JP2009201171A - Battery charger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery charger that prevents overcharge of a secondary battery and can control degradation of a secondary battery. <P>SOLUTION: When the time elapsed after power supply from a power supply 31 is interrupted before power supply is resumed and a multifunction facsimile 1 is started is shorter than a first reference time, a secondary battery 22 is not charged. When the elapsed time Toff exceeds the first reference time S but is shorter than a second reference time L, the secondary battery 22 is charged for a charging time based on the elapsed time Toff. When the elapsed time Toff exceeds the second reference time, the secondary battery 22 is charged for a maximum charging time corresponding to full charge. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a charging device for charging a secondary battery.

2. Description of the Related Art A device such as a facsimile machine or a multi-function machine is well known that includes a secondary battery that backs up a circuit such as a memory so that data is not lost in the event of a power failure. A circuit such as a memory is backed up by discharging the secondary battery during a power failure, and the secondary battery is charged when power supply is resumed. For example, in the technique described in Patent Document 1, the time during which a power failure occurs (T10) is counted, and when the time during which a power failure occurs is less than or equal to a specified time (T1), the time (T5) corresponding to the time (T10) Only the secondary battery is charged (paragraph [0060], FIG. 10 etc.). For this reason, the secondary battery is always charged when a power failure occurs.
JP 2000-341873 A

  However, in the technique described in Patent Document 1 described above, since the secondary battery is always charged when a power failure occurs, there is a problem such as deterioration of the secondary battery due to overcharging. For example, when the power outage time is short, such as an instantaneous power outage, the secondary battery discharge amount is small, so that the secondary battery is easily overcharged by charging, and the life of the battery is shortened.

  Therefore, the problem to be solved by the present invention is to provide a charging device that can prevent overcharge of the secondary battery and suppress deterioration of the secondary battery.

  In order to solve the above-described problem, a charging device according to the present invention includes a charging circuit that charges a secondary battery, and a predetermined time after or after restarting the supply of power from when the supply of power from the outside is interrupted. A time information management unit for calculating an elapsed time up to the timing; and if the elapsed time calculated by the time information management unit exceeds a first reference time, the charging circuit is charged with the secondary battery. A charging control unit that prevents the charging circuit from charging the secondary battery when the elapsed time is equal to or shorter than the first reference time.

  In the charging device according to the present invention, when the elapsed time exceeds a first reference time, the charge control unit charges the secondary battery to the charging circuit with a charge amount corresponding to the elapsed time. Let

  Further, in the charging device according to the present invention, when the elapsed time exceeds the first reference time and is equal to or shorter than a second reference time longer than the first reference time, When the charging circuit charges the secondary battery with a charging amount according to the elapsed time, and the elapsed time exceeds the second reference time, the charging circuit is charged with a charging amount corresponding to full charge. The secondary battery is charged.

  Further, in the charging device according to the present invention, a clock circuit having a clock function operable even when the supply of power is cut off, and a backup that is supplied with a backup power when the supply of electric power from a nonvolatile type or external is cut off The time information management unit acquires time information at that time from the timepiece circuit and records it in the memory when the supply of power is cut off.

  According to the present invention, the secondary battery is charged when the elapsed time from the interruption of the external power supply to the predetermined timing after the restart of the electric power supply or after the restart is equal to or less than the first reference time. Not. For this reason, by adjusting the length of the first reference time, when the time when the power supply is cut off is short, such as an instantaneous power failure, and the discharge amount of the secondary battery is small, the secondary battery It can be easily set so that the battery is not charged. As a result, the secondary battery can be prevented from being overcharged, the deterioration of the secondary battery can be suppressed, and the life can be extended.

  Further, according to the present invention, when the elapsed time from the interruption of the power supply from the outside to the predetermined timing at the restart of the power supply or after the restart exceeds the first reference time, The secondary battery is charged with a charge amount corresponding to the elapsed time. For this reason, it can charge with the charge amount according to the discharge amount of the secondary battery produced by the power failure etc., and the overcharge of a secondary battery can be prevented.

  Further, according to the present invention, the elapsed time from the interruption of the supply of power from the outside to the predetermined timing when the supply of power is restarted or after the restart exceeds the first reference time and the second reference If it is less than the time, the battery is charged with a charge amount corresponding to the elapsed time. For this reason, when the time when the supply of electric power is cut off due to a power failure or the like is in the middle, the overcharge of the secondary battery can be prevented by charging with a charge amount corresponding to the elapsed time.

  Further, when the elapsed time exceeds the second reference time, the secondary battery is charged with a charge amount corresponding to full charge. For this reason, when the supply of electric power is interrupted for a long time and the discharge amount of the secondary battery is large, the secondary battery can be reliably fully charged.

  According to the present invention, the time information is acquired from the clock circuit when the power supply from the outside is cut off, and is recorded in the non-volatile type or the backup type memory to which the backup power is supplied when the power supply is cut off. Therefore, the time information when power supply is interrupted can be reliably stored without being lost due to a power failure or the like.

  FIG. 1 is a block diagram of a facsimile multifunction peripheral (hereinafter simply referred to as “multifunction peripheral”) to which a charging apparatus according to an embodiment of the present invention is applied. In addition, although the case where the charging device according to the present embodiment is applied to the multifunction device 1 will be described here, the charging device according to the present embodiment can be applied to various devices including a secondary battery for backup.

  As shown in FIG. 1, the multi function device 1 includes an MPU (Micro Processing Unit) 11, an NCU (Network Control Unit) 12, a modem (MODEM) 13, a scanner 14, an operation panel 15, a printer 16, a power supply circuit 17, and a flash memory. 18, an SRAM (Static Random Access Memory) 19, an image memory 20, a clock circuit 21, a secondary battery 22, and a charging circuit 23. The functions provided in the multifunction device 1 include a facsimile function, a printer function, a copy function, and the like.

  The MPU 11 supervises the control of the multifunction machine 1 and operates by software. The MPU 11 includes a time information management unit 26 and a charge control unit 27 as functional elements, which will be described in detail later.

  The NCU 12 is hardware for connecting a line to an analog public telephone line network, and connects the modem 13 to the public telephone line network as necessary. The modem 13 is a facsimile modem capable of facsimile communication. The scanner 14 reads an image of a document. The operation panel 15 is used for operating the multifunction device 1 and includes a plurality of operation keys, a liquid crystal display unit, and the like. The printer 16 prints image data read from a document by the scanner 14, image data received by a facsimile, and the like on a recording sheet.

  The power supply circuit 17 supplies driving power to each unit of the multifunction device 1 based on power supplied from an external power supply (for example, commercial power supply) 31. When the supply of power from the external power supply 31 is cut off, the power supply circuit 17 gives a signal indicating the cut-off of the power supply to the MPU 11. The interruption of the supply of power from the power supply 31 to the power supply circuit 17 includes a power failure (including a power failure for a very short time), a case where the power cable of the multifunction device 1 is removed from the outlet, and a main power source (not shown) of the multifunction device 1 This occurs when the switch is turned off.

  The flash memory 18 stores various software read by the MPU 11, setting data, and the like. The SRAM 19 stores phone book data and the like. The image memory 20 stores image data transmitted and received by facsimile, image data read by the scanner 14, and the like.

  As the clock circuit 21, a so-called Real Time Clock is used and counts not only the hour and minute but also the date. Since the timepiece circuit 21 is provided with a dedicated battery (primary battery) 32, the time counting can be continued even if the supply of power from the external power supply 31 is interrupted. The clock circuit 21 is provided with a nonvolatile memory 33 for recording time information.

  The secondary battery 22 supplies backup power to each part in the multifunction peripheral 1 that needs to maintain the power supply when the power supply from the external power supply 31 is interrupted. In the present embodiment, backup power is supplied to, for example, the SRAM 19 and the image memory 20 by the secondary battery 22 when the supply of power from the power supply 31 is interrupted. As the secondary battery 22, for example, a nickel / cadmium battery or a nickel / metal / hydrogen battery is used. Note that the SRAM 19 may be backed up by another primary battery.

  The charging circuit 23 charges the secondary battery 22 based on a control signal given from the MPU 11. Specifically, the charging circuit 23 includes a semiconductor switching element 41, a constant current circuit 42, a diode 43, a transistor 44, and the like. The semiconductor switching element 41 turns on / off the supply of power from the power supply circuit 17 to the constant current circuit 42 according to the on / off operation of the transistor 44. The constant current circuit 42 outputs a constant current for charging the secondary battery 22 based on the power supplied from the power supply circuit 17. The diode 43 is inserted between the constant current circuit 42 and the secondary battery 22 so as to be in the forward direction toward the secondary battery 22, and the current discharged from the secondary battery 22 is transferred to the charging circuit 23 side. Prevent backflow. The transistor 44 is turned on / off according to a control signal supplied from the MPU 11 to turn on / off the semiconductor switching element 41.

  The time information management unit 26 of the MPU 11 acquires the time information from the clock circuit 21, so that the power supply from the external power supply 31 is interrupted, the power supply from the power supply 31 is restarted, or after the restart. An elapsed time Toff until a predetermined timing is calculated. As the predetermined timing, for example, the timing when the power supply from the power supply 31 is restarted and the power switch of the multifunction device 1 is turned on (the timing when the multifunction device 1 is activated) is employed. In this embodiment, the elapsed time Toff from when the power supply from the external power source 31 is interrupted until the time when the power supply from the power source 31 is restarted and the multifunction device 1 is activated is detected by the time information management unit 26. Is calculated. When the supply of power from the power supply 31 that has been interrupted due to a power failure or the like is resumed, if the power switch of the multifunction device 1 remains on, the multifunction device is associated with the resumption of power supply. 1 is activated. However, when the power switch of the multifunction device 1 is turned off, the multifunction device 1 is started when the power switch is turned on after the supply of power from the power source 31 is resumed.

  The calculation of the elapsed time Toff from the time when the supply of power from the power source 31 by the time information management unit 26 is stopped is performed as follows. That is, when the signal indicating that the power supply from the power supply 31 is cut off is input from the power supply circuit 17, the time information management unit 26 causes the clock circuit 21 to record the time information at that time in the nonvolatile memory 33 ( Step S1) in FIG. Then, the time information management unit 26 acquires the time information read from the nonvolatile memory 33 of the timepiece circuit 21 and the timepiece circuit 21 when the supply of power from the power supply 31 is resumed and the multifunction device 1 is activated. The elapsed time Toff is calculated based on the time information at that time.

  The time information management unit 26 also functions as a charge timer when charging the secondary battery 22, and uses the time information obtained from the clock circuit 21 to charge the secondary battery 22 when charging the secondary battery 22. The charging time set by 27 is counted.

  The charge control unit 27 of the MPU 11 is responsible for the control of the charging circuit 23 and the like, and when the multifunction device 1 is started after the supply of power from the power source 31 is resumed, the secondary battery is based on the following determination method. Whether or not charging is required is determined. Then, when charging is necessary, the charging control unit 27 controls the charging circuit 23 in cooperation with the time information management unit 26 and charges the secondary battery 22.

  Specifically, when the elapsed time Toff is equal to or shorter than the first reference time S, the secondary battery 22 is not charged. When the elapsed time Toff exceeds the first reference time S and is equal to or shorter than the second reference time L that is longer than the first reference time S, the secondary battery 22 has the charge amount corresponding to the elapsed time Toff. Charged. When the elapsed time Toff exceeds the second reference time L, the battery is charged with a charge amount corresponding to full charge. For example, when the elapsed time Toff is less than a few minutes, charging is avoided, and when the elapsed time Toff is about several hours, the charging is set to about half of the maximum charge amount.

  In the present embodiment, since the charging circuit 23 supplies the secondary battery 22 with a constant current for charging, the charging time is used as a reference for determining the amount of charge. The charging control unit 27 sets a charging time corresponding to the amount of charge in the time information management unit 26 that is a charging timer when the secondary battery 22 is charged. Then, after the start of charging, as shown in FIG. 4, the charging control unit 27 is notified to the charging circuit 23 when the end of charging time is notified from the time information management unit 26 (step S6). The charging of the battery 22 is terminated and a charging completion flag is set (step S7). Flag information related to this charge completion flag is stored in, for example, the SRAM 19.

  FIG. 5 is a flowchart illustrating an operation when the multifunction device is started by restarting the power supply from the outside in the multifunction device. As shown in FIG. 5, when the supply of power from the power source 31 is resumed and the multifunction device 1 is activated, the charge control unit 27 refers to the flag information and determines whether or not the charge completion flag is set. (Step S11). When the charge completion flag is not set, it is considered that the supply of power from the power source 31 is interrupted while the secondary battery 22 is being charged, so the charge timer is set to full charge. The secondary battery 22 is charged (step S12).

  When the charge completion flag is set, it is considered that the supply of power from the power source 31 is cut off in a state where the charging to the secondary battery 22 is completed. Is determined, the secondary battery 22 is charged as necessary. First, the elapsed time Toff from the time when the power supply from the power supply 31 is cut off to the time when the power supply is restarted and the multifunction device 1 is started is calculated by the time information management unit 26 as described above. (Step S13).

  Subsequently, the charging control unit 27 determines whether or not the elapsed time Toff exceeds the second reference time L (step S14). If the elapsed time Toff exceeds the second reference time L, the charge completion flag is cleared (step S15), the charge timer is set to full charge, and the secondary battery 22 is charged (step S12). . If the elapsed time Toff does not exceed the second reference time L, the charging control unit 27 determines whether or not the elapsed time Toff is equal to or less than the first reference time S (step S16), and the elapsed time. When Toff is equal to or shorter than the first reference time S, charging of the secondary battery 22 is avoided. When the elapsed time Toff exceeds the first reference time S, the charge control unit 27 clears the charge completion flag (step S17), sets the charge timer according to the elapsed time Toff, and sets the secondary battery. 22 is charged (step S18). When the charging in steps S12 and S18 is normally completed, the charging completion flag is set again by the process in step S7 described above.

  As described above, according to the present embodiment, the elapsed time Toff from when the power supply from the power supply 31 is interrupted until the power supply is restarted and the MFP 1 is started is equal to or less than the first reference time S. In the case, the secondary battery 22 is not charged. For this reason, by adjusting the length of the first reference time S, when the time when the supply of power is cut off, such as an instantaneous power failure, is short and the discharge amount of the secondary battery 22 is small, It can be easily set so that the secondary battery 22 is not charged. As a result, overcharge of the secondary battery 22 can be prevented, deterioration of the secondary battery 22 can be suppressed, and the life can be extended. For example, when the elapsed time Toff is less than about several minutes, processing such as avoiding charging of the secondary battery 22 can be performed.

  When the elapsed time Toff exceeds the first reference time S and is equal to or shorter than the second reference time L, the secondary battery 22 is charged with a charging time corresponding to the elapsed time Toff. For this reason, the overcharge of the secondary battery 22 can be prevented by charging with a charge amount corresponding to the discharge amount of the secondary battery 22 caused by a power failure or the like. For example, when the elapsed time Toff is about several hours, the charging time can be reduced to half (or several percent) of the maximum charging time corresponding to full charging.

  Further, when the elapsed time Toff exceeds the second reference time, the secondary battery 22 is charged with the maximum charging time corresponding to full charge. For this reason, when the supply of power is interrupted for a long time and the secondary battery 22 has a large amount of discharge, the secondary battery 22 can be reliably fully charged.

  In addition, since the time information of the clock circuit 21 is recorded in the nonvolatile memory 33 when the supply of power from the power supply 31 is interrupted, the time information when the supply of power is interrupted can be ensured without being lost due to a power failure or the like. Can be saved.

  In the above-described embodiment, the time information of the timepiece circuit 21 when the supply of power from the power supply 31 is cut off is recorded in the nonvolatile memory 33 provided in the timepiece circuit 21. As a modification regarding this point, time information at the time of interruption of power supply may be recorded in a nonvolatile memory (for example, the flash memory 18 or the like) provided separately from the clock circuit 21. Alternatively, a backup battery at the time of a power failure may be provided in another memory such as the SRAM 19 and time information at the time of power supply interruption may be recorded in the memory.

  In the above-described embodiment, the timepiece circuit 21 is provided in the multi-function device 1. However, time information of the timepiece circuit 21 provided in another device connected via a network or the like may be used.

1 is a block diagram of a facsimile multifunction machine to which a charging device according to an embodiment of the present invention is applied. FIG. 2 is a circuit diagram illustrating a configuration of a charging circuit provided in the facsimile multifunction peripheral of FIG. 1. 2 is a flowchart showing an operation when recording time information when power supply is cut off in the facsimile multifunction machine of FIG. 1. 2 is a flowchart illustrating an operation when charging of the secondary battery is completed in the facsimile multifunction peripheral of FIG. 1. 2 is a flowchart illustrating an operation when the external power supply of the facsimile multifunction peripheral of FIG. 1 is restarted and the facsimile multifunction peripheral is activated.

Explanation of symbols

1 Facsimile MFP 11 MPU
12 NCU
13 Modem 14 Scanner 15 Operation Panel 16 Printer 17 Power Supply Circuit 18 Flash Memory 19 SRAM
20 Image memory 21 Clock circuit 22 Secondary battery 23 Charging circuit 26 Time information management unit 27 Charging control unit 31 Power source 33 Non-volatile memory

Claims (4)

A charging circuit for charging the secondary battery;
A time information management unit for calculating an elapsed time from the interruption of the power supply from the outside to the predetermined timing at the time of restarting the power supply or after the restart;
When the elapsed time calculated by the time information management unit exceeds a first reference time, the charging circuit is charged with the secondary battery, and the elapsed time is equal to or less than the first reference time. In some cases, the charging device includes a charging control unit that does not charge the secondary battery in the charging circuit. The charging device according to claim 1,
The charging control unit causes the charging circuit to charge the secondary battery with a charge amount corresponding to the elapsed time when the elapsed time exceeds a first reference time. The charging device according to claim 2,
When the elapsed time exceeds the first reference time and is equal to or shorter than a second reference time longer than the first reference time, the charge control unit is charged with the amount of charge according to the elapsed time. Charging the secondary battery in a charging circuit, and when the elapsed time exceeds the second reference time, causing the charging circuit to charge the secondary battery with a charging amount corresponding to a full charge. Charging device characterized. The charging device according to any one of claims 1 to 3,
A clock circuit having a clock function operable even when the supply of power is interrupted;
A non-volatile type or a backup type memory to which power for backup is supplied when the supply of power from the outside is interrupted,
The said time information management part acquires the time information in that time from the said timepiece circuit at the time of interruption | blocking of the supply of electric power, and records it on the said memory.

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