JPH10225001A - Charger and charging system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and surely detect on the charger side whether a battery is connected by finding out the connecting condition of the battery based on the voltage appearing at a charging terminal and the current between the charging terminal and a power circuit during the cyclic on/off operation of a switch connected between the charging terminal and the power circuit. SOLUTION: When the power is turned on, a switch 3 is turned on and off in a constant cycle by a charge controlling circuit 9. During that period, the voltage Vout across a voltage detecting resistor 7 connected to a charging terminal 2 is detected by a voltage detecting circuit 8 and the current Iout in a charging current detecting resistor 5 is detected by a charging current detecting circuit 6. When a battery 10 is not connected, the voltage Vout across the voltage detecting resistor 7 becomes the same value as the output voltage of a power circuit 1 when the switch 3 is turned on and becomes a value equal to the divided output voltage of the power circuit 1 divided by a resistor 4 and the voltage detecting resistor 7 when the switch 3 is turned off. Meanwhile, the current in the charging current detecting resistor 5 is nearly 0mA. By this method, it can be detected whether the battery 10 is connected or not.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a battery charger,
The present invention relates to a battery to be charged and a charger capable of detecting whether or not a portable device is attached (inserted).

[0002]

2. Description of the Related Art When a charger detects whether or not a portable device (battery) is connected to a charger, that is, the attachment of a portable device (battery) to be charged to the charger is detected, and the attachment is detected. When the portable device (battery) to be charged is removed from the charger and the output of the charger is stopped, a resistor or thermistor is added in addition to the two terminals for charging. There is a method of providing a detection terminal for the portable device, etc., but in response to the demand for lower cost, smaller size, and weight reduction of portable equipment, the number of terminals has increased, resulting in higher cost and larger equipment. I was Especially for the weight of equipment, usually 1
The required weight per pin is determined, and the increase in the number of terminals reduces the size of the device and imposes a structural limitation on weight reduction.

Therefore, it is preferable to be able to detect whether or not a portable device (battery) is connected to a charger without providing a terminal for detection in both the charger and the portable device. As a specific method, as shown in JP-A-59-153427, a sawtooth wave is output at a predetermined period in a charging circuit, and a battery voltage appearing at a charging terminal at that time is calculated. Which controls the output of the charger by comparing the calculated value with the calculated value, as seen in JP-A-6-269132.
In some cases, the output of the charger is switched by a switch, and only the voltage of the battery appearing at the charging terminal at that time is compared to detect the presence or absence of the portable device (battery).

[0004]

However, a circuit for outputting a sawtooth wave and calculating a battery voltage has a complicated circuit configuration. In the case of a portable device (battery) which detects the presence or absence of a portable device (battery) by switching the output of the charger with a switch and comparing only the voltage of the battery, there is a risk of erroneous detection due to poor contact or oxidation of the terminal, which is a problem with reliability. There is.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and an object of the present invention is to simply and reliably detect whether or not a portable device (battery) is connected on a charger side.

[0006]

According to the present invention, there is provided a charger for charging a battery having two charging terminals and a switch connected between the charging terminal and a power supply circuit. Switching means for periodically opening and closing the switch, voltage detection means for detecting a voltage appearing at the charging terminal during the opening and closing operation of the switch, and current detection means for detecting a current flowing between the charging terminal and the power supply circuit. And detecting means for detecting whether or not the battery is mounted based on the detection results of these detecting means.

