JPH09149565A - Noncontact transfer power unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic coupling method of power unit small and high in power transfer efficiency. SOLUTION: This device drives its internal coil 10 on power supply side by single switch with its switching element 107, and also utilizes flyback power effectively, omitting a reflux diode used generally in single switch drive. Furthermore, this drives, by current resonance, the coil 104 on power supply side by flyback power with a power supply circuit including this power supply coil 104 so as to raise power transfer efficiency The transient power waveform generated in forward polarity can also be utilized by rectifying the output of the coil 111 on power reception side with a bridge constitution of diode 111.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact transfer power supply device for supplying power from a power supply side device to a power reception side device in a non-contact manner, and more particularly to a means for improving power transfer efficiency.

[0002]

2. Description of the Related Art In recent years, for example, as a database of an electronic notebook, an external storage medium of a computer, or an additional memory, a memory card having a semiconductor memory device such as SRAM has been put into practical use. As a non-contact power transfer method from an electronic organizer or a computer as a main device to a memory card as an external device, a coil provided on the main device side and a coil provided on the external device side have conventionally been opposed to each other. A method has been proposed in which an electric power transfer transformer is configured by arranging the electric power source and the electric power are contactlessly supplied by electromagnetic coupling through the electric power transfer transformer. This method is capable of transferring large amounts of power with a small and inexpensive device, compared to a method of transferring light energy or radio wave energy in a contactless manner and converting it into electricity, and the connector terminal provided on the main device side. Compared to the contact method in which power is transferred by mechanically contacting the connector terminal provided on the external device side with the contact terminal, poor contact resistance due to contamination of the connector terminal and deterioration of insertion / removal resistance due to miniaturization of the connector terminal It is excellent in that there are no such problems.

Conventionally, as a non-contact transfer power supply device for driving a coil provided in a main device (power supply side device) with a single switch, a forward single wave rectification is performed from a coil provided in an external device (power supply side device). It is known to obtain direct current by the method.

[0004]

However, in the non-contact transfer power supply device according to the above-mentioned known example, since the power transfer efficiency is low, not only the power consumption is large, but also when the coupled coils are separated from each other, As the gap between them becomes wider and the inductance decreases, more current flows into the coil, and the heat loss in the power supply side device increases, so an element with a large heat capacity and a heat dissipation device are required, and the device is large. There is a problem that it becomes.

The present invention has been made to solve the deficiencies of the prior art, and an object thereof is to provide an electromagnetic coupling type non-contact transfer power supply device which is small in size and has high power transfer efficiency. is there.

[0006]

In order to achieve the above object, the present invention provides a contactless transfer power source for supplying power from a power supply side device to a power reception side device by electromagnetic coupling via a transfer transformer in a contactless manner. In the device, among the coils forming the transfer transformer, a coil provided in the power supply side device is used for current resonance with flyback power of a resonance circuit configured by a combined inductance and a combined capacitance of the power supply side device. It was configured to let.

The coil drive circuit provided in the device on the power supply side has a circuit parasitic circuit including the inductance of the power supply side coil, the parasitic inductance of the circuit, the combined inductance of the inductance elements added to the circuit, and the stray capacitance of the coil. It can be regarded as a parallel resonance circuit composed of a capacitance and a combined capacitance of capacitance elements added to the circuit. When a unipolar rectangular voltage waveform corresponding to the resonance frequency is input to such a resonance circuit, the current waveform becomes a bipolar sine wave. On the other hand, in this resonance circuit, the inductance of the power supply side coil, the parasitic inductance of the circuit, the combined inductance of the inductance elements added to the circuit, and the parasitic capacitance and circuit of the circuit including the inter-electrode capacitance of the switching element When the flyback power defined by the combined capacitance of the capacitive elements added to is introduced, a bipolar current waveform that is not a sine wave but has a rapid polarity reversal change is obtained, as shown in FIG. This steep current change results in highly efficient power transfer.

