JP2008199729A - Power supply unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent malfunction of a power supply unit by preventing a counter electromotive force induced in a first load section, when power supply is interrupted from being supplied to other load section. <P>SOLUTION: A power supply section 13 supplying DC power is connected with a first load section 3, and constant voltage control sections (second load section, third load section) 9 and 11. A reverse current blocking diode D3 is inserted into the first load section 3 from the joint of the first load section 3 and the constant voltage control sections (second load section, third load section) 9 and 11, to block the output current from the first load section 3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a power supply apparatus, and more particularly to an improvement of a power supply apparatus that is suitable for being mounted in an image forming apparatus such as a copying machine, a printer, or a multifunction peripheral (MFP).

  For example, a configuration as shown in FIG. 4 is known as a power supply device in an image forming apparatus such as a copying machine.

  That is, the bridge-type rectifier diode D1 rectifies the alternating current from the alternating current power source A and smoothes it with the smoothing capacitor C1, and the smoothing current is switched with the FET transistor Q1 to supply power from the primary side T1 to the secondary side T2 of the transformer T. This is rectified by the rectifier diode D2 and smoothed by the smoothing capacitor C2, and the smoothed DC power supply voltage (for example, 24V) is detected as the connection voltage of the dividing resistors R1 and R2, and the detected value is a constant voltage. The control unit 1 outputs a PWM control signal whose deviation is smaller than the reference value to the transistor Q1, thereby switching the transistor Q1 so that the rectified and smoothed voltage on the secondary side T2 of the transformer T is stabilized. Has been.

  In addition to the 24V system load unit 3, for example, a constant voltage control unit 5 that converts DC 24V to 5V and a constant voltage control unit 7 that converts DC 24V to 3.3V are connected to both ends of the smoothing capacitor C2, for example. A 5 V system load unit 9 is connected to the constant voltage control unit 5, and a 3.3 V system load unit 11 is connected to the constant voltage control unit 7.

  However, in recent years, in an image forming apparatus, for example, back electromotive force (regenerative energy) generated in the process of stopping a motor connected to the 24V system load unit 3 is stored in a storage battery or the like and is used to save power. Proposals have been made.

  As this type of technology, for example, Japanese Patent Laid-Open No. 2005-278348 (Patent Document 1) has been proposed.

This Patent Document 1 discloses a DC motor that drives a predetermined load, a control circuit that drives and controls the DC motor at a predetermined rotational speed, and a battery that stores electric power generated when the DC motor is regeneratively braked by the control circuit. And a storage power supply circuit that supplies the power stored in the storage device when the DC motor is started, and the regenerative energy from the storage device is effectively used during the movement of the motor to reduce the supply power to the image forming apparatus. The reduction can be achieved.
JP 2005-278348 A

  However, in Patent Document 1 described above, the electric power from the battery is only used at the time of starting the motor to improve the energy efficiency, and there is room for further improvement in order to improve the energy efficiency.

  In addition, when regenerative energy is applied to the power supply device, there is a concern that the output power supply voltage to the load side may fluctuate and cause a malfunction of the control system. From this point of view, improvement has been desired.

  That is, in the power supply device shown in FIG. 4, when the power is turned off and turned off, the power supply voltage to the 24V system load unit 3, the 5V system load unit 9 and the 3.3V system load unit 11 as shown in FIG. However, when regenerative energy is applied to the constant voltage control unit 5 and the constant voltage control unit 7 from the motor of the 24V system load unit 3, for example, they re-activate to temporarily increase the power supply voltage. Therefore, there is a concern that the 5V system load unit 9 and the 3.3V system load unit 11 operate again and malfunction.

  The present invention has been made to solve such a problem, and an object thereof is to provide a power supply device capable of preventing malfunction due to regenerative energy.

  In order to solve such a problem, a first configuration according to the power supply device of the present invention includes a power supply unit that supplies DC power, a first load unit connected to the power supply unit, and the power supply A second load unit connected to the first load unit together with the first load unit, and the first load unit and the second load unit from the connection point between the first load unit and the first load unit, And a current blocking unit that blocks the flow of output current from one load unit.

  In the first configuration according to the present invention, a configuration in which the first load section generates an output current from a built-in motor is also possible.

  In the first configuration according to the present invention, a configuration in which the second load unit operates with a power supply voltage lower than that of the first load unit is also possible.

