PROTECTION DEVICE FOR CONVERTER OUTPUT SWITCH OF IMAGE BACKGROUND [0001] An image forming apparatus refers to an apparatus which prints print data generated on a terminal apparatus such as a computer on a recording printing medium. Examples of such an image forming apparatus may include a copier, a printer, a facsimile, a multi-function peripheral (MFP) serving functions of these in combination as one apparatus, and the like. BRIEF DESCRIPTION OF THE DRAWINGS [0002] FIG. 1 is a diagram illustrating an image forming apparatus including a converter including a bypass circuit according to an example; [0003] FIG.2 is a diagram illustrating the image forming apparatus including the converter in which an output terminal is separated according to an example; [0004] FIG.3 is a diagram illustrating the image forming apparatus in which a processor generates an error signal according to an example; [0005] FIG.4 is a diagram illustrating the image forming apparatus including the converter in which a power of a primary control IC is controlled according to an example; [0006] FIG.5 is a diagram illustrating the image forming apparatus including the converter in which an operation of the primary control IC is controlled according to an example; and [0007] FIG. 6 is a flowchart illustrating a method for controlling the image forming apparatus according to an example. DETAILED DESCRIPTION [0008] Hereinafter, various examples will be described with reference to the drawings. The examples described hereinafter may be modified and practiced in various different aspects. [0009] In the disclosure, the expression that a certain component is “connected” to another component not only includes a case where the components are “directly connected to each other”, but also a case where the components are “connected to each other with another component interposed therebetween”. In addition, when a certain component “includes” another certain component, it implies that a still another component may be further included, rather than excluding it, unless otherwise noted. Meanwhile, each example may be implemented or operated independently or the examples may also be implemented or operated in combination. [0010] In the disclosure, an “image forming job” may refer to various jobs relating to an image such as forming of an image or generating, saving, or transmitting of an image file (e.g., printing, scanning, or faxing), and the “job” may not only refer to the image forming job, but also refer to all of processes necessary for performing the image forming job. [0011] The “print data” may refer to data converted into a format that is printable by a printer. Meanwhile, if a printer supports direct printing, a file itself may be the print data. [0012] The “image forming apparatus” may refer to an apparatus which prints print data generated on a terminal apparatus such as a computer on a recording paper. Examples of such an image forming apparatus may include a copier, a printer, a facsimile, a scanner, and a multi-function peripheral (MFP) realizing functions of these as one apparatus in combination. [0013] The disclosure is to prevent accidents by reducing a load current of a converter, if an abnormality occurs in the converter. Hereinafter, various examples of converter which is included in the image forming apparatus to reduce the load current will be described. [0014] FIG. 1 is a diagram illustrating an image forming apparatus 1000 including a converter including a bypass circuit according to an example. [0015] Referring to FIG. 1, an image forming apparatus 1000 may include a primary circuit 1100 and a secondary circuit 1200, and a processor 1300 of the converter. The primary circuit 1100 of the converter may include a conversion circuit 1110 and a primary control circuit 1120, and the secondary circuit 1200 may include a feedback circuit 1230 and the like. The primary circuit 1100 and the secondary circuit 1200 may be connected to each other magnetically by a transformer T1. [0016] The converter may receive an input of an alternating current (AC) power from the outside. The input AC power may be input to the conversion circuit 1110. The conversion circuit 1110 may include a filter, a rectifier circuit, and a smoothing circuit and may convert the input AC power into a direct current (DC) power. The converted DC power may be provided as a primary coil of the transformer T1. The current flowing through the primary coil of the transformer T1 may be switched by a first switch 1121. The first switch 1121 may be switched by a signal provided by a control integrated circuit (IC) 1122 included in the primary control circuit 1120 according to an output load. The current switched by the primary coil of the transformer T1 may be transferred to a secondary coil of a transformer T2. A synchronous rectification control circuit 1210 included in the secondary circuit 1200 may determine on/off section of the first switch 1121 by using the power (voltage or current) transferred to the secondary coil. In an example, the synchronous rectification control circuit 1210 may allow the load current to flow through the second switch by turning on the second switch 1220 during a period in which the first switch 1121 is turned off and turning off the second switch 1220 in the other period. In this case, the feedback circuit 1230 may transfer a feedback signal to the control IC 1122 to provide a constant power as a load. The