In the charging system for a portable device according to the present invention, the first charging terminal has two terminals, and a first switch connected between the first charging terminal and the power supply circuit; Opening and closing means for periodically opening and closing the first switch, voltage detection means for detecting a voltage appearing at the first charging terminal during opening and closing of the first switch, A charger provided with current detection means for detecting a current flowing between the power supply circuits, and detection means for detecting whether or not a battery is mounted based on the detection results of these detection means; A second charging terminal to be separated, a second switch connected between the charging terminal and the battery, opening / closing means for periodically opening / closing the second switch, and opening / closing of the second switch The second during operation
And a detecting device for detecting whether or not the charger is mounted based on the detection result of the detecting device. It is characterized in that it is possible to detect the presence or absence of mutual mounting.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is a circuit block diagram showing Embodiment 1 of the present invention. In the drawing, reference numeral 1 denotes a power supply circuit that outputs a predetermined constant voltage and a constant current, and 2 denotes a pair of first power supply circuits connected to a power supply circuit 1. The charging terminal 3 is a first switch for main charging connected between the power supply circuit 1 and the first charging terminal 2. 4 is a resistor connected in parallel with the first switch 3,
5 is a charging current detecting resistor connected between the power supply circuit 1 and the first charging terminal 2, 6 is a charging current detecting circuit, 7 is a voltage detecting resistor connected between the first charging terminals 2, and 8 is A voltage detection circuit that appears between the first charging terminals 2, 9 is a charging control circuit that performs a charging operation including an opening and closing operation of the first switch 3 in accordance with a detection result of the charging current and the voltage between the charging terminals, and 10 is a first charging control circuit.
A battery, such as a lithium secondary battery, connected to the charging terminal 2 and charged, and 11 is a charged terminal of the battery connected to the first charging terminal 2. Note that the first switch 3 is configured by a semiconductor switch element such as a transistor or an FET.

FIG. 2 shows a flowchart of the detection operation of the present invention, and FIG. 3 shows a waveform diagram of each operation. Here, the operation in step S1 shown in FIG. 2 corresponds to the period of S1 shown in FIG.

The operation will be described below with reference to these drawings. The following operation is started when the power is turned on to the charger.

First, in FIG. 3, a step S1 is an operation for detecting whether or not the battery 10 or a portable device equipped with the battery 10 (hereinafter, portable device) is attached to the first charging terminal 2 in the charger. Is shown. Next, the detection operation in the charger will be described based on the flowchart of FIG.

There is no record of insertion (attachment) of the battery 10 or the portable device into the charger when the power is turned on to the charger (B)
AT = 0) is set as an initial value (step S201). In steps S202 and S204, the O of the first switch 3
FF / ON is repeatedly performed at regular intervals through the charge control circuit 9, and the voltage Vout across the voltage detection resistor 7 connected between the first charging terminals 2 is detected by the voltage detection circuit 8 in step S <b> 203. Check, step S205
Then, a current check is performed by detecting the current Iout flowing through the charging current detection resistor 5 by the charging current detection circuit 6. In the charging current detection circuit 6, the voltage value detected from the voltage across the charging current detection resistor 5 is converted into a current value from the resistance value of the charging current detection resistor 5 (in an actual circuit example, the resistance value is 1Ω).
And the detected voltage value = current value), and outputs as current value data.

If the battery 10 or the portable device is not attached to the first charging terminal 2, the voltage Vo across the voltage detecting resistor 7
When the first switch 3 is ON, the output voltage Vchg (4.1 V) of the power supply circuit 1 is changed to the output voltage Vchg (4.1 V).
Is OFF, the output voltage Vchg 47 obtained by dividing the output voltage Vchg of the power supply circuit 1 by the resistor 4 and the voltage detection resistor 7 is output.
(3.5 V). Further, the current Iout flowing through the charging current detection resistor 5 remains almost 0 mA. Therefore,
In the current check in step S205, I <20 mA, and it is determined that there is no battery (step S210).

If the battery 10 or the portable device is attached to the first charging terminal 2, V ≦ 3.9V (the charging is determined to be required if it is 3.9V or less) in the voltage check in step S203, and step S205. If I ≧ 20 mA in step S2, it is determined that a battery is present (step S208) and step S2
The state of charge 09 is entered. A current check is also performed during charging in step S209. When I <100 mA, charging is completed (step S211), and there is a record of insertion (attachment) to the battery 10 or the charger of the portable device (B).
AT = 1) is set.

