WO2003073579A1 - Apparatus for preventing erroneous input of power supply - Google Patents

Abstract

An apparatus for preventing an accident of inputting an unadaptable AC power supply erroneously to a rectifying means by providing means for selecting a rectifying means being inputted with an AC power supply inputted to a power supply unit depending on preset set information, means for judging the voltage level of the AC power supply inputted to the power supply unit, means for checking matching between the judgment results of the judging means and the voltage level of an input AC power supply represented by the set information, and means for allowing or rejecting an AC power supply inputted to the power supply unit to be inputted to a rectifying means selected by the selecting means.

Description

 Description Erroneous power input prevention device Technical field

 The present invention relates to a power supply unit that rectifies input AC power and converts it to appropriate DC power.In particular, in a power supply unit that can handle a plurality of different input voltages, an excessively high voltage is erroneously input. The present invention relates to an erroneous power supply input prevention device for preventing the occurrence of power failure.

 Background art

 In recent years, power supplies that perform rectification in response to multiple power supply voltages, such as power supply units that support both AC 100 V and commercial power of AC 200 V Units are being built into electronic devices such as personal computers and various information processing devices.

 By adopting such a power supply unit that supports multiple power supplies, for example, the power supply unit can be shared between products for domestic shipment and products for export, or products for domestic shipment can be used by users. Can be used overseas.

 Fig. 6 shows a configuration example of a conventional power supply unit that supports multiple power supplies.

 The power supply unit shown in FIG. 6 includes an AC filter circuit 411, a diode bridge including four diodes D 1, D 2, D 3, and D 4, and capacitors C 1 and C 2 connected in series. It has a switch SW. In this power supply unit, the AC power supplied from the commercial power supply is full-wave rectified or switched by switching the path of the current flowing through the diode bridge and the two capacitors C 1 and C 2 according to the opening and closing of the switch SW. A general configuration for double voltage rectification is employed.

 This power supply unit performs double voltage rectification by closing the switch SW when the supplied commercial power is 100 V system, and opens the switch SW when the commercial power supply is 200 V system and full wave. By performing rectification, in each case, a DC power supply having the same voltage (for example, DC 2.82 V) can be supplied to the load.

The switch SW provided in such a power supply unit provides power supply units and While the setting may be made at the time of mounting, the setting may be changed by the user who purchased the product equipped with the power supply unit.

 In the general configuration of the power supply unit described above, whether to perform full-wave rectification or voltage doubler rectification is determined only by opening and closing the switch SW. Therefore, if the switch SW is closed in the power supply unit shown in Fig. 6 even though AC power is supplied from the 200 V system commercial power supply, this switch SW setting error is fatal. Failure is caused. Because, in this setting, the input commercial power supply is double-voltage rectified, so that an excessive voltage of up to 282 V DC is applied to the two capacitors C 1 and C 2, and this causes This is because the supplied DC power supply also has an excessively high voltage value (for example, DC564V). Naturally, the ratings of the capacitors CI and C2 provided in the power supply unit described above are determined on the assumption that the combination of the switch SW setting and the input power supply is correct. If voltage is applied, not only the capacitors C1 and C2 inside the power supply unit, but also the load circuit will be damaged.

 As a technique for preventing the device from being damaged due to such a switch setting error, it was disclosed in Japanese Patent Application Laid-open No. Hei 6-0 545 737 or Japanese Patent Application Hei 9-1494963. Technology has been proposed. Each of these technologies basically detects an input power supply voltage and controls the closing of the switch SW based on the detection result. By applying these technologies, the switching between full-wave rectification and voltage doubler rectification itself can be automated by controlling the opening and closing of the switch SW according to the power supply voltage input to the power supply unit. Such a technology is effective when it is assumed that a product equipped with a power supply unit is compatible with both 100 V commercial power supply and 200 V commercial power supply. . This is because in such products, it is basically sufficient if the voltage value of the power supply input to the power supply unit and the rectification method applied to obtain DC power supply are compatible.

By the way, for example, in a personal computer or the like, the setting of the switch SW shown in FIG. 6 may be associated with the setting information of the power management function. In such a case, it is only necessary that the input power supply voltage and the rectification method match. Instead, these combinations must also match the settings of the switch SW.

 In addition, if the voltage fluctuation of the AC power supply is large, applying the technology that automatically switches the rectification method based on the voltage value of the input AC power supply as it is may directly damage the elements. May increase. This is because, depending on the magnitude of the voltage fluctuation, there is a possibility that an AC power supply that should be originally determined to be a 200 V AC power supply may be mistaken for a 100 V AC power supply. Because there is. In addition, in the conventional automatic switching method, the input voltage is directly applied to the detection circuit until the detection of the input voltage is completed.For example, a large voltage that is not expected when the detection circuit is designed is input. In this case, the circuit may be damaged regardless of the magnitude of the voltage fluctuation.

