JP3196654B2 - Multi-circuit parallel type laminated mold coil transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated molded coil transformer used for a switching power supply or the like, and more particularly to an improvement suitable for use in a multi-output power supply.

[0002]

2. Description of the Related Art A laminated molded coil transformer is disclosed in Japanese Patent Application Laid-Open No. H8-17658, proposed by the present applicant, as a transformer having a primary winding and a secondary winding for a switching power supply. Used. By the way, as a use of the switching power supply, there is also a use as a multi-output power supply.

FIG. 6 is a perspective view showing the structure of a conventional laminated mold coil transformer. In the figure, a core 10 is an EE type or an EI type and is made of a magnetic material such as iron. Coil laminate 20
Is a technology in which a plurality of coil substrates each having a spiral wiring pattern are laminated, electrical insulation is obtained by using a resin, and the coil substrates are mechanically integrated. Terminal 30 is
The transformer is implanted in the coil laminate 20 to facilitate the soldering of the transformer to the printed circuit board of the switching power supply.

FIG. 7 is a sectional view taken along line 7-7 of the laminated molded coil transformer of FIG. Here, the stacked state of the coil substrates 22 constituting each layer of the coil stacked body 20 is shown. The lowermost layer has a winding P for the primary winding, and the upper layer has windings N1 to N for the first to eighth secondary windings and auxiliary windings.
8 are stacked.

FIG. 8 is a circuit diagram of a switching power supply using the laminated mold coil transformer of FIG. In the figure, a DC input voltage Vin is applied to a primary winding P by a capacitor C.
₀ , a resistor R ₀ , and a diode D ₀ . The switching element Q such as an FET turns on and off the current flowing through the primary winding P, and an on / off control signal is sent from the switching control circuit 40 to the gate terminal. The auxiliary winding N ₈ includes a diode D ₈ and a capacitor C ₈
The rectifying / smoothing circuit acts as an auxiliary power supply and supplies the operating voltage Vcc of the switching control circuit 40.

The first secondary winding N ₁ is connected to a main output voltage Vo by a rectifying and smoothing circuit including a diode D ₁ and a capacitor C _1.
ut1 is output. In order to stabilize the main output voltage,
The error voltage signal output from the error voltage amplifier circuit 50 is sent to the switching control circuit 40 via the photocoupler PC, and the duty ratio of the on / off control signal is adjusted so that the main output voltage is stabilized at a predetermined voltage. Controlling. The photocoupler PC ensures insulation between the primary side and the secondary side of the power supply.

The second secondary winding N ₂ once rectifies the switching signal by a rectifying / smoothing circuit of a diode D ₂ and a capacitor C ₂ , and then stabilizes the slave output voltage Vout ₂ by a three-terminal regulator U ₂ . , and further outputs the secondary output voltage Vout2 through the output capacitor C _12. Third on from the secondary winding N ₃ seventh secondary winding N _7, by the same circuit configuration as the second secondary winding N _2, secondary output voltage Vo
ut3 to Vout7 are stabilized.

[0008]

[SUMMARY OF THE INVENTION However, in addition to the first secondary winding N ₁ and the auxiliary winding N ₈ for the auxiliary power supply for the main output voltage, the secondary windings for a large number of secondary output voltage In the switching power supply having the above, while the number of coil substrates 22 increases,
Since an insulating layer between the windings is also required, there is a problem that the thickness of the transformer increases as shown in FIG. Furthermore, the number of terminals connected to the outside increases according to the number of output voltages, and a creepage distance between terminals for insulation is required. Therefore, there is a problem that the entire transformer becomes large.

Therefore, Japanese Patent Laid-Open No.
When a laminated molded coil transformer using a biaxial core as disclosed in Japanese Patent No. 333759 is used, the number of laminations per axis is reduced to half. Then, as a characteristic of the switching power supply, as compared with the case of FIG. 7, the copper loss of the coil due to the proximity effect is reduced, the switching frequency can be increased, and the core shape is reduced, so that the iron loss is also reduced. It has the effect of being done. However, since the mutual interference between the secondary windings is large in the laminated molded coil transformer, there is a problem that if the primary winding and the secondary winding are indiscriminately laminated, the regulation characteristics of each output voltage are significantly deteriorated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a multi-circuit parallel-type laminated molded coil transformer which has good output voltage regulation characteristics and requires less copper loss and iron loss. Aim.