power controlled by the secondary circuit 1200 may be supplied as the power of the image forming apparatus through a secondary rectifier capacitor 1240. [0017] For various reasons, the synchronous rectification control circuit 1210 may not control the second switch 1220. In this case, the movement of the load current between a drain and a source of the second switch 1220 may be limited. The secondary circuit 1200 may operate in the same manner as a diode rectification control by a body diode component existing in the second switch 1220, regardless of on/off of the second switch 1220. An allowable current of the body diode component of the semiconductor switch may be smaller, even extremely smaller, than a general allowable current between drain-source. Accordingly, if the load current continuously flows through the body diode component of the second switch 1220, a temperature of the second switch 1220 may rapidly increase to cause an accident. According to the disclosure, it is possible to prevent an accident by disposing a temperature sensor 1250 on the secondary circuit 1220 and reducing the load current flowing through the second switch according to a temperature detected by the temperature sensor 1250. [0018] Referring to FIG. 1, the secondary circuit 1200 of the converter may include the temperature sensor 1250, and a bypass circuit which bypasses the temperature sensor 1250. The bypass circuit may include a third switch 1260 and a diode 1270. The bypass circuit may be connected to the second switch 1220 in parallel and the third switch 1260 and the diode 1270 of the bypass circuit may be connected in series. The diode 1270 may be disposed in a forward direction of the direction of the load current. [0019] The temperature sensor 1250 may be disposed in a region adjacent to the second switch 1220 to measure a temperature of the second switch 1220. The temperature sensor 1250 may transfer a signal proportional to a temperature level to the processor 1300. The processor 1300 may detect a temperature change of the second switch 1220 by the transferred signal and, if the temperature exceeds a threshold temperature, the processor may turn on the third switch 1260. Accordingly, the power flowing through the second switch 1220 may be reduced. [0020] The third switch 1260 may be maintained to be turned off while the second switch 1220 operates normally at a temperature equal to or lower than the threshold temperature. In addition, the bypass circuit may prevent a flow of the load current through the diode 1270, and accordingly, the secondary circuit 1200 is able to operate only by a synchronous rectification method. Therefore, the converter is able to maintain high efficiency in a normal state. If the temperature of the second switch 1220 exceeds the threshold temperature, the processor 1300 may turn on the third switch 1260, and accordingly the secondary circuit is able to operate as a diode rectifier circuit through the diode 1270. Therefore, the image forming apparatus 1000 may maintain the normal operation by reducing the load current flowing through the second switch 1220. [0021] FIG.2 is a diagram illustrating the image forming apparatus including the converter in which an output terminal is separated according to an example. [0022] Referring to FIG. 2, the output terminal of the secondary circuit may be separated into a first output terminal which supplies the power to the processor 1300 and a second output terminal which supplies the power to the image forming apparatus 1000. For example, the power output to the second output terminal may be a power greater (or larger) than the power output to the first output terminal. For example, the power output to the first output terminal may be minimal power necessary for the processor 1300 to control an idle mode and a fourth switch 1280, and the power output to the second output terminal may be a power necessary for the general operation of the image forming apparatus 1000. In addition, the second output terminal may be connected to the fourth switch 1280. [0023] In a normal state, the processor 1300 may turn on the fourth switch 1280, and accordingly, the converter may supply the power to the image forming apparatus 1000 through the second output terminal. As described above, if an abnormality occurs in the second switch 1220, the temperature of the second switch 1220 may increase. The temperature sensor 1250 may measure the temperature of the second switch 1220 and transfer a signal corresponding to the measured temperature to the processor 1300. The processor 1300 may determine whether the temperature of the second switch 1220 exceeds the threshold temperature based on the transferred signal. If the temperature of the second switch 1220 exceeds the threshold temperature, the processor 1300 may turn off the fourth switch 1280 to cut the power output through the second output terminal. [0024] In the image forming apparatus 1000, according to the turning off of the fourth switch 1280, the power output through the second output terminal may be cut off and only the power output through the first output terminal may be output. As described above, the power output through the first output terminal may be a power which is able to operate the processor 1300 in an idle mode. Accordingly, the load current flowing through the second switch 1220 may be reduced so that the abnormality does not occur in the second switch 