JP2932836B2 - Boost type switching converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a step-up switching converter.

[0002]

2. Description of the Related Art In a conventional step-up switching converter, when a high DC voltage is required, a converter insulated by a transformer is used to provide a converter with a turns ratio between a secondary winding and a primary winding. , The boost ratio is increased.

[0003]

In such a conventional step-up switching converter, in order to obtain a step-up voltage of several KV DC, if the step-up operation is to be performed only by the turns ratio of the transformer, a winding of several thousand turns is required. Because of the necessity, it is unavoidable to increase the size of the transformer.

[0004]

SUMMARY OF THE INVENTION A step-up switching converter according to the present invention comprises a step-up transformer, a main switch for turning on and off a DC power supply current to a primary winding of the transformer, and
An auxiliary switch that operates alternately with the main switch to turn on and off both ends of a series circuit formed by the main switch and the primary winding; an inductor connected in series to the primary winding via a diode; And a capacitor connected in parallel with the secondary winding of the transformer.
Ru give a boost output.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a circuit diagram of one embodiment of the present invention.
In the figure, reference numeral 7 denotes a step-up type transformer, 2 denotes an inductor having one end connected to an input terminal, and the other end connected to the primary winding of the transformer 7 via a diode 3, and 3 denotes an inductor 2. A diode having one end connected thereto and the other end connected to a transformer 7, and 6 connected to one end of a primary winding of the transformer 7.
Main switching element, 4 is the primary winding of the transformer 7 at one end, auxiliary switch <br/> quenching element connected at the other end to the main switching element 6, capacitors that are 5 connected in parallel with the auxiliary switching element 4 , 8 and the auxiliary switching element 4 Schuss
A control circuit connected to the switching element 6 to perform complementary output;
1 is a capacitor which is connected to the input end.

Next, the circuit operation of this embodiment will be described.

[0008] When the auxiliary switching element 4 is turned on (at this time, main switching element 6 is turned off), the inductor 2 is energized. Next, when the main switching element 6 is turned on (at this time, the auxiliary switching element 4 is turned off), the energy stored in the inductor 2 causes the primary winding of the transformer 7 to be turned on. In the line, the input voltage is Ei, the inductance of the inductor 2 is L, the capacitance of the capacitor 5 is C , and the auxiliary switching element 4 is turned on.
If the off time is TOFF ,

[0009]

Since a flyback voltage having a high peak characteristic is applied, the charge voltage of the capacitor 5 can be used as a primary voltage. Thus it is possible to suppress the winding ratio required to boost the high voltage, the number of turns of the secondary side can be reduced than the conventional circuit.

[0011] A high voltage AC obtained on the secondary winding of the transformer 7, which was rectified by the diode 9, inductor 1
1. High-voltage DC is output after smoothing by the capacitor 12.
This output voltage is divided by the resistors 13 and 14 and supplied to the control circuit 8, and the auxiliary switching element 4 and the main switching element 6
By controlling the switching timing, the output voltage can be stabilized.

[0012]

As described above, according to the present invention, the number of windings can be greatly reduced as compared with the conventional circuit in which the voltage is boosted only by the winding ratio of the transformer.
The boosting inductor configured using a common core and transformer can be further miniaturized circuit.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

[Explanation of symbols]

1, 5, 12 Capacitor 2, 11 Inductor 3, 9, 10 Diode 4 Auxiliary switching element 6 Main switching element 7 Transformer 8 Control circuit 13, 14 Resistance

Claims (1)

(57) [Claims] And 1. A step-up transformer, a main switch for turning on and off a DC power supply current to the primary winding of the transformer, between the main switch alternately operating with the main switch the primary winding
Comprising an auxiliary switch for turning on and off the ends of the formed series circuit, an inductor connected in series via a diode to said primary winding, and a capacitor connected in parallel to the auxiliary switch, the secondary of the transformer Boost from winding
Boost switching converter you and obtaining the output.