JP2006304534A - Switching power supply and imaging apparatus equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a switching power supply whose production management is easy and whose structure is cost-effective for different AC input voltage systems of 100 V system/200 V system, and provide an imaging apparatus equipped with the power supply. <P>SOLUTION: This switching power supply comprises power supplies of at least two systems that output a first secondary voltage with a first switching power supply by raising and smoothing an AC input voltage via a power factor improvement circuit, and that output a second secondary voltage with a second switching power supply by rectifying and smoothing the AC input voltage. The power factor improvement circuit outputs voltages raised to almost the same voltages, irrespective of at least two different AC input voltage systems. The power supply is divided into a power supply circuit which is made to correspond to each AC input voltage system with a group of different parts corresponding to each different AC input voltage system, and a fixed circuit which is made up of a power supply and a group of other parts, irrespective of the AC input voltage systems. This switching power supply is made applicable to a different AC input voltage system by changing the power supply circuit portion only that corresponds to the AC input voltage system for the fixed circuit according to the AC input voltage. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a switching power supply device having different 100V / 200V AC voltage systems, and more particularly to an image forming apparatus including a power supply device having a power factor correction circuit.

  In recent years, the development of switching elements that can withstand relatively large currents and voltages at high frequencies has led to the majority of power supply devices that rectify commercial power supply to obtain a desired DC voltage. . A switching power supply is used as a power source for various electronic devices such as an image forming apparatus as a high-power DC-DC converter while miniaturizing a transformer and other devices by increasing a switching frequency.

  By the way, in general, when a commercial power supply is rectified, the current flowing through the smoothing circuit becomes a distorted waveform, which causes a problem that the power factor indicating the utilization efficiency of the power supply is impaired. Further, there is a need for measures for suppressing harmonics generated by the distortion current waveform.

  In order to improve the power factor of the power supply, it is known to use a boost type active filter circuit (for example, see Patent Documents 1 and 2 below).

Also in an image forming apparatus using an electrophotographic process, with an increase in speed and diversification of options, there is a tendency that the power of the fixing heater increases and the capacity of the low-voltage power source increases. In such a situation, in order to increase the power factor of the low-voltage power supply unit and reduce the maximum current consumption, there is an increasing use of a switching power supply equipped with a power factor correction circuit such as a boost type active filter. In addition, since the image forming apparatus requires a large output during image formation, the secondary power supply voltage is output via the power factor correction circuit, and the output is reduced during non-image formation. A power supply system has also been proposed in which a secondary power supply voltage is output to increase power efficiency (see, for example, Patent Document 3).
Japanese Unexamined Patent Publication No. 7-99775 JP 2004-208357 A Japanese Patent Laid-Open No. 9-166942

  Switching power supply apparatuses are generally different AC input voltage systems, for example, 100V system and 200V system, and are often different switching power supplies. Also, the fixing heater and driving circuit are often different fixing heaters or driving circuits for the 100V system and the 200V system.

  As described above, as the power supply capacity increases and energy saving during standby, the main power supply capable of high-capacity output and the sub power supply that supplies standby power and logic power are used. In some cases, a DC-DC converter is provided via a rate improving circuit. In such a case, the main power supply unit and the sub power supply unit become circuit units corresponding to the AC input voltage system, and it is necessary to prepare separate substrates for, for example, 100V system and 200V system. When the power factor correction circuit is a boost type active filter system, if the boost voltage value is optimized for each of the 100V system and the 200V system, the power factor correction circuit section and the subsequent DC-DC converter section are also connected to the voltage system. It becomes a separate power supply.

  On the other hand, when the power factor correction circuit boosts the voltage to substantially the same DC voltage regardless of the AC input voltage system, the subsequent DC-DC converter unit becomes a common circuit unit regardless of the AC input voltage system.

  Generally, since the DC voltage boosted by the power factor correction circuit unit is used only for the input of the subsequent DC-DC converter, the power factor correction circuit unit and the DC-DC converter unit are used as one circuit unit. Often configured on the same substrate. In addition, the main power supply and the sub power supply are functionally different and are often configured on different substrates.

  As a result, although there are many common circuit sections in different input voltage systems, for example, 100V system and 200V system, there are several types of substrates, which complicates production management.

