JP2006178640A - Electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic device capable of preventing programs or data loaded into its memory at a factory or the like from being deleted by error before the device is installed in a market. <P>SOLUTION: The electronic device has a storage means (volatile memory 3), a backup power supply (installed on the main board of a card reader 1 or the like), and a power supply circuit 2 that electrically interconnects the storage means and the backup power supply. The power supply circuit 2 is provided with a bypass circuit 22 that transitions into a non-conducting state when supplied with power from an external power supply. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electronic device having a security function (for example, a card reader), and more particularly to an electronic device having a security function for erasing programs and data stored in a memory.

  2. Description of the Related Art Conventionally, there are electronic device apparatuses having a security function such as a card reader with a so-called fraud prevention function. For example, the unauthorized read prevention device described in Patent Document 1 automatically erases the stored contents of the EEPROM when it is detected that the housing has been opened. In addition, the card reader device described in Patent Document 2 automatically disables the original operation of the card reader device when the case is unpacked.

  Such an electronic device device operates normally (normally) when the casing is illegally unpacked for some reason and the program and data in the internal memory (various RAM) are automatically erased. It becomes impossible to do. Therefore, after the program and data in the built-in memory are automatically erased, in order for the electronic device device to perform a normal operation, the program or data corresponding to the erased program or data is reloaded (read). There is a need to.

  The initial loading of the program and data is performed by a maintenance man (service man) when, for example, an electronic device such as a card reader is incorporated in a bank ATM or installed in the market. If these programs and data are automatically erased as described above, a maintenance man (service man) goes to the site and reloads the programs and data into the memory, so that the electronic device apparatus Will work normally. Such a load may be downloaded using a telecommunication line such as the Internet, or may be loaded by special processing by storing a program or data in another memory or CPU.

  However, such a type to be loaded locally requires that the maintenance man carry the jig or storage medium loaded into the memory and go to the site, so that the jig or storage medium may be stolen. Moreover, even if the download is performed on the Internet, there is a possibility that the download data is illegally received. Furthermore, even if a program or data is stored in another memory or CPU and loaded by special processing, there is a possibility that a circuit such as a CPU is analyzed.

  In this way, the type that is loaded locally has a security problem. On the other hand, in order to solve this security problem, when installing in the market or automatically erasing the program or data, the program or data cannot be loaded at all. There are types that can only be loaded at the factory.

  In this type of factory load, programs and data are automatically loaded into the memory at the factory before the electronic device is installed in the market. After the electronic device is installed in the market, the program and data are automatically loaded. When the data is erased, the electronic device is brought back to the factory and a program or data is loaded at the factory. By doing so, it is not necessary to carry jigs and storage media loaded into the memory and go to the site, and it is not necessary to download them over the Internet, eliminating the various security problems described above. Can do.

JP 2001-84176 A (paragraph [0007]) JP 2001-291050 A (paragraph [0010])

  However, the type loaded at the factory described above may cause the loaded program or data to be erased by an erroneous operation after the program or data is loaded into the memory at the factory and before the electronic device is installed on the market.

  In particular, when a new product whose handling method has not penetrated into maintenance personnel is incorporated into a higher-level device such as an ATM, there is a high risk that a program or data loaded in the memory will be erased by an erroneous operation, and this is effective. Development of countermeasures is expected.

  On the other hand, it may be possible to prevent adverse effects due to erroneous operations by using a control circuit such as a CPU, but this is not a preferable measure from the viewpoint of circuit complexity and an increase in manufacturing cost.

  The present invention has been made in view of these points, and its purpose is to prevent accidental erasure of a program or data loaded into a memory at a factory or the like before being installed in the market. The object is to provide a possible electronic device.

  In order to solve the above-described problems, the present invention includes a storage unit and a backup power source, and in an electronic device device including a power supply circuit that electrically connects both, the power supply circuit includes: A detour circuit that transitions to a non-conductive state when power from an external power supply is supplied is provided.

  More specifically, the present invention provides the following.