  A second configuration according to the power supply device of the present invention includes a power supply unit that supplies DC power, a first load unit connected to the power supply unit, and a first load unit with respect to the power supply unit. A second load unit connected together with the regenerative energy recovery unit for recovering electrical energy due to the operation of the device on which the device is mounted, and the output unit is connected to the first and / or second load unit And a regenerative energy recovery unit.

  In the second configuration according to the present invention, a configuration in which the regenerative energy recovery unit recovers electric energy from a motor built in the device is also possible.

  In the second configuration according to the present invention, a configuration in which the second load unit operates with a power supply voltage lower than that of the first load unit is also possible.

  In the second configuration according to the present invention, a configuration in which the regenerative energy recovery unit outputs power to the second load unit to compensate for fluctuations in the power supply voltage of the second load unit is also possible.

  In the first configuration according to the power supply device of the present invention, the first load unit and the second load unit are connected to the power supply unit that supplies the DC power, and the first and second load units are connected. Since the current blocking unit for blocking the flow of the output current from the first load unit is inserted from the connection point to the first load unit side, the second load due to the output current from the first load unit is inserted. It is possible to prevent malfunction of the part.

  In the first configuration according to the present invention, in the configuration in which the first load unit generates an output current from the built-in motor, in particular, the malfunction of the second load unit due to the output current from the motor is surely prevented. It becomes possible.

  In the first configuration according to the present invention, the configuration in which the second load unit operates with a power supply voltage lower than that of the first load unit is particularly useful for preventing malfunction of the second load unit.

  Further, in the second configuration according to the power supply device of the present invention, the first load unit and the second load unit are connected to the power supply unit that supplies the DC power, and the operation of the device on which the device is mounted is performed. The electric energy from the regenerative energy recovery unit that recovers the electric energy is output to the first and / or second load units, and the regenerative energy can be used efficiently.

  In the second configuration according to the present invention, in the configuration in which the regenerative energy recovery unit recovers electrical energy from the motor built in the device, the regenerative energy from the motor can be efficiently used.

  In the second configuration according to the present invention, in the configuration in which the second load unit operates with a power supply voltage lower than that of the first load unit, it is easy to stabilize the power supply voltage of the second load unit. is there.

  In the second configuration according to the present invention, in the configuration in which the regenerative energy recovery unit outputs power supply power that compensates for fluctuations in the power supply voltage of the second load unit to the second load unit, in particular, It is easy to stabilize the power supply voltage of the load section.

  Embodiments of a power supply apparatus according to the present invention will be described below with reference to the drawings. Parts common to the conventional example are denoted by the same reference numerals.

  FIG. 1 is a circuit diagram showing an embodiment of a first configuration according to the power supply apparatus of the present invention.

  In FIG. 1, a smoothing capacitor C1 and one end of a primary side T1 of a transformer T are connected to one output terminal of a bridge-type rectifier D1 connected to an external AC power source A. One end is connected to the drain of the FET transistor Q1, and the other end of the source of the transistor Q1 and the smoothing capacitor C1 is connected to the other output terminal of the rectifier D1.

  The transistor Q1 has an output of a constant voltage control unit 1 to be described later connected to the gate, and the DC power rectified and smoothed by the rectification unit D1 and the smoothing capacitor C1 has a high frequency, for example, by a PWM control signal from the constant voltage control unit 1. Switching is performed at 100 KHz and transmitted from the primary side T1 of the transformer T to the secondary side T2. The constant voltage control unit 1 will be described later.

  A smoothing capacitor C2 and a series circuit of resistors R1 and R2 are connected in parallel to both ends of the secondary side T2 of the transformer T via a rectifier diode D2.

  The rectifier diode D2 and the smoothing capacitor C2 rectify and smooth the power supply current induced on the secondary side T2 of the transformer T and output a DC voltage, for example, 24V. The series circuit of the resistors R1 and R2 is rectified and smoothed. The power supply voltage is detected at the connection point of the resistors R1 and R2, and the connection point of the resistors R1 and R2 is connected to the constant voltage control unit 1.