Therefore, when the coil provided in the power supply side device is driven by the flyback power at the current resonance frequency of the resonance circuit constituted by the combined inductance of the coil and the combined capacitance of the coil,
The input current can be greatly reduced without reducing the output power, and the power transfer efficiency can be improved. In addition, the freewheeling diode can be omitted. Furthermore, since the impedance of the coil drive circuit is regulated by the resonance circuit, it is possible to limit the current that flows into the circuit when the electromagnetically coupled coils are separated, and a device with a large heat capacity or a heat dissipation device is not required. Therefore, the device can be downsized.

When a circuit constant corresponding to a heavy load is set in the power supply device having the above structure, an extremely high transfer efficiency can be obtained under a heavy load, but on the other hand, a power transfer efficiency is low under a light load. In some cases, the power consumption cannot be reduced sufficiently compared with the reduction of the load. Therefore, it is difficult to mount the power supply device having the above-mentioned configuration as it is on a device such as a fully automatic camera whose load switching frequency is high and power consumption is limited to an extremely low level.

As described above, when the decrease in the transfer efficiency of the power source when the load is low becomes a problem, the duty ratio of the coil driving signal for driving the coil provided in the power supply side device is set to the power receiving side. The transfer efficiency of the transfer transformer can be constantly maintained at a high level by switching the load so that the load is small when the load of the device is small, and conversely, the load is large when the load of the power receiving side device is large. It is possible to further reduce the amount of electric power.

That is, when a circuit constant corresponding to a heavy load is set in the power supply device having the above configuration, a high transfer efficiency can be obtained by increasing the duty ratio of the coil drive signal as shown in FIG. When the load is medium, a high transfer efficiency can be obtained by adjusting the duty ratio to a medium level, and when the load is low, a high transfer efficiency can be obtained by reducing the duty ratio. Therefore, by monitoring or predicting the load on the power supply / reception side device and switching the duty ratio to an appropriate value, it is possible to always maintain the transfer efficiency of the power supply at a high level, and to further reduce power consumption of the device. realizable. Note that, as is clear from FIG. 6, when the duty ratio is continuously changed, the transfer efficiency changes stepwise, so in order to simplify the circuit configuration, the duty ratio is changed stepwise (quantally). It is preferable to switch.
Further, in this case, in order to improve the reliability of the circuit, it is preferable to select the operating point duty ratio near the median of each stage.

The switching of the duty ratio can be performed by an appropriate automatic or manual means.
When the power supply circuit provided with the duty ratio switching means is mounted on the fully automatic camera, the duty ratio switching means and the release button composed of a manual multistage switch provided on the camera body are connected to each other to release the release. It is possible to switch the duty ratio of the coil drive signal according to the amount of button depression.

Normally, the release button in a fully automatic camera is adapted to perform focusing and determination of an exposure amount when it is pressed down by a half amount, and to operate a shutter, an aperture and a light exposure when pressed down by a full amount. There is. For the power supply device, focusing and determination of the exposure amount are low loads, and operation of the shutter, operation of the diaphragm, and exposure are heavy loads. Therefore, when the release button is pressed halfway down, the duty ratio of the power supply is switched to a small value via the duty ratio switching means, and when the release button is pressed down fully, the duty ratio of the power supply is switched via the duty ratio switching means. By switching to a large value, it is possible to constantly transfer power from the power supply side device (power supply device) to the power supply side device (camera) with high efficiency, and reduce the power consumption of the fully automatic camera. In a digital camera, after exposure, the exposure data is stored in the medium. This storage process is a medium load on the power supply device. Therefore, in this case, by switching the duty ratio to three stages of large, medium, and small, it is possible to constantly improve the efficiency of power transfer.

A flyback single-wave rectification method or a bridge double-wave rectification method can be used as a means for converting the output of the coil provided in the power receiving side device into a direct current.

In particular, a value obtained by multiplying the input voltage of the power supply side device by the winding ratio of the transfer transformer, the coupling coefficient, and the standard duty ratio of the switching waveform adds the diode loss voltage to the diode output voltage of the power supply side device. When the value does not exceed the value, the bridge double-wave rectification method is used as a means to convert the output of the coil provided in the power receiving side device to direct current, and the transient power waveform generated in the forward polarity in addition to the flyback polarity power. It is preferable that the power can be received. Also, the value obtained by multiplying the input voltage of the power supply side device by the winding ratio of the transfer transformer, the coupling coefficient, and the standard duty ratio of the switching waveform exceeds the value obtained by adding the diode loss voltage to the diode output voltage of the power supply side device. In this case, the bridge double-wave rectification method is used as a means for converting the output of the coil provided in the power receiving side device into direct current, and in addition to the flyback polarity power, the forward waveform and the transient power waveform generated in the forward polarity are also received. It is preferable to be able to do so.