1220. Meanwhile, the processor 1300 may generate an error signal for notifying breakdown of a power device to a user along with turning off the fourth switch 1280. [0025] FIG.3 is a diagram illustrating the image forming apparatus including the converter in which the processor generates an error signal according to an example. [0026] Referring to FIG. 3, the image forming apparatus including the converter including the processor 1300 and the temperature sensor 1250 is illustrated. If the abnormality occurs in the second switch 1220, the temperature of the second switch 1220 may increase. The temperature sensor 1250 may measure the temperature of the second switch 1220 and transfer a signal corresponding to the measured temperature to the processor 1300. The processor 1300 may determine whether the temperature of the second switch 1220 exceeds the threshold temperature based on the transferred signal. If the temperature of the second switch 1220 exceeds the threshold temperature, the processor 1300 may change the mode to a power saving mode and transfer the error signal to each element of the image forming apparatus 1000 to turn off each element of the image forming apparatus. For example, the processor 1300 may turn off a driver signal for operating each unit of the image forming apparatus 1000. Accordingly, the image forming apparatus 1000 may use only the minimum power to maintain the idle mode, and the load current flowing through the second switch 1220 may be reduced so that the abnormal does not occur in the second switch 1220. Meanwhile, the processor 1300 may generate the error signal for notifying the breakdown of the power device to the user. [0027] FIG.4 is a diagram illustrating the image forming apparatus including the converter in which a power of a primary control IC is controlled according to an example. [0028] Referring to FIG. 4, the converter including photo switches 1123 and 1290 connected to the processor 1300 is illustrated. The secondary circuit of the converter may include a transmission side photo switch 1290 connected to the processor 1300, and the primary circuit of the converter may include a reception side photo switch 1123 connected between a power terminal of the control IC 1122 and a ground. An inner diode may operate through an on signal output by the processor 1300 and the transmission side photo switch may perform the photo operation by the operation of the inner diode. The reception side photo switch may be turned on by the photo operation of the transmission side photo switch. [0029] The processor 1300 may determine whether the temperature of the second switch 1220 exceeds the threshold temperature by using a signal transferred from the temperature sensor 1250. If the temperature of the second switch 1220 exceeds the threshold temperature, the processor 1300 may turn on the transmission side photo switch 1290 and the turned-on transmission side photo switch 1290 may turn on the reception side photo switch 1123. Since the reception side photo switch 1123 is connected between the power terminal of the control IC 1122 and the ground, the power supplied to the control IC 1122 may flow to the ground by the turned-on reception side photo switch 1123. Accordingly, through the above process, the processor 1300 may cut off the power supplied to the control IC 1122 and the control IC 1122 may not operate. If the control IC 1122 does not operate, the switching operation of the first switch 1121 may stop and the converter is turned off, and accordingly, the operation of the image forming apparatus 100 may also stop. The operation of the second switch 1220 may stop due to the turning off of the converter, and accordingly, the load current flowing through the second switch 1220 may be reduced (or cut off). [0030] FIG.5 is a diagram illustrating the image forming apparatus including the converter in which an operation of the primary control IC is controlled according to an example. [0031] Referring to FIG. 5, the feedback circuit 1230 including the transmission side photo switch 1231 and the primary circuit including the reception side photo switch 1124 are illustrated. The transmission side photo switch 1231 may be controlled by the processor 1300 through a control path connected between the processor 1300 and the feedback circuit 1230. [0032] The processor 1300 may determine whether the temperature of the second switch 1220 exceeds the threshold temperature by using a signal transferred from the temperature sensor 1250. If the temperature of the second switch 1220 exceeds the threshold temperature, the processor 1300 may turn on the transmission side photo switch 1231 included in the feedback circuit 1230, and the turned-on transmission side photo switch 1231 may turn on the reception side photo switch 1124. Since the reception side photo switch 1124 is connected between the feedback terminal of the control IC 1122 and the ground, a signal input to the feedback terminal of the control IC 1122 may change by the turned-on reception side photo switch 1124. The control IC 1122 may perform a protection control operation by changing the signal input to the feedback terminal. The protection control operation of the control IC 1122 may stop the operation of the first switch 1121, and the operation stop of the first switch 1121 may stop the operation of the second switch 1220. Therefore, the load current flowing through the second switch 1220 may be reduced (or cut off). [0033] Hereinabove, the image forming apparatus including various examples of converter has been described. Hereinafter, a control method for reducing a load current of a switch included in a converter will be described. [0034] FIG. 6 is a flowchart illustrating a method for controlling the image forming apparatus according to an example. [0035] Referring to FIG. 6, the primary circuit of the converter included in the image forming apparatus may convert an input AC power into a DC power and transfer the DC power to the secondary circuit (S610), and the secondary circuit of the converter may switch the transferred DC power and output through the output terminal (S620). Meanwhile, while the converter operates, the temperature sensor included in the secondary circuit of the converter may detect a temperature of the second switch included in the secondary circuit (S630). [0036] If the detected temperature of the second switch exceeds a threshold temperature, the processor included in the image forming apparatus may reduce a load current flowing through the second switch (S640). For example, the converter of the image forming apparatus may include a bypass circuit connected to the second switch in parallel. In addition, the bypass circuit may include the third switch. If the detected temperature of the second switch exceeds the threshold temperature, the processor may turn on the third switch to bypass the current of the converted DC power to the bypass circuit. Since the load current bypasses to the bypass circuit, the load current flowing through the second switch may be reduced. [0037] Alternatively, the converter of the image forming apparatus may supply a first power through the first output terminal and supply a second power through the second output terminal. In an example, the first power may be a minimum power which performs the minimum operation of the processor, and the second power may be a power which operates all functions of the image forming apparatus. The fourth switch may be connected to the second output terminal. If the detected temperature of the second switch exceeds the threshold temperature, the processor may turn off the fourth switch. Due to the turning off of the fourth switch, the second power output to the second output may be cut off. Since the second power which is a power which operates all functions of the image forming apparatus is cut off, the load current flowing through the second switch may be reduced. [0038] Alternatively, if the detected temperature of the second switch exceeds the threshold temperature, the processor may change the mode to a power saving mode and transfer the error signal to each element of the image forming apparatus to turn off each element of the image forming apparatus. Since each element of the image forming apparatus is turned off, the load current flowing through the second switch may be reduced. [0039] Alternatively, the secondary circuit of the image forming apparatus may include a first transmission side photo switch and the primary circuit may include a first reception side photo switch. The first transmission side photo switch may be connected to the processor and the first reception side photo switch may be connected between the power terminal of the control IC and the ground. If the detected temperature of the second switch exceeds the threshold temperature, the processor may turn on the first transmission side photo switch included in the secondary circuit, and the first reception side photo switch may be turned on by the turned-on first transmission side photo switch. The power supplied to the control IC may flow through the ground by the turning on of the first reception side photo switch. In other words, the power supplied to the control IC may be cut off and the load current flowing through the second switch may be reduced. [0040] Alternatively, the secondary circuit of the image forming apparatus may include a second transmission side photo switch and the primary circuit may include a second reception side photo switch. The second reception side photo switch may be controlled by the processor and the second reception side photo switch may be connected between the feedback terminal of the control IC and the ground. If the detected temperature of the second switch exceeds the threshold temperature, the processor may turn on the second transmission side photo switch and the second receptions ide photo switch may be turned on by the turned-on second transmission side photo switch. The feedback signal input to the control IC may be changed by the turning on of the second reception side photo switch, and the control IC may stop a switching operation of the first switch according to the changed feedback signal. The switching operation of the second switch may stop due to the stop of the first switch operation, and the load current flowing through the second switch may be reduced. [0041] While examples of the disclosure have been shown and described, the disclosure is not limited to the aforementioned specific examples, and it is apparent that various modifications can be made by those having ordinary skill in the technical field to which the disclosure belongs, without departing from the gist of the disclosure as claimed by the appended claims. Also, it is intended that such modifications are not to be interpreted independently from the technical idea or prospect of the disclosure.