  The constant voltage control unit 1 outputs a PWM control signal whose duty ratio is changed so that the voltage at the connection point of the resistors R1 and R2 becomes a predetermined voltage to the gate of the transistor Q1, and the connection point between the resistors R1 and R2 A function for stabilizing the power supply voltage supplied to the gate of the transistor Q1 by outputting a PWM control signal having a large duty ratio if the voltage of the transistor is smaller than a predetermined reference value, and outputting a PWM control signal having a small duty ratio if the voltage is larger than the reference value. have.

  That is, the constant voltage control unit 1 has a control function of stabilizing the power supply voltage by transmitting to the secondary side T2 of the transformer T by feedback control from the secondary side T2 of the transformer T.

  For example, a 24V system load unit 3 as a first load unit is connected to both ends of the smoothing capacitor C2 (series circuit of resistors R1 and R2) via a backflow blocking diode D3, and the constant voltage control unit 5 and the constant voltage Each control unit 7 is also connected.

  The 24V system load unit 3 has a motor (not shown) in the image forming apparatus and is a load circuit that bears a part of the function of the image forming apparatus. The backflow prevention diode D3 has an output current that is output during regeneration of the motor. It functions as a current blocking unit that blocks the flow to the smoothing capacitor C2 side, that is, the constant voltage control unit 5 and the constant voltage control unit 7 side.

  The constant voltage control unit 5 and the constant voltage control unit 7 are DC-DC converters that generate a DC voltage of 5 V or 3.3 V from a DC voltage of 24 V rectified and smoothed by the rectifier diode D2 and the smoothing capacitor C2, respectively. The 5V system load unit 9 and the 3.3V system load unit 11 are connected.

  The 5V system load unit 9 is, for example, a logic system control circuit that has another function in the image forming apparatus, and the 3.3V system load unit 11 is, for example, a sensor system control circuit that has another function in the image forming apparatus.

  The constant voltage control unit 5 and the 5V system load unit 9 form a second load unit, and the constant voltage control unit 7 and the 3.3V system load unit 11 form a third load unit.

  Next, the operation of the first configuration according to such a power supply device will be described.

  As in the conventional example, this operation is performed by rectifying the AC power from the AC power source A with the rectifier diode D1 and smoothing it with the smoothing capacitor C1, and switching the smoothed power with the FET transistor Q1 and switching from the primary side T1 to the transformer T. This is transmitted to the next side T2, rectified by the rectifier diode D2, smoothed by the smoothing capacitor C2, and the smoothed power supply voltage is detected as a connection point voltage of the dividing resistors R1 and R2, and the detected value is a constant voltage control unit. 1, the transistor Q1 is switched based on a PWM control signal whose deviation is smaller than the reference value, and the rectified smoothing voltage on the secondary side T2 of the transformer T is stabilized.

  The rectifier diode D1 and the smoothing capacitor C1, and the rectifier diode D2 and the smoothing capacitor C2 together form a power supply unit 13.

  The DC voltage 24V across the smoothing capacitor C2 is supplied to the 24V system load unit 3 through the diode D2, and the motor and the like in the image forming apparatus are driven and controlled, while the constant voltage control unit 5 and the constant voltage control unit 7 are controlled. Is converted to DC 5V or 3.3V and supplied to the 5V system load unit 9 or 3.3V system load unit 11, and the logic system control circuit or the sensor system control circuit operates.

  When the AC power from the AC power source A to the rectifier diode D1 is turned off and turned off, the power source power is not transmitted from the primary side T1 to the secondary side T2 of the transformer T, and the 24V system load unit 3, 5V system Supply to the load section 9 and the 3.3V system load section 11 is cut off and the load drops.

  At this time, the counter electromotive force (regenerative energy) generated when the rotation of the motor in the 24V system load unit 3 is stopped is applied from the 24V system load unit 3 to the diode D3. Since this diode D3 is a backflow prevention unit, the constant voltage Since it does not flow to the control units 5 and 7, it is not supplied to the 5V system load unit 9 and the 3.3V system load unit 11, and as shown in FIG. 2A, the 5V system load unit 9 and the 3.3V system load unit 11 are not supplied. The power supply voltage decreases and disappears after a predetermined period.

  As described above, the first configuration of the power supply device of the present invention includes the power supply unit 13 that rectifies and smoothes the AC power supply, and the 24V system load unit (first load unit) 3 connected to the power supply unit 13. The 24V system load unit 3 and the 5V system load unit (second load unit) 9 and 3.3V system load unit (third load unit) 11 connected to the power supply unit 13 are included. 24V system load unit 3, 5V system load unit 5 and 3.3V system load unit 11 is inserted into the 24V system load unit 3 side from the connection point to block the flow of output current output from the 24V system load unit 3 And a diode (current blocking unit) D3.