  (1) A storage unit that stores a program or data and whose stored contents are erased when power supply is stopped, and a backup power source that supplies power to the storage unit, the storage unit and the backup power source In the electronic device device including the power supply circuit that electrically connects the power supply circuit, the power supply circuit includes a bypass circuit that transitions to a non-conductive state when power from an external power supply is supplied. apparatus.

  According to the present invention, there is provided a storage unit that stores programs or data, such as a volatile memory, and whose stored contents are erased when power supply is stopped, and a backup power source that supplies power to the storage unit. Then, in an electronic device apparatus having a power supply circuit that electrically connects the storage means and the backup power supply, when the power supply circuit is supplied with power from an external power source such as a host device, the electronic device apparatus transitions to a non-conductive state Since the detour circuit is provided, the power supply from the backup power supply can be performed through the detour circuit until the power from the external power source such as the host device is supplied.

  Therefore, until the electronic device is connected to the host device (power from the external power supply is supplied), the storage means and the backup power supply are electrically connected by mistake, for example, by removing a jig that should not be removed. Even if the connecting line is electrically disconnected, the power supply to the storage means is not interrupted by the detour circuit (because the memory erasing function is disabled), so it was loaded into the storage means at the factory or the like. It is possible to prevent the program or data from being erased.

  Then, when the electronic device is connected to the host device and the bypass circuit transitions to a non-conducting state, for example, power is supplied to the storage means via a switch or the like that operates (turns off) when the electronic device is removed from the host device. Therefore, if the electronic device is illegally removed from the host device, the power supply to the storage means is interrupted, and the program loaded in the storage means or Data is automatically deleted, and security can be ensured.

  Here, the “detour circuit” may be any circuit as long as it changes to the non-passing state when power from an external power source such as a host device is supplied. For example, it is composed of a fuse and a relay, and when power from an external power source such as a host device is supplied to the bypass circuit, it may be a circuit in which the fuse is spontaneously cut through the relay, A circuit that consists of a fuse and an IC, and when power from an external power source such as a host device is supplied to the bypass circuit, the power is supplied to the fuse at a predetermined timing by the IC and the fuse is cut. Also good.

  (2) The bypass circuit includes a first relay and a second relay to which electric power from an external power supply is supplied as an exciting current, and a fuse, and the fuse has a break contact of the first relay. And electrically connected to the storage means, and electrically connected to the backup power supply via the break contact of the second relay, and the electric power from the external power supply passes through the make contact of the first relay. (1) The electronic device apparatus according to (1),

  According to the present invention, the above-described bypass circuit is provided with the first relay and the second relay that operate when electric power (current) from an external power supply is supplied as an exciting current, and the fuse. , Electrically connected to the storage means via the break contact of the first relay and electrically connected to the backup power supply via the break contact of the second relay, while the power from the external power supply is the first Because the power is supplied via the make contact of the relay, when the power (current) from the external power source such as the host device is supplied, the detour circuit can be automatically switched to the non-conductive state, As a result, it is possible to prevent the program or data loaded in the storage means at the factory or the like from being erased until the electronic device is connected to the host device. That is, according to the present invention, by using the relay effectively and effectively, the bypass circuit can be automatically switched to the non-conduction state, and as a result, until the electronic device is connected to the host device, Thus, it is possible to prevent the program or data loaded in the storage means from being erased.

  Further, since the power supply path to the storage means when loading a program or data can be separated from the path through which the current flows when the fuse is cut, the current when cutting the fuse flows through the storage means. Can be prevented, and as a result, damage to the storage means can be prevented.

  Furthermore, since the detour circuit can be configured with inexpensive electrical elements such as relays and fuses, it is possible to contribute to a reduction in manufacturing cost. Also, since the bypass circuit can be changed to a non-conductive state by cutting the fuse once, the program or data loaded in the storage means at the factory or the like without using a reliable (expensive) relay Can be prevented from being erased.

  (3) The bypass circuit further includes a rectifying diode having a rectifying function for flowing a current in one direction, a break contact of the second relay is connected to a cathode of the rectifying diode, and the backup power supply is The electronic device apparatus according to (1) or (2), wherein the electronic device apparatus is connected to an anode of the rectifier diode.