If V> 3.9V in step S203,
In step S206, the insertion record is checked.
If BAT = 1, leave inserted after charging is completed,
The process proceeds to the completion of charging in step S211. If BAT = 0, it is determined that the portable device has been used last time, that is, the portable device has been detached from the charger, and step S
At 207, the voltage of the charging terminal 2 is checked. V ≧ 4.0
If it is 5 V, the process proceeds to step S211 to complete charging. This is, for example, 4.05V is the minimum battery voltage that can secure the specification of the continuous talk time in the portable device with respect to the full charge voltage of 4.1V, for example, and the charger turns on the red lamp during charging, When fully charged, there is an operation of turning on the green lamp, but with a continuous talk time guarantee voltage of 4.05 V as a threshold, when almost unused (battery voltage drop is small), the red lamp is turned on and the auxiliary charging operation is performed. This is because it is preferable to turn on the green lamp immediately to inform the user of the full charge, rather than turning on. If V <4.05V, it is determined that supplementary charging is necessary, and the process proceeds to the current check and charging operation in step S205 (step S209).

As described above, when the battery 10 or the portable device is not attached to the first charging terminal 2, both the voltage and the current appearing at the first charging terminal 2 during the opening / closing operation of the first switch 3 are reduced. By checking, it is detected whether the battery 10 or the portable device is attached to the first charging terminal 2.
Further, it can be determined from the insertion record (BAT = 0 or 1) whether the battery voltage immediately after the insertion of the battery 10 or the portable device (need to check whether supplementary charging is necessary) or remains after completion of charging (no supplementary charging is necessary).

Embodiment 2 FIG. In the first embodiment, when V> 3.9V in the terminal voltage check in step S203,
Although an example has been described in which the battery voltage or the battery voltage immediately after the insertion of the portable device or the battery voltage after the completion of charging is detected by insertion recording, the detection may be performed by recording the previous battery voltage data.

FIG. 4 is a flow chart showing the second embodiment of the present invention. If V> 3.9V in step S203, a charging terminal voltage check is also performed in the next step S207, and if V ≧ 4.05V Indicates that charging is unconditionally completed, and the process proceeds to step S211. If V <4.05 V, in step S401, the current step S
The voltage value Va at step 207 and the previous step S207
And if the difference is 0.1 V or more, it is determined that the battery 10 or the portable device has been inserted into the charger from the state of use, and the current check and the charging operation (step S205) are performed. Proceed to step S209). 0.1V
In the following cases, it is determined that supplementary charging is not required due to self-discharge of the fully charged battery (the battery is left alone) or a voltage drop due to a load connection (standby power ON of the portable device, leakage current, etc.), and the charging in step S211 is completed. move on.

As described above, by comparing the voltage data in step S207 in step S401, if V> 3.9V in the terminal voltage check in step S203,
It can be determined whether the battery voltage is just after the battery 10 or the portable device is inserted or the battery voltage after charging is completed. Operations and configurations other than those described above are the same as those in the first embodiment.

Embodiment 3 FIG. 5 is a circuit block diagram showing Embodiment 3 of the present invention.
Is a charger, 13 is a pair of second charging terminals of the portable device body,
14 is a pair of battery connection terminals of the main body of the portable device, 15 is a second switch connected between the second charging terminal 13 and the battery connection terminal 14, and 16 is a second switch that operates only when connected to the charger 12. An ON / OFF circuit for opening and closing the two switches 15 and a microcomputer 17 for detecting the presence or absence of a voltage from the charger 12 and sending a signal to the portable device. The second switch 1
Reference numeral 5 includes a semiconductor switch element such as a transistor or an FET.

FIG. 6 shows a flowchart of the detection operation of the present invention, and FIG. 7 shows a waveform diagram of each operation. Note that the configuration and operation of the charger 12 are the same as those described in the first embodiment.

Next, the detection operation in the portable device will be described with reference to the flowchart of FIG. Normally, when the charging operation is not performed, the state of the second switch 15 is OFF, the portable device checks the voltage of the second charging terminal 13 as needed (S601), and when the charger 12 is connected to the portable device. ,
ON / OFF of the first switch 3 is provided to the second charging terminal 13
Appears, a voltage (Vchg or Vchg47) synchronized with
The operation start voltage of the ON / OFF circuit 16 in the portable device (1
V) or more, so there is a charger (step S602)
And the ON / OFF circuit 16 operates according to the voltage (step S603). O of ON / OFF circuit 16
When N (the second switch 15 is ON), the charger 12 and the battery 10 are connected to perform charging. O of ON / OFF circuit 16
When FF (the second switch 15 is OFF), the charger 12 and the battery 10 are disconnected, and the voltage of the second charging terminal 13 is checked. A voltage (Vchg) in which the voltage of the second charging terminal 13 is synchronized with the ON / OFF of the first switch 3 of the charger 12
Or Vchg 47), it is determined that the charger is connected, and when 0 V (1 V or less), the charger is not connected (step S604). In this way, the portable device can detect that the portable device has been inserted into or removed from the charger 12, and when the portable device is removed from the charger, the portable device automatically goes off-hook (without key operation). And a function of changing the display on the display unit (for example, “charging” → normal standby display).