 Based on these facts, based on the setting of the switch SW, an erroneous power supply input protection device is provided to protect the power supply unit and load circuit from the input of a power supply with an incorrect voltage value.

That is, an erroneous power supply input prevention device for preventing input of a power supply voltage that does not conform to the setting of the switch SW is required. Disclosure of the invention

 An object of the present invention is to select only a power supply having a voltage value indicated by setting information in a power supply unit that converts power input from an AC power supply having a plurality of voltage values into power having a predetermined DC voltage value. It is an object of the present invention to provide a device for preventing incorrect input of power supply.

 A further object of the present invention is to provide an erroneous power supply input prevention device capable of reliably preventing a power supply unit from being damaged by inputting a power supply voltage that does not match setting information.

 It is still another object of the present invention to provide an erroneous power supply input prevention device that verifies the consistency between setting information and an input voltage value using an analog circuit.

The above-described object is to determine, in accordance with setting information set in advance, a selection unit for selecting a rectifying unit to receive an AC power input to a power supply unit and a voltage value of the AC power input to the power supply unit. Discriminating means, the discrimination result by the discriminating means and the setting information Inspection means for inspecting the consistency with the voltage value of the input AC power supply indicated by the report, and the AC power supply input to the power supply unit to the rectification means selected by the selection means according to the inspection result by the inspection means. This is achieved by an erroneous power input prevention device having an input permitting means for permitting or rejecting input. In particular, it is preferable that the determination means is connected to the AC power supply in parallel with the power supply unit, and the power supply unit main body and the determination means are separated. A more desirable configuration is a configuration in which the determining means is formed using a transformer, and the AC power supply is separated from the element for determining the voltage value of the AC power supply.

 According to such an erroneous power supply input prevention device, the power supplied from the AC power supply can be input to the rectifier only when the setting information matches the voltage value of the input AC power supply. For example, it is possible to prevent erroneous input of the power supply, such as accidentally inputting the AC power supply of the 200 V system to the rectification means compatible with the 100 V system. Damage to elements inside the unit can be prevented. In a preferred configuration, the determination means is separated from the power supply unit, so that the voltage value of the AC power supply can be determined without affecting the power supply unit body at all. In a more desirable configuration, the voltage of the AC voltage reduced at a predetermined rate is applied to the element for determining the voltage value by the action of the transformer provided in the determination means. Can also be achieved.

 The above object is to provide a relay switch wherein the input permitting means connects or opens a terminal connected to a plurality of rectifying means and a terminal connected to the input AC power supply in accordance with a test result by the test means. Until the inspection result by the inspection means is determined,

-This is achieved by an erroneous power input prevention device having a configuration including a maintaining means for maintaining an open state between two terminals provided on the switch.

 According to such an erroneous power input prevention device, by keeping the power supply path shut off until the inspection result by the inspection means is determined, an AC power supply that does not match the rectification means at the beginning of power-on is provided. Since it is possible to prevent a situation where the power supply unit is accidentally turned on, it is possible to reliably protect the elements inside the power supply unit.

The above-mentioned object is to provide a voltage discriminating means for discriminating a voltage value of an AC power supply input to a power supply unit and outputting a DC voltage having a magnitude proportional to the voltage value, and a switch SW. It opens and closes in conjunction, and a predetermined reference DC voltage V1 smaller than the voltage value obtained by the voltage determination means is applied to one terminal according to the input of a 200 V AC power supply, and the other terminal Is a switch grounded via two resistors R 1 and R 2 connected in series, a potential at a connection point between the switch and the resistor R 1, and a potential corresponding to a DC voltage obtained by the voltage determining means. And a discriminating potential comparator that compares the resistance of the resistor R 2 with the sum of the potential of the connection point of the two resistors R 1 and R 2 and the resistance of the two resistors R 1 and R 2 A set potential comparator that compares a coefficient α having a value with a potential obtained by multiplying the reference DC voltage V1, and a comparison result obtained by the discrimination potential comparator and a comparison result obtained by the set potential comparator satisfying a predetermined condition. Drive means that outputs a predetermined drive current when Correspondingly, Ru achieved by erroneous supply input prevention apparatus that includes a Riresuitsuchi closing a path to enter the AC power to the diode bridge. In particular, it is preferable that the voltage determining means is connected to the AC power supply in parallel with the power supply unit, and the power supply unit main body and the voltage determining means are separated.

 According to such an erroneous power supply input prevention device, by comparing the voltage values in an analog manner, it is possible to determine the consistency between the input AC power supply and the rectification method selected by the switch SW. In a desirable configuration, the voltage determining means is separated from the power supply unit, so that the voltage value of the AC power supply can be determined without affecting the power supply unit body at all.

