JPH05219656A - Batter charger - Google Patents

Abstract

PURPOSE:To realize positive charging of battery or power supply to machine by interrupting output and producing an alarm upon detection of abnormality in the supply voltage or current under any one of charging mode or adapter mode. CONSTITUTION:If a battery is loaded between output terminals through insufficient contact at the time of charging, charging voltage increases over a correct level. That state is detected through an overvoltage circuit 9a. If a control circuit 18 fails under adapter mode, supply voltage increases over an appropriate level. That state is detected through the overvoltage circuit 9a by detecting a voltage higher than a level set by a setting circuit 13 for a predetermined time. If the adapter current is sustained higher than a level set by a setting circuit 12 for a predetermined time, that state is detected through an overcurrent detecting circuit 8. Upon detection of such abnormality, the control circuit 18 controls an output interrupting circuit 19 to interrupt power supply and to produce an alarm from an alarm circuit 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery charger which can charge a secondary battery and can also be used as an adapter, and more particularly, when an abnormality occurs during charging of the battery or during use as an adapter. The present invention relates to a battery charger that informs this and stops the output.

[0002]

2. Description of the Related Art Secondary batteries such as nickel-cadmium batteries and lead batteries are widely used as a power source for portable small electric devices because they can be repeatedly used by recharging even when discharged. This battery is charged by a battery charger, but the battery charger that charges the batteries used for these small electric devices transforms the commercial AC power supply into a desired voltage and converts it into DC, and charges the battery loaded between the output terminals. Is.

Further, the battery charger converts commercial alternating current into desired direct current except when charging the battery,
Some can also be used as an adapter to supply DC power.

[0004]

However, when the battery is charged by the battery charger,
If the battery is not securely inserted between the output terminals, the battery will not be charged properly.

When used as an adapter,
In the case where the inside of the adapter is out of order, the supply voltage rises, and if it is used as it is, the connected equipment may be damaged.

Therefore, conventionally, when charging a battery, it is necessary to confirm whether or not the battery is securely mounted between the output terminals before starting charging, and when using the battery as an adapter. It was necessary to connect the proper adapter securely. Therefore, it is necessary to charge the battery after checking these.

The present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a battery charger having various protection functions for detecting an abnormality when charging a battery or when using it as an adapter. It is intended to be provided.

[0008]

The structure according to the present invention for achieving the above object is to charge a battery in a battery charger having a charging mode for charging the battery and an adapter mode for supplying a predetermined electric power. When the charging voltage is within a predetermined range, an open terminal voltage detection circuit that outputs an abnormal signal, a low voltage detection circuit that outputs an abnormal signal when the charging voltage is below a certain level, and a charging voltage above a certain level A charging mode that has an overvoltage detection circuit that outputs an abnormal signal at times and an overcurrent detection circuit that outputs an abnormal signal when the charging current is at or above a certain level; An adapter mode having an overvoltage detection circuit that outputs an abnormal signal when the supply current exceeds a certain level, and an overcurrent detection circuit that outputs the abnormal signal when the supply current exceeds a certain level. With the alarm display, comprising as characterized by providing the abnormality judging circuit for stopping the output.

[0009]

[Operation] In the battery charger having the above structure,
When the battery is charged, the battery is not surely loaded. For example, if the battery is loaded in a poor contact state, the charging voltage becomes higher than the proper value. Therefore, if the battery has a poor contact, the overvoltage detection circuit detects this, stops the output, and displays an alarm. Further, when the battery charger is used as an adapter, for example, when the supply voltage rises, the overvoltage detection circuit detects it and stops the output, and also displays an alarm. By such a protection function, the battery is charged and the power is properly supplied to the device.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the battery charger according to the present invention to which the above means is applied will be described with reference to FIGS. 1 is a block diagram of the configuration of the battery charger, and FIG. 2 is a flowchart of the operating procedure.

This battery charger converts an AC power supply 1 into a predetermined DC voltage by a DC conversion circuit 2. As the conversion circuit 2, for example, a switching regulator including a switching transistor and a high frequency transformer is used, and is configured to convert into a desired DC voltage. Then, the converted DC voltage is switched between the charging mode and the adapter (AD) mode by the changeover switch 3 and used.

