Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
  • A61N2/00—Magnetotherapy
  • A61N2/004—Magnetotherapy specially adapted for a specific therapy
  • A61N2/006—Magnetotherapy specially adapted for a specific therapy for magnetic stimulation of nerve tissue
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
  • A61N2/00—Magnetotherapy
  • A61N2/02—Magnetotherapy using magnetic fields produced by coils, including single turn loops or electromagnets
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03K—PULSE TECHNIQUE
  • H03K3/00—Circuits for generating electric pulses; Monostable, bistable or multistable circuits
  • H03K3/02—Generators characterised by the type of circuit or by the means used for producing pulses
  • H03K3/53—Generators characterised by the type of circuit or by the means used for producing pulses by the use of an energy-accumulating element discharged through the load by a switching device controlled by an external signal and not incorporating positive feedback
  • H03K3/57—Generators characterised by the type of circuit or by the means used for producing pulses by the use of an energy-accumulating element discharged through the load by a switching device controlled by an external signal and not incorporating positive feedback the switching device being a semiconductor device

Definitions

• the present invention relates, in general, to magnetic stimulators for medical treatment and, more particularly, to a magnetic stimulator for medical treatment, in which a switching power transformer, which is a power supply unit, also functions as a current limiting inductor, and to an electric circuit for the magnetic stimulator.
• a switching power transformer which is a power supply unit, also functions as a current limiting inductor
• a magnetic stimulator used for medical treatment is a non-contact type stimulator that remarkably reduces pain compared to an electric stimulator and generates current at the affected body part using a magnetic force generated near the affected body part. Accordingly, the magnetic stimulator has attracted attention as a device capable of stimulating the surface of the skin, or a region of the brain or spinal column into which an electrode cannot be easily inserted.
• Such a magnetic stimulator basically includes a capacitor for storing energy necessary for stimulation and a coil for discharging the energy to form a strong magnetic field.
• FIG. 1 is a view showing an example of a conventional non-contact type medical instrument for treating urinary incontinence.
• a process for treating urinary incontinence is described in brief.
• a magnetic field generation device for generating a magnetic field is arranged below a chair- shaped medical instrument, and a pulse current generates a magnetic field in a core if the pulse current is supplied to a coil wound around the core while a patient sits down on the chair.
• This magnetic field forms a magnetic field closed loop between both ends of the core.
• the affected part of the patient is placed in the middle of the closed loop, so that an eddy current is induced again at the affected part due to the magnetic field, thus electrically stimulating the affected part.
• FIG. 2 is a view showing a brain stimulator as another example to which the magnetic stimulator is applied.
• a magnetic field generation device 132 is placed on an affected region of the brain 130 of a patient, and the brain is stimulated using a magnetic field and an eddy current in the same principles as those of the above example.
• a magnetic field of several tesla must be generated in the form of a pulse having a width of several hundreds of micro seconds ( ⁇ s) .
• FIG. 3 is a circuit diagram of the power supply circuit of a magnetic stimulator proposed previously by the present applicant, which shows a circuit capable of generating the magnetic field having the above-described intensity.
• AC Alternative Current
• Vs typical Alternative Current
• Boosted current I 4 is full-wave rectified by a bridge diode B, and rectified current Ii is charged in a capacitor through a resistor R 1 and a coil Li.
• the resistor R x limits overcurrent of the current I ⁇ to protect related circuits, and the coil Li also functions to prevent overcurrent that may flow through circuits.
• a switch S2 is turned on, thus starting discharging while causing high current I 2 to instantaneously flow through a discharge coil L 2 .
• the current I 2 flows only through the discharge coil L 2 , and current does not flow in the reverse direction -Ii of the current Ii because the current is interrupted by diodes, etc.
• the current I 2 flowing through the discharge coil L 2 is maximized when the voltage Vc of the capacitor is OV. Thereafter, this energy is charged in the capacitor in the polarity -Vc opposite to the initial polarity.
• the coil Li is an important and essential component. Further, as described above, this coil must have an inductance much higher than that of the discharge coil L 2 according to the characteristics thereof.
• the coil L 1 is actually manufactured to have a relatively large size of about 10cm X 10cm X 5cm and have a weight of lkg or more, so that the coil Li is an obstruction to simplify the circuit. Further, there is a problem that the manufacturing cost of a device greatly increases due to the coil L 1 .