 The above-described object is to provide a driving device in which a driving circuit is configured to use a Zener diode corresponding to a discrimination potential comparator and a setting potential comparator and a Zener diode corresponding to a voltage corresponding to an output of the discrimination potential comparator and the setting potential comparator. This is achieved by an erroneous power input prevention device having a configuration including two delay circuits for delaying the timing applied to the power supply.

 According to such an erroneous power input prevention device, power is supplied by closing the relay switch based on a valid determination result, regardless of fluctuations in the output of the voltage determination means and the output of the determination potential comparator that appear immediately after the power is turned on. Therefore, the input of an AC power supply having a voltage value that does not match the setting of the switch SW can be reliably prevented.

The above-described object is achieved by the voltage determining means for detecting a voltage value of an input AC power supply. A voltage obtained by multiplying the voltage value detected by the voltage detecting means and the voltage value detected by the voltage detecting means by a predetermined coefficient ^ that is larger than a ratio of the reference DC voltage V1 to the voltage value corresponding to the 200 V AC power supply. This is achieved by an erroneous power supply input prevention device having a configuration including a voltage conversion unit that converts a voltage into a value and inputs a potential corresponding to the converted voltage value to a discrimination potential comparator. A more desirable configuration is one in which the voltage detecting means is formed using a transformer, and the AC power supply is separated from the element for determining the voltage value of the AC power supply.

 According to such an erroneous power supply input prevention device, by appropriately adjusting the value of the reference DC voltage V1 and the value of the coefficient?, An appropriate threshold value is provided regardless of the fluctuation of the input AC power supply voltage value. It is possible to reliably detect the mismatch between the setting by the switch SW and the voltage value of the input AC power supply, and to stop the supply of power, so that an excessive voltage is erroneously applied to the elements forming the power supply unit. It is possible to prevent application. In a more desirable configuration, the voltage after the AC voltage is reduced at a predetermined rate is applied to the element for determining the voltage value by the action of the transformer provided in the voltage detecting means. Regardless of the fluctuation of the voltage value, and regardless of the magnitude of the input AC power supply voltage value, it is possible to protect the circuits and elements that determine the voltage value. BRIEF DESCRIPTION OF THE FIGURES

 FIG. 1 is a principle block diagram of first and second erroneous power supply input prevention devices according to the present invention.

 FIG. 2 is a principle block diagram of the third to fifth erroneous power supply input prevention devices according to the present invention.

 FIG. 3 is a diagram showing an embodiment of the erroneous power supply input prevention device according to the present invention. FIG. 4 is a diagram illustrating a detailed configuration of the voltage detection circuit.

 FIG. 5 is a diagram showing a detailed configuration of the relay control circuit.

 FIG. 6 is a diagram illustrating a configuration example of a conventional power supply unit that supports a plurality of power supplies. BEST MODE FOR CARRYING OUT THE INVENTION

First, referring to FIGS. 1 and 2, the principle of the erroneous power input prevention device according to the present invention will be described. Will be described.

 FIG. 1 is a principle block diagram of first and second erroneous power supply input prevention devices according to the present invention.

 The erroneous power input prevention device shown in FIG. 1 includes a selection unit 111, a determination unit 112, a detection unit 113, and an input permitting unit 114.

 The first principle of the erroneous power supply input prevention device according to the present invention is as follows. In the erroneous power supply input prevention device in a power supply unit provided with rectifying means 101 corresponding to input AC power supplies having different voltage values, the selecting means 111 selects a power supply according to preset setting information. Select the rectification means 101 to receive the AC power input to the unit.

 The determination means 1 determines the voltage value of the AC power supply input to the power supply unit. The checking means 113 checks the consistency between the result of the judgment made by the judging means 112 and the voltage value of the input AC power supply indicated by the setting information.

 The input permitting means 1 14 allows the AC power input to the power supply unit to be input to the rectifying means 101 selected by the selecting means 111 according to the inspection result by the inspecting means 113. Or reject.

 The operation of the erroneous power supply input prevention device having such a configuration is as follows.

 The voltage value of the AC power supply input to the power supply unit is determined by the determination unit 112, and the determination result is determined by the inspection unit 113 to determine whether or not it matches the preset setting information. . If the inspection means 113 determines that the voltage value of the AC power supply matches the setting information, the AC power supply input to the power supply unit is switched to the selection means via the input permitting means 114. 1 1 1 is input to the rectifying means 101 selected according to the setting information. On the other hand, when the inspection result by the inspection means 113 indicates that the voltage value of the input AC power supply does not match the setting information, the input of the AC power supply is rejected by the input permission means 114. Therefore, no signal is input to any of the rectifiers 101.

 The input permitting means 114 provided in the second erroneous power supply input prevention device shown in FIG. 1 includes a relay switch 115 and a maintaining means 116.