  Therefore, even if the back electromotive force (regenerative energy) from the motor generated in the 24V system load unit 3 is output after the external power supply is turned off, it is blocked by the current blocking diode D3, and the 5V system load unit (constant voltage control unit 5). ) And 3.3V system load units (constant voltage control unit 7) 9, 11, and malfunction of these 5V system load units and 3.3V system load units 9, 11 can be prevented.

  In particular, in a configuration in which the 5V system load unit 9 and the 3.3V system load unit 11 operate at a voltage lower than the power supply voltage of the 24V system load unit 3, even if a small regenerative current (energy) from the 24V system load unit 3 is 5V Since the system load unit 9 and the 3.3V system load unit 11 are easily affected, the first configuration according to the present invention is useful.

  The power supply unit 13 is not necessarily a circuit that rectifies and smoothes AC power, and may be a power supply that directly supplies DC power.

  The first configuration of the present invention is not limited to the configuration having the 24V system load unit 3, the 5V system load unit 9 and the 3.3V system load unit 11, that is, the first to third load units, but at least the first configuration. It is possible to achieve the object of the present invention by implementing it in the configuration having the second load section (the same applies hereinafter).

  Next, a second configuration according to the power supply device of the present invention will be described with reference to FIG.

  FIG. 3 is a circuit diagram showing a second configuration according to the power supply device of the present invention. Since the other configuration excluding the regenerative energy recovery unit is substantially the same as that in FIG. 1, only the regenerative energy recovery unit 15 will be described for the specific configuration.

  In FIG. 3, the regenerative energy recovery unit 15 controls a drive circuit 17 that supplies a DC voltage of 24 V to the DC motor M in the 24 V system load unit 3, and a drive current value that is supplied from the drive circuit 17 to the DC motor M. A control circuit 19 that controls the start, stop, and rotation speed of the DC motor M, a capacitor 21 that stores the generated power generated by the regenerative braking of the motor M from when the drive current is turned off until it stops, and a capacitor The power amount counter 23 for detecting and controlling the storage capacity to the power source 21 is provided.

  In other words, the DC motor M is stopped when the power supply from the drive circuit 17 is stopped by the control circuit 19, but after the power supply is stopped, the rotation operation continues by the inertial force until it mechanically stops. Then, it is reversely induced until it stops, and this is stored in the battery 21 via the diode D4.

  The electric energy counter 23 counts the electric power stored in the battery 21 and outputs a count-up signal to the transistor Q2 when the electric power storage of a predetermined sufficient capacity is counted and turns it on, and stores it in the battery 21. The generated electric power is supplied to the DC motor M.

  In addition, when the electric power counter 23 counts the electric power storage exceeding the electric power storage having a capacity sufficient for the starting rotation of the DC motor M, the electric power counter 23 controls the electric power stored in the battery 21 through the transistor Q3 and the diode D5. While supplying power to the units 5 and 7, the power supply voltages of the 24V system load unit 3, 5V system load unit 9 and 3.3V system load unit 11 are monitored, and the power supply voltages are lowered and unstable. Is turned on, the transistor Q3 is turned on, and the power stored in the battery 21 via the protective diode D5 is supplied to the constant voltage control unit 5 and the constant voltage control unit 7, that is, the second load unit and the third load. Each is supplied to each part.

  A symbol D6 in FIG. 3 is a diode that does not supply power from the battery 21 to the first load unit side.

  In the second configuration according to the power supply device of the present invention, when the rotation of the DC motor M is stopped, the rotation operation is continuously counter-induced by the inertial force, and this is accumulated in the battery 21 and the DC motor M is started and rotated. When a sufficient amount of power is stored, in the regenerative energy recovery unit 15, the power amount counter 23 supplies power stored in the battery 21 to the DC motor M from the transistor Q 2.

  Further, when the power accumulation exceeding the power accumulation with a capacity sufficient for the start-up rotation of the DC motor M is counted, the regenerative energy recovery unit 15 converts the power accumulated in the capacitor 21 into the transistor Q3 and the diode D5. The power supply power is supplied to the constant voltage control units 5 and 7 via.