  Accordingly, a first invention according to the present application aims to solve the above-described problems and provide a power supply configuration that allows easy production management for different AC input voltage systems.

  The second invention according to the present application aims to solve the above-described problems and provide a simple configuration in which production management is easy and functionally classified for different AC input voltage systems. To do.

  The third invention according to the present application aims to solve the above-described problems and to make the production control easy and inexpensive for different AC input voltage systems.

  The fourth invention according to the present application solves the above-described problems, has a configuration in which production management is easy and inexpensive for different AC input voltage systems, and the configuration can reduce the number of substrates. For the purpose.

  A fifth invention according to the present application solves the above-described problems, has a structure that is easy to manage and inexpensive for different AC input voltage systems, and has a high efficiency in using AC input power. An object is to provide an apparatus.

  According to a sixth aspect of the present application, there is provided an image forming apparatus including a switching power supply unit that solves the above-described problems and that is easy to manage and inexpensively configures different AC input voltage systems. The purpose is to provide.

  The seventh invention according to the present application solves the above-described problems, and as a power source of an image forming apparatus including a fixing heating device driving circuit for different AC input voltage systems, production management is easy. An object of the present invention is to provide an image forming apparatus including a power supply device having an inexpensive configuration.

In order to achieve the above object, the first invention according to the present application provides:
A power supply for outputting a first secondary voltage from a first switching power supply via an AC input voltage via a power factor correction circuit;
And having at least two power sources that rectify and smooth the AC input voltage and output the second secondary voltage from the second switching power source,
The power factor correction circuit outputs a voltage boosted to approximately the same voltage regardless of at least two different AC input voltage systems,
A power supply circuit unit corresponding to each AC input voltage system by a group of parts that are different parts for different AC input voltage systems,
It is divided into a power supply unit that does not depend on the AC input voltage system and a fixed circuit unit consisting of other parts.
Only the power supply circuit unit corresponding to the AC input voltage system is changed with respect to the AC input voltage with respect to the fixed circuit unit so as to correspond to a different AC input voltage system.

In order to achieve the above object, the second invention according to the present application provides:
In the switching power supply having the features of the first invention,
The power factor correction circuit and the second switching power supply are power supply circuit units corresponding to the AC input voltage system,
The circuit unit operating with the first switching power supply and the first and second secondary voltages is a fixed circuit unit.

In order to achieve the above object, the third invention according to the present application provides:
In the switching power supply having the features of the first or second invention,
The fixed circuit unit is mounted on at least one board, and the power supply circuit unit corresponding to the AC input voltage system is a separate mounting board for each AC input voltage system,
A mounting board corresponding to each AC power supply system is configured to be replaceable with respect to the mounting board of the process circuit unit.

In order to achieve the above object, the fourth invention according to the present application provides:
In the switching power supply having the features of the third invention,
A common substrate is used as a mounting substrate of the power supply circuit unit corresponding to the AC input voltage system.

In order to achieve the above object, a fifth invention according to the present application provides:
In the switching power supply having the features of any one of the first to fourth inventions,
The power factor correction circuit receives AC input voltage, turns on / off the current flowing through the choke coil via the rectifier circuit by the switching means, and is stored in the choke coil by the diode connected in parallel with the switching means. It is a boost type active filter system that outputs a voltage to be rectified and smoothed by a smoothing capacitor.

In order to achieve the above object, the sixth invention according to the present application provides:
An image forming apparatus comprising: an image forming unit that forms a toner image on a recording material; and a fixing device that heats and fixes the toner image to the recording material.
The power supply device that outputs the secondary side voltage is the switching power supply device according to any one of claims 1 to 5.

In order to achieve the above object, the seventh invention according to the present application provides:
In the image forming apparatus having the features of the sixth invention,
The fixing device includes heating means;
Power is supplied to the heating means by the AC input voltage turning on / off the power supply means,
The power supply means is composed of respective heating device drive circuits for different AC input voltage systems,
Each of the heating device drive circuits constitutes a power supply circuit unit corresponding to an AC input power supply system together with a power supply circuit unit corresponding to the AC input voltage system.

  According to the first invention of the present application, it is possible to provide a switching power supply device having a power supply configuration with easy production management for different AC input voltage systems.

  In addition, according to the second invention of the present application, it is possible to provide a switching power supply device that can be easily managed for different AC input voltage systems and that has a simple configuration functionally classified. .