The second principle of the erroneous power supply input prevention device according to the present invention is as follows. The relay switch 1 15 provided in the input permitting means 1 14 is connected to the terminal commonly connected to the plurality of rectifiers 101 and the input AC power supply according to the inspection result by the inspection means 113. Or open the connected terminal.

 The maintaining means 116 maintains an open state between the two terminals provided in the relay switch 115 until the inspection result by the inspection means 113 is determined.

 The operation of the erroneous power supply input prevention device having such a configuration is as follows.

 The maintaining means 1 16 keeps the relay switch 115 open until the result of the inspection by the inspection means 113 is confirmed, and then turns the relay switch 115 on the basis of the inspection result by the inspection means 113. Operable. In response, the relay switch 115 connects the two terminals described above, for example, when the determined test result indicates that the setting information matches the voltage value of the AC power supply. A path for supplying AC power to the rectifier 101 is formed. On the other hand, if the mismatch is indicated, the relay switch 115 prevents the supply of power to the rectifier 101 by keeping the above-mentioned two terminals open. I do.

 FIG. 2 is a principle block diagram of the third to fifth erroneous power supply input prevention devices according to the present invention.

 The erroneous power supply input prevention device shown in FIG. 2 includes a voltage discriminating means 1 28, a switch 122, a discriminating potential comparator 122, a set potential comparator 122, a driving means 124, It is composed of a switch and a switch.

 The third principle of the erroneous power supply input prevention device according to the present invention is as follows.

 Two capacitors C 1 and C 2 connected in series between the output ends DO 1 and DO 2 of the diode bridge are connected, and the connection point of these capacitors C 1 and C 2 is connected to the diode bridge. By connecting or disconnecting one of the input terminals DI 1 and DI 2 in response to the opening and closing of the switch SW, the erroneous power supply input prevention device in the power supply unit that performs voltage double rectification or full wave rectification of the input AC power The voltage determining means 128 determines the voltage value of the AC power supply input to the power supply unit, and outputs a DC voltage having a magnitude proportional to this voltage value.

The switch 121 opens and closes in conjunction with the switch SW, and has one terminal smaller than the voltage value obtained by the voltage determining means 128 in response to the input of a 200 V AC power supply. A predetermined reference DC voltage V1 is applied, and the other terminal is grounded via two series-connected resistors Rl and R2.

 The discrimination potential comparator 122 compares the potential at the connection point between the switch 122 and the resistor R1 with the potential corresponding to the DC voltage obtained by the voltage discrimination means 128.

 The set potential comparator 1 2 3 is smaller than the ratio of the resistance of the resistor R 2 to the sum of the potential of the connection point of the two resistors R l and R 2 and the resistance of the two resistors R 1 and R 2. The value is compared with a potential obtained by multiplying the reference DC voltage V 1 by a coefficient α having a value.

 The driving means 124 outputs a predetermined drive current when the comparison result by the discrimination potential comparator 122 and the comparison result by the set potential comparator 123 satisfy predetermined conditions.

 The relay switch 125 closes a path for inputting AC power to the diode bridge in response to input of a predetermined drive current.

 The operation of the erroneous power supply input prevention device having such a configuration is as follows.

The voltage proportional to the voltage value of the input AC power supply obtained from the voltage determining means 1 28 is compared with the reference DC voltage VI when the switch 1 2 1 is closed by the determining potential comparator 1 2 2. Compared to 0 V when open. Therefore, when the switch 121 is open, the output of the discrimination potential comparator 122 is ¹ "L" regardless of the voltage value of the input AC power supply, and the switch 122 is closed. Is high when the voltage proportional to the input AC power supply voltage value does not exceed the reference DC voltage V1. The voltage α VI proportional to the reference DC voltage VI is compared with a potential obtained by dividing the reference DC voltage VI by the resistors R l and R 2 when the switch 1 21 is closed by the set potential comparator 1 23. It is compared to 0 V when switch 1 2 1 is open. Therefore, the output of the set potential comparator 123 becomes “L” when the switch 121 is closed, and becomes “H” when the switch 121 is open. On the basis of the comparison result obtained in this way, the driving means 124 may, for example, drive the driving current when the output of the discrimination potential comparator 122 or the output of the set potential comparator 123 is "H". To the relay switches 1 2 5. As a result, a path for inputting the AC power to the diode bridge is formed through the relay switch 125. In this way, when full-wave rectification is selected by the switch SW, regardless of the voltage value of the input AC power, the AC power is input to the diode bridge, and the double voltage rectification is selected. In this case, the AC power supply can be input to the diode bridge only when the reference DC voltage V1 is larger than the voltage proportional to the voltage value of the input AC power supply. It is possible to avoid double rectification of the 200 V AC power supply.

 Driving means 124 provided in the fourth erroneous power supply input prevention device shown in FIG. 2 includes two zener diodes 1 27 and two delay circuits 1 26.

