JPH0511745U - Battery charger - Google Patents

Abstract

(57) [Abstract] [Purpose] The object is to optimize the charging currents of a plurality of battery packs having different battery capacities according to the battery capacities. [Structure] With the terminal configuration of the battery pack 1 as + terminal 2, −terminal 5, thermistor terminal 3, and battery capacity identification terminal 4, a resistor 6 corresponding to the battery capacity is connected between the battery capacity identification terminal 4 and −terminal 5. Then, it is installed together with the battery. The battery pack 1 is connected to the main body 13 to generate a comparison voltage determined by the ratio of the resistance 6 and the resistance 11, and the comparison voltage is compared with the reference voltage generated by the reference voltage generation circuit 12 by the comparator 10. The constant current circuit 9 is controlled based on the comparison result to determine the charging current.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a battery charging device for charging a battery pack used in a mobile phone or the like.

[0002]

[Prior Art]

 FIG. 2 shows the configuration of a conventional battery charger. In FIG. 2 (A), 1 is a battery pack, and the terminal configuration is + terminal 2, thermistor terminal 3, battery capacity identification terminal 4, and − terminal 5. Reference numeral 15 is a battery, and 16 is a thermistor. FIG. 1B shows a main body 131 for charging, which has a + terminal 21, a thermistor terminal 31, a battery capacity identifying terminal 41, and a-terminal 51 which are connected to each terminal of the battery pack 1. Reference numeral 71 is a control circuit for controlling the current value of the constant current circuit 91, and 81 is an external power source.

Next, the operation will be described. In FIG. 2 (A), if the switch 7 connected to the battery capacity identification terminal 4 is open and the switch 7 is closed B, there are two states A and B. The two states A and B correspond to two battery capacities, for example, the state A corresponds to charging a battery having a battery capacity of 350 wAH, and the state B corresponds to charging of a battery having a battery capacity of 1000 wAH.

When the battery pack 1 is coupled to the main body 131, the negative terminal 2, thermistor terminal 3, the battery capacity identification terminal 4, and the positive terminal 5 of the battery pack 1 are respectively the negative terminal 21, the thermistor terminal of the main body 131. 31, the battery capacity identification terminal 41, and the + terminal 51. When the switch 7 is controlled to open / close according to the capacity of the battery 15 to be charged, the control circuit 71 of the main body 131 controls the current value of the constant current circuit 91 in two steps according to the opening / closing. The charging current from the external power supply 81 is applied to the + terminal of the battery 15 whose current value is controlled by the constant current circuit 9, charges the battery 15 and flows to the-terminal. The battery 15 is thus charged. The thermistor 16 protects the heating of the battery 15 due to overcharging.

As described above, the conventional battery capacity identifying device described above can identify two different battery capacities.

[0006]

[Problems to be solved by the device]

 However, since the conventional battery capacity identifying battery pack has only two states, that is, the switch 7 is open or closed, there is a problem that only two kinds of battery capacities can be identified.

The present invention solves such a conventional problem, and an object of the present invention is to provide an excellent battery charger capable of distinguishing a plurality of different battery capacities.

[0008]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention has a built-in resistor corresponding to the battery capacity in the battery pack, and a built-in reference voltage generation circuit and comparator in the main body to control the charging current suitable for the battery capacity. It is the one.

[0009]

[Action]

 Therefore, according to the present invention, by comparing the comparison voltage generated based on the resistance built into the battery pack with the reference voltage and controlling the constant current circuit, it is possible to charge with the charging current corresponding to the battery capacity. This has the effect that the battery life can be maintained for a long time.

[0010]

【Example】

 FIG. 1 shows the configuration of a battery side embodiment of the present invention. FIG. 1B shows the construction of the embodiment of the present invention on the main body side. In FIG. 1 (A), 1 is a battery pack, and the terminal configuration is a + terminal 2, a thermistor terminal 3, a battery capacity identification terminal 4, and a − terminal 5. Reference numeral 6 is a resistor having a value determined according to the capacity of the battery 15, and 16 is a thermistor for heating protection due to overcharge or the like.