Conventionally, in a non-contact transfer power supply in which a coil provided in a power supply side device is driven by a single switch, a single-wave rectification method based on the forward method is used in the power supply side device. It's just because it follows the theory as it is. That is,
In a switching regulator, generally, the efficiency of the transformer is high, so the flyback power is relatively small in the forward method, and if the secondary side output is bridge rectified in order to receive this flyback power, the rectifier power is more than that obtained. The loss due to the increase becomes larger,
On the contrary, the efficiency decreases. Therefore, even in the non-contact transfer power supply, single-wave rectification is used when the coil provided in the power supply side device is driven by the single switch.

However, according to the research conducted by the present inventors, the non-contact transfer power supply device has a low transfer transformer efficiency.
Most of the energy applied to the transfer transformer remains as magnetic energy in the coil on the supply side, and a large flyback power is generated at the moment when the switching element is turned off.
Then, the flyback power at this time is larger than the loss due to the increase in the rectifier when performing bridge rectification on the output of the receiving side coil.

Therefore, in the non-contact transfer power supply device in which the coil provided in the power supply side device is driven by a single switch, the bridge double wave rectification method is used as a means for converting the output of the coil provided in the power supply side device into direct current. By using, the large flyback power can be effectively received, and the power transfer efficiency can be improved. Even in the design as a flyback converter, since the power waveform due to the transient vibration is generated in the forward polarity in the non-contact transfer power supply, the bridge double-wave rectification method is preferably used as a means for receiving the waveform and improving the efficiency. You can

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION

<First Embodiment> FIG. 1 is a circuit diagram of a non-contact transfer power supply device according to the first embodiment. In this figure, 10
1 is a power supply side device, 102 is a power supply side device, 103
Is a power transfer transformer formed by facing these devices 101 and 102, 104 is a power supply side coil that constitutes the transfer transformer 103, 105 is a parasitic capacitance of the power supply side coil 104, and a capacitive element. Equivalent synthetic capacitance when added, 106 is a DC power source provided in the power supply side device 101, 107 is a switching element that drives the power supply side coil 104 by a single switch, 108 is a parasitic capacitance or a capacitive element of the switching element 107 Is an equivalent synthetic capacitance when added, 109 is its control signal source, and 110 is the transfer transformer 1.
Reference numeral 111 denotes a power receiving side coil, and reference numeral 111 denotes a diode having a bridge configuration for rectifying the output of the power receiving side coil 110.

Although not shown in the figure because it is a general method, when a capacitor input type power supply circuit is constructed, a smoothing capacitor is connected in parallel with the output of the diode 111. When a choke input type power supply circuit is configured, a smoothing inductor is connected in series with the output of the diode 111, and a smoothing capacitor is connected in parallel with the output of the smoothing inductor. Normally, a regulator circuit is inserted in the output of these smoothing circuits for stabilization.

In the non-contact transfer power supply device of this configuration, the winding ratio of the transfer transformer 103 is 1, the coupling coefficient is 0.55, and the resonance frequency of the resonance circuit composed of the power supply side coil 104 and the equivalent combined capacitance 105 is 1. When a circuit having a frequency of 0.2 MHz was manufactured and its characteristics were measured, when a rectangular wave signal having a duty ratio of 50% and a repetition frequency of 210 kHz was output from the control signal source 109, a current resonance clearly appeared in the flyback waveform. . At this time, the DC power source 106
The output of the diode was 5V-120mA, and the output of the diode 111 was 5V-60mA. In addition, the temperature rise of the power receiving side coil 110 at this time was a rise of 18 degrees with respect to room temperature after being left for 10 hours after energization.