• a more serious problem is that, as shown in the drawing, since the coil Li and/or the resistor Ri are connected in series in a power charge path, part of power is always lost in the coil and the resistor at the time of charging power. Moreover, because power lost in this way is changed into heat, problems related to heat generation and cooling caused by the heat generation become serious. Therefore, with respect to the essential coil and/or resistor, which increase manufacturing cost and cause power loss, the necessity for variously modifying and designing the coil or resistor has been recently required, and the present invention is developed to satisfy this necessity.
• an object of the present invention is to provide a new electric circuit, which is manufactured to allow an inductor on the secondary side of a transformer to function as a buffer inductor, so that there is no need to provide a separate buffer inductor, and the structure of a magnetic stimulator using the electric circuit.
• the present invention provides an electric circuit, comprising a power supply unit; rectification means for rectifying current from the power supply unit; a transformer having an inductor on a primary side thereof connected to the power supply unit through the rectification means; a capacitor connected to an inductor on a secondary side of the transformer corresponding to the inductor on the primary side of the transformer, and operated so that, if power is supplied by the power supply unit through the primary side inductor of the transformer, the capacitor is supplied with the power from the secondary side of the transformer and stores charges at both ends thereof; reverse flow prevention means connected in series between the capacitor and the transformer to prevent charges stored in the capacitor from reversely flowing toward the transformer when the power is supplied; a discharge inductor for receiving the charges stored in the capacitor as discharge current and forming a magnetic field; first switching means for turning on or off flow of the discharge current that flows in one direction from the capacitor to the discharge inductor; and bypass means for causing current to flow in one direction from the discharge inductor to the capacitor, wherein
• the electric circuit may further comprise second switching means connected in series between the power supply unit and the transformer.
• the second switching means may be used as means for controlling on/off of a circuit on the primary side of the transformer when power is supplied in a fly-back mode or a forward mode, or used as means for preventing reverse current or overcurrent that may flow through the primary side of the transformer or the power supply unit.
• the present invention provides a magnetic stimulator, the magnetic stimulator comprising a power supply unit, a circuit unit supplied with power from the power supply unit to generate a magnetic field, and a control unit for controlling the circuit unit, the magnetic stimulator generating a magnetic field required for medical treatment
• the circuit unit comprises rectification means for rectifying current from the power supply unit; a transformer having an inductor on a primary side thereof connected to the power supply unit through the rectification means; a capacitor connected to an inductor on a secondary side of the transformer corresponding to the inductor on the primary side of the transformer, and operated so that, if power is supplied by the power supply unit through the primary side inductor of the transformer, the capacitor is supplied with the power from the secondary side of the transformer and stores charges at both ends thereof; reverse flow prevention means connected in series between the capacitor and the transformer to prevent charges stored in the capacitor from reversely flowing toward the transformer when the power is supplied; a discharge inductor for receiving the charges stored in the capacitor as discharge current and forming a magnetic field;
• the present invention provides an electric circuit, comprising a power supply unit; rectification means for rectifying current from the power supply unit; a transformer having an inductor on a primary side thereof connected to the power supply unit through the rectification means; a capacitor connected to an inductor on a secondary side of the transformer corresponding to the inductor on the primary side of the transformer, and operated so that, if power is supplied by the power supply unit through the primary side inductor of the transformer, the capacitor is supplied with the power from the secondary side of the transformer and stores charges at both ends thereof; reverse flow prevention means connected in series between the capacitor and the transformer to prevent charges stored in the capacitor from reversely flowing toward the transformer when the power is supplied; a discharge inductor for receiving the charges stored in the capacitor as discharge current and forming a magnetic field; first switching means for turning on or off flow of the discharge current that flows in one direction from the capacitor to the discharge inductor; bypass means for causing current to flow in one direction from the discharge inductor to the capacitor; and second switching means connected in series between the
• the present invention provides a magnetic stimulator, the magnetic stimulator comprising a power supply unit, a circuit unit supplied with power from the power supply unit to generate a magnetic field, and a control unit for controlling the circuit unit, the magnetic stimulator generating a magnetic field required for medical treatment
