JP2929697B2 - Power supply circuit device - Google Patents

Description

The present invention relates to a power supply circuit device used for, for example, an IC card, an ID data storage unit, and the like, in particular, utilizing electromagnetic induction.
The present invention relates to a power supply circuit device that receives power supply in a non-contact manner.

(B) Conventional technology Conventional power supply circuit devices that utilize electromagnetic induction and receive power in a contactless manner include those shown in FIGS. 7 and 8. FIG. 7 view of the circuit device includes an exciting coil (transmission coil) from the AC power source 1 magnetic flux generated by the current flowing in L ₁ phi
There interlinked to the receiving coil L _2, the AC voltage to the receiving coil L ₂ by the electromagnetic induction due to a change in the magnetic flux phi. This AC voltage is half-wave rectified by the diode D, smoothed by the capacitor C, and supplied to the load 2. The power supply circuit device of FIG.
While the one in Fig. 7 is half-wave rectification, a diode
Using full-wave rectifier circuit consisting of _{D 1, D 2, D 3} , D 4.
Others are the same as FIG.

(C) Problems to be Solved by the Invention The above-described conventional power supply circuit device has a structure in which a voltage drop always occurs due to the self-inductance of the receiving coil. Voltage cannot be obtained. As the load current increases, there is a problem that the output voltage decreases, the stability is poor, and the transmission efficiency is poor.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides an output voltage equal to or higher than the peak value of the open-circuit voltage of a receiving coil, and furthermore, a stabilized output voltage (or current).
And to provide a power supply circuit device with good transmission efficiency.

(D) Means and Action for Solving the Problems A power supply circuit device according to the present invention includes a receiving coil that generates an electromotive force by linking a magnetic flux φ generated by an excitation coil;
A first switching device that is connected to both ends of the receiving coil and, when turned on, short-circuits the receiving coil and generates a current flowing back to the receiving coil, thereby storing electric energy generated by the electromotive force in the receiving coil; Means, a second switching means for supplying the electric energy stored in the receiving coil to a load, and an on / off timing of the first and second switching means by detecting a phase of the magnetic flux φ. And switching control means for controlling.

In this power supply circuit device, the magnetic flux φ linked to the receiving coil
, The first switching means is first turned on for a predetermined time under the control of the switching control means. This turning on causes the receiving coil to be short-circuited, and the electric energy generated during this period is stored in the self-inductance of the receiving coil. Next, the switching control means turns off the first switching means and turns on the second switching means. As a result, the receiving coil is opened, and power is supplied to the load in a form in which the stored electric energy is superimposed on the induced electromotive force of the receiving coil.

(E) Examples Hereinafter, the present invention will be described in more detail with reference to examples.

FIG. 1 is a circuit diagram of a power supply circuit device showing one embodiment of the present invention. In the figure, the AC power supply 1, the exciting coil (transmission coil) L ₁ is connected. By voltages V ₁ than the AC power source 1 is applied, the current I ₁ flows through the exciting coil L _1, a magnetic flux φ is generated by the current I _1. The magnetic flux φ are so interlinked with the receiving coil L _2,
The switching element SW ₁ is connected in parallel with the receiving coil L _2.
There are connected, the switching element SW ₂ is connected between one end of the reception coil L ₂ of the load 2 end. An output side of the switching element SW _2, between the other end of the receiver coil L _2,
The smoothing capacitor C and the load 2 are connected in parallel.
Further, the output voltage phase detection circuit 3 for detecting the phase of provided receiving coil L _2, so that the switching control unit 4 in response to this output controls the on / off switching elements SW _1, SW ₂ Has become.

In the power supply device of this embodiment, the second
When AC voltages V ₁ shown in FIG. Is applied to the exciting coil L _1, a current I ₁ flows, magnetic flux φ is generated in response to the receiving coil L _2,
The magnetic flux φ is linked, and an electromotive force is generated by electromagnetic induction. In the phase detection circuit 3 detects the zero cross point of the AC voltage, the switching control unit 4, in response to the detection output of the zero cross, to turn on the switching elements SW _1. While the switching element SW ₁ is turned on, the short circuit receiving coil L _2, the ring current I ₂ flows. The ring current I _2, by flowing, the self-inductance of the receiving coil L _2, electrical energy is stored. The switching control unit 4, after a predetermined time has elapsed, turns on the switching element SW ₂ turns off the switching element SW _1. Thereby, the receiving coil L ₂
Is opened, the energy accumulated in the self-inductance, is smoothed by the capacitor C via the switching element SW ₂ superimposed electromotive force generated by electromagnetic induction,
The load 2 is supplied. By repeatedly turning on / off the switching elements SW ₁ and SW ₂ , it is possible to simply apply a voltage boosted to a value equal to or higher than the peak value when the receiving coil L ₂ is opened.