  According to the third invention of the present application, it is possible to provide a switching power supply device that can be easily managed and inexpensively configured for different AC input voltage systems.

  According to the fourth invention of the present application, it is possible to provide a switching power supply device that has a configuration that is easy to manage and inexpensive for different AC input voltage systems and that can reduce the number of substrates. it can.

  According to the fifth aspect of the present application, it is possible to provide a power supply apparatus that is easy to manage production and has a low-cost configuration and good utilization efficiency of an AC input power supply for different AC input voltage systems.

  According to the sixth invention of the present application, it is possible to provide an image forming apparatus including a switching power supply device having a configuration that is easy to manage and inexpensive for different AC input voltage systems.

  According to a seventh aspect of the present application, a power supply device having a structure that is easy to manage production and is inexpensive as a power supply for an image forming apparatus including a fixing heating device driving circuit for different AC input voltage systems. An image forming apparatus can be provided.

  The best mode for carrying out the present invention will be described below based on examples.

  FIG. 1 is a block diagram of a switching power supply device according to the present invention.

  The switching power supply device according to the present invention includes a common substrate 17 and a 100V system substrate 16 or a 200V system substrate 46. The 100V system board 16 is a power supply apparatus when the AC input power source 1 is 100V system, for example, 85 to 139.7Vac, and the 200V system board 46 is an AC input power source 1 having 200V system, for example, 187 to 264Vac, In this case, the common substrate 17 is a power supply device that does not depend on the voltage of the AC input power supply 1 connected to the subsequent stage of the 100V system substrate 16 or the 200V system substrate 46.

  In the 100 V system substrate 16, the AC input power source 1 is input to the diode bridges 3 to 6 and 9 to 12 through the AC filter 2. The pulsating waveform that has been full-wave rectified by the diode bridges 3 to 6 is input to the PFC circuit (power factor correction circuit) 7. The input voltage of the PFC circuit 7 is, for example, a pulsating waveform voltage having a peak value of about 120 to 197 V with respect to the point M at the point P. By being boosted by the PFC circuit 7 and smoothed by the smoothing capacitor 8, a DC voltage Vdc of about 380 to 420 V is output. On the other hand, full-wave rectification is performed by the diode bridges 9 to 12 and smoothed by the smoothing capacitor 13. The smoothed voltage is input to the switching power supply 14 that is a DC-DC converter, and the switching power supply 14 outputs the secondary side voltage Vb. The switching power supply 14 uses an insulating transformer to ensure insulation between the primary and secondary. The 100V system board 16 outputs the primary DC voltage Vdc and the secondary side voltage Vb to the common board.

  In the common substrate 17, the primary DC voltage Vdc is input to the switching power supply 18, and the secondary voltage Va is output. The secondary-side voltage Va is, for example, a high-capacity power source, a large-capacity power source such as a motor or an actuator, or a power source for a device that is energized only during operation without having to be energized during standby of a device in which the power source device is mounted. used. The secondary side voltage Vb is input to the common circuit unit 20 and needs to be energized directly or via a DC-DC converter, for example, mainly in the standby state of the power supply of the logic unit or the device on which the power supply device is mounted. Used as a power source for devices.

  In the 200 V system board 46, the AC input power source 1 is input to the diode bridges 33 to 36 and 39 to 42 through the AC filter 32, as in the 100 V system board 16. The pulsating waveform that has been full-wave rectified by the diode bridges 33 to 36 is input to the PFC circuit 37. The input voltage of the PFC circuit 37 is, for example, a pulsating waveform voltage having a peak value of about 264 to 373 V with respect to the point M at the point P. By being boosted by the PFC circuit 37 and smoothed by the smoothing capacitor 38, a DC voltage Vdc of about 380 to 420 V is output. The DC voltage Vdc is substantially the same voltage as that of the 100V system board 16. On the other hand, full-wave rectification is performed by the diode bridges 39 to 42 and smoothed by the smoothing capacitor 43. The smoothed voltage is input to a switching power supply 44 that is a DC-DC converter, and the switching power supply 44 outputs a secondary side voltage Vb. The switching power supply 44 uses an insulation type transformer to ensure insulation between the primary and secondary.