  According to the present invention, the above-described bypass circuit is provided with a rectifier diode having a rectification function for flowing a current in one direction, the break contact of the second relay is connected to the cathode of the rectifier diode, and the backup power supply is Since the operation of the second relay is delayed due to the connection with the anode of the rectifier diode, even if the external power supply and the backup power supply are electrically connected, the path of the external power supply → the backup power supply is used. Current can be prevented from flowing, and thus damage to the backup power supply can be prevented.

  (4) The electronic device further includes a first switch connected in series with the backup power supply, a circuit board attached to the electronic device and mounted with the power supply circuit, and the circuit board. Any one of (1) to (3), wherein the first switch is in a non-conductive state when the cover is removed from the circuit board. The electronic device apparatus of description.

  According to the present invention, the electronic device described above includes a first switch connected in series with a backup power supply, a circuit board attached to the electronic device and mounted with a power supply circuit, and a circuit mounting of the circuit board. A cover for protecting the surface, and the first switch is brought into a non-conductive state when the cover is removed from the circuit board. When trying to access the inside, the first switch is turned off and the program or data loaded in the storage means is automatically deleted, so that security can be ensured.

  (5) The electronic device apparatus further includes a second switch connected in series with the backup power source and connected in parallel with the bypass circuit, and the second switch is connected to the electronic device apparatus. The electronic device apparatus according to any one of (1) to (4), wherein the electronic apparatus apparatus is in a non-conducting state when removed from the host apparatus.

  According to the present invention, the electronic device described above is provided with the second switch connected in series with the backup power supply and connected in parallel with the bypass circuit, and the second switch is connected to the electronic device. When the card reader 1 is removed from the host device and attempted to be stolen, for example, the micro switch SW2 is turned off and loaded into the storage means. Since the stored program or data is automatically deleted, security can be ensured.

  (6) The program or data stored in the storage unit is stored in the storage unit in advance before the electronic device is supplied with power from an external power source. (1) to (5) The electronic device device according to any one of the above.

  According to the present invention, the program or data stored in the storage unit described above is stored in the storage unit in advance before the electronic device apparatus receives power from the external power supply. However, it is not necessary to carry a jig or storage medium loaded in the memory and go to the site where the host device is installed, and security can be improved.

  As described above, the electronic device device according to the present invention is in a non-conductive state when power from an external power source is supplied to a power supply circuit that electrically connects a storage unit such as a volatile memory and a backup power source. Since a detour circuit for transition is provided, it is possible to prevent the power supply to the storage means from being interrupted by the detour circuit until the electronic device is connected to the host device and power is supplied from the external power supply. As a result, it is possible to prevent erasing the program or data loaded in the storage means at the factory or the like.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

[Power supply system]
FIG. 1 is a block diagram for explaining an outline of a power supply system for a volatile memory 3 in a card reader 1 according to an embodiment of the present invention. In the present embodiment, the card reader 1 is employed as an example of the electronic device apparatus according to the present invention. In FIG. 1, the main substrate of the card reader 1 on which a CPU, a ROM, and the like are mounted is omitted.

  1, the power supply system for the volatile memory 3 in the card reader 1 according to the embodiment of the present invention includes a volatile memory 3 for storing a program or data used in the card reader 1, a backup power supply 4, And a power supply circuit 2 that supplies power from the backup power supply 4 to the volatile memory 3.

  The volatile memory 3 may be any memory as long as it can receive a power supply from the backup power supply 4 and store a program or data. For example, a DRAM (Dynamic Random Access Memory) or an SRAM (Static Random). Access Memory).

  The power supply circuit 2 mainly includes a first switch 21, a bypass circuit 22, and a second switch 23. The first switch 21 becomes non-conductive when a cover (not shown) that protects the circuit mounting surface of the circuit board on which the power supply circuit 2 is mounted is (illegally) removed from the card reader 1. This is a switch (from on to off). The first switch 21 is in a conductive state (ON) when the card reader 1 is manufactured and the cover is attached.