On the other hand, when the power receiving coil 110 is removed and energized, the output of the DC power supply 106 is 5V.
The temperature rise was −180 mA, and the temperature rise was 40 ° C. with respect to room temperature after standing for 10 hours after energization.

FIG. 2 shows an inter-terminal voltage waveform 301 and a current waveform 302 of the power supply side coil 104 according to this embodiment.
3, a terminal voltage waveform 303 and a current waveform 304 of the power receiving side coil 110, and a control signal source waveform 305 are shown.
From this figure, a current resonance waveform (a steep peak) appears in the power supply side coil 104 when flyback power is generated, and the power supply side coil 110 receives the steep magnetic field change due to this current with high efficiency. I understand that. Therefore, according to the non-contact transfer power supply device of the present embodiment, the power transfer efficiency can be further increased by causing the current resonance in the power supply side coil 104 when flyback power is generated.

<Second Embodiment> FIG. 3 shows a circuit diagram of a non-contact transfer power supply device according to the second embodiment. In this figure, reference numeral 211 denotes a diode for flyback rectifying the output of the power receiving side coil 110, and the other elements shown in FIG.
The parts corresponding to are given the same reference numerals.

As is apparent from this figure, in the non-contact power transfer device of this embodiment, the bridge diode 111 of the non-contact power transfer device of the first embodiment is inserted in a direction in which only flyback polarity is received. The diode 211 is changed.

In the non-contact transfer power supply device of this configuration, the winding ratio of the transfer transformer 103 is 1, the coupling coefficient is 0.55, and the resonance frequency of the resonance circuit composed of the power supply side coil 104 and the equivalent synthetic capacitance 105 is 1. When a circuit having a frequency of 0.2 MHz was manufactured and its characteristics were measured, when a rectangular wave signal having a duty ratio of 50% and a repetition frequency of 210 kHz was output from the control signal source 109, a current resonance clearly appeared in the flyback waveform. . At this time, the DC power source 106
The output of the diode was 5V-120mA, and the output of the diode 211 was 5V-55mA. In addition, the temperature rise of the power receiving side coil 110 at this time was a rise of 19 degrees with respect to room temperature after being left for 10 hours after energization. Also in the apparatus of this example, a waveform diagram almost equivalent to that in FIG. 2 was obtained.

<First Comparative Example> FIG. 4 shows a circuit diagram of a non-contact transfer power supply device according to a first comparative example. In this figure,
Reference numeral 411 denotes a diode that forward rectifies the output of the power receiving side coil 110, and other parts corresponding to those in FIG. 1 described above are denoted by the same reference numerals.

As is apparent from this figure, in the non-contact power transfer device of this comparative example, the bridge diode 111 of the non-contact power transfer device of the first embodiment is inserted in the direction for receiving only the forward polarity. This is a diode 411.

In the transfer of the non-contact power supply device of this structure, the resonance frequency of the resonance circuit composed of the winding ratio of the transfer transformer 103, the coupling coefficient of 0.55, the power supply side coil 104 and the equivalent synthetic capacitance 105 is 8 MHz. Circuit was manufactured and its characteristics were measured.
%, When a rectangular wave signal having a repetition frequency of 210 kHz was output from the control signal source 109, no current resonance appeared in the flyback waveform. At this time, the output of the DC power supply 106 was 24V-100mA and the output of the diode 311 was 5V-60mA. In addition, the temperature rise of the power receiving side coil 110 at this time was a rise of 50 degrees with respect to room temperature after being left for 10 hours after energization.

Further, when the power receiving side coil 110 is removed and energized, the output of the DC power source 106 is 24V-35.
It was 0 mA, and the temperature rise was 95 ° C. with respect to room temperature after standing for 10 hours after energization.

<Second Comparative Example> In the contactless transfer power supply device having the same structure as the contactless transfer power supply device of the second embodiment, the resonance of the resonance circuit including the power supply side coil 104 and the equivalent combined capacitance 105. The relationship between the frequency and the pulse waveform of the flyback power introduced into the resonant circuit was changed.