  That is, the 200 V system substrate 46 outputs the same primary DC voltage Vdc and secondary side voltage Vb as the 100 V system substrate 16 to the common substrate 17.

  FIG. 2 shows a schematic circuit diagram of the PFC circuit 7 (37). A full-wave rectified pulsating waveform voltage is applied between the points P and M, and the waveform is shaped by the capacitor 51. The capacitor 51 is connected to reduce the influence of switching of the switching element 53 on the AC power supply 1 and to make the power factor approximately 1. The input pulsating voltage is turned on / off by a switching element 53, for example, a MOSFET via a choke coil 52. When the switching element 53 is on, an input voltage is applied to the choke coil 52 and current is accumulated. When the switching element 53 is turned off, the current accumulated in the choke coil 52 flows through the diode 55 and the voltage is boosted and smoothed by the capacitor 8 (38).

  The switching element 53 is controlled by a controller 54. Although not shown, the controller 54 feeds back the output voltage Vdc and controls the output to be constant.

  As described above, by adopting the configuration of the present embodiment, the power supply can be handled by simply replacing the mounting boards (100V system mounting board 16 and 200V system mounting board 46) for different AC input power supply voltages. Can do. By setting the output of the power factor correction circuit to the same voltage Vdc regardless of the voltage system, the subsequent switching power supply can be made a common circuit regardless of the AC input voltage.

  In addition, the circuit parts 2 to 7 and 9 to 14, or the parts 32 to 37 and 39 to 44 that need to use different rated parts for different voltage systems are made into one mounting board 16 or 46. This makes it easy to handle different AC input voltages and manage production.

  In addition, only 2 to 7 and 9 to 14, or 32 to 37 and 39 to 44, which are parts of the circuit section that need to use parts with different ratings, are changed to make the bare board common, thereby managing production. Can be made easier.

  A duplicated point with the first embodiment is omitted.

  FIG. 3 is a schematic configuration diagram of an image forming apparatus using an electrophotographic process, and shows, for example, a laser printer.

  The laser beam printer main body 101 has a cassette 102 for storing the recording paper S, a cassette presence sensor 103 for detecting the presence of the recording paper S in the cassette 102, and a cassette size sensor 104 for detecting the size of the recording paper S in the cassette 102. A paper feed roller 105 that feeds the recording paper S from the cassette 102 is provided (consisting of a number of micro switches).

  A registration roller pair 106 that synchronously conveys the recording paper S is provided downstream of the paper supply roller 105. An image forming unit 108 that forms a toner image on the recording paper S based on the laser beam from the laser scanner unit 107 is provided downstream of the registration roller pair 106. A fixing device 109 for thermally fixing the toner image formed on the recording paper S is provided downstream of the image forming unit 108.

  Downstream of the fixing device 109, a paper discharge sensor 110 that detects the conveyance state of the paper discharge unit, a paper discharge roller 111 that discharges the recording paper S, and a stacking tray 112 on which the recording paper S that has been recorded are stacked are provided. ing. The conveyance reference of the recording paper S is set so as to be centered with respect to the length of the recording paper S in the direction orthogonal to the conveyance direction of the image forming apparatus, that is, the width of the recording paper S.

  The laser scanner 107 emits a laser beam modulated based on an image signal (image signal VDO) sent from an external device 131 (to be described later), and a photosensitive drum 117 (to be described later) from the laser unit 113. A polygon motor 114 for scanning upward, an imaging lens 115, a folding mirror 116, and the like are included.

  The image forming unit 108 includes a photosensitive drum 117, a primary charging roller 119, a developing device 120, a transfer charging roller 121, a cleaner 122, and the like necessary for a known electrophotographic process. The fixing device 109 includes a fixing film 109a, an elastic pressure roller 109b, a ceramic surface heater 109c provided in the fixing film 109a, and a thermistor 109d for detecting the surface temperature of the ceramic surface heater 109c.

  The main motor 123 applies driving force to the paper feed roller 105 via the paper feed roller clutch 124 and to the registration roller pair 106 via 125. The main motor 123 also applies driving force to each unit of the image forming unit 108 including the photosensitive drum 117, the fixing device 109, and the paper discharge roller 111.

  The engine controller 126 controls the electrophotographic process by the laser scanner unit 107, the image forming unit 108, and the fixing device 109, and controls the conveyance of the recording paper in the laser beam printer main body 101.

