JPH11260424A - Power source discriminating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To discriminate a secondary battery from a dry battery independent of the number of charge/discharge cycles of the secondary battery and the ambient temperature. SOLUTION: In the case where a secondary battery is housed, the device is constituted with a terminal C to which an output signal of a temperature detecting signal built in the secondary battery is applied; a power supply means 103 for supplying power to the terminal C; a voltage measuring means 105 for measuring the synthetic voltage of the terminal C and the power supply means 103; and a discriminating means 106 for discriminating between the secondary battery and a dry battery from a battery mounted by comparing the measured voltage value with a given threshold.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply identification device applicable to portable terminal devices and the like.

[0002]

2. Description of the Related Art Conventionally, in this type of apparatus, for example,
As disclosed in JP-A-331767, by connecting a dummy resistor to a battery and detecting the output voltage of the battery at that time, the battery mounted as a power source is a secondary battery or a primary battery (dry battery). ).

[0003] With respect to such a conventional power supply identification device,
This will be described with reference to FIG. FIG. 4 is a block diagram showing the overall configuration of a conventional power supply identification device. The conventional power supply identification device includes a secondary battery (NiCd battery or the like) or a dry battery (alkaline dry battery or the like) 401 mounted as a power supply, a first load 402, and a second load 403 as a dummy resistor. I have.

[0004] Further, the power supply to the second load 403 is turned on.
A switch 404 for turning off and a voltmeter 405 for detecting a voltage are provided.

Next, the operation of the conventional power supply identification device thus configured will be described. The current to or from the second load 403 is connected or disconnected, and the internal resistance of the battery used is detected from the difference in the degree to which the output voltage drops at that time. The detection of the internal resistance of the battery is performed by forcibly changing the load current of the electronic device by turning on or off the switch 404 and detecting the change in the output voltage at that time by the voltmeter 405. From this internal resistance, it is possible to identify whether the used battery is a secondary battery or a dry battery.

[0006]

However, the secondary battery is
As the number of charging / discharging increases, the internal resistance also increases,
At the end of the life of the next battery, it becomes equal to the internal resistance of the dry battery.
For this reason, in the conventional power supply identification device that detects the internal resistance of the battery and identifies the power supply based on the difference in the detected internal resistance,
When the number of times of charging / discharging of the secondary battery increases, there is a problem that it is impossible to distinguish between the secondary battery and the dry battery.

Further, since a secondary battery is unlikely to undergo a chemical change at a low temperature, a voltage drop becomes large when a dummy load is connected, and the output voltage cannot be distinguished from a dry battery. .

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has a power supply identification device capable of distinguishing a secondary battery from a dry battery regardless of the number of times of charging and discharging of the secondary battery and the surrounding temperature condition. The purpose is to provide.

[0009]

SUMMARY OF THE INVENTION In the power supply identification device, the present inventors generally detect the temperature at which rapid transfer charging is started and charge the secondary batteries such as NiCd, Ni hydrogen, lithium ion, etc. Focusing on the fact that a thermistor is built in the secondary battery in order to perform control such as stopping charging when the temperature of the battery is abnormally high, the output voltage of the thermistor is converted to an A / D input terminal of a CPU or the like in the portable terminal. , It can be determined whether the power supply attached to the mobile terminal is a secondary battery or a dry battery,
The present invention has been made.

That is, the present invention measures a combined voltage of a terminal to which an output signal of a thermistor incorporated in a secondary battery is applied and a voltage supplied to this terminal, and determines the measured voltage value and a predetermined threshold value. Are compared to determine whether the mounted battery is a primary battery or a secondary battery.

As described above, the inventor of the present invention has solved the above-mentioned problems and has eliminated the need for a dedicated device or mechanism for identifying a power supply, thereby reducing the circuit scale and, consequently, reducing the overall cost of the apparatus. It is possible to achieve reduction.

[0012]

According to a first aspect of the present invention, when a secondary battery is stored, a terminal to which an output signal of a temperature detecting means incorporated in the secondary battery is applied, A power supply means for supplying power to the terminal; a voltage measurement means for measuring a combined voltage of the terminal and the power supply means; An identification means for identifying whether the battery is a battery or a secondary battery is employed. According to a fourth aspect of the present invention, when a secondary battery is stored, a terminal to which an output signal of a temperature detecting means incorporated in the secondary battery is applied, and a terminal to which the output signal is supplied are provided. The combined voltage and the measured voltage are measured, and the measured voltage value is compared with a predetermined threshold to identify whether the mounted battery is a primary battery or a secondary battery.

According to these configurations, the power source can be identified only by comparing the composite voltage of the voltage from the temperature detecting means and the voltage from the power supply means with a predetermined threshold value. The secondary battery and the dry battery can be distinguished regardless of the surrounding temperature condition. In addition, without providing a special device or mechanism for identifying whether the battery is a primary battery or a secondary battery, these can be easily identified, and the circuit size can be reduced and the cost can be reduced. Can be planned.

According to a second aspect of the present invention, in the power supply identification device according to the first aspect, when the measured voltage value is larger than a predetermined threshold value, the battery is identified as a primary battery, and when the measured voltage value is smaller than the predetermined threshold value, the secondary battery is identified. The battery is identified as a battery.

According to this configuration, the power supply can be identified only by comparing the measured voltage value with a predetermined threshold value.
Whether the battery is a primary battery or a secondary battery can be easily identified.

According to a third aspect of the present invention, in the power supply identification device according to the first or second aspect, the power supply means includes a constant voltage source for supplying a constant voltage, and a resistor. Take the configuration.

