JPH0475433A - Electronic appliance - Google Patents

Abstract

PURPOSE:To prevent trouble such as damage of appliance, burning or firing by detecting deterioration of a rechargeable battery based on the terminal voltage thereof and interrupting charging operation or producing an alarm upon detection of deterioration. CONSTITUTION:Upon insertion of an AC adapter into a power jack PJ, charging operation of a rechargeable battery BAT takes place through a charging resistor R and a relay (e). At this time, a voltage detector (d) monitors the terminal voltage of the chargeable battery BAT. If the battery BAT is abnormal to cause voltage drop, a microcomputer (c) reads out existence of the AC adapter through a voltage detector (a) and then reads out the battery BAT voltage through the voltage detector (d) thus judging the power supply condition of the rechargeable battery BAT. On the contrary, when the AC adapter is connected and the battery BAT voltage is lower than 6V, charging operation of the chargeable battery BAT is interrupted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electronic device, and particularly to an electronic device having a means for charging a built-in rechargeable battery by supplying power from an external DC power source.

[Prior Art] Various electronic devices powered by rechargeable batteries such as NiCd batteries and lead-acid batteries have been used.

In this type of electronic equipment, a rechargeable battery BAT is connected in a power supply circuit as shown in FIG.

In the figure, the symbol PJ is a power jack for supplying power from an external DC power source such as an AC adapter for the purpose of charging or driving equipment, and the diodes D1 and D2 are the power jack or the output of the rechargeable battery BAT. This is for supplying power to equipment with the output of either high voltage side.

The rechargeable battery BAT is connected to the output terminals of diodes D1 and D2 (
(cathode) via a resistor R and a fuse F.

The fuse F is for preventing overcharging or overdischarging of the rechargeable battery BAT, and is composed of a temperature fuse, a current fuse, or the like.

[Problems to be Solved by the Invention] The conventional configuration as described above is merely for preventing overcharging or overdischarging, and cannot be said to be a sufficient safety measure.

For example, in the case of a dendrite short circuit, which has recently become a problem, in which an internal short circuit occurs in one cell of a rechargeable battery, the resistor R generates heat before the fuse blows, and there is a risk of smoke or fire.

An object of the present invention is to solve the above problems and provide an electronic device that uses a rechargeable battery as a power source and can be operated safely.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides an electronic device having a means for charging a built-in rechargeable battery by supplying power from an external DC power source. means for detecting deterioration of the rechargeable battery via the terminal voltage of the;
A control means is provided to stop charging the rechargeable battery when deterioration of the rechargeable battery is detected based on the output of the detection means, or a deterioration of the rechargeable battery is detected based on the output of the detection means. case! We have adopted a structure that provides a means for issuing public notices.

[Function 1] According to the above configuration, when deterioration of the rechargeable battery is detected, charging is immediately stopped or! A public notice can be made.

[Example] Hereinafter, the present invention will be described in detail based on the example shown in the drawings. In the following, the same reference numerals will be used for the same members as in the conventional example, and detailed explanation thereof will be omitted.

First example FIG. 1 shows the structure of an electronic device adopting the present invention.

In Figure 1, power jack PJ, diode Di
, D2, the connection structure of rechargeable battery BAT is the same,
In this embodiment, a relay e is inserted in series with the resistor H.

The voltages at the output ends of the diodes D1 and D2 are supplied to the power supply circuit. The power supply circuit is composed of a known stabilizing circuit and the like, and supplies power to each part of the device.

In the figure, C is a control unit consisting of a microprocessor, etc., which is supplied with power from the power supply circuit via the power line L1, and charges the rechargeable battery BAT by controlling the relay e via the signal line L2. or rechargeable battery B
Controls power supply from AT.

Control of relay e by control unit C is performed based on the input voltage to the power supply circuit S detected via voltage detectors a and b, and the output voltage of rechargeable battery BAT. Voltage detectors a and d are comparators consisting of operational amplifiers, etc.
Alternatively, it may be composed of an A/D converter or the like.

Note that the voltage detector a is mainly used to detect whether or not the AC adapter is connected to the power jack by detecting the line voltage.

Next, the operation of the above configuration will be explained.

In addition, here, the rated voltage of the NiCd battery that constitutes the rechargeable battery BAT is 7.2V (1.2V x G),
It is assumed that a voltage equivalent to 6v to 7v is supplied to the power supply circuit.

Now, when you insert the AC adapter into the power jack PJ,
Charging of the rechargeable battery BAT begins via the charging resistor R and the relay e.

At the same time, voltage detector d monitors the terminal voltage of rechargeable battery BAT.

At this point, the battery BAT becomes abnormal, for example, a dendrite short occurs, and the rated voltage drops from 7.2V to around 6V (
2 microconverter C first reads the presence or absence of the AC adapter via voltage detector a, then reads the voltage of battery BAT via voltage detector d, and then detects the voltage from rechargeable battery BAT. Determine the power supply status.