That is, in the non-contact transfer power supply device of the second embodiment, the transfer transformer 103 has a coupling coefficient of 0.5.
5, the resonance frequency of the resonance circuit including the power supply side coil 104 and the equivalent synthetic capacitance 105 is 1.2M.
A circuit having a frequency of 0.1 Hz was prepared and its characteristics were measured. In this comparative example, the coupling coefficient of the transfer transformer 103 was 0.
At 55, the resonance frequency of the resonance circuit composed of the power supply side coil 104 and the equivalent synthetic capacitance 105 is 8 MH.
A z circuit was prepared and its characteristics were measured. As a result, duty ratio 50%, repetition frequency 210 kHz
When a rectangular wave signal of is output from the control signal source 109,
No current resonance appeared in the flyback waveform. At this time, the output of the DC power supply 106 was 5V-360mA and the output of the diode 211 was 5V-16mA. In addition, the temperature rise of the power supply side coil 104 at this time was 65 degrees with respect to room temperature after being left for 10 hours after energization.

When the power receiving coil 110 is further removed and energized, the output of the DC power supply 106 is 5V-52.
It was 0 mA, and the temperature rise was 80 ° C. with respect to room temperature after standing for 10 hours after energization.

<Third Embodiment> FIG. 5 shows a circuit diagram of a non-contact transfer power supply device according to a third embodiment. In this figure, 600 is a duty ratio switching means, 601
Is a smoothing capacitor, 602 is a load resistance, 603 is an ammeter, and other parts corresponding to those in FIG. 1 are denoted by the same reference numerals.

As is apparent from this figure, the contactless power transfer device of this embodiment is a control signal source 1 provided in the power supply side device 101 of the contactless power transfer device of the first embodiment.
The duty ratio switching means 600 is provided at 09 so that the duty ratio of the coil drive signal can be appropriately switched according to the size of the load resistor 602 of the power receiving side device 102.

In the non-contact transfer power supply device of this structure, the winding ratio of the transfer transformer 103 is 1, the coupling coefficient is 0.55, and the resonance frequency of the resonance circuit composed of the power supply side coil 104 and the equivalent synthetic capacitance 105 is 1. When a circuit having a frequency of 0.2 MHz was manufactured and its characteristics were measured, when a rectangular wave signal having a duty ratio of 50% and a repetition frequency of 660 kHz was output from the control signal source 109, a current resonance clearly appeared in the flyback waveform. .

In the non-contact power transfer device of this example, the load of the power supply side device 102 is 100 mW, 300 mW, 5
While changing to 00 mW, the duty ratio switching means 60
When the duty ratio of the coil drive signal output from the control signal source 109 is continuously changed from 5% to 70% by operating 0, the power transfer efficiency of the transfer transformer 103 is as follows: Figure 6 according to the size of
It changed as shown in. Further, a load of 100 mW is applied to the power supply / reception side device 102, and the duty ratio switching means 6
When the duty ratio of the coil drive signal output from the control signal source 109 is continuously changed from 5% to 70% by operating 00, the maximum output of the power supply / reception side device 102 is as shown in FIG. changed.

As is apparent from these figures, in the contactless power transfer device of this example, the load of the power supply side device 102 is 1
When the output power is 00 mW, the transfer efficiency of the transfer transformer 103 can be maximized by adjusting the duty ratio of the coil drive signal to 5% to 20%.
The maximum output of W can be obtained. Further, when the load of the power supply / reception side device 102 is 300 mW, the transfer efficiency of the transfer transformer 103 can be maximized by adjusting the duty ratio of the coil drive signal to 20% to 40%, which is about 400 mW. The maximum output of can be obtained. Furthermore, the load of the power supply / reception side device 102 is 500 mW
If it is, the duty ratio of the coil drive signal is set to 40
% To 70% by adjusting the transfer transformer 103
The transfer efficiency can be maximized and a maximum output of about 600 mW can be obtained.

Therefore, according to the non-contact power transfer device of this example, the transfer efficiency of the transfer transformer 103 is always high by monitoring or predicting the load applied to the power receiving device 102 and switching the duty ratio to an appropriate value. The level can be maintained, and further power saving of the device can be realized.

<Fourth Embodiment> FIG. 8 shows a circuit diagram of a non-contact transfer power supply device according to a fourth embodiment. In this figure, reference numeral 211 denotes a diode for flyback rectifying the output of the power receiving side coil 110, and the other elements shown in FIG.
The parts corresponding to are given the same reference numerals.