With this configuration, when a dry battery is installed, nothing is connected to the terminal to which the thermistor is originally connected, so that the voltage from the constant voltage source can be directly measured. In this case, a voltage lower than that of the constant voltage source can be measured by the resistor, so that the power source can be easily identified only by the presence or absence of the thermistor. This eliminates the need for a dedicated device or mechanism for identifying the power supply, thereby reducing the circuit scale and the cost of the apparatus.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1A is a block diagram showing an overall configuration when a power supply identification device 100 according to one embodiment of the present invention is applied to a portable terminal 101. The mobile terminal 101 includes an input terminal A to a power supply unit, an input terminal B to GND, a terminal C to which a thermistor output is connected, and a power supply identification device 100. Input to the device 100.

The power supply identification device 100 includes a power supply voltage 103 for pulling up the output of the thermistor to +5 V via a dividing resistor 102, and a control unit 104 for identifying a power supply based on the voltage from the thermistor output. Control unit 104
Is an A / D input terminal 1 for inputting a voltage from the thermistor
05 and a control means 106 for identifying a power source from the input voltage and displaying the same on a display unit (not shown).

Here, the thermistor is a semiconductor device utilizing the fact that the resistance value changes with temperature.
Secondary batteries such as NiCd, Ni hydrogen, and lithium ion
Since it is necessary to detect the temperature at which the rapid charging starts, and to control the charging to be stopped at an abnormally high temperature during the charging, it is common to incorporate a thermistor in the secondary battery.

FIG. 1B is a diagram showing the structure of a secondary battery. When the secondary battery is mounted on the portable terminal, the + pole is connected to the terminal A of the portable terminal 101, the-pole is connected to the same terminal B, and the thermistor output is connected to the same terminal C.

FIG. 1C is a diagram showing the structure of a dry battery. When a dry battery is connected to the portable terminal, the + pole is connected to the terminal A of the portable terminal 101 and the − pole is connected to the same terminal B.

The operation of the thus configured power supply identification device according to one embodiment of the present invention will be described. FIG.
FIG. 4 is a flowchart showing a flow of an operation in which the power supply identification device according to the embodiment of the present invention identifies a secondary battery and a dry battery. FIG. 3 is a diagram showing a judgment voltage between a secondary battery and a dry battery.

First, it is determined whether the operation of the control unit 104 is possible, and if power supply is possible (step S1),
It is determined whether the voltage of the thermistor output is 2.4 V or more (step S2). If it is 2.4 V or more, it is determined that a dry battery is connected (step S3), and the operation mode of the portable terminal is switched to the dry battery specification (step S3).
4), end (step S5). That is, when the dry battery is connected to the portable terminal, the power supply voltage (+5 V) is supplied to the A / D input terminal to which the thermistor of the portable terminal is originally connected via the pull-up resistor. 3
As shown in (2), the voltage becomes higher than the predetermined determination voltage VTH, and it can be detected that the dry battery is connected.

On the other hand, if the voltage of the thermistor output is less than 2.4 V in step S2, it is determined that a secondary battery is connected (step S6), and the operation mode of the portable terminal is switched to the secondary battery specification. (Step S7), and ends (Step S5). That is, when the secondary battery is connected, the divided voltage of the resistance value of the thermistor and the voltage dividing resistor of the pull-up resistor is supplied to the A / D input terminal to which the thermistor of the portable terminal is connected. You. Therefore, as shown in FIG. 3, the voltage becomes lower than the predetermined determination voltage VTH, and it can be detected that the secondary battery is connected.

[0026]

As is apparent from the above description, according to the present invention, the power supply can be identified only by comparing the composite voltage of the voltage from the temperature detecting means and the voltage from the power supply means with a predetermined threshold value. Therefore, the secondary battery and the dry battery can be distinguished regardless of the number of times of charging and discharging of the secondary battery and the surrounding temperature condition. In addition, without providing a special device or mechanism for identifying whether the battery is a primary battery or a secondary battery, these can be easily identified, and the circuit size can be reduced and the cost can be reduced. Can be planned.

[Brief description of the drawings]

FIG. 1A is a block diagram illustrating an overall configuration of a power supply identification device according to an embodiment of the present invention. FIG. 1B is a diagram illustrating a configuration of a secondary battery. FIG. 1C is a diagram illustrating a configuration of a dry battery.

FIG. 2 is a flowchart of an identification operation of the power supply identification device according to the embodiment.

FIG. 3 is a graph of temperature and voltage divided by a thermistor and a pull-up resistor.

FIG. 4 is a block diagram showing the overall configuration of a conventional power supply identification device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 power supply identification device 101 portable terminal 102 dividing resistor 103 power supply voltage 104 control unit 105 A / D input terminal 106 control means

Claims (4)

[Claims] When a secondary battery is stored, a terminal to which an output signal of a temperature detecting means incorporated in the secondary battery is applied, power supply means for supplying power to the terminal, and said terminal. Voltage measuring means for measuring a combined voltage with the power supply means, and identification for identifying whether the mounted battery is a primary battery or a secondary battery by comparing the measured voltage value with a predetermined threshold. And a power supply identification device. 2. The power supply identification device according to claim 1, wherein when the measured voltage value is larger than a predetermined threshold value, it is identified as a primary battery, and when it is smaller, it is identified as a secondary battery. 3. The power supply identification device according to claim 1, wherein the power supply unit includes a constant voltage source for supplying a constant voltage, and a resistor. 4. When a secondary battery is stored, a composite voltage of a terminal to which an output signal of a temperature detecting means incorporated in the secondary battery is applied and a voltage supplied to the terminal is measured. A power source identification method comprising: comparing the measured voltage value with a predetermined threshold to identify whether the mounted battery is a primary battery or a secondary battery.