• the circuit unit comprises rectification means for rectifying current from the power supply unit; a transformer having an inductor on a primary side thereof connected to the power supply unit through the rectification means; a capacitor connected to an inductor on a secondary side of the transformer corresponding to the inductor on the primary side of the transformer, and operated so that, if power is supplied by the power supply unit through the primary side inductor of the transformer, the capacitor is supplied with the power from the secondary side of the transformer and stores charges at both ends thereof; reverse flow prevention means connected in series between the capacitor and the transformer to prevent charges stored in the capacitor from reversely flowing toward the transformer when the power is supplied; a discharge inductor for receiving the charges stored in the capacitor as discharge current and forming a magnetic field;
• the present invention provides an electric circuit, comprising a power supply unit; a transformer having an inductor on a primary side thereof connected to the power supply unit; a capacitor connected to an inductor on a secondary side of the transformer corresponding to the inductor on the primary side of the transformer, and operated so that, if power is supplied by the power supply unit through the primary side inductor of the transformer, the capacitor is supplied with the power from the secondary side of the transformer and stores charges at both ends thereof; rectification/reverse flow prevention means connected in series between the capacitor and the transformer to simultaneously supply Direct Current (DC) current to the capacitor and prevent charges stored in the capacitor from reversely flowing toward the transformer when the power is supplied; a discharge inductor for receiving the charges stored in the capacitor as discharge current and forming a magnetic field; first switching means for turning on or off flow of the discharge current that flows from the capacitor to the discharge inductor; bypass means for causing current to flow in one direction from the discharge inductor to the capacitor; and second switching means connected in series between the power supply unit and the transformer
• the present invention relates to a magnetic stimulator and an electric circuit thereof, and is characterized in that an inductor on the secondary side of a power supply transformer also functions as a buffer inductor. Therefore, the magnetic stimulator of the present invention is advantageous in that, since there is no need to provide a separate buffer inductor compared to a conventional magnetic stimulator, a heat problem or power loss problem occurring due to the inductor can be eliminated, and, in addition, the circuit part of the stimulator can be simplified and production cost thereof can be reduced.
• FIG. 1 is a view showing a magnetic stimulator used for a medical instrument for treating urinary incontinence
• FIG. 2 is a view showing a magnetic stimulator used as a brain stimulator
• FIG. 3 is a circuit diagram of a conventional magnetic stimulator
• FIG. 4 is a circuit diagram showing an embodiment of the present invention in which only a rectification circuit exists on the primary side of a transformer
• FIG. 5 is an operating waveform diagram of FIG. 4;
• FIG. 6 is a circuit diagram showing an embodiment of the present invention in which a current limiting means exists on the primary side of a transformer;
• FIGS. 7 and 8 are circuit diagrams showing circuits of the present invention, in which a half-wave rectification means and a full-wave rectification means are included as a rectification means, respectively, in the embodiment of FIG. 4;
• FIGS. 9 and 10 are a circuit diagram and an operating waveform diagram of another embodiment of the present invention, respectively, in which a fly-back power supply mode is used;
• FIG. 11 is a circuit diagram showing a further embodiment of the present invention for feedback controlling a first switching means;
• FIG. 12 is a circuit diagram showing still another embodiment of the present invention, in which a switching device, instead of a rectification circuit, is included on the primary side of a transformer; and
• FIG. 13 is a circuit diagram showing still another embodiment of the present invention, in which a rectification circuit and a switching means are arranged on the primary side of a transformer.
• FIG. 4 is a circuit diagram of a basic embodiment of the present invention, which shows a circuit diagram of a magnetic stimulator according to the present invention, which is manufactured to integrate a buffer inductor with an inductor on the secondary side of a transformer, or constructed to allow the inductor on the secondary side of the transformer to function as a buffer inductor.
• a power supply unit On the primary side (Np) of a power supply unit, that is, a transformer, placed on the left side of the circuit, an AC power source (Vs) for supplying power to an entire circuit system, a rectification circuit for full-wave rectifying or half-wave rectifying AC current supplied by the AC power source, and the transformer TS for supplying power to a capacitor while transforming a voltage, are provided.
• Vs AC power source
• TS transformer
• a capacitor C for supplying power to a discharge inductor L2 is arranged, and a diode D x , which is an example of a means for preventing stored charges from reversely flowing toward the transformer at the time of supplying current to the capacitor C, is disposed between the transformer and the capacitor C.
• a diode D x which is an example of a means for preventing stored charges from reversely flowing toward the transformer at the time of supplying current to the capacitor C, is disposed between the transformer and the capacitor C.