  On the other hand, when the input power voltage of the 24V load unit 3, 5V load unit 9 and 3.3V load unit 11 decreases or becomes unstable due to the up and down movement of the power amount counter 23, the transistor Q3 is turned on. It is turned on and supplied to each.

  Therefore, in the second configuration according to the power supply device of the present invention, in addition to the effect according to the configuration of FIG. 1 described above, the power from the battery 21 can be used when starting the DC motor M to improve the energy efficiency. It is possible to further improve the energy efficiency.

  Further, since the regenerative energy recovery unit 15 supplies the power source voltage to the 5V system constant voltage control unit 5 and the 3.3V system constant voltage control unit 7, the AC power source A is turned off if the power amount counter 23 is appropriately formed. Even if the power is turned off, the power is supplied to the 5V system load unit 9 and the 3.3V system load unit 11, so that even after the AC power source A is turned off, as shown in FIG. 9 and 3.3V load section 11 can be operated.

  Therefore, when the AC power source A is turned off, for example, data saving processing in the image forming apparatus can be performed, and data such as an operation state immediately before the AC power source is turned off can be stored and stored to prepare for the next activation. There are advantages.

  Further, since the regenerative energy recovery unit 15 supplies the power supply voltage by monitoring the 5V system load unit 9 and the 3.3V system load unit 11, the power supply voltage of the 5V system load unit 9 and the 3.3V system load unit 11 is supplied. Even if it becomes unstable, it is possible to supply a compensation power source, and it is easy to stabilize it.

  In the description of the second configuration of the present invention, the output unit of the regenerative energy recovery unit 15 is connected to the constant voltage control units (second load unit and third load unit) 5 and 7. A configuration in which the regenerative energy recovery unit 15 is connected to the first and / or second load units can achieve the object of the present invention.

  The power supply apparatus of the present invention is preferably mounted on an apparatus having a drive motor in addition to an image forming apparatus such as a copying machine, a printer, or a multifunction machine.

1 is a circuit diagram showing an embodiment of a first configuration according to a power supply device of the present invention. It is a figure explaining operation | movement of the power supply device of this invention. It is a circuit diagram which shows embodiment of the 2nd structure which concerns on the power supply device of this invention. It is a circuit diagram explaining the conventional power supply device. It is a figure explaining operation | movement of the power supply device of FIG.

Explanation of symbols

1 constant voltage control unit 3 24V system load unit (first load unit)
5 Constant voltage controller (second load unit)
7 Constant voltage controller (third load unit)
9 5V system load section (second load section)
11 3.3V system load section (third load section)
13 power supply unit 15 regenerative energy recovery unit 17 drive circuit 19 control circuit 21 capacitor 23 power amount counter A AC power source C1, C2 smoothing capacitor D1, D2 rectifier diode D3 reverse current blocking diode (current blocking unit)
D4, D5, D6 Diode M DC motor R1, R2 Resistors Q1, Q2, Q3, Q4, Q5 Transistor T Transformer T1 Primary side T2 Secondary side

Claims (7)

A power supply for supplying DC power;
A first load unit connected to the power supply unit;
A second load unit connected to the power supply unit together with the first load unit;
A current blocking unit that is inserted from the connection point between the first load unit and the second load unit to the first load unit side and blocks the flow of output current from the first load unit;
A power supply device comprising: The power supply device according to claim 1, wherein the first load unit generates the output current from a built-in motor. The power supply apparatus according to claim 1 or 2, wherein the second load section operates at a power supply voltage lower than that of the first load section. A power supply for supplying DC power;
A first load unit connected to the power supply unit;
A second load unit connected to the power supply unit together with the first load unit;
A regenerative energy recovery unit that recovers electrical energy due to the operation of the device on which the device is mounted, the regenerative energy recovery unit connected to the first and / or second load unit;
A power supply device comprising: The power supply apparatus according to claim 4, wherein the regenerative energy recovery unit recovers the electric energy from a motor built in the device. The power supply apparatus according to claim 4 or 5, wherein the second load section operates at a power supply voltage lower than that of the first load section. The power supply apparatus according to claim 6, wherein the regenerative energy recovery unit outputs power to the second load unit to compensate for fluctuations in the power supply voltage of the second load unit.

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