[0011]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention comprises a primary coil P and a secondary coil N each having a spiral conductor pattern, and the primary coil and the secondary coil N are laminated. Wherein the primary side coil is arranged in parallel with respect to the axis of each core so that the input power is supplied evenly to the axis of each core. The side coil is characterized in that it is arranged such that the sum of the output powers of the relevant axis is equal to the sum of the output powers of the other axes.

According to the configuration of the present invention, since the laminated molded coil transformer has two cores, the number of laminated coil substrates is half that of a uniaxial core, and the characteristics as a switching power supply are excellent. Become. In addition, since the sum of the input power of the primary coil and the output power of the secondary coil in each axis is arranged to be equal, when the output power varies between each output like a multiple output power supply However, the regulation characteristics of the switching power supply are improved.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a configuration perspective view showing an embodiment of the present invention. Here, a biaxial core 12 is used, and the core shape is π-shaped or U-shaped.
The coil laminated body 24 has a spiral conductor pattern of one coil substrate 2 because of the center of the biaxial core 12.
6, two are provided. The terminal 30 is connected to the coil laminate 2
4 is planted.

FIG. 2 is a sectional view of a main part of the transformer shown in FIG. The biaxial core 12 includes a first shaft Ni1 and a second shaft Ni1.
Two. The first axis Ni1 has a coil substrate 26
a, a primary coil P1, a balance coil NC1, and a secondary coil N are mounted on the coil substrate 26a.
Five layers 1, N3 and N5 are stacked in this order. A coil substrate 26b is mounted on the second shaft Ni2, and five layers of a primary coil P2, a balance coil NC2, and secondary coils N2, N4, and N6 are stacked in this order on the coil substrate 26b. Have been.

FIG. 3 is a circuit diagram of a switching power supply using the laminated mold coil transformer of FIG. Primary winding P, secondary winding N, balance winding NC in FIG.
Respectively correspond to the primary coil P, the secondary coil N, and the balancing coil NC in FIG. In the figure, a DC input voltage Vin is applied to primary windings P ₁ and P ₂ via a capacitor C ₀ , a resistor R ₀ and a smoothing circuit of a diode D ₀ . The primary windings P ₁ and P ₂ have the same number of turns, are mounted on a first shaft Ni1 and a second shaft Ni2, and are connected in series here. FET
The switching element Q turns on and off the current flowing through the primary windings P ₁ and P _2.
Sends an on / off control signal to the gate terminal. Auxiliary winding N ₁₆ is the rectifier smoothing circuit of the diode D ₈ and the capacitor C _8, and acts as an auxiliary power source, and supplies the operating voltage Vcc of the switching control circuit 40.

The balance winding NC1 and the balance winding N
C2 has the same number of turns as the first axis Ni1.
And the second shaft Ni2, and are connected in parallel with each other. Balance winding NC1,2 is by the rectifying smoothing circuit of diode D ₁₀ and the capacitor C _20, and outputs a main output voltage Vout10. In order to stabilize the main output voltage, an error voltage signal output from the error voltage amplifier circuit 50 is sent to the switching control circuit 40 via the photocoupler PC, and the main output voltage is stabilized at a predetermined voltage. Thus, the duty ratio of the on / off control signal is controlled. The main output voltage Vout10 is a voltage having the largest output power among the multiple output voltages.

The first secondary winding N ₁₁ is the rectifier smoothing circuit of the diode D ₁₁ and the capacitor C _21, and outputs the secondary output voltage Vout11. From the secondary winding N ₁₂ 5
The secondary winding N ₁₅ also show, by the same circuit configuration as that of the first secondary winding N _11, and outputs the secondary output voltage Vout12～Vout15. The sum of the output powers of the secondary windings N ₁₁ , N ₁₃ , N ₁₅ mounted on the first shaft Ni 1 and the secondary windings N ₁₂ , N ₁₄ mounted on the second shaft Ni 2 When the sum of the output power of the winding N ₁₆ is arranged so as to be equal, regulation characteristic is improved. Furthermore, compared to the conventional example shown in FIG. 8, since the secondary output voltage Vout without providing a three-terminal regulator U Each secondary winding N ₂ can be stabilized to the extent necessary for the load, secondary output voltage The circuit configuration is simplified.

FIG. 4 is a modified circuit diagram of a switching power supply using the laminated molded coil transformer of FIG. The difference from the circuit diagram of FIG. 3 is that the primary windings P ₁ and P ₂ are connected in parallel. As described above, even if the primary windings P ₁ and P ₂ are connected in parallel, the input powers of the first axis Ni1 and the second axis Ni2 become equal to each other.