• any type of device capable of performing a reverse flow prevention function can be used in addition to the diode.
• the discharge inductor L2 for causing L-C resonation together with the capacitor using current and generating a magnetic stimulation pulse is connected through a Silicon Controlled Rectifier (SCR) and a bypass diode D3 for providing a resonance path.
• SCR Silicon Controlled Rectifier
• the SCR functions as a switch for switching on/off between the capacitor and the discharge inductor L2.
• the circuit has an advantage in that problems caused by the coil and the resistor do not fundamentally occur, but a method of implementing the essential function of the conventional coil and resistor, that is, the function of charging the capacitor in L-C resonance and limiting overcurrent flowing through the primary side of a transformer may be an issue.
• the operating waveform of the circuit is described first, and the solving method thereof is described later.
• FIG. 5 is a diagram showing the operating waveform of FIG. 4.
• the current I 3 charges the capacitor in the polarity opposite to the initial polarity while passing through the discharge inductor L2 until time reaches T2.
• current generates a pulse magnetic field in the discharge inductor L2 once again while flowing in the direction of -I 3 , which is opposite to the initial direction.
• the current starts to recharge the capacitor in the same polarity as the initial polarity.
• Such a phenomenon continues up to time T4 at which charges stored in the capacitor C are completely discharged and move to the opposite side.
• the maximal voltage of the capacitor recharged in the initial polarity becomes Vc-2Vf, that is, a value decreasing from Vc by a value consumed during the generation of the pulse magnetic field twice if another resistance in a lead wire is ignored.
• the step of compensating for decreased power of the capacitor from the power source Vs during the interval between T4 and T5 is performed so as to perform a subsequent discharging cycle.
• a switching device on the primary side of the transformer is turned on to cause rectified current Io to flow and induce I ⁇ from the current Io, thus charging the capacitor.
• a forward mode or a fly-back mode can be used as a charging method used in this step.
• the circuit of FIG. 4 is not provided with a buffer inductor or a buffer resistor, unlike the circuit of FIG. 3, it may be preferable that the current I 3 , flowing through a branch node "a" during the interval ranging from time T2 to T4, become current Ii flowing through the secondary side of the transformer rather than the capacitor, and be consumed as heat while circulating between the transformer and the discharge inductor L2.
• the circuit of the present invention of FIG. 4 is constructed to cause the inductor on the secondary side (Ns) of the transformer to have an inductance 10 to 1000 times higher than that of the discharge inductor L2.
• the circuit is constructed so that most current I 3 , passing through the branch node "a" during the interval ranging from time T2 to time T4, can flow through the capacitor and can be used to charge the capacitor in the opposite polarity. Due to this construction, there is no need to use a conventional buffer inductor or buffer resistor. Further, as shown in FIG. 5, even though the two inductors have a high inductance difference therebetween, part of I 3 flows as Ii at the branch node "a" during the interval between the time Tl and time T3.
• this current Ii can generate, on the primary side of the transformer, an induced electromotive force, sufficient to destroy the power source Vs or apply at least a strong electric shock to the power source, and overcurrent or reverse current -Io, caused by the induced electromotive force, while flowing through the secondary side of the transformer.
• the rectification circuit is provided, and current is set to flow only in the direction of Io, so that the reverse current -I 0 cannot flow, as far as breakdown or dielectric breakdown does not occur in parts constituting the rectification circuit, for example, diodes, thus solving the problem.
• the core technical feature of the embodiment of the present invention resides in the fact that the embodiment is constructed to eliminate a buffer inductor and/or a buffer resistor, which were essential components in the prior art, from the magnetic stimulator circuit, and instead allow the inductor on the secondary side of the transformer to perform a buffering function, and is constructed to provide a rectification means on the primary side of the transformer to safely protect power.
• the buffer inductor is physically integrated with the inductor on the secondary side (Ns) of the transformer, because the inductor on the secondary side clearly temporally separates and performs two functions. That is, in the interval ranging from time T4 to T5, during which the power supply unit supplies power to the capacitor, the inductor on the secondary side functions as the secondary side of the transformer for supplying lost power to the capacitor. In contrast, in the interval ranging from time TO to T4, during which the capacitor causes L-C resonance while being discharged, the inductor on the secondary side clearly functions only as a buffer inductor.