 The fourth principle of the erroneous power supply input prevention device according to the present invention is as follows. The two power diodes 127 correspond to the discrimination potential comparator 122 and the set potential comparator 123, respectively.

 The two delay circuits 1 26 delay the timing at which the voltage corresponding to the output of the discrimination potential comparator 122 and the output of the set potential comparator 123 is applied to the corresponding zener diode 127.

 The operation of the erroneous power supply input prevention device having such a configuration is as follows.

 The two delay circuits 1 26 delay the supply of the drive current from the corresponding zener diode 1 27 to the relay switch 125, respectively. Regardless of the voltage value of the AC power supply, the open state of the relay switch 125 is maintained. After that, after the output of the voltage discriminating means 1 28 is surely stabilized and the comparison result by the discriminating potential comparator 1 22 is surely stabilized, the voltage corresponding to the valid comparison result is reduced by the Zener diode 1 2 7 Applied to

 The voltage discriminating means 128 provided in the fifth erroneous power supply input prevention device shown in FIG. 2 includes a voltage detecting means 131, and a voltage converting means 1332.

 The fifth principle of the erroneous power supply input prevention device according to the present invention is as follows. The voltage detecting means 13 1 detects a voltage value of the input AC power supply.

The voltage conversion means 13 2 converts the voltage value detected by the voltage detection means 13 1 into a predetermined coefficient larger than the ratio of the reference DC voltage V 1 to the voltage value corresponding to the 200 V AC power supply. /? Is converted to a voltage value obtained by multiplying Is input to the discrimination potential comparator 1 2 2.

 The operation of the erroneous power supply input prevention device having such a configuration is as follows.

 The voltage conversion means 1332 converts the voltage value obtained by the voltage detection means 131, and outputs a voltage having a value obtained by multiplying the input AC power supply voltage value by a coefficient / ?. , Input to the discrimination potential comparator 1 2 2.

 By performing such voltage conversion, when a 200 V AC power supply is input, be sure to input a voltage higher than the reference DC voltage V 1 to the discrimination potential comparator 122. Can be.

 〔Example〕

 FIG. 3 shows an embodiment of the erroneous power supply input prevention device according to the present invention.

 Note that, of the components shown in FIG. 3, those equivalent to the components shown in FIGS. 2 and 6 are denoted by the same reference numerals as those given to the components shown in FIG. Description is omitted.

 In the power supply unit shown in FIG. 3, the erroneous power supply input prevention device 210 according to the present invention is arranged between the AC filter circuit 411 and the diode bridge. In this erroneous power supply input prevention device 210, the rectifier circuit 211 and the voltage converter circuit 212 are connected to the AC filter circuit 411 in parallel with the diode page, so that AC power is supplied. In response, it generates power and operating voltage for operating the relay control circuit 214. In FIG. 3, the voltage detection circuit 2 13 is connected to the AC filter circuit 4 11 in parallel with the diode bridge, and detects the voltage value of the input AC power supply. Pass to 14 The relay control circuit 214 drives the relay switch 215 based on the detection result of the voltage detection circuit 213 and the setting of the switch SW to form or cut off a path for supplying input AC power to the diode bridge. I do.

 Figure 4 shows the detailed configuration of the voltage detection circuit.

Voltage detecting circuit 2 1 3 shown in FIG. 4 charges the capacitor by the rectifier circuit 2 1 1 the output current, and outputs a voltage across the Kondenza as a voltage value V _AC of the input AC power source. In FIG. 4, after the rectifier circuit 211 appropriately reduces the AC power supplied from the AC filter And rectify using a capacitor. Also, in FIG. 4, the voltage conversion circuits 2 1 and 2 were connected to the three-terminal regulator and between the input terminal and the ground terminal, and between the output terminal and the ground terminal of the three-terminal regulator. It is formed from a capacitor. The voltage conversion circuit 211 converts the output voltage of the rectification circuit 211 to a predetermined voltage V _DC corresponding to the above-described reference DC voltage V 1.

 As shown in FIG. 3, the rectifier circuit 211 and the voltage detection circuit 213 are connected to the AC filter circuit 411 in parallel with the diode package which is the main body of the power supply unit. Since the power supply unit is separated from the main body of the power supply unit, the voltage detection operation by the voltage detection circuit 2 13 can be performed independently of the operation of the power supply unit. Further, as shown in FIG. 4, the voltage detection circuit 2 13 is separated from the AC power supply by the transformer provided in the rectification circuit 2 1 1, thereby forming the voltage detection circuit 2 13 Protection can also be achieved. The reason is that the voltage applied to the voltage detection circuit 2 13 is independent of the voltage value of the AC power supply by appropriately setting the rate at which the transformer shown in FIG. 4 reduces the voltage input from the AC power supply. This is because the value can be reliably set to be equal to or lower than the withstand voltage of the circuit element forming the voltage detection circuit 21.

