JPH1169638A - Charger and charging method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charger which can start a charging operation, only when a secondary battery is used, and to provide a charging method. SOLUTION: The internal resistance of a portable information terminal device (HHT) 7 is detected by a resistance-value detection means 5, so as to be compared with a prescribed value by a resistance-value comparison means 6. When the internal resistance is smaller than a prescribed value, it is determined that a secondary battery is used. A power-supply start means 4 is operated under the control of a CPU 1, and charging electric power is supplied from a power supply means 3. As a result, it is possible to prevent a danger that a primary battery is charged by mistake, and it is possible to eliminate an irrational situation in which the structure of a power supply part 8 in the HHT 7 becomes complicated, in order to discriminate a primary battery from a secondary battery.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an external device which can use a primary battery (non-rechargeable battery) or a secondary battery (rechargeable battery) for a power supply section of the external device. On the other hand, the present invention relates to a charger and a charging method for charging by connecting to the power supply unit.

[0002]

2. Description of the Related Art Hereinafter, a description will be given using a charger of a portable information terminal as a charger.

[0003] It goes without saying that the present invention is not limited to the charger of the portable information terminal.

Conventionally, a charger for a portable information terminal (hereinafter, referred to as HHT) has means for connecting to a power supply unit of the HHT,
The charging was unilaterally started when the HHT was simply connected without determining whether the primary battery or the secondary battery was mounted on the HHT.

[0005] In order to prevent this, there has been a method in which the shape of the power supply unit of the HHT is distinguished by using two types of battery packs for a primary battery and a secondary battery. For example, a charging terminal is not provided in a battery pack for a primary battery so that charging cannot be performed even when an HHT is connected to a charger, and a charging terminal is provided for a secondary battery to allow charging.

[0006]

However, in the conventional charger, charging is started even when the primary battery is mounted on the HHT, and there is a risk of generation of heat, leakage, and the like. Was.

Further, if the battery pack is divided into two types in order to prevent the above danger, the cost of a mold and the like increases, and additionally, the internal connection circuit of the HHT must correspond to the two types of battery packs. Complicated circuit configuration.

SUMMARY OF THE INVENTION The present invention eliminates the above-mentioned conventional problems, prevents the risk of erroneously charging a primary battery, and has the complexity and irrationality of having two types of battery packs. It is an object of the present invention to provide a charger and a charging method that solve the problem.

[0009]

In order to achieve the above object, a first charger of the present invention determines the necessity of supplying charging power according to the resistance value of a power supply unit of an external device. is there.

[0010] The second charger of the present invention includes a connection means for connecting to a power supply of the external device, a power supply means for supplying charging power to the power supply of the external device via the connection means,
Resistance value detecting means for detecting a resistance value of a power supply unit of the external device, comparing means for comparing the resistance value detected by the resistance value detecting means with a predetermined value, and the resistance detected by the comparing means Supply start means for supplying charging power from the power supply means when the value is smaller than the predetermined value.

The third charger of the present invention has a predetermined value set to 50 mΩ to 100 mΩ.

Also, the charging method of the present invention includes a first step of connecting a power supply unit of an external device and a charger, a second step of detecting a resistance value of a power supply unit of the external device, A third step of comparing the detected resistance value with a predetermined value, and a fourth step of supplying charging power from the power supply means when the detected resistance value is smaller than the predetermined value.
And the following steps.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS With the above configuration, the first charger of the present invention can distinguish between a primary battery and a secondary battery based on the resistance value of the power supply unit, and erroneously starts charging the primary battery. Never do.

Further, the second and third chargers of the present invention detect whether the primary battery or the secondary battery is mounted on the external device, detect the internal resistance, and determine the magnitude of the detection. The determination can be made by comparing with a predetermined value, and the danger of erroneously charging the primary battery can be prevented.

Further, the charging method of the present invention detects the internal resistance of a power supply unit of an external device whether a primary battery or a secondary battery is mounted, and determines the magnitude of the internal resistance to a predetermined value. It can be determined by comparing with a value.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes a CPU, and 2 denotes a ROM. The CPU 1 controls a whole system by reading a program stored in the ROM 2.

Reference numeral 3 denotes power supply means for supplying charging power under the control of the CPU 1. Reference numeral 4 denotes a power supply start unit that performs a switch function of starting or not starting power supply.

Reference numeral 5 denotes a resistance value detecting means, and when the HHT 7, which is an external device, is connected to the charger, first, the CPU 1
, The internal resistance of the HHT 7 is detected. Reference numeral 6 denotes a resistance value comparing means for comparing the resistance value detected by the resistance value detecting means 5 with a predetermined value. It is desirable to set the predetermined value to 50 mΩ to 100 mΩ.

When a primary battery is used for the HHT 7, the internal resistance of the primary battery is 120 mΩ to 200 m for an alkaline dry battery.
Ω and manganese dry batteries are as large as 300 mΩ to 500 mΩ, while the internal resistance of secondary batteries is 15 mΩ for NiCad batteries.
Because it is as small as ~ 20 mΩ, when it is smaller than the predetermined value,
The power supply means 3 operates the power supply start means 4 under the control of the CPU 1 to supply charging power. Reference numeral 8 denotes a power supply unit of the HHT 7, and a primary battery or a secondary battery is used.

As described above, in the charger of the present embodiment,
Whether the primary battery or the secondary battery is used in the power supply unit 8 of the HHT 7 is determined by detecting the internal resistance of the power supply unit 8 when the HHT 7 is connected to the charger and determining the magnitude of the internal resistance to a predetermined value. By comparing with, when it is smaller than a predetermined value, it is determined that the battery is a secondary battery, and charging is started. This can eliminate the complexity and irrationality of erroneously charging the primary battery or distinguishing the primary battery from the secondary battery by the structure of the battery pack.

[0021]

As is apparent from the above description, the first battery charger of the present invention can distinguish between the primary battery and the secondary battery based on the resistance value of the power supply unit, and erroneously recognizes the primary battery. Never start charging.

Further, the second and third chargers of the present invention detect whether an external device is equipped with a primary battery or a secondary battery, and detect the internal resistance. Can be determined by comparing the magnitude of the primary battery with a predetermined value, and the risk of erroneously charging the primary battery can be prevented.

Also, the charging method of the present invention detects whether the primary battery or the secondary battery is mounted on the power supply section of the external device, detects the internal resistance, and compares the magnitude of the internal resistance with a predetermined value. Can be determined.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a charger according to an embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 CPU 2 ROM 3 Power supply means 4 Power supply start means 5 Resistance value detection means 6 Resistance value comparison means 7 HHT 8 Power supply unit

Claims (4)

[Claims] 1. A charger for determining whether supply of charging power is necessary according to a resistance value of a power supply unit of an external device. 2. A connection means for connecting to a power supply unit of the external device, a power supply means for supplying charging power to the power supply unit of the external device via the connection means, and detecting a resistance value of the power supply unit of the external device. Resistance value detecting means, comparing means for comparing the resistance value detected by the resistance value detecting means with a predetermined value, and when the resistance value detected by the comparing means is smaller than the predetermined value. And a supply start means for supplying charging power from the power supply means. 3. The charger according to claim 2, wherein the predetermined value is set to “50 mΩ to 100 mΩ”. 4. A first step of connecting a power supply unit of an external device to a charger, a second step of detecting a resistance value of a power supply unit of the external device, and a step of determining the detected resistance value by a predetermined value. And a fourth step of supplying charging power from the power supply means when the detected resistance value is smaller than the predetermined value.