JPH09298847A - Non-contact charger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-contact charger whereby its conversion efficiency from an AC power into a DC power can be improved and both the maximum allowable current of its element and its loss can be reduced. SOLUTION: In a non-contact charger 1, an inverter 4 converts a DC voltage fed from a constant-voltage circuit 3 into a high-frequency voltage according to the control of a control circuit 5 to generate a magnetic line of force by a magnetic-force generating coil L1. On the other hand, in a slave machine 10, a coupling coil L2 takes out a high-frequency power from the magnetic line of force of the foregoing magnetic-force generating coil L1 by an electromagnetic induction, and after rectifying the high-frequency power by a rectification circuit 11, a rectified DC voltage is fed to a charging circuit 12 to charge a battery 13 by the rectified DC voltage. Also, a pickup coil L3 takes out the leakage magnetic flux generated between the magnetic-force generating coil L1 and the coupling coil L2 to feed it to a feedback circuit 6. After the high-frequency power in response to the foregoing leakage magnetic flux is converted into a DC voltage, the feedback circuit 6 feeds back it to the constant-voltage circuit 3. A light emitting diode LED is lit by the DC voltage obtained from the leakage magnetic flux to indicating that the battery 13 is being charged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact charger for a communication device that charges a battery built in a cordless telephone handset or the like.

[0002]

2. Description of the Related Art In recent years, waterproofness has become essential in PHS, cellular phones, cordless telephones used at home, etc. due to the environment in which they are used. Therefore, from a mechanical perspective, the problem is the contact terminal that is provided for charging and that contacts the charger that is exposed to the outside of the housing. Avoiding this and improving the overall waterproof performance For this reason, the non-contact charging method has become popular.

In the above non-contact charger, the high frequency power generated in the inverter circuit on the charger side is applied to the magnetic force generating coil (L
The high frequency power is taken out by electromagnetic induction by the coupling coil (L2) built in the telephone which is supplied to and charged in 1), and the battery is charged by the rectified DC voltage.

[0004]

However, in the conventional non-contact charger, since the coupling coefficient k between the magnetic force generating coil (L1) and the coupling coil (L2) is considerably small, the battery on the telephone side can be charged with a predetermined current. In order to charge the battery, a large amount of power is required in the charger, including the loss, which deteriorates the conversion efficiency from AC to DC when viewed from a commercial AC power supply. Even if it is a type in which an AC adapter is connected to the charger, a considerable amount of direct current is required, and therefore the rated capacity of the adapter itself must be increased, which causes a problem of cost increase.

Further, as described above, since the current in the charger becomes large, it is necessary to increase the current rating value of the control element including the voltage regulator, which causes a problem of cost increase. Further, most chargers are provided with a lighting device such as an LED controlled by a switching element or the like in order to make the user recognize charging / non-charging, but the circuit configuration becomes complicated, and Since the number of parts is increased, there is a problem that the cost is increased.

Therefore, the present invention can improve the conversion efficiency from AC to DC, reduce the maximum allowable current value and loss of the element, and charge without using any special circuit. / It aims at providing the non-contact charger which can display non-charge.

[0007]

In order to achieve the above object, a contactless charger according to the present invention is a charger for charging a battery of an electronic device, and a high frequency power is supplied to a coupling coil provided on the electronic device side. In a non-contact charger that supplies a charging power to the electronic device in a non-contact manner by electromagnetic induction between the magnetic force generation coil and the coupling coil, the magnetic force generation coil is arranged in the vicinity of the magnetic force generation coil. A pickup coil for extracting high frequency power due to a leakage magnetic flux between the magnetic force generating coil and the coupling coil; and a feedback unit for feeding back the high frequency power extracted by the pickup coil as a power source of a constant voltage control circuit system. To do.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

A. Embodiment A-1. Configuration of Embodiment FIG. 1 is a circuit diagram showing a schematic configuration of a non-contact charger according to an embodiment of the present invention and a slave unit of a telephone charged by the non-contact charger, and FIG. 2 is a non-contact charger. FIG. In the figure, the non-contact charger 1 includes a rectifier circuit 2, a constant voltage circuit 3, an inverter circuit 4, a control circuit 5, and a magnetic force generation coil L.
1, a pickup coil L3, and a feedback circuit 6. The rectifier circuit 2 is a diode D
It is composed of a bridge circuit composed of 1 to D4, rectifies the commercial power supply AC, and supplies it to the constant voltage circuit (regulator) 3.

The constant voltage circuit 3 smoothes the rectified DC voltage and controls it so that it becomes a predetermined voltage, and supplies it to the inverter circuit 4. The inverter circuit 4 converts the DC voltage into a high frequency, and causes the magnetic force generation coil L1 to generate magnetic force lines. The control circuit 5 controls the inverter circuit 4 to generate a predetermined high frequency. The pickup coil L3 takes out a leakage magnetic flux that is not electromagnetically coupled by the magnetic force generation coil L1 and a slave unit side coupling coil L1 to be described later, and supplies it to the feedback circuit 6.

The feedback circuit 6 includes a resistor R1, a Zener diode ZD, a diode D5 and a capacitor C.
1, a resistor R2 and a light emitting diode LED. The leakage magnetic flux is converted into a DC voltage by the diode D5, smoothed by the capacitor C1 and fed back to the constant voltage circuit 3, and the resistor R2 and the light emitting diode are also provided. Turn on the LED. Therefore, during the charging, the leakage magnetic flux is taken out by the pickup coil L3, so that the light emitting diode LED is turned on. In addition, the efficiency of conversion from alternating current (AC) to direct current (DC) can be improved by supplying the leaked power to the direct current voltage source.