  The second switch 23 is a switch that is turned off (turned from on to off) when the card reader 1 is removed from a host device such as an ATM. The second switch 23 is not in a conductive state when the card reader 1 is manufactured and a cover is attached, and is in a conductive state (ON) when incorporated in a host device such as an ATM. is there.

  The bypass circuit 22 includes a plurality of relays that operate when an excitation current is supplied, a fuse that is cut when the card reader 1 is connected to a host device, and the like. For example, this fuse is blown (dissolved) when a current of less than 1 A is supplied from the 12 V power supply of the host device.

  In the power supply system described above, the flow of supplying power from the backup power supply 4 to the volatile memory 3 will be described with reference to FIG. FIG. 2 is a block diagram for explaining a flow of supplying power from the backup power supply 4 to the volatile memory 3 in the card reader 1 according to the embodiment of the present invention. In FIG. 2, the same elements as those in FIG. 1 are denoted by the same reference numerals.

  In FIG. 2, when the card reader 1 is manufactured in a factory and the above-described cover is attached, the first switch 21 becomes conductive. When supplying power from the backup power supply 4 to the volatile memory 3 in the factory, the second switch 23 is not in a conductive state, and therefore, a route as indicated by a thick arrow in FIG. Power is supplied. That is, the path is backup power supply 4 → first switch 21 → bypass circuit 22 → volatile memory 3.

  When power supply to the volatile memory 3 is completed, a program or data is written. More specifically, a CPU (not shown) mounted on the main board of the card reader 1 accesses the volatile memory 3 and writes a necessary program or data.

  When the writing to the volatile memory 3 is completed, the card reader 1 is transported (shipped) from the factory to a place where a host device such as ATM is installed. When the card reader 1 is incorporated into the host device, the second switch 23 is turned on (on), and the card reader 1 is electrically connected to the host device.

  When the card reader 1 is electrically connected to the host device and a current of less than 1 A is supplied from the 12 V power source of the host device to the bypass circuit 22, the fuse in the bypass circuit 22 is cut and power is supplied to the volatile memory 3. The route is switched to a route as indicated by a thick arrow in FIG. Then, in the case where power is supplied through the path shown by the thick arrow in FIG. 2B, for example, when the card reader 1 is illegally removed from the host device, the second switch 23 becomes non-conductive. (From on to off), the power supply to the volatile memory 3 is interrupted, and the program or data loaded in the volatile memory 3 is automatically erased.

  Here, the second switch 23 is disabled after the writing of the program or data to the volatile memory 3 is completed and before the card reader 1 is shipped and electrically connected to a host device such as ATM. Has been. Therefore, the program and data loaded in the volatile memory 3 will not be erased by an erroneous operation of the second switch 23.

  That is, if the second switch 23 is turned on with a jig or the like from the stage of writing a program or data at the factory, and power is supplied to the volatile memory 3 through the second switch 23. In the case where power is supplied from the beginning through the path shown by the thick arrow in FIG. 2B, when the second switch 23 is turned off by an erroneous operation, power is supplied to the volatile memory 3. As a result, the program and data loaded in the volatile memory 3 before the card reader 1 is connected to the host device are erased. On the other hand, according to the card reader 1 according to the present embodiment, power is supplied to the volatile memory 3 via the bypass circuit 22 until the card reader 1 is electrically connected to the host device. Since the power supply to the volatile memory 3 is not interrupted even when the second switch 23 is turned on or off, the second switch 23 is loaded into the volatile memory 3 due to an erroneous operation of the second switch 23. Programs and data are never lost. Therefore, it is possible to prevent the program or data loaded in the volatile memory 3 at a factory or the like from being accidentally erased before being installed in the market.

  FIG. 3 is a circuit diagram showing an electrical configuration of a power supply system for the volatile memory 3 in the card reader 1 according to the embodiment of the present invention.

