denote first and second circuit boards on which the DC / DC converters 3 and 7 are mounted.

  The first and second DC power supply units 1 and 5 are power systems, and a DC power supply voltage of 24 V is supplied to the motor 13 and a mechanism unit (not shown) in addition to the DC / DC converters 3 and 7. Reference numeral 7 denotes a signal system, and a DC power supply voltage of 5 V is supplied to a circuit portion of a device (not shown).

  If the conventional structure of the 1 converter system is shown, there exists an image processing apparatus of Unexamined-Japanese-Patent No. 2003-266878 (patent document 1).

This patent document 1 is an image forming apparatus having two types of operation modes, ie, a normal image forming mode and a power saving mode with reduced power consumption. A commercial AC current is converted into a direct current via an AC / DC converter. A power supply unit having a 24V output for conversion output and a 5V output for transforming the direct current converted by the AC / DC converter via the DC / DC converter is provided. In the power saving mode, an output current of 24V output is supplied as a power source. Cut off at the output part of the unit and use the current detection circuit to change the voltage of the current output from the 24V output to a voltage that maximizes the conversion efficiency of the AC / DC converter. This is a reduction from the one-converter type power supply device.
JP 2003-266878 A

  However, in Patent Document 1 described above, in the power system and signal system mixed configuration, the power consumption in the energy saving mode is simply reduced, and there is a problem with the DC / DC converter and other loads connected to the AC / DC converter. When this occurs, it is difficult to achieve power supply safety to other components connected to the AC / DC converter.

  For example, in FIG. 2 described above, when the motor 13 is connected to the first DC power supply unit 1 and the power supply line 15 of the DC / DC converter 3, and the motor 13 is damaged and the 24V power supply line 15 is short-circuited, It is easy to stop the operation when the DC / DC converter 3 detects the abnormality.

  For this reason, in the first circuit board 9, for example, a storage unit (not shown) such as a RAM that receives power supply from the DC / DC converter 3 stops operating, and all stored data is lost. It is easy to generate.

  Therefore, the inventor carefully observed and studied the configuration of the power supply device of the electronic device. As a result, in the electronic device such as the image forming apparatus, the first and second DC power supply units 1 and 2 of the plurality of power systems as described above. The present invention was completed by paying attention to the point 5.

  The present invention has been made to solve such a problem, and even if some of the plurality of loads connected to the DC power supply unit that converts and outputs the AC power supply to the DC power supply voltage are defective, It is an object of the present invention to provide a power supply device for an electronic device capable of supplying a DC power supply voltage to a load.

In order to solve such a problem, a power supply device for an electronic apparatus according to claim 1 of the present invention includes a first DC power supply unit that converts and outputs a first DC power supply voltage from an AC power supply, and a first DC power supply unit that converts the first DC power supply voltage from the AC power supply . A second DC power supply section that converts and outputs a second DC power supply voltage at the same level as the first DC power supply voltage, and the first DC power supply voltage is supplied from the first DC power supply section, and the supplied first DC power supply voltage is supplied . The first load unit that converts and outputs a DC power supply voltage lower than the DC power supply voltage of the first DC power supply, and the second DC power supply voltage is supplied from the second DC power supply unit, and the DC power is lower than the supplied second DC power supply voltage. a second load portion which the power supply voltage converted output, a detector for detecting the first is inserted in series from a DC power supply unit to the power line between the first load portion abnormality of the power supply line, the first 1 connected to the power line between the DC power supply unit and the detection unit A third load unit driven by a DC power supply voltage of 1, and a power supply line between the detection unit and the first load unit is inserted in series with the detection unit, resulting from a failure of the third load unit And a switch unit for switching and supplying the second DC power supply voltage from the second DC power supply unit to the first load unit based on the abnormality detection result by the detection unit .

A power supply device for an electronic device according to a second aspect of the present invention includes a first circuit board on which the first load unit, the storage unit, and the control circuit are mounted. The first circuit board includes a predetermined circuit board. When there is no operation input over a period of time, the power supply to a circuit other than the circuit required for activation on the first circuit board is shut off, and a sleep mode function is restarted when there is an operation input. It has a function of saving setting data and image data in the storage unit at the time of migration .

According to a third aspect of the present invention, there is provided a power supply device for an electronic device , wherein when the detection unit detects an abnormality, the first circuit board performs the same operation as the sleep mode function based on the detection signal, and sets them. After the data and image data are stored in the storage unit, the entire apparatus is shut down .