The charging mode circuit 4 is for charging a battery loaded between the output terminals, applies a charging voltage to the battery for charging, and detects the charging voltage during charging-
The completion of charging is detected by detecting ΔV. When charging a battery, the charging voltage rises during charging, reaches a peak when charging is completed, and then drops afterwards, so if the charging voltage drops to a certain voltage value, that voltage The value is peak-held, and when the voltage drops by a predetermined voltage (ΔV) from the peak value, it is determined that the charging is completed and the main charging is stopped. After the main charging is stopped, trickle charging is continued for a predetermined time. In this embodiment, the charging voltage changes within the range of about 14-15V.

The adapter mode circuit 5 supplies DC power to an electric device or the like connected to the output terminal, and is used as a DC power supply by applying the DC voltage converted by the DC conversion circuit 2.

The charge mode circuit 4 is connected to an open terminal voltage detection circuit 6, a low voltage detection circuit 7, an overcurrent detection circuit 8, an overvoltage detection circuit 9, a constant voltage circuit 10 and a constant current circuit 11,
The adapter mode circuit 5 is connected to an overcurrent detection circuit 8, an overvoltage detection circuit 9, and a constant voltage circuit 10.

The open-circuit voltage detection circuit 6 detects whether or not the charging voltage has maintained a voltage value within a certain range (21 to 23 V in this embodiment) for several seconds when charging the battery. Is. When this circuit 6 detects the above state, it is determined that charging is started without inserting a battery between terminals.

The low voltage detecting circuit 7 is a circuit for detecting whether or not the charging voltage is kept below a constant voltage (9 V in this embodiment) for several seconds during charging. For example, when a set of batteries is charged by a plurality of cells and some of the cells are short-circuited, the charging voltage does not rise to an appropriate value. Therefore, the above-mentioned case is detected by the low voltage detection circuit 7.

When the overcurrent detection circuit 8 is in the charging mode,
It is a circuit that detects whether or not the charging current has continued for a few seconds within the range (2.7 to 3 A in this embodiment) set via the overcurrent setting circuit 12. For example, in the charging mode, when the inside of the battery charger is out of order, an overcurrent may flow. In such a case, it is detected by the overcurrent detection circuit 8 to determine the abnormality.
Further, in the adapter mode, an overcurrent may flow when a device to be connected has a failure in addition to the internal failure. For this reason, if the adapter current continues to exceed the current value set by the setting circuit 12 (110% of the rated current of the electrical equipment connected between the terminals in this embodiment) for several seconds, this is detected. To determine abnormality.

The overvoltage detection circuit 9 is a circuit for detecting whether the charging voltage or the adapter voltage is equal to or higher than the voltage value set by the setting circuit 13. The overvoltage detection circuit 9 has an overvoltage circuit 9a and a circuit 9b for detecting the maximum charging voltage in the charging mode. During charging, if the battery loaded between the output terminals has poor contact, the charging voltage will be higher than the appropriate value. Therefore, in this case, the above state can be detected by the overvoltage circuit 9a.
(In this embodiment, if a voltage of 21 V or higher is detected, it is detected as a battery connection failure.) Also, the charging maximum voltage value set by the charging voltage during charging (19 V in this embodiment, +
0.7V, -0.3V), the charging maximum voltage detection circuit detects this, and even if it does not detect the decrease in ΔV, it judges that the charging is completed, stops the main charging, and switches to trickle charging. It is a thing. On the other hand, in the adapter mode, if the control circuit or the like fails, the supply voltage may become higher than the appropriate value, but the voltage value set by the setting circuit 13 by the overvoltage circuit 9a (14 in the present embodiment).
V) This is detected by continuously detecting the above for several seconds.

The constant voltage circuit 10 is a control circuit 15 that feeds back the output voltage to a constant value by feeding back the output voltage to the voltage value set by the voltage setting circuit 14 in the charging mode and the adapter mode.
It stabilizes the voltage applied to the output terminal via.

In the charging mode, the constant current circuit 11 controls the charging current to be constant via the control circuit 15 because the charging voltage fluctuates and ΔV is erroneously detected if the charging current is not stable. Is.

Although each of the detection circuits 6, 7, 8 and 9 is connected to the abnormality determination circuit 17, in the case of the charging mode, the abnormality determination circuit 17 performs the abnormality determination via the delay circuit 16. I have to. The delay circuit 16 causes the abnormality determination circuit 17 to make a determination after a certain period of time, based on the detection by the detection circuit. That is, when the battery is charged in the charging mode, the charging voltage may not be stable immediately after the start of charging, and the voltage that should be increased may drop sharply.
Therefore, the abnormality determination by each of the detection circuits is not performed immediately after the start of charging, and the abnormality determination by the detection circuits is performed after the charging voltage is stabilized after a certain amount of time has elapsed. In the adapter mode, the abnormality determination circuit 17 does not use the delay circuit 16 to determine the abnormality.

The control circuit 18 operates the output stop circuit 19 to stop the power supply when the abnormality judgment circuit 17 judges the abnormality. Further, the alarm circuit 20 is composed of an LED or the like, and when the abnormality determination circuit 17 makes an abnormality determination, it blinks the LED to indicate that there is an abnormality.

Next, the operation of the battery charger having the above structure will be described with reference to the flowchart of FIG. When charging, load a battery to be charged between output terminals, and when using as an adapter, connect an electric device to the output terminal. Then, in step S1, an overcurrent detection circuit 8, an overvoltage detection circuit 9 for detecting an abnormality in the charging mode or the adapter mode, respectively,
Each current and voltage value in the constant voltage circuit 10 is set, and the charging mode or the adapter mode is selected by the changeover switch 3.

In step S2, when the selection by the change-over switch 3 is the charging mode, the battery inserted between the output terminals is charged. If the initial time in step S3 elapses during this charging, abnormality detection is performed in steps S4 to S7. That is, the open terminal voltage detection circuit 6, the low voltage detection circuit 7, the overcurrent detection circuit 8, and the overvoltage detection circuit 9
The charging voltage or the charging current is detected by, and when it is judged to be abnormal by the abnormality judging circuit 17, the process proceeds to step S8 to stop the output to the output terminal, and at the same time, in step S9, an alarm display indicating the abnormality To do.

If the abnormality does not occur, step S
In 10, it is determined whether or not the charging is completed, that is, it is detected whether or not the charging voltage has decreased by ΔV, and if it has not decreased by ΔV, the process returns to step S4 to continue charging. ..

On the other hand, in step S2, when the selection by the change-over switch 3 is the adapter mode, it works as the DC power source of the equipment connected to the output terminal. At this time, abnormality detection is performed in steps S11 and S12. That is, the overcurrent detection circuit 8 and the overvoltage circuit 9a detect the supply voltage and the supply current from the output terminal, and when the abnormality determination circuit 17 determines that there is an abnormality, the process proceeds to step S8 and the output to the output terminal is stopped. At the same time, an alarm display indicating that there is an abnormality is displayed in step S9.

If the abnormality does not occur, step S
Supply DC voltage until end of adapter mode at 13.

When each of the above circuits is configured by using circuit elements such as resistors and capacitors without using a microcomputer or the like, some elements may be changed to set overvoltage or overcurrent. Can be set freely, increasing the versatility of design.

[0029]

As described above, the present invention provides a voltage to be supplied in both charging mode and adapter mode.
When it is uncertain that the battery or the like is loaded due to the current value, the output can be stopped and an alarm can be displayed to inform the user.

[Brief description of drawings]

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

FIG. 2 is a flowchart showing an operation of the battery charger.

[Explanation of symbols]

 1 ... AC power supply 2 ... DC conversion circuit 3 ... Changeover switch 4 ... Charge mode circuit 5 ... Adapter mode circuit 6 ... Open terminal voltage detection circuit 7 ... Low voltage detection circuit 8 ... Overcurrent detection circuit 9 ... Overvoltage detection circuit 10 ... Constant Voltage circuit 11 ... Constant current circuit 16 ... Delay circuit 17 ... Abnormality judgment circuit 19 ... Output stop circuit 20 ... Alarm circuit

Claims (1)

[Claims] 1. In a battery charger having a charging mode for charging a battery and an adapter mode for supplying a predetermined electric power, when charging the battery, an abnormal signal is output when the charging voltage is within a predetermined range. Open terminal voltage detection circuit, low voltage detection circuit that outputs an abnormal signal when the charging voltage is below a certain level, overvoltage detection circuit that outputs an abnormal signal when the charging voltage is above a certain level, and charging current above a certain level When the charging mode has an overcurrent detection circuit that outputs an abnormal signal, an overvoltage detection circuit that outputs an abnormal signal when the supply voltage is above a certain level when supplying a predetermined power, and the supply current is above a certain level. An adapter mode having an overcurrent detection circuit that sometimes outputs an abnormal signal, and an abnormality determination time for stopping the output while inputting the abnormal signal and displaying an alarm. A battery charger having a road.