  3, the power supply system for the volatile memory 3 in the card reader 1 according to the embodiment of the present invention is an interface 5 connected to a backup power source (not shown) installed on the main board or the like of the card reader 1. A volatile memory 3 that stores programs and data used by the card reader 1, a power supply circuit 2 that supplies power from the backup power source supplied via the interface 5 to the volatile memory 3, have. The card reader 1 also has an interface 6 connected to a 12V power supply (not shown) installed on the main board or the like of the card reader 1. From the 12V power supply supplied via the interface 6 Electric power is supplied to a fuse F described later.

  The power supply circuit 2 includes a micro switch SW1, a micro switch SW2, and a bypass circuit 22. The microswitch SW1 is in a non-conductive state when a cover (not shown) that protects the circuit mounting surface of the circuit board on which the power supply circuit 2 is mounted is removed from the card reader 1. This corresponds to the first switch 21 shown in FIG. The microswitch SW2 is in a non-conductive state when the card reader 1 is removed from a host device such as an ATM, and corresponds to the second switch 23 shown in FIG.

  The bypass circuit 22 and the micro switch SW2 are connected in parallel to each other, and the micro switch SW1 is connected in series to the parallel circuit. With this configuration, until the card reader 1 is electrically connected to a higher-level device such as an ATM, the backup power supply can be used regardless of whether the microswitch SW2 is turned on or off due to an erroneous operation. Can be supplied to the volatile memory 3 through the bypass circuit 22, and thus the program or data loaded in the volatile memory 3 due to an erroneous operation can be prevented from being erased.

  In addition, after the card reader 1 is electrically connected to a host device such as ATM, power is supplied to the volatile memory 3 via the microswitch SW1 and the microswitch SW2 connected in series. Therefore, for example, if the cover is opened illegally to access the memory or the inside of the card reader 1, the micro switch SW1 becomes non-conductive, and for example, the card reader 1 is removed from the host device and stolen. In other cases, the microswitch SW2 is turned off, so that the program or data stored in the volatile memory 3 is automatically erased, and security is maintained.

  The detour circuit 22 receives a current (for example, a current of up to 1 A) from the first relay RL1 and the second relay RL2 in which the make contact and the break contact operate when an excitation current is supplied, and the interface 6 from the 12V power supply. It consists of a fuse F that is cut (melted) when it flows, and a rectifier diode D that has a rectifying function to flow current in one direction. The fuse F may be of a type that melts the resistance wire, or may be of a type that melts the low melting alloy by the heat generated by the resistance wire. In particular, the bypass circuit 22 can be manufactured at low cost by using a type that melts the resistance wire.

  The circuit operation of the bypass circuit 22 will be described in detail below with reference to FIGS.

[Circuit operation]
FIG. 4 is a flowchart showing an outline of circuit operation until the card reader 1 according to the embodiment of the present invention is manufactured in a factory or the like and installed in the market. The circuit operation here will be described by paying particular attention to the circuit operation of the bypass circuit 22.

  In FIG. 4, first, when the card reader 1 is manufactured in a factory and a cover for protecting the circuit mounting surface of the circuit board on which the power supply circuit 2 is mounted is attached, the microswitch SW1 becomes conductive (step S1). .

  Next, power is supplied from the backup power source to the volatile memory 3 (step S2). More specifically, a description will be given with reference to FIG.

  FIG. 5 is a circuit diagram for explaining that the process (power supply) in step S2 of FIG. 4 is executed in the electrical configuration shown in FIG. The current flow from the backup power supply is represented by a thick arrow. In FIG. 5, two terminals “A” indicate that they are electrically connected. In FIG. 5, the same components as those shown in FIG. 3 are denoted by the same reference numerals.

  In FIG. 5, the current from the backup power source (for example, 5V) is as follows: predetermined terminal of interface 5 → micro switch SW1 → rectifier diode D → 7 pin of second relay RL2 → 6 pin of second relay RL2 → fuse F → It flows in the order of 3 pins of the first relay RL 1 → 2 pins of the first relay RL 1 → volatile memory 3.

