JPH05316664A - Ac adapter with built-in battery charger - Google Patents

Abstract

PURPOSE:To prevent the performance deterioration of a battery by limiting the quick charge starting condition of the battery. CONSTITUTION:After AC power supply is started to the title adapter 1 and the AC-DC section 2 converts the alternating current into a direct current and fixes the voltage, and then, an LED 3 lights, a control circuit 4 receives each detecting data about the mounting of a battery, output of the AC power supply, turning on/off the switch of electronic equipment, set timer time, and a value of the battery voltage from a detection circuit 5 and, only when each data meets prescribed conditions, performs quick charge of a battery by supplying a quick charging current to the battery. When the data do not meet the prescribed conditions, the circuit 4 charges the battery by trickle charge.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AC adapter having a built-in battery charger for quick charging.

[0002]

2. Description of the Related Art FIG. 6 is a block diagram of a conventional battery charger for electronic equipment. Most of the conventional battery chargers 101 are built-in electronic devices, and the AC / D is supplied from a commercial AC power source with an AC cord.
After being converted into a DC voltage by the rectifier circuit in the C section 102, it is converted into a constant voltage by the regulator.

When the output DC voltage of the AC / DC section 102 is stabilized, the LED 103 is turned on. In this state, the CPU 104 in the electronic device detects the presence / absence of Battery by the detection circuit 106 at the charging terminal (+ C), which is the output of the charging circuit 105, and turns on the switch of the charging circuit 105 to start rapid charging.

Next, the charging operation during this period will be described.
FIG. 5 is a charging characteristic curve of a nickel-cadmium battery, in which the terminal voltage VC of the battery changes in a mountain shape, the mountain-shaped peak PVC indicates the level of full charge, and the charging current I is always a constant value, for example, 1.25A. Is maintained.

As shown in the VC curve of FIG. 5, when the charge starts, the terminal voltage of the battery rises, and when the battery reaches the fully charged state PVCC, the extra energy injected by the charging current I becomes heat to change the battery temperature. Raise and the battery voltage will start to drop.

The change in the battery voltage Vc during this time is detected by the detection circuit 106 by the A / D converter as CP voltage data.
Send to U104. When the battery voltage VC drops by ΔV (for example, 120 mV) from the peak value PVCC, the CPU 104
The switch of the charging circuit 105 is turned off to stop charging.
Alternatively, it switches to trickle charging (supplementary charging) that continues to supply a small current (for example, 7 mA).

[0007]

SUMMARY OF THE INVENTION Such a conventional -Δ
In the V-voltage control type battery charger, frequent rapid charging that does not depend on the desirable charge / discharge characteristics of the battery irrespective of the use state or consumption state of the electronic device that supplies power is a cause of degrading the battery performance. There's a problem. Further, since the conventional battery charger is a built-in type of the electronic device body, there is a problem that it cannot be used together with other AV devices as an AC adapter or a charger.

The present invention has been made in view of the above circumstances, and the performance of the battery is improved by setting the rapid charging conditions other than the -ΔV voltage in detail and performing efficient charging to prevent overcharging. An object of the present invention is to provide an AC adapter with a built-in battery charger that is not deteriorated and can also be used for other AV equipment, which is small in size and power saving.

[0009]

In order to achieve the above object, the present invention relates to an AC adapter having a built-in battery charger for charging a secondary battery such as a nickel cadmium battery used in electronic equipment, with or without a battery attached. And A
C The presence or absence of power input, the ON / OFF state of the power switch of the electronic device, the detection circuit for detecting the -ΔV voltage value of the battery and the timer time, and the rapid charging when the detection data of the detection circuit are all H. The charging circuit is controlled by the control circuit so as to perform only the trickle charging after the quick charging is performed once and then the AC power is not turned on again.

[0010]

With the above configuration, the detection circuit detects whether or not the battery is installed, the output voltage value from the AC power supply, the switch on / off of the electronic device body side, the elapsed time of the timer,
The control circuit judges each signal data by detecting the -ΔV drop voltage value of the battery at the same time and logically processing the data of each detection signal. Only when all signals are in a predetermined state The AC adapter, which is configured to instruct quick charge and to perform trickle charge otherwise, is used by connecting the cable independently of the electronic device body, so it is possible to improve efficiency by setting detailed quick charge conditions to prevent overcharging. In addition to enabling good quick charging, it can be used not only as an exclusive AC adapter with a built-in, power-saving, miniaturized battery charger for electronic devices, but also in combination with other devices.

[0011]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of an AC adapter with a built-in battery charger according to an embodiment of the present invention. Where 1
Is an AC adapter, 2 is an AC / DC unit, 3 is an LED (light emitting diode), 4 is a control circuit (microcomputer, etc.), 5 is a charge / detection circuit, 5a is a charge voltage output terminal,
5b is a power input switch signal input terminal of the main body, and 5c is an output terminal to the LED of the main body.

In FIG. 1, an AC adapter 1 with a built-in battery charger supplies AC voltage from a commercial power source,
The AC / DC unit 2 performs DC conversion and constant voltage conversion (terminals of 5V, 24V, etc. may be provided in addition to DC + 15V).

FIG. 2 is a perspective view of the outer shape of the AC adapter shown in FIG. 1. When the output DC + 15V of the AC / DC section 2 enters a stable state, the AC power of the LED 3 is turned on in green, and in this state. The control circuit (microcomputer, etc.) 4 is based on detection of the charging / detection circuit 5, battery mounting data, output voltage value when AC power is turned on, ON / OFF data of the switch of the electronic device body, and a clock circuit incorporated in the control circuit 4. Set timer time and battery voltage -ΔV
Receives a voltage value data signal.

The received data signals are NAND-processed, and a quick charge command is issued to the charging circuit 5 by the low-level "L" output of the NAND when all the data signals are high-level "H". Receiving the command, the charging circuit 5 supplies a charging constant current I (1.25 A as an example) to the battery from the charging output terminal + C to perform rapid charging, and QUICK / TR of the LED 3 is supplied.
Make ICKLE light orange.

During the rapid charging, the control circuit 4 monitors the rise of the battery voltage from the A / D conversion data of the detection circuit 5, and after the battery voltage VC reaches PVC as shown in FIG. 5, ΔV (for example, 120 mV). ) When the battery voltage drops, it is regarded as full charge and switched to trickle charge (for example, 7 mA). In addition, NAND
When the output of is "H", all trickle charging is instructed.
When trickle charging starts, the LED 3 lights up in green.

FIG. 3 is a connection diagram of the AC adapter and the main body of the electronic device. The signal of the CHARGE LED (charge state is “H”, non-charged state is supplied through the DC cable connected from the AC adapter 1 of FIG. 3 to the main body of electronic device). Sends "L") from the DC / DC converter unit 6 on the main unit side to the main PC
It is output to B7 and the LED on the electronic device body side is turned on to indicate that charging is in progress.

FIG. 4 shows the AC adapter 1 and the electronic equipment body 8.
3 is a connection diagram of the switch of FIG. 1, in which the detection circuit 5 detects the on / off state of the slide switch for power input of the main body through the DC cable from the main body switch signal and notifies the control circuit 4.

Next, the operation will be described. Detection circuit 5
The respective detection data according to (1) is “H” and “L” after checking the battery voltage Vc from the 5a terminal after the AC power is applied to the AC adapter 1 and whether or not the battery is mounted. As for the AC power data, the supply is "H" and the non-supply is "L" by the 15V output check of the AC / DC unit 2. DC on / off check of the power input switch
According to the main body switch signal from the cable, when the main body switch is off, it is high level as "H", and when it is on, it is low level of "L".

In addition to this, if the quick charging time is set to 2 hours, the timer setting time is confirmed, and the inside of the setting time is set to "H" and the outside thereof is set to "L". In the detection data of -ΔV of the battery voltage check from the terminal 5a, the full charge pressure value is "L" and the reduced voltage value is "H".

When there is no battery, no charging command is sent from the control circuit 4, and when the electronic equipment main body power input switch is ON ("L", low level), the electronic equipment D
DC15V is output from the DC cable to the C / DC converter unit 6, the charging output + C is not output, and the LED of the main body
The lighting signal CHARGE LED is not output to the DC cable.

When there is a battery, when the detection data are all "H", that is, AC power data supply is "H", when the main body switch is off "H", timer "H", -ΔV.
Only when "H", the 5a terminal has a rapid charging current I (1.25
A) is output and rapid charging is performed. If the quick charge state is stopped once, the control of the microcomputer will be turned off and AC power will not be reapplied (unplugged and plugged in again).
Quick charging is not possible again. CHARGE to the body
The LED signal is output simultaneously with the start of charging.

When the rapid charging progresses and the battery voltage reaches Pvc and -ΔV is detected, the charging is completed and the trickle charging is started. To stop the quick charge, immediately stop when the full charge is completed by detecting -ΔV, when the quick charge setting timer time elapses, and when the electronic device switch is turned on (“L”), Prevents overcharging and protects electronic devices.

Therefore, when the switch of the electronic equipment main body is turned on ("L") during the quick charge, the control circuit 4 detects the main body switch signal and instructs the charge circuit 5 to stop the quick charge, and trickle charge. The switching charging circuit 5 has a terminal 5a
Continue to supply trickle charging current (7 mA).

In this embodiment as described above, if the electronic device is operated during the rapid charging, a huge amount of power is required and the adapter becomes large. Therefore, either the rapid charging or the electronic device supplying operation should be performed. As a result, the power consumption will be halved, and it will be possible to save power and downsize the adapter.

In the above embodiment, the AC adapter of the type separated from the main body of the electronic device has been described, but it is standardized as an AC adapter with a built-in battery charger, and is diverted as a built-in type to the production of other types of electronic devices. Of course, it is also possible.

[0026]

As described above, according to the present invention, the detection circuit detects the battery mounting, the AC input power, the switch on / off of the electronic equipment body, the timer time, and the -ΔV voltage as the detection data. Only when each data is “H”, the quick charge constant current is output from the charging circuit, and the quick charge is performed. Once the quick charge is performed, the quick charge cannot be performed unless the AC power is turned on again, resulting in trickle charge. Since it is configured to control, it enables efficient and rapid charging that suppresses overcharging, prevents deterioration of battery performance, and saves power and reduces size independently of the electronic device itself. It is possible to reduce the cost by making it possible to use it for other models in production, and to use it together with other devices in terms of user use.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an AC adapter with a built-in battery charger according to an embodiment of the present invention.

FIG. 2 is an external perspective view of the AC adapter shown in FIG.

FIG. 3 is a connection diagram between the AC adapter shown in FIG. 1 and an electronic device body.

FIG. 4 is a connection diagram of the AC adapter shown in FIG. 1 and an electronic device body switch.

FIG. 5 is a charging characteristic curve of a nickel-cadmium battery.

FIG. 6 is a configuration diagram of a battery charger in a conventional electronic device.

[Explanation of symbols]

 1 AC Adapter 2 AC / DC Section 3 LED 4 Control Circuit (Microcomputer etc.) 5 Charging / Detection Circuit

Claims (1)

[Claims] 1. An AC adapter having a built-in battery charger for charging a secondary battery such as a nickel-cadmium battery used in an electronic device, wherein a battery is installed, an AC power input is present, and a power switch of the electronic device is turned on. / OFF state and -ΔV of the battery
A detection circuit that detects the voltage value and the timer time, and quick charge is performed when the detection data of the detection circuit are all H, and after quick charge is performed, only trickle charge is performed unless the AC power is turned on again. AC adapter with a built-in battery charger, which is provided with a charging circuit controlled by the control circuit.