On the other hand, in FIG. 1B, 13 is a main body, which is composed of an external power supply 8, a reference voltage generating circuit 12, a comparator 10, a resistor 11, and a constant current circuit 9. The terminal configuration includes a + terminal 21, a thermistor terminal 31, a battery capacity identification terminal 41, and a-terminal 51.

Next, the operation of the above embodiment will be described. The resistor 6 inserted between the battery capacity identification terminal 4 and the-terminal 5 has a predetermined value according to the capacity of the battery 15, and is incorporated in the battery pack 1 together with the battery 15 in advance.

When the battery pack 1 is connected to the main body 13, the positive terminal 2, the thermistor terminal 3, the battery capacity identification terminal 4, and the negative terminal 5 of the main body 1 correspond to the corresponding terminals of the main body 13, that is, the terminals. , + Terminal 21, thermistor terminal 31, battery capacity identification terminal 41, and − terminal 51. At this time, the charging current flows in the route of external power source 8 → constant current circuit 9 → + terminal 21 → + terminal 2 → battery 15 → -terminal 5 → -terminal 51 → ground. On the other hand, a current also flows in the path of the external power source 8 → the reference voltage generating circuit 12 → the resistor 11 → the battery capacity identifying terminal 41 → the battery capacity identifying terminal 4 → the resistor 6 → −terminal 5 → the ground. This current path is for generating a comparison voltage described later.

The reference voltage generation circuit 12 is driven by the external power supply 8 and operates as a regulator to generate a comparison reference voltage of the comparator 10 and a voltage for generating a comparison voltage. That is, the stable output voltage from the reference voltage generating circuit 12 is divided by the resistors 11 and 6 according to the current path described above, and the voltage obtained by the divided voltage ratio is applied to the comparator 10 as the comparison voltage. The resistance 6 is changed according to the capacity of the battery 15 as described above, and therefore the comparison voltage also changes according to the capacity of the battery 15. In this way, a comparison voltage is created by the ratio of the resistance 6 and the resistance 11, and the reference voltage created by the reference voltage generation circuit 12 is compared by the comparator 10, and according to the comparison result, the constant current circuit 9 outputs the external power from the external power supply 8. Controls the charging current that flows. That is, the current from the external power supply 8 is set in the constant current circuit 9 so as to give the optimum charging current for the battery capacity.

Since the value of the resistor 6 is different in other battery packs having different battery capacities, the charging current also changes accordingly.

As described above, by incorporating the resistor 6 having a predetermined value corresponding to the capacity of the battery 15 into the battery pack 1, it is possible to always give the optimum charging current only by changing the battery pack 1. .

[0017]

[Effect of the device]

 As is apparent from the above-described embodiment, the present invention provides the optimum charging current with respect to the battery capacity, and thus has the effect of keeping the battery life long.

[Brief description of drawings]

FIG. 1A is a schematic view of a battery pack portion of a battery charger according to an embodiment of the present invention. FIG. 1B is a schematic view of a main body portion of a battery charger according to an embodiment of the present invention.

FIG. 2A is a schematic view of a battery pack part of a conventional battery charging device, and FIG. 2B is a schematic view of a main body part of a conventional battery charging device.

[Explanation of symbols]

 1 battery pack 2,21 + terminal 3,31 thermistor terminal 4,41 battery capacity identification terminal 5,51-terminal 6 resistance 8 external power supply 9 constant current circuit 10 comparator 11 resistance 12 reference voltage generation circuit 13 main body

Claims (1)

Claims for utility model registration: 1. A battery pack having a battery and a resistor having a value corresponding to the capacity of the battery, and a main body coupled to the battery pack, the main body being a constant current circuit. And a means for controlling the current value of the constant current circuit according to the value of the resistance built into the battery pack.