The output voltage VAC of the voltage detection circuit ₂₁₃ and the output voltage _VDC of the voltage conversion circuit ₂₁₂ are both input to a relay control circuit 214 described later.

 Figure 5 shows the detailed configuration of the relay control circuit.

 The switch 221 provided in the relay control circuit 214 shown in FIG. 5 and the switch SW are both one of the switch elements forming a composite switch. Are configured to operate in conjunction with each other.

In the relay control circuit 214 shown in FIG. 5, the positive input terminal of the comparator (CMP) 222 (indicated by a sign “+” in FIG. 5) is connected to the switch 222 described above. The output voltage V _DC (hereinafter referred to as the reference voltage V _DC ) of the above-described voltage conversion circuit 212 is input to the other terminal of the switch 221. . The connection point between the switch 22 1 and the plus terminal of the comparator 22 2 is grounded via resistors R 1 and R 2. On the other hand, the comparator (CMP) 222 The input terminal (shown by the symbol “1” in FIG. 5) is connected to the connection point of the resistors R 3 and R 4, and the other end of the resistor R 3 is connected to the above-described voltage detection terminal. circuit 2 1 3 output voltage V _AC (hereinafter, the detection voltage referred to as V _AC) is input, the other end of the resistor R 4 is grounded. The negative terminal of the comparator 223 shown in FIG. 5 is connected to the connection point of the above-mentioned resistors R l and R 2, and the positive terminal of the comparator 223 is connected to another resistor. Connected to the connection point of R5 and R6. The above-described reference voltage _VDC is input to the other terminal of the resistor R5, while the other terminal of the resistor R6 is grounded. The output terminals of the comparators 222 and 222 described above are connected to the anode terminals of the corresponding Zener diodes 222 and 227, respectively, and the resistors R7 and Pulled up via R8. Further, the output terminals of these comparators 222, 223 are grounded via transistors 224, 225. Also, the base terminals of these transistors 222 and 225 are grounded via an RC circuit having a predetermined time constant. By supplying a current output from the cathode side of the above-mentioned power diodes 226 and 227 to the relay switch 215, the relay switch 215 operates.

 Here, the correspondence relationship between each unit shown in FIGS. 3 to 5 and each unit shown in FIGS. 1 and 2 will be described.

 The voltage detection circuit 21 shown in FIG. 3 corresponds to the determination means 112 shown in FIG. 1 or the voltage detection means 131 shown in FIG. The switch SW shown in FIG. 3 corresponds to the selection unit 111 shown in FIG. The diode bridge and the capacitors C1 and C2 shown in FIG. 3 correspond to the rectifier 101 shown in FIG. Further, the relay control circuit 214 shown in FIG. 3 corresponds to the inspection means 113 shown in FIG. Further, the relay switch 2 15 shown in FIG. 3 corresponds to the relay switch 115 shown in FIG. 1 or the relay switch 125 shown in FIG.

Switch 221 shown in FIG. 5 corresponds to switch 122 shown in FIG. Further, the comparator 222 shown in FIG. 5 corresponds to the discrimination potential comparator 122 shown in FIG. 2, and the comparator 222 shown in FIG. 5 has the set potential shown in FIG. This corresponds to the comparator 123. Further, the Zener diodes 222 and 227 shown in FIG. 5 correspond to the Zener diodes 127 shown in FIG. Also, the resistor R 7 and the transistor shown in Fig. 5 2 2 4 and the RC circuit connected to the transistor 2 24 and the resistor R 8, the transistor 2 25 and the RC circuit connected to the transistor 2 25 are the delay circuit 1 2 shown in FIG. 6 or the maintenance means 1 16 shown in FIG. Further, the resistors R 3 and R 4 shown in FIG. 5 correspond to the voltage conversion means 132 shown in FIG. Next, the operation of the relay switch control circuit shown in FIG. 5 will be described.

When the double voltage rectification method is selected by the switch SW, that is, when the connection point of the capacitors C1 and C2 and the input terminal DI2 of the diode bridge are connected, the switch SW is linked. And switch 2 2 1 is also closed. Therefore, in this case, the reference voltage _VDC is inputted to the plus terminal of the comparator 222, and the detection voltage VAC is inputted to the minus terminal of the comparator ₂₂₂ , R3, R The potential divided by 4 is input. At this time, the potential obtained by dividing the reference voltage V _DC by the resistors R 1 and R 2 and the potential obtained by dividing the reference voltage V _DC by the resistors R 5 and R 6 are also calculated by the comparator 2 23. Be compared. Here, for example, if the ratio of the resistance values of the resistors R 1 and R 2 is 1: 1 and the ratio of the resistance values of the resistors R 5 and R 6 is 4: 1, the switch 221 is closed. Output, the output of the comparator 22 3 is “L” because the potential of the positive terminal of the comparator 22 3 is always lower than the potential of the negative terminal, regardless of the input AC power supply voltage value. Becomes In this case, a current flows to the output terminal side of the comparator 2 23 via the pull-up resistor R 8, so that the relay switch 2 1 7 is connected via the zener diode 2 27 corresponding to the comparator 2 2 3. No drive current flows through 5.