  After power is supplied to the volatile memory 3 in this way, the volatile memory 3 is electrically connected to the interface 6 and is connected to the volatile memory 3 by a CPU (not shown) mounted on the main board of the card reader 1. A necessary program or data is written. After that, it is transported from the factory to the place where the host device such as ATM is installed. At this time, the micro switch SW2 is invalidated. That is, the power supply to the volatile memory 3 is not interrupted even when the microswitch SW2 is turned on or off. Therefore, it is possible to prevent the program or data loaded in the volatile memory 3 at a factory or the like from being accidentally erased before being installed in the market.

  Next, when the card reader 1 is attached to the host device at a place where a host device such as ATM is installed, the microswitch SW2 is turned on (step S3). When the card reader 1 is electrically connected to the host device (step S4), a current flows through the fuse F of the bypass circuit 22. More specifically, a description will be given with reference to FIG.

  FIG. 6 is a circuit diagram for explaining a state in which the process of step S4 in FIG. 4 (connected to the host device) is executed in the electrical configuration shown in FIG. The flow of current from the power supply of the host device is represented by a thick line arrow. In FIG. 6, two terminals “B” represent that they are electrically connected. In FIG. 6, the same components as those shown in FIG. 3 are denoted by the same reference numerals.

  In FIG. 6, the power (current) from the power supply of the host device flows from the predetermined terminal of the interface 6 as the exciting current to the relay coil of the first relay RL1, so that the first relay RL1 is activated and the pin 3 Pin 4 is shorted. At the same time, pins 5 and 6 of the first relay RL1 are also short-circuited. Then, the power (current) from the power supply of the host device also flows as an exciting current to the relay coil of the second relay RL2, and the second relay RL2 is activated to short-circuit the 5th pin and the 6th pin. As a result, the current from the power supply (for example, 12V) of the host device is obtained from the predetermined terminal of the interface 6 → the 4th pin of the first relay RL1 → the 3rd pin of the first relay RL1 → the fuse F → the 6th of the second relay RL2. It flows in the order of pin → 5 pin of second relay RL2 → PG.

  Note that a rectifier diode D exists between the 7th pin of the second relay and the microswitch SW1, and it is assumed that the timing at which the first relay RL1 operates and the timing at which the second relay RL2 operates. , A time lag occurs, and the current from the power supply of the host device does not flow even if it tries to flow through pins 6 and 7 of the second relay. Therefore, it is possible to prevent a current of less than 1 A from flowing through the path from the power supply from the host device to the backup power supply (reverse flow), and thus to prevent damage to the backup power supply.

  Next, when a current (for example, less than 1 A) from the power supply (for example, 12 V) of the host device flows into the fuse F, the fuse F is melted and cut (step S5). Then, the power supply path for the volatile memory 3 is switched to one that passes through the micro switch SW2. More specifically, a description will be given with reference to FIG.

  FIG. 7 is a circuit diagram for explaining a state after the process of step S5 of FIG. 4 (fuse F cutting) is performed in the electrical configuration shown in FIG. The current flow from the backup power supply is represented by a thick arrow. In FIG. 7, two terminals “A” represent that they are electrically connected. In FIG. 7, the same circuit elements as those shown in FIG. 3 are denoted by the same reference numerals.

  In FIG. 7, when the fuse F is cut by the process of step S5, the bypass circuit 22 is in a non-conductive state, so that the supply of excitation current to the first relay RL1 and the second relay RL2 is interrupted. It will not work. If it does so, the relay contact of 1st relay RL1 and 2nd relay RL2 will return to what is shown in FIG. 5 from what is shown in FIG. However, since the bypass circuit 22 is in a non-conductive state by cutting the fuse F (indicated by x in FIG. 6), the power supply path to the volatile memory 3 is switched to that passing through the microswitch SW2. It will be. As a result, the current from the backup power source (for example, 5V) flows in the order of a predetermined terminal of the interface 5 → microswitch SW1 → microswitch SW2 → volatile memory 3.