As is apparent from this figure, in the contactless power transfer device of this embodiment, the bridge diode 111 of the contactless power transfer device of the first embodiment is inserted in a direction in which only the flyback polarity is received. This is a diode 211.

In the non-contact transfer power supply device of this structure, the winding ratio of the transfer transformer 103 is 1, the coupling coefficient is 0.55, and the resonance frequency of the resonance circuit composed of the power supply side coil 104 and the equivalent synthetic capacitance 105 is 1. When a circuit having a frequency of 0.2 MHz was manufactured and its characteristics were measured, when a rectangular wave signal having a duty ratio of 50% and a repetition frequency of 660 kHz was output from the control signal source 109, a current resonance clearly appeared in the flyback waveform. .

In the non-contact power transfer device of this example, the load of the power receiving side device 102 is 100 mW, 300 mW, 5
While changing to 00 mW, the duty ratio switching means 60
When 0 is operated to continuously change the duty ratio of the coil drive signal output from the control signal source 109 from 5% to 70%, the power transfer efficiency of the transfer transformer 103 is equal to the load of the power supply / reception side device 102. It changed as shown in FIG. 6 depending on the size. In addition, the power supply side device 102 has 10
With a load of 0 mW, the duty ratio switching means 600
When the duty ratio of the coil drive signal output from the control signal source 109 was continuously changed from 5% to 70% by operating, the maximum output of the power supply / reception side device 102 changed as shown in FIG. . Therefore, also in the non-contact power transfer device of this example, the transfer efficiency of the transfer transformer 103 is always maintained at a high level by appropriately adjusting the duty ratio of the coil drive signal according to the load of the power receiving side device 102. Therefore, the power consumption can be further reduced.

<Fifth Embodiment> FIG. 9 shows a circuit block diagram of a digital camera equipped with a power supply device of the present invention. In this figure, reference numeral 501 denotes a multi-step switch that interlocks with a release button provided on the camera body. When the multi-step switch 501 is pressed down by half, the photometer 511, range finder 512, and focus actuator 513 are operated. Then, the camera is focused and the exposure amount is determined. Further, the duty ratio switching means 600 is operated to adjust the duty ratio of the coil drive signal to 35% or less, more preferably 5% to 20%. On the other hand, when the multistage switch 501 is fully depressed, the diaphragm actuator 521, the shutter actuator 522, the photosensitive device 523, and the data recording circuit on the medium are operated to perform shooting and data storage. Further, the duty ratio switching means 600 is operated to adjust the duty ratio of the coil drive signal to 40% or more.

As described above, by adjusting the duty ratio of the coil drive signal according to the magnitude of the load on the camera side, the transfer efficiency of the transfer transformer 103 can be constantly maintained at a high level as described above. , It is possible to reduce the power consumption of the digital camera.

[0046]

As described above, according to the inventions of claims 1 and 4, the power transfer efficiency can be improved by causing current resonance in the power supply side coil when flyback power is generated. In addition, the freewheeling diode can be omitted.

On the other hand, according to the fifth and sixth aspects of the present invention, the transient power waveform generated in the forward polarity can also be received by configuring the output of the power receiving side coil to obtain direct current by the bridge rectification method. Therefore, the power transfer efficiency is further improved.

Further, according to each of these inventions, the power transfer efficiency is improved, and as a result, the heat loss in the power supply side device is reduced, so that an element having a large heat capacity and a heat dissipation device are not required, and the size of the device can be reduced. .

Further, according to the inventions of claims 2 and 3, the transfer efficiency of the transfer transformer is always maintained at a high level by appropriately adjusting the duty ratio of the coil drive signal according to the load of the power receiving side device. Therefore, it is possible to further reduce the power consumption.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a non-contact transfer power supply device according to a first embodiment.

FIG. 2 is a graph showing a voltage waveform and a current waveform between terminals of a power supply side coil, a voltage waveform and a current waveform between terminals of a power supply side coil, and an output waveform of a control signal source according to the first embodiment. Is.