Here, the AC adapter is connected and the rechargeable battery BA
If the voltage of T is 7.2V or more, the microcomputer C determines that there is no deterioration of the battery BAT.

Conversely, if the AC adapter is connected and the voltage of battery BAT is 6V or less, microcomputer C determines that there is an abnormality in battery BAT, and immediately sends the control signal line L2 to
Operate the J-ray e and stop charging the rechargeable battery BAT.

FIG. 2 shows the power supply control procedure of the control section C in detail. Note that in a normal operating state, relay e is controlled to be in a conductive state.

The microcomputer C determines whether or not the AC adapter is inserted (step SL). If it is not connected, the process ends; if it is connected, the process proceeds to step S2. This determination is made by detecting the input line voltage of the power supply circuit S by the voltage detector a.

In step S2, the voltage of the rechargeable battery BAT is rated (7,
I am checking whether it is above 2V) or below 6V (this state will occur if one battery in 6 water deteriorates due to a dendrite short and an internal short occurs). This determination is made by detecting the terminal voltage of the rechargeable battery BAT using the voltage detector d.

If the voltage is normal in step S2, the process ends, and if it is 6V or less, the process proceeds to the next step S3. Here it is idle for 2 minutes.

The reason for idling in step S3 is the rechargeable battery BAT
If the battery is empty, the voltage will not rise to the specified voltage for a while even if it is charged, so this is a wait time for waiting a predetermined time and checking again.

Next, in step S4, a check similar to step S2 is performed, and if the voltage of the rechargeable battery BAT is 6V or less, the process moves to step S5 to cut off relay e and stop charging.

According to the above embodiment, a means for detecting the terminal voltage of the rechargeable battery BAT is provided, and a relay e is inserted in series with the charging (discharging) resistor R. If an abnormality is detected in the voltage, the charging circuit can be shut off by the relay e, and dangers such as smoke and fire can be prevented.

Second Embodiment In the first embodiment, the relay e is provided in series with the resistor R, but in FIG. 3, the relay e is inserted in the line between the power jack PJ and the diode DI.

In such a configuration, the same control method as in FIG. 2 can be used.

In this case, in step S5 of FIG. 2, by cutting off relay e, power supply to the entire device including power supply to the charging system is stopped.

Even with such a configuration, substantially the same effects as in the first embodiment can be expected.

In the third embodiment and above, a configuration is used in which the power is cut off when an abnormality occurs in the rechargeable battery, but even if a dendrite short circuit occurs, smoke or fire does not necessarily occur immediately, so only a warning display is used. Just by doing this, you can expect to be effective in preventing danger.

In the configuration shown in FIG. 4, the relay on the power supply line is omitted and a display g is provided instead. The display g is a device such as a word processor or a personal computer.
For devices that originally have a display mechanism, that configuration may be used.

In such a configuration, instead of cutting off the charging circuit or power supply circuit using the relay in step S5 of FIG. 2, a warning message is displayed in the same step to warn the user of danger.

! In a configuration in which only notifications are displayed, there is almost no need to modify the power supply system, and it can be implemented by simply changing the display message.

Such a warning mechanism may be combined with the first and second embodiments, that is, a message is displayed at the same time as the charging circuit or power supply circuit is cut off.

Note that the warning message may be sent in various formats such as audio or buzzer sound instead of visual display.

The configurations of the above embodiments can be applied to various electronic devices using rechargeable batteries.

[Effects of the Invention] As is clear from the above, according to the present invention, in an electronic device having a means for charging a built-in rechargeable battery by supplying power from an external DC power source, the charging method can be applied to a terminal voltage of the rechargeable battery. and a control means for stopping charging of the rechargeable battery when deterioration of the rechargeable battery is detected based on the detection means.
Alternatively, since the structure includes a means for displaying a warning when deterioration of the rechargeable battery is detected based on the output of the detection means, charging can be immediately stopped if deterioration of the rechargeable battery is detected. , No! It can be displayed in blue, which has an excellent effect of preventing accidents such as damage to equipment, burns, and fires.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the power supply system of an electronic device according to the present invention, FIG. 2 is a flowchart showing the power supply control procedure of the device shown in FIG. 1, and FIG. FIG. 4 is a block diagram showing the configuration of a still different power supply system according to the present invention, and FIG. 5 is a block diagram showing the configuration of a power supply system of a conventional electronic device.

Claims (1)

[Claims] 1) In an electronic device having means for charging a built-in rechargeable battery by supplying power from an external DC power source, means for detecting deterioration of the rechargeable battery via a terminal voltage of the rechargeable battery. An electronic device comprising: a control means for stopping charging of the rechargeable battery when deterioration of the rechargeable battery is detected based on the output of the detection means. 2) In an electronic device having a means for charging a built-in rechargeable battery by supplying power from an external DC power source, a means for detecting deterioration of the rechargeable battery via a terminal voltage of the rechargeable battery; An electronic device characterized by providing a means for displaying a warning when deterioration of a rechargeable battery is detected based on the output.