  In such a power supply device for an electronic device according to claim 1 of the present invention, when the detection unit detects an abnormality in the power supply line between the first DC power supply unit and the first load unit, the switch is based on the detection result. Since the unit switches the first DC power supply voltage to the second DC power supply voltage and supplies the first DC power supply voltage to the first load unit, even if there is an abnormality in the power supply line from the first DC power supply unit, the second DC power supply The second DC power supply voltage is switched and applied from the unit to the first load unit, and the operation of the first load unit is ensured.

Power supply of an electronic device according to claim 1 of the present invention, the first load portion, because a function to lower the supplied their first or second DC power supply voltage, the first load portion It is easy to protect the signal system components important for control, which are often connected to.

According to a first aspect of the present invention, there is provided a power supply device for an electronic device, wherein the third load section is driven by the first DC power supply voltage from the first DC power supply section to the power supply line between the first load sections. Therefore, even if there is a malfunction in the third load section and there is an abnormality in the power line between the first DC power supply section and the first load section, it is applied to the first load section and operates. Since the first and second DC power supply units output the same level of DC power supply voltage, the first load unit is the same as when the DC power supply voltage is applied from the first DC power supply unit. Therefore, it is easy to ensure an accurate operation.

According to the second and third aspects of the present invention, when there is no operation input over a predetermined period, the power supply device for the electronic device cuts off the power supply to a circuit other than the circuit necessary for starting on the first circuit board. Since it has a sleep mode function that restarts when there is an error, the setting data and image data are saved in the storage unit when the sleep mode function is shifted, so that data loss can be prevented and the detection unit is abnormal Is detected, the setting data and the image data are saved in the storage unit after being saved in the same manner as the sleep mode function, so that the shutdown is possible.

  Embodiments of a power supply device for an electronic apparatus according to the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the part which is common in a prior art example.

  FIG. 1 is a schematic block diagram showing an embodiment of a power supply device according to the present invention.

  In FIG. 1, a first DC power supply unit 1 is formed of an AC / DC converter that converts a commercial AC power supply of AC 100V into a DC power supply voltage, and has a function of outputting a first DC power supply voltage of 24V, for example. The power supply line 15 is connected to the motor 13 and the detection unit 17.

  The second DC power supply unit 5 is an AC / DC converter that has the same configuration as that of the first DC power supply unit 1 and converts AC 100 V commercial AC power into DC power supply voltage. It has a function of outputting a voltage and is connected to the DC / DC converter 7 via a power supply line 19.

  For example, the first and second DC power supply units 1 and 5 reduce the voltage with a transformer (not shown) to rectify and smooth the voltage, and use a constant voltage element to convert the first and second DC power supply voltages of 24 V to a constant voltage. A constant power supply circuit that makes the output voltage 24 V constant by a known switching power supply circuit, and functions as a power system.

  When the power supply apparatus of the present invention is mounted on an image forming apparatus, the first and second DC power supply voltages from the first and second DC power supply units 1 and 5 are supplied from a DC / DC converter 3, as will be described later. 7. In addition to being supplied to the motor 13, it is supplied and applied to a heater (not shown), a mechanism displacement solenoid, and a mechanism driven by a high voltage power source.

  A motor 13 connected via a power supply line 15 extending from the first DC power supply unit 1 is a DC stepping motor or a DC brushless motor, and is used, for example, for driving a sheet conveying roller or an image forming drum in an image forming apparatus. The

  The detection unit 17 inserted in the middle of the power supply line 15 detects an abnormality of the power supply line 15, for example, that the DC voltage has dropped below a predetermined level, and has a function of outputting a detection signal to the switch unit SW. doing.

  As a form in which the DC voltage level of the power supply line 15 is lowered, there are various causes other than a short circuit due to the breakage of the motor 13 and a malfunction in the operation of the first DC power supply unit 1.

  The detection unit 17 can also be formed so as to detect an overcurrent of the power supply current flowing through the power supply line 15 as an abnormality of the power supply line 15.

  The switch unit SW is an electronic switch or a mechanical switch having one circuit and two contacts, for example, a movable contact P0 and fixed contacts P1 and P2 that are selectively connected to the movable contact P0, and a power source extending from the first DC power source unit 1 The fixed contact P1 is connected to the line 15, the fixed contact P2 is connected to the power supply line 19 extending from the second DC power supply unit 5, and the movable contact P0 is connected to the DC / DC converter 3.