  The video controller 127 is connected to an external device 131 such as a personal computer via a general-purpose interface (Centronics, RS232C, etc.) 130. The video controller 127 expands the image information sent from the general-purpose interface 130 into bit data, and sends the bit data to the engine controller 126 as a VDO signal.

  FIG. 4 shows a block diagram of a power supply device including a switching power supply in this embodiment.

  The power supply device according to this embodiment includes a common substrate A77 and a common substrate B80, and a 100V substrate 76 or a 200V substrate 96. The 100V system board 76 is a power supply apparatus when the AC input power supply 61 is a 100V system, for example, 85 to 139.7Vac, and the 200V system board 96 is an AC input power supply 61 having a 200V system, for example, 187 to 264Vac, The common substrate A77 and the common substrate B80 are power supply devices that do not depend on the voltage of the AC input power supply 61 that is connected to the subsequent stage of the 100V system substrate 76 or the 200V system substrate 96.

  In the 100 V system board 76, the AC input power supply 61 is input to the diode bridges 63 to 66 and 69 to 72 via the AC filter 62. A pulsating waveform that has been full-wave rectified by the diode bridges 63 to 66 is input to a PFC circuit (power factor correction circuit) 67. The input voltage of the PFC circuit 67 is, for example, a pulsating waveform voltage having a peak value of about 120 to 197 V with respect to the point M at the point P. By being boosted by the PFC circuit 67 and smoothed by the smoothing capacitor 68, a DC voltage Vdc of about 380 to 420V is output. On the other hand, full-wave rectification is performed by the diode bridges 69 to 72, and smoothing is performed by the smoothing capacitor 73. The smoothed voltage is input to a switching power supply 74 that is a DC-DC converter, and the switching power supply 74 outputs a secondary side voltage Vb. The switching power supply 74 uses an insulating transformer in order to ensure insulation between the primary and secondary.

  The AC input power supply 61 is branched and input to the fixing heater driving circuit via the AC filter 85. The AC input voltage is input to the fixing heater 93 (109c) via the relay 86, the switching element 88, and the fixing connector 92. Electric power is supplied to the fixing heater 93 by energizing and shutting off the triac 88.

  89 and 90 are bias resistors for the triac 88, and 87 is a capacitor for noise removal and time constant adjustment. Reference numeral 91 denotes, for example, a phototriac coupler for securing a creepage distance between the primary and secondary. When the light emitting diode of the phototriac coupler 91 is energized, the triac 88 is turned on and operates according to a signal from the CPU. The relay 86 is a means for cutting off the power supply to the fixing device when the image forming apparatus is on standby or when the fixing heater is abnormally heated. Although not shown, the relay 86 operates according to a signal from the temperature detection circuit unit or the CPU. .

  In other words, the 100V system substrate 76 outputs the primary DC voltage Vdc and the secondary side voltage Vb to the common substrates A and B, and supplies power to the fixing heater via the connector 87.

  In the common substrate A77, the primary DC voltage Vdc is input to the switching power supply 78, and the secondary voltage Va is output. The secondary voltage Va is used, for example, as a high-voltage power source, a large-capacity power source such as a motor or an actuator, or a power source for a device that does not need to be energized during standby of the image forming apparatus and energizes only during image formation. . The secondary side voltage Vb is input to the common circuit unit 83 of the common substrate B80, and is directly or via a DC-DC converter, for example, mainly for the power supply of the logic unit such as the CPU 82 and the power supply device of the device on which the power supply device is mounted. Used as a power source for devices that need to be energized during standby. The CPU 82 controls the circuit unit disposed on the common substrate A via the signal bundle 81. Further, the CPU 82 controls the fixing heater driving circuit unit mounted on the 100V system substrate 76, controls the operation / stop of the PFC circuit 67, and controls the oscillation mode of the switching power supply 74 via the signal bundle 84.

  Similarly to the 100 V system board 76, the 200 V system board 96 receives the AC input power supply 61 and outputs the same primary DC voltage Vdc and secondary side voltage Vb as the 100 V system board 76 to the common boards A 77 and B 80. Then, electric power is supplied to the fixing heater 97 via the connector 92. The illustration of the internal circuit is omitted because it has the same configuration as 62-67, 69-74, 85-91 of the 100V substrate 76.