FIG. 3 is a circuit diagram of a power supply circuit device showing another embodiment of the present invention. The power supply circuit device of this embodiment is different from that of the embodiment device shown in FIG. 1 in that an output voltage V ₀ is detected by a voltage detection circuit 5 and added to a switching control unit 4, and other circuit units are the same. It is.

In the power supply circuit device of this embodiment, the output voltage V ₀ is detected by the voltage detection circuit 5, and when the output voltage V ₀ is large, the switching control section 4 sets the ON / OFF duty ratio of the switching elements SW ₁ and SW ₂ to On the other hand, the output voltage V ₀ is controlled to be small, and when the output voltage V ₀ is small, the switching control unit 4 controls the output voltage V ₀ to have the opposite duty, so that the output voltage V ₀ is constant. Control.

FIG. 4 is a circuit diagram of a power supply circuit device showing still another embodiment. The power supply circuit device of this embodiment is the same as that of FIG. 3 in that the output voltage V ₀ is detected by the voltage detection circuit 5, but instead of returning to the switching control unit 4, the feedback coils L ₃ , L ₄ The frequency / amplitude control circuit 6 controls the frequency or amplitude of the AC power supply 1 via the control circuit to control the output voltage to be constant. Thus it is possible to stabilize the output voltage V _0.

For feeding back the output voltage from the voltage detection circuit 5 to the frequency / amplitude control circuit 6, instead of the electromagnetic coupling by the coil L _3, L _4, using the circuit shown in FIG. 5, the light emitting diode L, phototransistor PT The AC power supply 1 may be controlled via the.

Figure 6 shows a specific circuit construction of the embodiment the power supply circuit device of FIG. 3, a diode d as a switching element SW _1
1 , a field effect transistor Q is connected in series, a variable duty oscillator 4a constituting a switching control unit is connected to the gate of the field effect transistor Q, and a pulse width modulated (PWM) signal from the variable duty oscillator 4a is used. , The field effect transistor Q is turned on / off. The phase detection circuit 3, one end of the receiving coil L _2, enter the ground point to the comparator 3a, when both inputs match, and so as to enter a zero cross point detection signal to the variable duty oscillator 4a, also , Voltage detection circuit 5
Includes a comparator 5a and a reference voltage source 5b,
So that to enter the deviation voltage to the variable duty oscillator 4a so that the output voltage V ₀ becomes equal to the reference voltage.

(F) Effects of the Invention According to the present invention, when connected to both ends of the receiving coil and turned on, the receiving coil is short-circuited, and the electric current generated by the electromotive force is generated by generating a current flowing back to the receiving coil. The first is stored in the receiving coil.
Switching means, a second switching means for supplying the electric energy stored in the receiving coil to a load, and an on / off timing of the first and second switching means by detecting a phase of the magnetic flux φ. Switching control means for controlling the on / off timing of the switching element by pulse width modulation (PWM) control, whereby a boosted output voltage equal to or higher than the peak value of the open voltage of the receiving coil is obtained. A stabilized output voltage can be obtained. There are advantages such as improved transmission efficiency.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a power supply circuit device showing one embodiment of the present invention, FIG. 2 is a waveform diagram for explaining the operation of the power supply circuit device, and FIG. FIG. 4 is a circuit diagram of a power supply circuit device showing an embodiment, FIG. 4 is a circuit diagram of a power supply circuit device showing still another embodiment of the present invention, and FIG. 5 is a feedback diagram of the power supply circuit device of the embodiment shown in FIG. FIG. 6 is a circuit diagram of an optical feedback circuit connected in place of the electromagnetic coil for use, FIG. 6 is a circuit diagram showing the power supply circuit device of the embodiment of FIG. 3 more specifically,
7 and 8 are circuit diagrams showing a conventional power supply circuit device. 1: AC power supply, 2: load 3: phase detector circuit, 4: switching control unit, 5: Voltage detection circuit, L _2: the receiving coil, SW _1: first switching element, SW _2: the second switching element .

Claims (1)

(57) [Claims] 1. A receiving coil which generates an electromotive force by linking with a magnetic flux φ generated by an exciting coil, and is connected to both ends of the receiving coil. When the receiving coil is turned on, the receiving coil is short-circuited and returned to the receiving coil. First switching means for storing electric energy generated by the electromotive force in the receiving coil by generating a current to generate electric current, and second switching means for supplying electric energy stored in the receiving coil to a load. And a switching control means for detecting the phase of the magnetic flux φ to control the on / off timing of the first and second switching means.