Therefore, when the switch 221 is closed, whether or not the drive current is supplied to the relay switch 215 is determined according to the comparison result by the comparator 222, where the resistance R 3 , R4 is 1: 3, and the reference voltage _VDC is an appropriate voltage of less than 150 V. When the switch 221 is closed, 200 V When the AC power of the system is input, the output of the comparator 222 is surely in the “L” state. In this case, since a current flows to the output terminal side of the comparator 222 through the pull-up resistor R7, the relay switch 222 is connected via the Zener diode 226 corresponding to the comparator 222. No drive current flows through 15. On the other hand, under the same conditions, when an AC power supply of 100 V is input, the output of the comparator 222 becomes “H” without fail. In this case, the current flowing through the pull-up resistor R7 first charges the capacitor provided in the RC circuit connected to the pace terminal of the transistor 224. Thereafter, after the transistor 224 is turned off, the current flowing through the pull-up resistor R7 is supplied to the relay switch 215 via the zener diode 226. In other words, in this case, after the AC power is input, after a delay time corresponding to the time constant of the RC circuit, the relay switch 215 operates, and power from the AC power is supplied to the diode bridge. Thus, in the erroneous power supply input prevention device according to the present invention, when double voltage rectification is selected by the switch SW, the relay switch is only activated when the 100 V AC power is input. 2 15 can be closed to start power input. In other words, only the power from the AC power supply of the 100 V system can be selectively voltage-doubled rectified, preventing the application of excessive voltage to the capacitors CI and C2, and the element of the power supply unit. Can be reliably protected.

 Next, a case where full-wave rectification is selected by opening the switch SW will be described.

At this time, the switch 22 1 is also opened in conjunction with the switch SW, so that the plus terminal of the comparator 2 22 and the minus terminal of the comparator 2 2 3 are the same as when both are grounded. Potential. Therefore, the output of the comparator 222 becomes “L” irrespective of the detection voltage V _AC , and the relay switch 215 via the Zener diode 226 corresponding to the comparator 222 is output. No drive current flows through the switch.

Therefore, when the switch 221 is open, whether or not the drive current is supplied to the relay switch 215 is determined according to the comparison result by the comparator 223. When the switch 2 21 is open, the potential at the connection point of R 5 and R 6 connected to the positive terminal of the comparator 2 23 becomes relatively higher than the potential at the negative terminal. Regardless of the detection voltage _VAC , the output of the comparator 223 becomes “H”. At this time, the current flowing through the pull-up resistor R8 first charges the capacitor provided in the RC circuit connected to the base terminal of the transistor 225. Then, after transistor 2 25 is turned off, pull-up resistor R The current flowing through 8 is supplied to the relay switch 2 15 through the zener diode 2 27. In other words, in this case, after the AC power is input, after a delay time corresponding to the time constant of the RC circuit, the relay switch 215 operates, and power from the AC power is supplied to the diode bridge.

 Therefore, the relay control circuit 214 shown in FIG. 5 controls the open / close state of the relay switch 215 as shown in Table 1 according to the setting of the switch SW and the voltage value of the input AC power supply. .

〔table 1〕

 Here, when full-wave rectification is selected by the switch SW, even if a 200 V AC power supply or a 100 V AC power supply is input to the diode bridge, the capacitor No excessive voltage is applied to CI and C2. Therefore, when the switch SW and the switch 221 are open, as described above, the drive current is supplied to the relay switch 215 regardless of the voltage value of the input power supply, and the switch SW 221 is opened. Even if 215 is closed, the purpose of protecting elements inside the power supply unit can be sufficiently achieved.

 Also, as shown in FIG. 5, the transistors 2 2 4 and 2 2 5 corresponding to the 2 comparators 2 2 and 2 2 3 and the RC circuit, respectively, are connected via the zener diodes 2 2 6 and 2 2 7. By delaying the timing at which the drive current is supplied to the relay switch 2 15, even if the voltage value fluctuates when the power is initially turned on, the relay switch 2 15 can be controlled based on the highly accurate determination result. 15 can be operated, so that the reliability of the erroneous power input prevention device can be improved. For example, if the resistance values of the pull-up resistors R7 and R8 are set to 0.025 times the resistance value of the resistor R1 and the time constant of the RC circuit is set to 100 ms, these circuits can be compared. Sufficient delay can be provided to the outputs of comparators 222, 223 to stabilize the outputs of comparators 222, 223.