[0023]

According to the present invention, in a charger for charging a battery having two charging terminals, a switch connected between the charging terminal and a power supply circuit, opening and closing means for periodically opening and closing the switch, and the switch Voltage detecting means for detecting a voltage appearing at the charging terminal during the opening and closing operation of the, current detecting means for detecting a current flowing between the charging terminal and the power supply circuit,
It is another object of the present invention to provide a detection means for detecting the presence or absence of a battery based on the detection results of these detection means, thereby enabling simple and reliable detection of the presence or absence of a battery.

The first charging terminal has two terminals, a first switch connected between the first charging terminal and the power supply circuit, and opening / closing means for periodically opening / closing the first switch. Voltage detecting means for detecting a voltage appearing at the first charging terminal during opening and closing operations of the first switch; current detecting means for detecting a current flowing between the first charging terminal and the power supply circuit; A charger provided with detection means for detecting the presence or absence of a battery based on the detection results of these detection means, a second charging terminal which comes into contact with and separates from the first charging terminal, A second switch connected between the second switch and the second switch, a switch for periodically opening and closing the second switch, and the second switch during opening and closing of the second switch.
And a detecting device for detecting whether or not the charger is mounted based on the detection result of the detecting device. Another object of the present invention is to make it possible to detect the presence or absence of mutual attachment.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram of a charger according to Embodiment 1 of the present invention.

FIG. 2 is a flowchart illustrating an operation procedure according to the first embodiment;

FIG. 3 is a waveform chart of each operation of the first embodiment.

FIG. 4 is a flowchart showing an operation procedure according to the second embodiment.

FIG. 5 is a circuit block diagram of a portable device according to Embodiment 3 of the present invention.

FIG. 6 is a flowchart showing an operation procedure of the portable device according to the third embodiment.

FIG. 7 is a waveform chart of each operation of the portable device in the third embodiment.

[Explanation of symbols]

 Reference Signs List 1 power supply circuit 2 first charging terminal 3 first switch 4 resistor 5 current detection resistor 6 charging current detection circuit 7 voltage detection resistor 8 voltage detection circuit 9 charge control circuit 10 battery 11 battery charged terminal 12 charger 13 second Charging terminal 14 battery connection terminal 15 second switch 16 ON / OFF circuit 17 microcomputer

Claims (2)

[Claims] 1. A charger for charging a battery having two charging terminals, a switch connected between the charging terminal and a power supply circuit, opening and closing means for periodically opening and closing the switch, and the switch Voltage detecting means for detecting a voltage appearing at the charging terminal during the opening and closing operation of the, current detecting means for detecting a current flowing between the charging terminal and the power supply circuit,
A battery charger comprising a detecting means for detecting whether or not a battery is mounted based on a detection result of the detecting means. And a first switch connected between the first charging terminal and a power supply circuit, and an opening and closing device for periodically opening and closing the first switch. Means, voltage detecting means for detecting a voltage appearing at the first charging terminal during opening and closing operations of the first switch, and current detecting means for detecting a current flowing between the first charging terminal and the power supply circuit A charger having detection means for detecting the presence or absence of a battery based on the detection results of these detection means, a second charging terminal which comes into contact with and separates from the first charging terminal, A second switch connected between the second switch and the battery; opening and closing means for periodically opening and closing the second switch; and a second switch during opening and closing of the second switch.
And a detecting device for detecting whether or not the charger is mounted based on the detection result of the detecting device. A charging system for a portable device, characterized in that it is possible to detect the presence or absence of mutual mounting.