JPS59123463A - Switching power source circuit - Google Patents

Abstract

PURPOSE:To readily perform light weight and high efficiency of a switching power source circuit by employing a non-insulated (auto) transformer for a converter transformer. CONSTITUTION:A switching power source circuit is composed of a non-insulated (auto) transformer 12, switching transistors 14, 15, a switching drive transformer 13 of transistors 14, 15, rectifying diodes 16, 17, and a condenser 18. The transistors 14, 15 are symmetrically connected, and the output is rectified by the diodes 16, 17 through the transformer 12.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a switching power supply circuit, and an object of the present invention is to obtain a small and highly efficient switching power supply circuit.

In general, a switching power supply circuit consists of two transistors 2 and 3 connected symmetrically, as shown in the push-pull type DC-DC power supply shown in FIG. , the secondary coil of the switching drive transformer 1 is connected between the bases and emitters of the transistors 2 and 3, and the primary coil of the insulated converter transformer 4 is connected between the collectors of each of the transistors 2 and 3. DC between the neutral point of converter transformer 4, the emitter of transistor 2.3, and the neutral point +1Ji of the secondary coil of drive transformer 1.
In many cases, input voltage is applied and rectification is performed via a secondary coil of an isolated converter transformer 4 through a diode 5.6 and a capacitor 7. 8.9
is an input terminal, and 10.1.1 is an output terminal.

Even if the input and output of the power supply are in a non-insulated circuit configuration as shown in Figure 1, the converter transformer 4 is insulated so that 61 < m is used, and the primary coil and secondary coil each handle the current flowing through the coil. π "Because it is designed to have a thickness that allows for troughs and can be turned to a predetermined turn ratio, there is a limit to the number of times it can be made into a shape, and its efficiency is low."

In order to solve the above-mentioned problems, the present invention uses a non-isolated (auto) transformer as a converter transformer.

In other words, a plurality of switching elements are symmetrically
This switching power supply circuit is characterized in that a non-isolated (auto) transformer is used as the converter transformer in the switching power supply circuit in which the output of the converter transformer is rectified through a converter transformer.

The present invention will be explained below with reference to embodiments shown in FIGS. 2 to 4.

Figure 2 is a principle diagram of a non-isolated (auto) transformer, where the input voltage V1 is applied to the coil VC1 of the non-isolated transformer 12.
is applied and the primary (input) current 11 flows, the coil 0
A secondary (output) current i! due to electromagnetic induction occurs between 0 and 0. flows, and the output voltage V2 is severely increased. At this time, the coil (A) Of
If the number of turns of f6 is 11%■■ and the number of turns between them is 12, then the non-insulated (auto) transformer]20 primary side and 2=il(1-!
l! A current of -1) flows, and a current of 2 Fii+ flows between the coils 00 and 00. This not only eliminates the need for a primary winding like the isolated converter transformer 4, but also
Since there is a winding portion where the secondary (input) current 11 and the secondary (output) current 12 cancel each other out, the current capacity of the coil can be designed to be smaller (V can be made smaller and lighter).

FIG. 3 is a push-pull switching power supply circuit diagram using the above-mentioned non-isolated (auto) transformer 12.
13 is a switching drive transformer for transistors 14 and 15, 16 and 17 are rectifying diodes, and 18 is a capacitor.

In this case, since the autotransformer 12 is used in the transformer, it is possible to achieve a significantly reduced shape and weight, and in particular, the closer the turns ratio is to 1, the greater the effect is.

2 Moreover, since the mutual inductance between the primary coil and the secondary coil of the transformer is extremely small, the efficiency of the switching power supply circuit can be greatly improved.

Fig. 4 shows a push-pull type DC-DC converter power supply with a rated input voltage of 8 and a rated output voltage of ±15 V based on the embodiment shown in Fig. 3 above, and the efficiency [( Output 11], pressure x output current/input voltage x
Input current)

As is clear from the table and FIG. 4, the DC-DC of the present invention
It has been demonstrated that converter power supplies have significantly improved efficiency characteristics and can be made smaller and lighter.

In the above embodiment, the input and output Q-pole terminals 9. Empty 031M terminal 8. Explaining the switching circuit diagram of the push-pull combination method in which both IJ and 1iEa are connected. A similar effect can be obtained if the rivers are connected in common or if they are connected to multiple outputs.

As described above, the switching power supply circuit of the present invention can easily realize small size, light weight, and high efficiency, and is of great industrial value.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of a conventional switching power source, Fig. 2 is a principle circuit diagram of a non-isolated (auto) transformer according to the present invention, Fig. 3 is a switching power supply circuit diagram of Kazuo's embodiment of the present invention, and Fig. 4 is a circuit diagram of a switching power supply according to an embodiment of the present invention. The figure is an efficiency-output current characteristic diagram of a DC-DC converter power supply comparing a product of the present invention and a conventional product. 2.3, I4.15: Transistor 5.6.16.17: Rectifier diode 7.18: Capacitor 12: Non-isolated (auto) transformer Patent applicant Nippon Capacitor Industry Co., Ltd.

Claims (2)

[Claims] (1) In a switching power supply circuit in which multiple notching elements such as transistors are symmetrically connected and their outputs are rectified via a parallel transformer,
A switching power supply circuit characterized in that a non-isolated (mate) transformer is used as the converter transformer. (2) The switching power supply circuit according to claim 1, wherein the switching power supply circuit is of a push-pull type.