JP2006238647A - Resonant power supply - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resonant power supply which can reduce the cost while raising the operating efficiency of winding. <P>SOLUTION: The resonant power supply is equipped with a transformer 10 which receives AC power supplied from an AC power supply, a capacitor 11 which is connected to one end of the secondary winding 10a of this transformer 10, and a half wave voltage doubler rectifier circuit which is constituted by serially connecting a coil 13 between a plurality of serially connected diodes 12 and 14 including the first diode 12 connected to the other end of the secondary winding 10a. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a resonant power supply device, and more particularly to a method for rectifying a transformer secondary current.

  Conventionally, a resonance type power supply apparatus has been developed in order to improve the power conversion efficiency of the power supply and reduce the generated noise. The resonance type power supply device does not perform a switching operation close to a square wave or a triangular wave for both the current waveform and the voltage waveform unlike a normal switching type power supply device, but resonates with either or both waveforms using a coil or a capacitor. Thus, by performing a sinusoidal operation, the transient loss is almost zero. As a result, the resonant power supply apparatus has a small current change rate per unit time, can reduce the amount of noise generated, and can reduce the loss of the transistor.

  In such a resonance type power supply device, the following method is mainly used to rectify the transformer secondary side current.

  First, as a first method, as shown in FIG. 2 (a) or FIG. 2 (b), two windings 101 and 102 are provided on the secondary side of a transformer 100 with a center tap. This is called center-tap double-wave rectification in which 101 and 102 are rectified using two diodes 103 and 104, respectively, at opposite phase timings. This center-tap double-wave rectification also rectifies the remaining half cycle in the AC that was not used in the half-wave rectification. In this center tap double-wave rectification, the output ripple is twice the power supply frequency, and the reverse withstand voltage of the diodes 103 and 104 is required to be at least three times the secondary AC voltage of the transformer 100. 2A shows a capacitor input type center tap double-wave rectifier circuit, and FIG. 2B shows a choke input type center tap double-wave rectifier circuit. (For example, see Patent Document 1 and FIG. 10)

As a second method, as shown in FIG. 3A or 3B, one winding 151 is provided on the secondary side of the transformer 150, and this winding 151 is connected to the diode bridge 152. This is referred to as bridge rectification that rectifies using the. In this bridge rectification, the output ripple is twice the power supply frequency, and the reverse withstand voltage of the diode constituting the diode bridge 152 is required to be 1.5 times or more the secondary side AC voltage of the transformer 150. 3A shows a capacitor input type bridge rectifier circuit, and FIG. 3B shows a choke input type bridge rectifier circuit.
JP 08-186981 A

  However, in the first method described above, since the two windings 101 and 102 and the two diodes 103 and 104 are used, there is a problem that the usage efficiency of the windings is poor.

  In the second method described above, since one winding 151 and four diodes constituting the diode bridge 152 are used, the use efficiency of the winding is approximately 100%, but a large number of diodes are required. There has been a problem of incurring higher costs.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a resonance type power supply apparatus that can reduce the cost while increasing the use efficiency of the winding.

  In order to achieve the above-described object, a resonant power supply apparatus according to the present invention includes a transformer for inputting AC power supplied from an AC power supply, a capacitor connected to one end of a secondary winding of the transformer, A half-wave voltage doubler rectifier circuit configured by connecting a coil in series between a plurality of diodes connected in series including a first diode connected to the other end of the secondary winding. It is a feature.

  In such a resonant power supply device according to the present invention, half-wave voltage doubler rectification is performed by a half-wave voltage doubler rectifier circuit configured by connecting a coil in series between a plurality of diodes connected in series. Therefore, in the resonance type power supply device according to the present invention, the transformer secondary side current can be rectified only by using one secondary side winding and a diode connected in series.

  Specifically, the half-wave voltage doubler rectifier circuit has one end connected to the first diode having an anode electrode connected to the other end of the secondary winding and the cathode electrode of the first diode. It is preferable that the half-wave voltage doubler rectifier circuit is composed of the coil and a second diode having an anode electrode connected to the other end of the coil. In this case, the positive electrode of the capacitor is connected between the coil and the second diode. Thereby, in the resonance type power supply device according to the present invention, the transformer secondary side current can be rectified only by using one secondary winding and two diodes connected in series.

  According to the present invention, since it is only necessary to provide one winding on the secondary side of the transformer, it is possible to improve the use efficiency of the winding, and it is only necessary to provide a diode connected in series. Therefore, cost reduction can be achieved.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings.