FIG. 3 is a circuit diagram of a non-contact transfer power supply device according to a second embodiment example.

FIG. 4 is a circuit diagram of a non-contact transfer power supply device according to a first comparative example.

FIG. 5 is a circuit diagram of a non-contact transfer power supply device according to a third embodiment.

FIG. 6 is a graph showing the relationship between the duty ratio of the coil drive signal and the power transfer efficiency of the transfer coil.

FIG. 7 is a graph showing the relationship between the duty ratio of the coil drive signal and the maximum output of the power supply side coil.

FIG. 8 is a circuit diagram of a non-contact transfer power supply device according to a fourth embodiment.

FIG. 9 is a circuit block diagram of a digital camera equipped with the power supply device of the present invention.

[Explanation of symbols]

 101 power supply side device 102 power supply side device 103 transfer transformer 104 power supply side coil 105 equivalent synthetic capacitance 106 direct current power supply 107 switching element 108 equivalent synthetic capacitance 109 control signal source 110 power receiving side coil 111 bridge configuration diode 211 Flyback rectifier diode 301 Voltage waveform between terminals of power supply side coil 302 Power supply side coil current waveform 303 Voltage waveform between terminals of power supply side coil 304 Current waveform of power supply side coil 305 Control signal source waveform 411 For forward rectification Diode 501 Multi-stage switch 511 Photometer 512 Distance meter 513 Focus actuator 521 Aperture actuator 522 Shutter actuator 523 Photosensitive device 524 Data recording circuit 600 Yuti ratio switching means 601 smoothing capacitor 602 load resistor 603 current meter

Claims (6)

[Claims] 1. A non-contact transfer power supply device for supplying electric power from a device on the power supply side to a device on the power reception side by electromagnetic coupling via a transfer transformer in a non-contact transfer power supply device, wherein the power supply is one of coils constituting the transfer transformer. A non-contact transfer power supply device, wherein a coil provided in a power supply side device is caused to resonate with current by flyback power of a resonance circuit configured by a combined inductance and a combined capacitance of the power supply side device. 2. The non-contact transfer power supply device according to claim 1, wherein a duty ratio of a coil drive signal for driving a coil provided in the power supply side device is set when a load of the power supply side device is small. Is small, and is switched to be large when the load on the power receiving side device is large,
A non-contact transfer power supply device, characterized in that the transfer efficiency of the transfer transformer is always maintained at a high level. 3. The non-contact transfer power supply device according to claim 2, wherein a manual multistage switch is connected to the duty ratio switching means, and the duty ratio of the coil drive signal is set in accordance with the amount of depression of the multistage switch. A non-contact transfer power supply device characterized by switching. 4. The non-contact transfer power supply device according to claim 1, wherein, of the coils forming the transfer transformer, a flyback is provided as a means for converting an output of a coil provided in the power receiving side device into a direct current. A non-contact transfer power supply device characterized by using a single-wave rectification method. 5. The non-contact transfer power supply device according to claim 1, wherein a value obtained by multiplying an input voltage of the power supply side device by a winding ratio of the transfer transformer, a coupling coefficient, and a standard duty ratio of a switching waveform is A means for converting the output of the coil provided in the power receiving side device into a direct current among the coils forming the transfer transformer when the value does not exceed the value obtained by adding the diode loss voltage to the diode output voltage of the power receiving side device. A non-contact transfer power supply device characterized in that it is capable of receiving not only power of flyback polarity but also transient power waveform generated in forward polarity by using a bridged double-wave rectification method as the above. 6. The non-contact transfer power supply device according to claim 1, wherein a value obtained by multiplying an input voltage of the power supply side device by a winding ratio of the transfer transformer, a coupling coefficient, and a standard duty ratio of a switching waveform is If the value obtained by adding the loss voltage of the diode to the diode output voltage of the power receiving side device is exceeded, among the coils constituting the transfer transformer,
The bridge double-wave rectification method is used as a means for converting the output of the coil provided in the power receiving side device into direct current, and in addition to the power of flyback polarity, it is also possible to receive the forward waveform and the transient power waveform generated in the forward polarity. A non-contact transfer power supply device characterized by the above.