• the two functions temporally separated in this way are physically implemented in a single inductor, so that the magnetic stimulator of the present invention has a compact and efficient circuit compared to the conventional magnetic stimulator.
• the secondary side inductor of the transformer In order for the secondary side inductor of the transformer to function as a buffer inductor in addition to the secondary side function of the transformer, the following conditions must be preferably satisfied.
• the inductance of the secondary side inductor must be relatively higher than that of the inductor L2, as described above. This definition is required to cause the intensity of the current I 1 to be as low as possible when the capacitor is discharged in the opposite polarity, as described above.
• the secondary side inductor of the transformer may have an inductance of about ImH, which is ten times that of the inductor L2.
• an inductance ratio is only an example for estimating intensity, and can be freely varied depending on the purpose of a system to be used and the capacity of other devices.
• the saturation magnetic value of the core be higher. The reason for this is that, if the saturation magnetic value of the core constituting the inductor is low, there may occur a problem in that the core is saturated by current Ii and the secondary side path of the transformer is shorted, so that the above-described buffering effect no longer occurs .
• a material having a saturation value sufficient to prevent the core from being saturated by current flowing through the secondary side of the transformer when the capacitor is discharged, can be used.
• a ferrite series material or a multi-layered silicon steel sheet can be used as the core.
• overcurrent may flow through the primary side of the transformer because a resistor does not exist on the primary side of the transformer in the drawing, or only a very low conductor resistance exists.
• Vs constant voltage source
• a current limiting means can be additionally provided on the primary side of the transformer, as shown in FIG. 6.
• the function of the current limiting means is to prevent infinite current from flowing.
• the current limiting means is implemented using a resistor having a suitable resistance or using a switch, thus turning off the circuit if current higher than a certain intensity is flowing.
• the current limiting means may be additionally attached when there is a risk of causing overcurrent, it is not an essential component necessary for the present invention. Further, when a switching device, etc. are provided on the primary side of the transformer to supply power in a fly-back mode, the switching device can also function as a current limiting means without separately providing the current limiting means.
• FIGS. 7 and 8 are circuit diagrams showing the rectification circuit of FIG. 4 in detail according to other embodiments of the present invention.
• FIG. 7 an embodiment, in which current I 0 , half- wave rectified by a diode DO connected in series between a power source and the primary side of a transformer, is used, is shown. If the half-wave rectified current is used, there is a disadvantage in that half of the current cannot be used, and, accordingly, energy efficient is decreased, and charging time, ranging from time T4 to T5, is increased, but there is an advantage in that a rectification circuit can be simply implemented and used when a charge/discharge frequency is not very high and the power of a required magnetic field pulse is low.
• FIG. 8 illustrates an embodiment in which current I 0 , full-wave rectified by a bridge diode (BD) , is used as power.
• BD bridge diode
• the diode DO or the bridge diode used in FIG. 7 or 8 also functions to protect the power source Vs from a reverse current, which may be induced to the primary side of the transformer along the current flow of the secondary side of the transformer and may flow in a direction opposite to that shown in the drawing, or surge current, in addition to a rectification function. Therefore, such a reverse current prevention function should be considered to be a type of rectification described in the present invention in a broad sense. It is apparent that, even in the embodiment of FIG. 8, a current limiting means can be attached to the primary side of the transformer.
• FIGS. 9 and 10 are circuit diagrams showing a circuit of supplying power in a fly-back mode according to other embodiments of the present invention.
• the supply of power in a fly-back mode is a Switched-Mode Power Supply (SMPS) method, which is operated so that, if a power supply unit supplies relatively low power to an inductor on the primary side of a transformer connected to the power supply unit, and turns off a switch in the center of the circuit to interrupt the supply of power, induced power is generated at the secondary side inductor of the transformer by the energy stored in the primary side inductor of the transformer, and the induced power is supplied to the output terminal of the secondary side of the transformer.
• SMPS Switched-Mode Power Supply
• the fly-back mode is a method of implementing a high voltage or a high current at the output terminal using relatively low power.
• the circuit of FIG. 9 is designed to implement such a fly-back power supply mode and is constructed so that a switching device is disposed between the primary side of a transformer and a power supply unit. Further, the switching device on the primary side of the transformer repeatedly performs on/off operations at short periods during the above-described interval ranging from T4 to T5, which is the power supply interval, so as to supply power in the fly-back mode.