On the other hand, the slave unit (handset) 10 includes a coupling coil L2, a rectifying circuit 11, a charging circuit 12, and a battery 1.
3, the main power supply circuit 14 is provided. The coupling coil L2 is
The rectifier circuit 1 is coupled to the magnetic force generation coil L1 of the non-contact charger 1 by electromagnetic induction to extract high frequency power.
Feed to 1. The rectifier circuit 11 is composed of a diode D6 and a capacitor C2. The high frequency power is rectified by the diode D6, smoothed by the capacitor C2, and then supplied to the charging circuit 12. The charging circuit 12 charges the battery 13 with the DC voltage. The main power supply circuit 14 generates a drive voltage for driving a communication-related circuit (not shown) from the output voltage of the battery 13 and supplies it to each unit.

As shown in FIG. 2, the magnetic force generating coil L1 and the pickup coil L3 described above are arranged concentrically inside the surface on which the cordless handset 10 is placed on the non-contact charger 1 during charging. Similarly, as shown in FIG. 2, the coupling coil L2 is also concentrically arranged so as to face the magnetic force generation coil L1.

B. Operation of Embodiment Next, the operation of the above-described non-contact charger will be described.
In the non-contact charger 1, the commercial power AC is converted into a DC voltage by the rectifier circuit 2, controlled to a predetermined voltage by the constant voltage circuit 3, and then supplied to the inverter 4. The DC voltage is converted into a high frequency by the inverter 4 under the control of the control circuit 5 and supplied to the magnetic force generating coil L1. As a result, magnetic force lines are generated from the magnetic force generation coil L1.
On the other hand, in the handset 10, the coupling coil L2 extracts high frequency power from the magnetic force lines of the magnetic force generation coil L1 by electromagnetic induction. The high frequency power is rectified by the rectifier circuit 11 and then supplied to the charging circuit 12. Charging circuit 1
In 2, the battery 13 is charged with the rectified DC voltage.

In the above charging operation, the magnetic force generating coil L
The leakage magnetic flux that is not completely coupled between 1 and the coupling coil L2 is taken out by the pickup coil L3 and supplied to the feedback circuit 6. The high frequency power corresponding to the leakage magnetic flux is rectified by the diode D5 of the feedback circuit 6, smoothed by the capacitor C1, and fed back to the constant voltage circuit 3. At this time, the light emitting diode LED lights up, which indicates that the battery is being charged.

As described above, in the above-described embodiment, the non-contact charger 1 is provided with the pickup coil L3, and the high frequency power corresponding to the leakage magnetic flux extracted by the pickup coil L3 is converted into the DC voltage by the feedback circuit 6. After that, by feeding back to the DC voltage source, alternating current (AC) → direct current (D
The conversion efficiency to C) can be improved. Further, a light emitting diode LED that is taken out by the pickup coil L3 and is turned on by a DC voltage according to the leakage magnetic flux.
By providing, it is possible to display that the battery is being charged without using a special switching element.
Also, by feeding back the power corresponding to the leakage magnetic flux to the DC voltage source, for example, the supply current of the element of the constant voltage circuit can be reduced. The allowable current value and the loss can be set to be low, and the cost can be reduced.

[0017]

As described above, according to the present invention, the charger for charging the battery of the electronic device has the magnetic force generating coil for inducing high frequency power in the coupling coil provided on the electronic device side. A non-contact charger that supplies charging power to the electronic device in a contactless manner by electromagnetic induction between the magnetic force generating coil and the coupling coil, the magnetic force generating coil and the coupling coil being disposed in the vicinity of the magnetic force generating coil. Conversion from AC to DC is provided by providing a pickup coil for extracting the high frequency power due to the leakage magnetic flux between the two and a feedback means for feeding back the high frequency power extracted by the pickup coil as a power source of the constant voltage control circuit system. It is possible to improve the efficiency and reduce the maximum allowable current value and loss of the device. The advantage that wear is obtained.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a schematic configuration of a non-contact charger and a handset (handset) charged by the non-contact charger according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a non-contact charger and a slave unit (handset) charged by the non-contact charger.

[Explanation of symbols]

1 ... Non-contact charger, 2 ... Rectifier circuit, 3 ... Constant voltage circuit, 4 ... Inverter circuit, 5 ... Control circuit, 6 ... Feedback circuit (feedback means), 10 ... Slave unit, 11 ...... Rectifier circuit, 12 ... Charging circuit, 13 ... Battery, 14 ... Main power circuit, L1 ... Magnetic force generating coil, L2 ... Coupling coil, L3 ... Pickup coil, D5 ... Diode (rectifying means) , LED ... Light emitting diode (display means).

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication H02J 17/00 H02J 17/00 B H04M 1/00 H04M 1/00 N

Claims (3)

[Claims] 1. A charger for charging a battery of an electronic device, comprising a magnetic force generating coil for inducing high-frequency power in a coupling coil provided on the electronic device side, and between the magnetic force generating coil and the coupling coil. A contactless charger that supplies charging power to the electronic device in a contactless manner by electromagnetic induction, a pickup coil that is disposed in the vicinity of the magnetic force generation coil and that extracts high-frequency power by leakage magnetic flux between the magnetic force generation coil and the coupling coil. And a feedback means for feeding back the high frequency power extracted by the pickup coil as a power source of a constant voltage control circuit system. 2. The non-contact charger according to claim 1, further comprising a display unit that is turned on by the high frequency power extracted by the pickup coil. 3. The contactless charger according to claim 1, wherein the feedback unit includes a rectifying unit that converts the high frequency power into a direct current.