  In this way, after the power supply path is switched, the circuit operation of the card reader 1 ends. Thereafter, for example, when the cover is illegally opened to try to access the memory or the inside of the card reader 1, or when the card reader 1 is removed from the host device and stolen, for example, the micro switch SW1 or the micro switch When SW2 becomes non-conductive, power supply to the volatile memory 3 is interrupted, and the program or data stored in the volatile memory 3 is automatically erased, and security is maintained.

[Modification]
FIG. 8 is a block diagram showing an electrical configuration of the detour circuit 22 of the card reader 1 according to another embodiment of the present invention.

  In the card reader 1 according to the embodiment of the present invention described above, the first relay RL1 and the second relay RL2 are used in order to appropriately cut the fuse F by the current from the power supply of the host device. The present invention is not limited to this. For example, as shown in FIG. 8, an IC (including a transistor) or the like can be used. For example, the current from the power supply of the host device is supplied to the bypass circuit 22 and the current flows through the fuse F after a predetermined time lag, and the timing for cutting the fuse F is controlled. Can do.

  The electronic device device according to the present invention is useful as a device that can prevent a program or data loaded in a memory at a factory or the like from being accidentally erased before being installed in the market.

FIG. 2 is a block diagram for explaining an outline of a power supply system for a volatile memory in the card reader according to the embodiment of the present invention. It is a block diagram for demonstrating the flow which supplies electric power from a backup power supply with respect to the volatile memory in the card reader which concerns on embodiment of this invention. It is a circuit diagram which shows the electric constitution of the electric power supply system with respect to the volatile memory in the card reader which concerns on embodiment of this invention. It is a flowchart which shows the outline | summary of the circuit operation | movement until the card reader which concerns on embodiment of this invention is manufactured in a factory etc. and installed in a market. FIG. 5 is a circuit diagram for explaining a state in which the process (power supply) in step S2 of FIG. 4 is executed in the electrical configuration shown in FIG. FIG. 4 is a circuit diagram for explaining a state in which the process of step S4 in FIG. 4 (connected to a host device) is executed in the electrical configuration shown in FIG. FIG. 4 is a circuit diagram for explaining a state after the process of step S5 of FIG. 4 (fuse F cutting) is executed in the electrical configuration shown in FIG. It is a block diagram which shows the electric constitution of the detour circuit of the card reader which concerns on other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Card reader 2 Power supply circuit 3 Volatile memory 4 Backup power supply 21 1st switch 22 Detour circuit 23 2nd switch

Claims (6)

Storage means for storing a program or data and erasing the stored content when power supply is stopped;
A backup power supply for supplying power to the storage means,
In an electronic device apparatus comprising a power supply circuit that electrically connects the storage means and the backup power source,
The electronic device apparatus, wherein the power supply circuit includes a bypass circuit that transitions to a non-conduction state when power from an external power supply is supplied. The bypass circuit includes a first relay and a second relay to which power from an external power source is supplied as an exciting current, and a fuse.
The fuse is electrically connected to the storage means via a break contact of the first relay, and electrically connected to the backup power source via a break contact of the second relay,
2. The electronic device apparatus according to claim 1, wherein electric power from an external power source is supplied through a make contact of the first relay. The bypass circuit further includes a rectifying diode having a rectifying function of flowing a current in one direction,
The break contact of the second relay is connected to the cathode of the rectifier diode,
The electronic device apparatus according to claim 1, wherein the backup power source is connected to an anode of the rectifier diode. The electronic apparatus device further includes a first switch connected in series with the backup power source,
A circuit board mounted on the electronic device device and mounted with the power supply circuit;
A cover for protecting the circuit mounting surface of the circuit board,
4. The electronic device apparatus according to claim 1, wherein the first switch is turned off when the cover is removed from the circuit board. 5. The electronic device apparatus further includes a second switch connected in series with the backup power source and connected in parallel with the bypass circuit,
5. The electronic device apparatus according to claim 1, wherein the second switch is in a non-conductive state when the electronic device apparatus is removed from a host device. 6. The program or data stored in the storage unit is stored in the storage unit in advance before the electronic device is supplied with electric power from an external power source. Electronic device equipment.