In addition, the target to be compared with the reference voltage V _DC in the comparator 22 is a detection voltage V _AC. It is possible to determine whether the input AC power supply voltage value is a 200 V system or a 100 V system while assuming a desired fluctuation range by setting the voltage value to be proportional to it can. In other words, by changing the ratio of the resistance values of R 3 and R 4, even in regions where the input commercial power voltage may fluctuate significantly, the power supply voltage can be reliably determined and the power supply unit can be connected. Can be protected. Industrial applicability

 According to the erroneous power supply input prevention device according to the present invention, in a power supply unit configured to switch between voltage doubler rectification and full-wave rectification, an AC power supply having a high voltage value is erroneously input to the voltage doubler rectifier circuit. Therefore, elements such as a capacitor inside the power supply unit can be protected, and the reliability of the power supply unit can be improved. In particular, it is assumed that a switch that switches between voltage doubler rectification and full-wave rectification is set, and the AC power supply is used only when the rectification method selected by this switch matches the voltage value of the input AC power supply. Input to the rectifier circuit, it is possible to reliably protect the elements inside the power supply unit even in areas where the voltage of the commercial power supply is expected to fluctuate significantly, for example. It is. Therefore, by applying the erroneous power supply input prevention device according to the present invention to a power supply unit provided in a device intended for use in such a region, the reliability of the device can be significantly improved. .

Claims

The scope of the claims (1) In a power supply unit provided with rectifying means corresponding to input AC power supplies having different voltage values,  Selecting means for selecting AC power input to the power supply unit as a rectifying means to be input, according to setting information set in advance;  Determining means for determining the voltage value of the AC power supply input to the power supply unit; checking means for checking consistency between the determination result by the determining means and the voltage value of the input AC power supply indicated by the setting information;  Input permitting means for permitting or refusing to input AC power to the power supply unit to the rectifying means selected by the selecting means, according to a test result by the testing means;  An erroneous power input prevention device comprising:  (2) In the erroneous power supply input prevention device according to claim 1,  The input permission means  A relay switch for connecting or disconnecting a terminal commonly connected to a plurality of rectifiers and a terminal connected to an input AC power supply in accordance with an inspection result by the inspection means; and A means for maintaining an open state between the two terminals provided in the relay switch.  An erroneous power input prevention device, characterized in that:  (3) Two capacitors C 1 and C 2 connected in series are connected between the output ends DO 1 and DO 2 of the diode bridge. The connection point of these capacitors C 1 and C 2 is By connecting or opening either of the input ends DI 1 and DI 2 of the quad bridge according to the opening and closing of the switch SW, erroneous power supply in the power supply unit that performs voltage double rectification or full wave rectification of the input AC power In the input prevention device,  Voltage determining means for determining a voltage value of an AC power supply input to the power supply unit and outputting a DC voltage having a magnitude proportional to the voltage value; The switch is opened and closed in conjunction with the switch SW, and the AC power of 200 V A predetermined reference DC voltage VI smaller than the voltage value obtained by the voltage discriminating means is applied according to the force, and the other terminal is grounded via two series-connected resistors R 1 and R 2. Switch  A discrimination potential comparator for comparing a potential at a connection point between the switch and the resistor R1 with a potential corresponding to a DC voltage obtained by the voltage discrimination means;  A coefficient α having a value smaller than the potential of the connection point of the two resistors Rl and R2 and the ratio of the resistance value of the resistor R2 to the sum of the resistance values of the two resistors Rl and R2 is defined as A set potential comparator for comparing the potential with the reference DC voltage V1,  A drive unit that outputs a predetermined drive current when a comparison result by the discrimination potential comparator and a comparison result by the set potential comparator satisfy a predetermined condition; and in response to the input of the predetermined drive current. A relay switch for closing a path for inputting AC power to the diode bridge.  An erroneous power input prevention device comprising:  (4) In the erroneous power supply input prevention device according to claim 3,  The driving means is  A Zener diode corresponding to each of the discrimination potential comparator and the set potential comparator,  And two delay circuits for delaying a timing at which a voltage corresponding to the output of the discrimination potential comparator and the output of the set potential comparator is applied to the corresponding zener diode.  An erroneous power input prevention device, characterized in that:  (5) In the erroneous power supply input prevention device according to claim 3,  The voltage determining means is  Voltage detection means for detecting a voltage value of an input AC power supply;  The voltage value detected by the voltage detection means is converted into a voltage value obtained by multiplying a predetermined coefficient? Larger than a ratio of the reference DC voltage V1 to a voltage value corresponding to the 200 V AC power supply. And a voltage conversion means for inputting a potential corresponding to the converted voltage value to the discrimination potential comparator.  An erroneous power input prevention device, characterized in that: