JPH05189095A - Electronic device - Google Patents

Abstract

(57) [Summary] [Object] The present invention relates to a device driven by a battery, and in particular, to a power supply thereof, a device capable of more efficiently using a rechargeable battery dedicated to memory backup. For the purpose of provision. [Structure] A power source output is supplied from a battery 10 as a main power source and a rechargeable battery 12 dedicated to data backup, and the power source output of the battery 10 is sent to each unit to be supplied to the battery 10.
Output voltage of the battery 10 from the battery 12 to the circuit portion in which data to be backed up is stored when the output voltage of the battery drops below the output voltage of the second battery 12. A charging circuit 16 that charges the battery 12 with the power output of the battery 10 when

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device such as a small portable terminal driven by a battery and, more particularly, to a power source thereof.

Electronic devices such as word processors, personal computers, copy machines, and facsimile devices are being made smaller and lighter, and those which can be cooperated with each other are provided.

In many cases, a battery is used as a main power source in these small portable terminals, and therefore, it is possible to use the terminal at any time while going out or on the way.

However, since the data inside the terminal is generally stored in a volatile memory, when the battery used as the main power source is exhausted, these data are lost.

Therefore, a battery dedicated to memory backup is prepared separately from the battery for the main power source, and when the battery for the main power source is exhausted, the battery is powered by the volatile memory storing data inside the terminal. Is supplied.

[0006]

2. Description of the Related Art A small-sized and large-capacity lithium battery is widely used as a battery dedicated to memory backup. According to this type of battery, even if the terminal is left unattended while the main power battery is exhausted, It is possible to guarantee the data on the memory for a long time.

However, in that case, it is necessary to periodically replace the battery, and if the battery is neglected, the battery for the main power supply as well as the battery dedicated to the memory backup will be consumed, and important data will be lost unexpectedly. Disappears.

For this reason, in a terminal in which the built-in battery is repeatedly charged and discharged with a relatively high frequency of connection with an external power source, it can be charged as a battery dedicated to memory backup, such as a nickel-cadmium storage battery. A secondary battery is used.

[0009]

However, since this type of battery has a smaller capacity than a primary battery such as a lithium battery, it has been desired to extend the memory backup time.

The present invention has been made in view of the above conventional circumstances, and an object of the present invention is to provide an apparatus capable of more efficiently using a rechargeable battery dedicated to a memory backup. ..

[0011]

In order to achieve the above object, the electronic device according to the first invention is configured as shown in FIG. 1, in which the first battery 10 of the main power source and a dedicated data backup are provided. When the output voltage of the first battery 10 is supplied to each unit and the output voltage of the first battery 10 becomes lower than the output voltage of the second battery 12, When the output voltage of the first battery 10 is higher than that of the second battery 12, the power supply circuit 14 that supplies the power output of the second battery 12 to the circuit portion in which the data to be backed up is stored. A first charging circuit 16 that is charged by the power supply output of the first battery 10.

In addition, in the device according to the second invention, in FIG. 1, FIG. 3 and FIG. 4, the power output is supplied from the first battery 10 of the main power source and the rechargeable second battery 12 dedicated to the data backup, The power output of the battery 10 is sent to each part, and when the output voltage of the first battery 10 is lower than that of the second battery 12, the power output of the second battery 12 is sent to a circuit part in which data to be backed up is stored. A power supply circuit 14 for supplying power, a backup power supply path 22 that branches from the output side of the power supply circuit 14 to the group 68 of the circuit parts that is divided according to the importance of the stored data, and a branch path of the backup power supply path 22. The switch 24 inserted into each of the backup power supply path 22 and the reference voltage set for each branch path of the backup power supply path 22 are compared with the output voltage of the second battery 12, A switch control circuit 26 to open the switch 24 corresponding with the reference voltage when the output voltage of Tteri 12 is below the one of the reference voltage.

Further, in the device according to the third invention, the power output is supplied from the first battery 10 of the main power source and the rechargeable second battery 12 dedicated to the data backup in FIG. 1, FIG. 5 and FIG. The power supply output of the battery 10 is sent to each part, and when the output voltage of the first battery 10 becomes lower than the output voltage of the second battery 12, the second battery 12 is sent to a circuit part in which data to be backed up is stored.
A power supply circuit 14 for transmitting the power output of the power supply, a backup power supply path 22 branching from the output side of the power supply circuit 14 to the group 68 of the circuit parts divided by the importance of the stored data, and a backup power supply. The switch 24 inserted into each branch of the path 22 is compared with the timer time set for each branch of the backup power supply path 22 and the time elapsed after the power supply by the second battery 12 is started, And a switch control circuit 26 that opens the switch 24 corresponding to the timer time when the elapsed time exceeds any timer time.

1 and 7, the device according to the fourth aspect of the present invention is supplied with power output from a first battery 10 as a main power source and a rechargeable second battery 12 dedicated to data backup. The power output is sent to each part, and the output voltage of the first battery 10 is changed to the second battery 12.
Power supply circuit 14 that supplies the power output of the second battery 12 to the circuit portion in which data to be backed up is stored when the output voltage drops below the output voltage of Circuit part group 68
The backup power supply path 22 branched from the output side of the power supply circuit 14, the switch 24 inserted in each branch of the backup power supply path 22, and the reference voltage and the timer time correspond to each branch of the backup power supply path 22. Is set by
When the time elapsed from when the output voltage of the second battery 12 falls below any reference voltage exceeds the timer time corresponding to the reference voltage, the switch 24 of the branch path in which both reference voltages and the timer time are set And a switch control circuit 26 for opening.

[0015]

In FIG. 1, the second battery 12 is a rechargeable secondary battery dedicated to memory backup.

When the first battery 10 is taken out for replacement or is consumed, the memory backup operation by the second battery 12 is started, and the second battery 12 is gradually consumed.

According to the first aspect of the present invention, when the first battery 10 is replaced with a fully charged one (or when an external power source is connected and charging is started), the second battery 12 is used.
When the output voltage is high and the consumption has not progressed, the second battery 12 is trickle charged from the first battery 10 side with a constant voltage or a constant current.

Further, in this case, the second battery 12
If the output voltage of the second battery 12 is low, the second battery 12 is normally charged or rapidly charged.

That is, in the case where the first battery 10 is exhausted and the second battery 12 is exhausted, the device is reused each time the second battery 12 is not fully charged by trickle charging. The first invention assumes a case where the second battery 12 is driven by a battery and the wear of the second battery 12 gradually progresses, and the second battery 12 is rapidly charged in a state where the wear of the second battery 12 progresses to some extent.

Therefore, the second battery 12 can be maintained in a fully charged state at all times, and therefore, the memory data in the device can be backed up for a longer time. In contrast to the above first invention, the second, third, and fourth inventions reduce the load (data) of the second battery 12 in stages to extend the guaranteed time of backup, and the importance of backup is high. Backup is stopped in order from the lowest load.

Of these, the output voltage of the second battery 12 is used in the second invention, the backup time is used in the third invention, and the output voltage of the second battery 12 is used in combination with the backup time in the fourth invention. , The load at which backup is stopped is determined.

As a result, the more important the load is, the longer the battery is backed up by the second battery 12.

[0023]

【Example】

First Embodiment: FIG. 1 shows a first embodiment, in which a battery 10 of the same drawing is used as a main power source of the apparatus, and is a set of five 1.2V nickel-cadmium storage batteries. 0V
The voltage of can be output.

The battery 10 shown in the figure is dedicated to the memory backup of the apparatus. It is a set of three 1.2V nickel-cadmium storage batteries and can output a voltage of 3.6V.

The power supply paths of the batteries 10 and 12 are connected to the power supply circuit 14, and the power supply circuit 14
Is composed of diodes 50 and 52 respectively inserted in both power supply paths and a diode 54 connecting both power supply paths on the circuit output side.

These power supply paths are connected to a circuit portion that does not require data backup and a circuit portion that requires backup, respectively. The output of the battery 10 is prioritized by the diode 54 over the output of the battery 12. Therefore, when the output voltage of the battery 10 is higher than the output voltage of the battery 12, the battery 10 is supplied to both the circuit portion requiring the backup and the circuit portion not requiring the backup.
The power supply output of is supplied from the power supply circuit 14.

When the battery 10 is exhausted and its output voltage drops to the output voltage of the battery 12, the power supply circuit 14 supplies the power output of the battery 12 only to the circuit portion requiring backup.

Charging circuits 16 and 20 are inserted on the battery side of the power supply circuit 14, and the charging circuit 16 has a circuit configuration in which a diode 56 and a resistor 58 having a relatively high value are connected in series. ..

This diode 56 turns on when the output voltage of the battery 10 is higher than the output voltage of the battery 12,
Therefore, the battery 12 is charged by the power output of the battery 10.

However, since the resistor 58 having a relatively high value is connected in series to the diode 56, the battery 12 is trickle charged (about 0.01 to 0.05 C) with a small current.
To be done.

The other charging circuit 20 has a circuit configuration in which a switch (transistor) 60, a diode 62, and a resistor 64 having a relatively low value are connected in series, and the switch 60 has a power detection circuit 18 (IC Used) output is being supplied.

The output of the battery 12 is detected in the voltage detection circuit 18, and when the output voltage drops to a predetermined voltage (3.5V), the switch 60 is closed by the output of the voltage detection circuit 18.

Therefore, in this case, since the resistor 64 having a low value is used, the battery 12 is rapidly charged by the power output of the battery 10 (normal charging,
Quick charge).

In this embodiment, the main power battery 10
Is not consumed and its output voltage is high, or power is supplied from an external power supply (power adapter),
The battery 12 dedicated to the memory backup is charged.

If the battery 10 is taken out for replacement with the external power supply not connected, or if the battery 10 is depleted by the battery drive of the apparatus and its output voltage drops, the memory is stored in the battery 12. The above data is backed up.

Further, when the battery 10 is replaced with a fully charged one, or when the external power source is connected again, the memory backup dedicated battery 12 is charged.

Here, the battery 12 dedicated to backup
Is not exhausted at all, or when the degree thereof is slight, trickle charging is performed by the charging circuit 16, but the battery 10 of the main power source is exhausted and the battery 1 is consumed.
When the device is repeatedly used to start discharging, the battery 12 is discharged more and more and the output voltage gradually decreases when the amount more than the trickle charge is discharged each time. When the voltage drops to 5 V), the switch 60 is closed and the battery 12 is rapidly charged by the charging circuit 20.

The rapid charging is performed even when the apparatus 10 is left for a long time while the main power source battery 10 is exhausted and the battery 12 is being exhausted. Therefore, the backup dedicated battery 12 is always used. The battery is kept fully charged, so that the memory backup can be reliably performed for a long time.

When the battery 12 dedicated for memory backup is almost fully charged (4.0 V or more), the switch 60 is opened, so that the battery 12 by the charging circuit 16 is opened.
Return to trickle charging.

Second Embodiment: FIG. 2 illustrates the configuration of the second embodiment. In this example, a plurality of voltage detection circuits 18 and charging circuits 20 are provided.

Therefore, it is possible to finely control the charging current, the charging start voltage, and the charging end time of the battery 12 dedicated to the memory backup, if necessary.

Third Embodiment: FIG. 3 illustrates the configuration of the third embodiment. In this example, the power supply path 22 of the memory backup dedicated battery 12 is branched into three at the output side of the power supply circuit 14. ing.

These branch paths are respectively connected to the circuit portion group 68-1 for the main memory and the internal clock (timer), the circuit portion group 68-2 for the extended memory board and the circuit portion group 68-3 for the IC memory card. And
A switch 24 (transistor) is inserted in each branch path.