FIG. 5 is a diagram for explaining the operation of the balance winding NC1 and the balance winding NC2. Consider a case where the output power W on the first axis Ni1 side is large and the output power W on the second axis Ni2 side is small. Then, energy of the primary winding P ₂ is largely transmitted to the balancing winding NC2, balanced winding NC1 is suppressed reversed. Thereby, the unbalanced state of both axes of the biaxial core 12 is compensated.

In the above embodiment, the case where the balance winding NC1 and the balance winding NC2 are used also as the secondary winding for the main output is shown, but the present invention is not limited to this. However, it may be provided completely independently of the secondary winding. That is, by the balance windings NC1 and NC2,
Since the degree of coupling and the degree of balance between the two axes of the biaxial core 12 can be adjusted, even if a non-equilibrium state of output power or input power exists between the first axis Ni1 and the second axis Ni2. , Can be compensated.

[0021]

As described above, according to the present invention, the primary coil and the secondary coil are arranged symmetrically on both axes of the biaxial core 12, and the input power and the output power are also adjusted on both axes. Since they are arranged almost equally, there is an effect that the regulation characteristics of multiple output voltages are improved.
Furthermore, since the number of stacked coils per axis is reduced by half as compared with the uniaxial core, the copper loss of the coil due to the proximity effect is reduced, and the switching frequency can be increased. In addition, the entire outer peripheral portion of the coil laminated body 24 to which the biaxial core 12 is mounted is a terminal area, so that a multi-output power supply having a large number of terminals and an insulating creepage distance that defines the distance between the terminals is ensured. On the other hand, since the shape of the entire transformer is smaller than that of the related art, there is an effect that iron loss is reduced.

According to the second aspect of the present invention, the degree of coupling and balance between the two axes of the biaxial core 12 can be adjusted by the balance windings NC1 and NC2. Even if there is an unbalanced state between the output power and the input power between the axes Ni2, the compensation can be performed, and there is an effect that the regulation characteristics of the multi-output voltage are further improved.

[Brief description of the drawings]

FIG. 1 is a configuration perspective view showing an embodiment of the present invention.

FIG. 2 is a sectional view of a main part of the transformer of FIG. 1;

FIG. 3 is a circuit diagram of a switching power supply using the laminated molded coil transformer of FIG. 2;

FIG. 4 is a modified circuit diagram of a switching power supply using the laminated molded coil transformer of FIG. 2;

FIG. 5 shows a balance winding NC1 and a balance winding NC2.
It is operation | movement explanatory drawing of FIG.

FIG. 6 is a configuration perspective view of a conventional laminated mold coil transformer.

FIG. 7 is a sectional view taken along line 7-7 of the laminated molded coil transformer of FIG. 6;

FIG. 8 is a circuit diagram of a switching power supply using the laminated molded coil transformer of FIG. 7;

[Explanation of symbols]

 Reference Signs List 10 core 20 coil laminated body 30 terminal 40 switching control circuit 50 error voltage amplifying circuit P primary coil N secondary coil NC balancing coil

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-U 61-27325 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01F 27/28, 30/00, 30 / 04 H02M 3/28

Claims (2)

(57) [Claims] 1. A primary coil (P) and a secondary coil (N) each having a spiral conductor pattern are laminated, and a core penetrating through the center of the primary coil and the secondary coil is provided.
A laminated molded coil transformer having an axis, wherein the primary coil is arranged in parallel with the axis of each core so that input power is supplied equally, and the secondary coil is output power applied to the axis. Are arranged so that the sum of them is equal to the sum of the output powers applied to other axes. 2. A primary coil (P) having a spiral conductor pattern and a secondary coil (N) are laminated, and a core penetrating through the center of the primary coil and the secondary coil is provided.
A laminated molded coil transformer having an axis, wherein the primary coil is arranged in parallel with the axis of each core so that input power is supplied equally, and the secondary coil is output power applied to the axis. Are arranged so as to be equal to the sum of the output powers applied to the other axes, and a balancing coil (NC) having the same number of turns connected in parallel to the two axes is provided. A multi-circuit parallel-type laminated mold coil transformer, wherein the degree of coupling and balance between both axes is adjusted to compensate for the unbalanced state of output power between both axes of the secondary coil.