  As shown in FIG. 1, the resonance type power supply device is configured by connecting a capacitor 11 to one end of a secondary winding 10 a of a transformer 10 that receives AC power supplied from an AC power source (not shown). In addition, the anode of the first diode 12 is connected to the other end of the secondary winding 10 a of the transformer 10. Further, one end of the coil 13 is connected in series to the cathode electrode of the first diode 12, and the anode electrode of the second diode 14 is connected in series to the other end of the coil. Furthermore, the positive electrode of the capacitor 11 is connected between the coil 13 and the second diode 14. The positive electrode of the capacitor 15 is connected to the cathode electrode of the second diode 14, and the negative electrode of the capacitor 15 is connected to the anode electrode of the first diode 12.

  That is, this resonance type power supply device is configured to perform half-wave voltage doubler rectification by a half-wave voltage doubler rectifier circuit configured by connecting a coil 13 in series between diodes 12 and 14 connected in series. Is done.

  Here, a multi-stage voltage doubler circuit in which a plurality of diodes are connected in series may be used for a circuit that requires a high-voltage weak current. However, since the resonance type power supply device requires a relatively large current, it is different from this concept. In such a resonant power supply device that performs half-wave voltage doubler rectification, the output ripple can be made the same as the power supply frequency.

Thus, in the resonance type power supply device, one winding 10a is provided on the secondary side of the transformer 10.
Therefore, the use efficiency of the winding can be improved. Therefore, in the resonance type power supply device, a thick wire can be used as the secondary winding 10a, and the resistance value can be lowered to reduce heat generation and loss. In addition, in the resonance type power supply device, it is only necessary to provide the two diodes 12 and 14, so that the cost can be reduced.

  Furthermore, in the resonance type power supply device, by using a small and small capacity capacitor 11 as the added capacitor 11, energy can be stored as a voltage while being inexpensive.

  Furthermore, since the resonance type power supply apparatus uses a voltage doubler rectification method, when the output voltage V is constant, it is relatively ½ times the secondary AC voltage of the transformer 10, and the current is The number of windings can be reduced without changing.

  The present invention is not limited to the embodiment described above. For example, in the above-described embodiment, the half-wave double voltage rectification using the two diodes 12 and 14 has been described. However, the present invention can be realized by using a plurality of diodes connected in series. The present invention can be applied to a device that performs arbitrary half-wave voltage doubler rectification, such as wave triple voltage or half wave quadruple voltage.

  In the above-described embodiment, the present invention may be configured such that the order of connection between the first diode and the coil is changed, or the first and second diodes are replaced with other switch means such as a transistor. The same effect can be obtained.

  Further, by replacing the anode electrode and the cathode electrode of the first and second diodes of the present invention, a circuit configuration for generating a negative voltage is obtained.

  Thus, it goes without saying that the present invention can be modified as appropriate without departing from the spirit of the present invention.

It is a figure which shows the circuit structure of the resonance type power supply device shown as embodiment of this invention. (a) It is a figure which shows the conventional capacitor | condenser input type center tap double wave rectifier circuit. (b) It is a figure which shows the conventional choke input type center tap double wave rectifier circuit. (a) It is a figure which shows the conventional capacitor | condenser input type bridge rectifier circuit. (b) It is a figure which shows the conventional choke input type bridge rectifier circuit.

Explanation of symbols

10 transformer, 10a secondary winding, 11, 15 capacitor, 12, 14 diode, 13 coil

Claims (4)

A transformer for inputting AC power supplied from an AC power source;
A capacitor connected to one end of the secondary winding of the transformer;
A half-wave voltage doubler rectifier circuit configured by connecting a coil in series between a plurality of diodes connected in series including a first diode connected to the other end of the secondary winding. A characteristic resonance power supply device. The half-wave voltage doubler rectifier circuit includes: the first diode having an anode electrode connected to the other end of the secondary winding; the coil having one end connected to the cathode electrode of the first diode; A second diode having an anode electrode connected to the other end of the coil;
The resonant power supply device according to claim 1, wherein one end of the capacitor is connected between the coil and the second diode. The half-wave voltage doubler rectifier circuit includes: the first diode having a cathode electrode connected to the other end of the secondary winding; the coil having one end connected to the anode electrode of the first diode; A second diode having a cathode electrode connected to the other end of the coil;
The resonant power supply device according to claim 1, wherein one end of the capacitor is connected between the coil and the second diode. 4. The resonance type power supply device according to claim 2, wherein the order of the coil connected to the other end of the secondary winding and the first diode is switched.

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