Further, a switch control circuit 26 composed of a voltage detection circuit 70 (using an IC) for providing an output to each switch 24 is provided, and each voltage detection circuit 70 has an output voltage of the memory backup dedicated battery 12 of 3 0.0V,
The switch 24 corresponding to the corresponding group 68-1, 68-2, 68-3 when the voltage becomes 3.3 V or 3.6 V or less
Open each (close each when above).

Therefore, as the memory backup dedicated battery 12 is consumed, the groups 68-3, 68-2, 68-2,
In the order of 68-1, that is, in the reverse order of the importance of the data to be backed up (IC memory card → extended memory board → main memory and internal clock), the backup power supply is cut off.

Therefore, highly important data is backed up to the end, and its contents are guaranteed for a longer time.

Fourth Embodiment: FIG. 4 illustrates the configuration of the fourth embodiment. In this example, a large number of groups 68-1.
68-2 ... 68-n are divided into circuit parts of the device (targets for backup), and a switch 24 and a power supply detection circuit 70 are provided for each of them.

Therefore, the control of the third embodiment in which the power supply to the memory backup is cut off in order can be performed more finely.

Fifth Embodiment: FIG. 5 illustrates the configuration of the fifth embodiment, in which a timer 80 is used in place of the power supply detector 70 of FIG.

The time-up times of the timers 80 are set to 30 hours, 10 hours and 3 hours respectively corresponding to the groups 68-1.68-2 and 68-3, and the external power source is not connected. When the output voltage of the main power supply battery 10 falls below 3.6V, the timer starting circuit 82 simultaneously starts up.

Therefore, after the memory backup is started, the power supply of the memory back is cut off in the order of the groups 68-3, 68-2, 68-1.

Sixth Embodiment: FIG. 6 illustrates the configuration of the sixth embodiment, and in this example, a large number of groups 68 are provided.
68-n are divided into circuit parts (targets for backup) of the device, and a switch 24 and a timer 80 are provided for each of them.

Therefore, the control of the fifth embodiment in which the voltage supply for the memory backup is cut off in order can be performed more finely.

Seventh Embodiment: FIG. 7 illustrates the configuration of the seventh embodiment. This embodiment is a combination of the third and fifth embodiments, which is supported by the output of the power supply detection circuit 70. The timer 80 is started.

Therefore, each group 68-3, 68-
The data Nos. 2 and 68-1 are backed up until the corresponding time elapses after the output voltage of the battery 12 drops to the voltage of the corresponding setting. Therefore, it is possible to back up those data more reliably. Become.

Constitution of voltage detection circuit, switch and timer: FIG. 8 illustrates the constitution of the voltage detection circuit and the switch used in each embodiment. The voltage to be detected is the series of resistors 800 and 820. Supplied to the circuit.

The voltage between the resistors 800 and 820 is input to a comparator (which may be an operational amplifier) 840, and the output of the comparator 840 is passed through a resistor 860 to a semiconductor switch (transistor, FET).
Etc.) is input to 880.

A relay can be used instead of the semiconductor switch 880. In that case, the output of the comparator 840 is supplied to the relay coil 900, and the relay coil 90 is supplied.
At 0, the relay contact 920 is driven.

FIG. 9 illustrates the structure of the timer.
A timer element (in this case, a one-chip IC without an enable terminal, but an one with an enable terminal can be used, in which case a start signal is input to the enable terminal) 940, a switch 960 (see FIG. 8) Power is supplied via.

The timer element 94 is externally provided with a resistor 980 and a capacitor 1000 for setting a timer time, and the timer output of the timer element 940 serves as a switch control signal.

[0061]

As described above, according to this embodiment,
The battery dedicated to memory backup is always almost fully charged, and the backup power supply is cut off from less important data, so the capacity of the battery can be effectively used to extend the time during which memory backup can be guaranteed. Become.

[Brief description of drawings]

FIG. 1 is a structural explanatory view of a first embodiment.

FIG. 2 is an explanatory diagram of a configuration of a second embodiment.