  The switch unit SW is normally connected to the movable contact P0 and the fixed contact P1 so that the first DC power supply voltage from the first DC power supply unit 1 is supplied to the DC / DC converter 3 and is detected. When the detection signal is output from the unit 17, the second DC power supply voltage from the second DC power supply unit 5 is supplied to the DC / DC converter 3.

  The DC / DC converter 3 is a known voltage converter that converts a DC power supply voltage 24V of 24V to a DC power supply voltage of 5V or 3.5V lower than this, and functions as a first load unit. Arranged on the circuit board 9.

  Similarly to the DC / DC converter 3, the DC / DC converter 7 is a known voltage converter that converts a DC power supply voltage of 24V to a DC power supply voltage of, for example, 5V or 3.5V, and serves as a second load unit. It functions and is arranged on the second circuit board 11.

  The DC / DC converters 3 and 7 are signal systems, and a DC power supply voltage of 5 V or 3.5 V is applied to a CPU, a storage unit, and other control circuits (not shown) arranged on the first and second circuit boards 9 and 11. Supply.

  The first circuit board 9 is not shown in the figure, but when there is no operation input for a predetermined period (for example, several minutes), the power supply to the circuit other than the circuit necessary for starting on the first circuit board 9 is cut off. In addition, it has a configuration having a so-called sleep mode function that restarts when an operation input is received, and has a function of saving setting data and image data in the storage unit when the sleep mode function is shifted to, for example. .

  An image forming apparatus equipped with the power supply apparatus of the present invention includes a document reading unit that optically reads a surface image from a document to generate electronic image data, a storage unit that stores the image data and an operation program, and operation of the device It has an operation panel unit that receives status indications and device operation instructions, a transfer fixing unit that develops the image data into print image data and transfers and fixes the toner image, a print control unit that controls these, etc. Since it is not a main part of the invention, illustration and explanation are omitted.

  Next, the operation of the power supply device of the present invention will be described briefly.

  In FIG. 1, when AC 100V AC power is applied to the first and second DC power supply units 1 and 5, the first and second DC power supply units 1 and 5 have AC 100V AC voltage of 24V The first DC power supply voltage of 24V is converted to the second DC power supply voltage and applied to the motor 13 and the fixed terminal P1 of the switch unit SW, while the second DC power supply voltage of 24V is applied to the DC / DC converter 7 and the switch. Supplied to the fixed terminal P2 of the part SW.

  Normally, since the movable contact P0 and the fixed contact P1 of the switch unit SW are connected, the first DC power supply voltage from the first DC power supply unit 1 is supplied to the DC / DC converter 3.

  Therefore, since the DC / DC converters 3 and 7 as the first and second load units perform voltage conversion operation and output a low-voltage DC power supply voltage, the first and second circuit boards 9 and 11 operate normally. However, the motor 13 as the third load unit is also driven to rotate normally.

  Here, for example, when the motor 13 is damaged and the power supply terminals are short-circuited, the DC power supply voltage level of the power supply line 15 decreases or becomes “0 level”, and the detection unit 17 detects it and outputs a detection signal. Output to the switch SW.

  In the switch unit SW, the movable terminal P0 is thereby switched to the fixed terminal P2 side, and the DC / DC converter 3 has the second DC power supply instead of the first DC power supply voltage from the first DC power supply unit 1. The second DC power supply voltage from the unit 5 is switched and supplied.

  Therefore, the DC / DC converter 3 operates normally by the second DC power supply voltage from the second DC power supply unit 5, and the operation of the first circuit board 9 is also continued.

  The switch SW is configured such that the movable terminal P0 returns to the fixed terminal P1 side by a reset mechanism (not shown) or the like.

  As described above, the power supply device for the electronic device according to the present invention includes the first DC power supply unit 1 that converts and outputs the first DC power supply voltage from the AC power supply, and the first DC power supply voltage from the AC power supply at the same level as the first DC power supply voltage. The second DC power supply unit 5 that converts and outputs the two DC power supply voltages, and the first DC power supply voltage is supplied from the first DC power supply unit 1 and the DC power supply voltage lower than the first DC power supply voltage is converted and output. The DC / DC converter 3 to be supplied, the DC / DC converter 7 to which the second DC power supply voltage is supplied from the second DC power supply unit, and the power line 15 of the DC / DC converter 3 from the first DC power supply unit 1. , A detection unit 17 that detects that the voltage level of the power supply line 15 has dropped below a predetermined level, and a second detection result from the first DC power supply voltage based on the detection result of the detection unit 17. DC power supply voltage A switch portion SW is supplied switched to C / DC converter 3, which comprises a.