• the supply current Io of the primary side of the transformer is composed of a plurality of pulse waves having a short period in response to the on/off control of the switching device
• the secondary side current Ii induced at the secondary side inductor of the transformer is also generated in the form of pulse waves having the same period, because of the current Io.
• the secondary side current is stored in a capacitor, and the primary side of the transformer is turned off by the switching device at each storage time, all energies induced at the secondary side inductor are stored only in the capacitor. That is, all energies are transmitted regardless of the quantity of electric charge stored in the capacitor. Therefore, this embodiment is advantageous in that the high power necessary for the present invention can be easily obtained using fly-back principles.
• FIG. 11 illustrates another embodiment of the present invention, which shows the case where, when power is supplied to a capacitor by a power source in a Switched- Mode Power Supply (SMPS) mode, a switching device is controlled by a switching device control circuit for receiving the feedback of the voltage at the capacitor until the voltage at the capacitor reaches a suitable voltage Vc.
• SMPS Switched- Mode Power Supply
• This embodiment is advantageous in that it is possible to supply power in a more precise fly-back mode by controlling the on/off operation of a switching device in real time depending on the quantity of electric charge in the capacitor.
• the switching device may be controlled using a timer or counter instead of the feedback control, but it must be considered that such a feedback circuit is more precise and stable than the timer or counter.
• the present invention also includes the case where the switching device is controlled using a timer, counter or similar device, instead of the feedback circuit, as another embodiment.
• MOSFET Metal Oxide Semiconductor Field-Effect Transistor
• IGBT Insulated Gate Bi-polar Transistor
• IPM Intelligent Power Module
• GTO Gate Turn Off
• FIG. 12 illustrates still another embodiment of the present invention, which shows the case where a rectification circuit does not exist on the primary side of a transformer.
• the operations of the remaining circuit parts are substantially the same as those of the above embodiments .
• a rectification circuit does not exist on the primary side of the transformer, AC power is supplied to the transformer.
• the reason for supplying the AC power in this way is that a rectified voltage can be always transferred to a capacitor because a diode Dl exists on the secondary side of the transformer.
• the diode Dl may be designated as a rectification/reverse flow prevention means existing on the secondary side of the transformer.
• power can be supplied in either a forward mode or a fly-back mode.
• a switching device connected in series with the primary side of the transformer performs only the function of controlling overcurrent that may flow through the primary side of the transformer. That is, in order to prevent an induced current, which is induced from the secondary side of the transformer and may flow through the primary side of the transformer, from influencing a power supply unit when L-C resonance occurs or the capacitor is discharged, the primary side path of the transformer is turned off using the switching device existing on the primary side of the transformer.
• the off-state of the switching device replaces the above-described power protection function using the rectification circuit.
• the switching device In the case of the supply of power in a fly-back mode, the switching device also functions to protect the above-described power supply unit on the primary side of the transformer while being used as a fly-back switch. That is, the switching device is used to store charges in a capacitor while being repeatedly turned on or off during the supply of power, and is turned off to prevent overcurrent from flowing into the power supply unit on the primary side of the transformer during the discharging of the capacitor or L-C resonance.
• FIG. 13 illustrates still another embodiment of the present invention, in which both a rectification circuit and a switching device are placed on the primary side of a transformer, and which is identical to that of FIG. 9.
• the switching device is used as a switching means for supplying power in a fly-back mode, and also performs the function of preventing a reverse current that may flow through the primary side of the transformer. Therefore, this embodiment is characterized in that the rectification circuit on the primary side of the transformer is used only as a means for supplying DC current, and the function of preventing overcurrent from flowing through the primary side during L- C resonance is performed by turning off the switching device.
• a rectification function can be performed using only a single diode or bridge circuit existing on the primary or secondary side of the transformer. Therefore, the rectification circuit described in the present invention is not necessarily provided on the primary side of the transformer, but a rectification circuit existing on the secondary side of the transformer can be implemented. Further, even when a switching device is placed on the primary side of the transformer, current can be supplied in a simple forward mode or half-bridge mode. In this case, the switching device performs only the function of preventing a reverse current from flowing through the primary side of the transformer. Further, as the switching device and the rectification circuit of the present invention, any well- known devices can be used, so that they are not limited to the shown devices .

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• 2005
  • 2005-11-26 DE DE112005002910.7T patent/DE112005002910B4/de active Active
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