FIG. 3 is an explanatory diagram of a configuration of a third embodiment.

FIG. 4 is an explanatory diagram of a configuration of a fourth embodiment.

FIG. 5 is a structural explanatory view of a fifth embodiment.

FIG. 6 is a structural explanatory view of a sixth embodiment.

FIG. 7 is an explanatory diagram of a configuration of a seventh embodiment.

FIG. 8 is a configuration explanatory diagram of a voltage detection circuit and a switch used in the embodiment.

FIG. 9 is an explanatory diagram of a configuration of a timer used in the embodiment.

[Explanation of symbols]

 10 First Battery 12 Second Battery 14 Power Supply Circuit 16 First Charging Circuit 18 Voltage Detection Circuit 20 Second Charging Circuit 22 Backup Power Supply Path 24 Switch 26 Switch Control Circuit 68 Line Part Group 70 Voltage Detection Circuit 80 Timer 82 Timer Start Circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasunori Mizutani 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited

Claims (4)

[Claims] 1. A power source output is supplied from a first battery (10) of a main power source and a rechargeable second battery (12) dedicated to data backup, and the power source output of the first battery (10) is sent to each part. Then, when the output voltage of the first battery (10) becomes lower than the output voltage of the second battery (12), the power output of the second battery (12) is sent to the circuit portion in which the data to be backed up is stored. When the output voltage of the first battery (10) is higher than that of the power supply circuit (14) and the second battery (12), the second battery (12) is gradually charged with the power output of the first battery (10). First charging circuit (1
6) An electronic device comprising: 2. A power source output is supplied from a first battery (10) as a main power source and a rechargeable second battery (12) dedicated to data backup, and the power source output of the first battery (10) is sent to each part. Then, when the output voltage of the first battery (10) becomes lower than the output voltage of the second battery (12), the power output of the second battery (12) is sent to the circuit portion in which the data to be backed up is stored. And a backup power supply path (22) branching from the output side of the power supply circuit (14) to the group (68) of the circuit parts divided by the importance of the stored data, A switch (24) inserted into each branch of the backup power supply path (22), a reference voltage set for each branch of the backup power supply path (22), and an output voltage of the second battery (12). Compare
When the output voltage of the second battery (12) falls below any reference voltage, the switch (2
An electronic device comprising: a switch control circuit (26) for opening 4). 3. A power supply output is supplied from a first battery (10) of a main power supply and a rechargeable second battery (12) dedicated to data backup, and the power output of the first battery (10) is sent to each part. Then, when the output voltage of the first battery (10) becomes lower than the output voltage of the second battery (12), the power output of the second battery (12) is sent to the circuit portion in which the data to be backed up is stored. And a backup power supply path (22) branching from the output side of the power supply circuit (14) to the group (68) of the circuit parts divided by the importance of the stored data, Only by the switch (24) inserted into each branch of the backup power supply path (22), the timer time set for each branch of the backup power supply path (22), and the second battery (12) A switch control circuit (26) that compares the time elapsed after the power supply is started and opens the switch (24) corresponding to the timer time when the elapsed time exceeds any timer time
An electronic device comprising: 4. A power source output is supplied from a first battery (10) of a main power source and a rechargeable second battery (12) dedicated to data backup, and the power source output of the first battery (10) is sent to each part. Then, when the output voltage of the first battery (10) becomes lower than the output voltage of the second battery (12), the power output of the second battery (12) is sent to the circuit portion in which the data to be backed up is stored. And a backup power supply path (22) branching from the output side of the power supply circuit (14) to the group (68) of the circuit parts divided by the importance of the stored data, The switch (24) inserted into each branch of the backup power supply path (22) and the reference voltage and the timer time corresponding to each branch of the backup power supply path (22) are set to correspond to the second battery. When the time elapsed from when the output voltage of (12) falls below any reference voltage exceeds the timer time corresponding to the reference voltage, the switch (24) of the branch path in which both reference voltages and the timer time are set. And a switch control circuit (26) for opening the electronic device.