  Therefore, for example, even if the motor 13 is defective and the voltage level of the power supply line 15 from the first DC power supply unit 1 is lowered, the second DC power supply voltage is supplied from the second DC power supply unit 5 to the DC / DC converter. 3 is switched and applied, and the operation of the DC / DC converter 3 is ensured.

  In addition, since the DC / DC converter 3 has a function of reducing the supplied first or second DC power supply voltage, it is important for control of, for example, a storage unit or a CPU that is driven by the DC / DC converter 3. Protection of various signal system components is easy.

  Therefore, when the detection unit 17 detects an abnormality, the operation of the DC / DC converter 3 is ensured, while the first circuit board 9 is operated in the same manner as the sleep mode transition based on the detection signal from the detection unit 17. The setting data and the image data can be saved in the storage unit. The first circuit board 9 may be formed in accordance with this, and then the entire apparatus can be shut down, and a configuration that issues an alarm based on the detection signal from the detection unit 17 is also possible.

  In such a configuration, after processing the data being processed based on the detection signal from the detection unit 17, it is possible to shut down and prevent data loss and to notify the outside of an abnormal state or failure location. It is.

  Further, since the first and second DC power supply units 1 and 5 output the first and second DC power supply voltages at the same level, the DC / DC converter 3 can be switched even if the power supply to the DC / DC converter 3 is switched. The DC converter 3 is in the same operation state as the operation by the application of the first DC power supply voltage from the first DC power supply unit 1, and it is easy to ensure an accurate operation.

  In the power supply device for an electronic apparatus according to the present invention, the load unit connected to the first and second DC power supply units 1 and 5 is not limited to the DC / DC converters 3 and 7, and various load circuits may be used. Is possible.

  In the electronic apparatus power supply device of the present invention, a motor 13 is connected as a third load unit in addition to the DC / DC converter 3 as a load unit connected to the power supply line 15 from the first DC power supply unit 1. Although the configuration has been described, a configuration in which a load other than the motor 13 is connected as the third load unit is also possible.

  Furthermore, in the power supply device for an electronic apparatus according to the present invention, the first and second DC power supply units 1 and 5 are not limited to the configuration for outputting the first and second DC power supply voltages at the same level, and are different from each other. The first and second DC power supply voltages can be output.

It is a block diagram which shows embodiment of the power supply device of the electronic device which concerns on this invention. It is a block diagram which shows the power supply device of the conventional electronic device.

DESCRIPTION OF SYMBOLS 1 1st DC power supply part 3 DC / DC converter (1st load part)
5 Second DC power supply unit 7 DC / DC converter (second load unit)
9 First circuit board 11 Second circuit board 13 Motor (third load section)
15, 19 Power line 17 Detector SW Switch P0 Movable terminals P1, P2 Fixed terminal

Claims (3)

A first DC power supply unit that converts and outputs a first DC power supply voltage from the AC power supply;
A second DC power supply unit that converts and outputs a second DC power supply voltage at the same level as the first DC power supply voltage from the AC power supply;
A first load unit which is supplied with the first DC power supply voltage from the first DC power supply unit and converts and outputs a DC power supply voltage lower than the supplied first DC power supply voltage ;
A second load section that is supplied with the second DC power supply voltage from the second DC power supply section and converts and outputs a DC power supply voltage lower than the supplied second DC power supply voltage ;
A detection unit that is inserted in series from a first DC power supply unit to a power supply line between the first load units and detects an abnormality of the power supply line;
A third load unit connected from the first DC power supply unit to the power supply line between the detection units and driven by the first DC power supply voltage;
Based on the inserted into the detector in series with the power supply line between said detector first load portion, the third of the abnormality detection by the detecting unit due to failure of the load unit results, the A switch unit for switching and supplying the second DC power source voltage from the second DC power source unit to the first load unit;
A power supply device for electronic equipment, comprising: A first circuit board on which the first load unit, a storage unit, and a control circuit are mounted; and when the first circuit board has no operation input over a predetermined period of time, the first circuit board is mounted on the first circuit board; Has a sleep mode function that shuts off the power supply to circuits other than those required for startup and restarts when there is an operation input, and saves setting data and image data in the storage unit when the sleep mode function is shifted The power supply device for an electronic apparatus according to claim 1, having a function. The first circuit board performs the same operation as the sleep mode function based on the detection signal when the detection unit detects an abnormality, and saves the setting data and the image data in the storage unit. The power supply device for an electronic device according to claim 2, having a function of shutting down the entire device.

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