  As described above, by adopting the configuration of the present embodiment, the power supply of the power supply device can be handled by simply replacing the mounting boards 76 and 96 for different AC input power supply voltages. By setting the output of the power factor correction circuit to the same voltage Vdc regardless of the voltage system, the subsequent switching power supply can be made a common circuit regardless of the AC input voltage. Further, the circuit units 62 to 67, 69 to 74, and 85 to 91, which need to use parts with different ratings for different voltage systems, are made into one mounting board 76 or 96, thereby fixing the fixing heater driving circuit. In addition, it becomes easy to handle different AC input voltages and manage production.

  Furthermore, it is easier to manage production by changing the parts 62-67, 69-74 and 85-91 only for parts of the circuit section that need to use parts with different ratings, and making the bare board common. Can do.

  Further, for different AC input power supply voltages, the image forming apparatus can be powered by simply replacing the fixing device including the fixing heater 93 or 97 together with the mounting substrate 76 or 96. By changing the pin arrangement in the connector 92 with respect to different AC input voltages, it is possible to prevent erroneous insertion of the fixing device.

It is a figure explaining the switching power supply device in this invention. It is a figure explaining the schematic circuit diagram of the PFC circuit in this invention. It is a figure explaining the image forming apparatus in 2nd Example of this invention. It is a figure explaining the switching power supply device of the 2nd Example in this invention.

Explanation of symbols

1,61 AC input power source 16,76 100V system mounting board 46,96 200V system mounting board 7,37 PFC circuit (power factor correction circuit)
14, 18, 44, 74, 78 Switching power supply 17, 77, 80 Common substrate 93, 97 Fixing heater 109 Fixing device 101 Image forming apparatus.

Claims (7)

A power supply for outputting a first secondary voltage from a first switching power supply via an AC input voltage via a power factor correction circuit;
And having at least two power sources that rectify and smooth the AC input voltage and output the second secondary voltage from the second switching power source,
The power factor correction circuit outputs a voltage boosted to approximately the same voltage regardless of at least two different AC input voltage systems,
A power supply circuit unit corresponding to each AC input voltage system by a group of parts that are different parts for different AC input voltage systems,
It is divided into a power supply unit that does not depend on the AC input voltage system and a fixed circuit unit consisting of other parts.
A switching power supply apparatus, wherein only the power supply circuit unit corresponding to the AC input voltage system is changed with respect to the AC input voltage with respect to the fixed circuit unit, and the AC circuit is adapted to a different AC input voltage system. The power factor correction circuit and the second switching power supply are power supply circuit units corresponding to the AC input voltage system,
2. The switching power supply device according to claim 1, wherein the circuit unit that operates with the first switching power supply and the first and second secondary voltages is a fixed circuit unit. The fixed circuit unit is mounted on at least one board, and the power supply circuit unit corresponding to the AC input voltage system is a separate mounting board for each AC input voltage system,
3. The switching power supply device according to claim 1, wherein the mounting board is configured to be replaceable with respect to the mounting board of the fixed circuit unit corresponding to each AC power supply pressure system.   The switching power supply according to claim 3, wherein a common substrate is used as a mounting substrate for a power supply circuit unit corresponding to the AC input voltage system.   The power factor correction circuit receives AC input voltage, turns on / off the current flowing through the choke coil via the rectifier circuit by the switching means, and is stored in the choke coil by the diode connected in parallel with the switching means. 5. The switching power supply device according to claim 1, wherein the switching power supply device is a step-up active filter system that outputs a voltage to be rectified and smoothed by a smoothing capacitor. An image forming apparatus comprising: an image forming unit that forms a toner image on a recording material; and a fixing device that heats and fixes the toner image to the recording material.
6. The image forming apparatus according to claim 1, wherein the power supply device that outputs the secondary side voltage is the switching power supply device according to any one of claims 1 to 5. The fixing device includes heating means;
Power is supplied to the heating means by the AC input voltage turning on / off the power supply means,
The power supply means is composed of respective heating device drive circuits for different AC input voltage systems,
The image forming apparatus according to claim 6, wherein each of the heating device driving circuits constitutes a power supply circuit unit corresponding to an AC input power supply system together with a power supply circuit unit corresponding to the AC input voltage system. apparatus.

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