JPH02168861A - Switching circuit - Google Patents

Abstract

PURPOSE:To enable a low tension-resistance switching element to be used by enabling a circuit accommodated to the DC input voltage of a high level and a circuit accommodated to the DC input voltage of a low level, to be automatically selected from the switching circuits which can cope with any of the DC input voltage of the high level and the DC input voltage of the low level. CONSTITUTION:When switches are required to be worked by the DC input voltage of a high level, then a switch 5 is connected to the side of the DC input voltage side of the high level, and a switch 14 is connected to the side of a winding N1, and a switch 15 is connected to the side of a winding N'1, respectively, and the input windings N1, N'1 and transistors 7, 7' are connected in series. When a commercial power source 1 is stopped in this state, then this is detected by a service interruption detecting circuit 16, and the switches 5, 14, 15 are automatically switched. Then, the switch 5 is connected to the side of the DC input voltage of the low level, and the serially connected circuit of the input winding N1 and the transistor 7, and the serially connected circuit of the input winding N'1 and the transistor 7' are connected to each other in parallel.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a switching circuit that can handle both high-level DC input voltage and low-level DC input voltage.

[Conventional technology]

FIG. 2 is a diagram for explaining a conventional switching circuit. In the figure, ■ is a commercial power supply of AClooV, which supplies a high-level DC input voltage through a rectifying and smoothing circuit consisting of a rectifier 2 and a capacitor 3. 4 is DC
It is a 48V DC power supply and provides a low level DC input voltage. Reference numeral 5 includes a switch for switching between the high-level DC input voltage and the low-level DC input voltage, 6 a drive circuit for driving the transistor 7, which is a switching semiconductor element, and 8 an input winding Nl and an output winding N2. Transformer 9 10 is a diode 11 is an inductor 12 is a capacitor 13 is a load. In this circuit, i!
If it is necessary to operate with a DC input voltage of 1i level, connect switch 5 to the high level DC input electrification side as shown in Figure 2, and connect the switch 5 to the high level DC input electrification side as shown in Figure 2. If it is necessary to operate with a DC input voltage, switch 5 is switched to the DC power supply 4 side.

[Problem that the invention seeks to solve]

However, in this switching circuit, the same circuit can handle both high-level DC input voltage and low-level DC input voltage, so it is necessary for the switching semiconductor element to match the high-level DC input voltage. This results in the need for a device with high breakdown voltage, which generally results in poor switching characteristics and reduced efficiency. Further, since the conduction angle needs to be adjusted to a low level DC input voltage, the utilization rate of the transformer and the switching semiconductor element deteriorates, resulting in a decrease in efficiency.

(Means for Solving the Problems) In order to eliminate the above-mentioned drawbacks, the present invention uses a human-powered winding of a transformer in a switching circuit that can handle both high-level DC input voltages and low-level DC input voltages. The input winding Nl of step 8 is divided into a plurality of 11 AI human-powered windings.
1 and N'l, and correspondingly the transistor 7 described in FIG. 'l are connected in series with each other. Also, 1
4 is a switch for switching between the winding Nl side and the power supply side, and 15 is a switch for switching between the winding N"! side and the ground side. Switches 14 and 15 are linked to switch 5, respectively, and are shown in Figure 2. Either they are connected as shown, or switches 514 and 15 are switched simultaneously.

In this circuit, if it is necessary to operate with a DC input voltage of iI'li level, as shown in this figure,
Switch 5 connects switch 14 to the high level DC input voltage side.
are connected to the winding Nl side, switch I5 is connected to the winding N'1 side, and the input windings N1. N'l, ) Langistaf, 7' are connected in series. In this state, if there is a power outage in the commercial power supply 1, for example, this will be detected by the power outage detection circuit 16, and switches 5, 14, and 15 will automatically switch at the same time. The switching semiconductor elements are connected in series, and the plurality of input windings and switching semiconductor elements are connected in series for the high-level DC input voltage, and the plurality of input windings and the switching semiconductor elements are connected in series for the low-level DC input voltage. The present invention provides a switching circuit characterized in that input windings and switching semiconductor elements are connected in parallel.

[Effect]

Since the present invention has the above-described configuration, it automatically selects a circuit suitable for a high level DC input voltage and a circuit suitable for a low level DC input voltage, thereby producing a low withstand voltage product of a switching semiconductor element. This enables efficient operation without reducing the utilization rate of switching semiconductor elements and transformers.

〔Example〕

FIG. 1 is a diagram for explaining one embodiment of the present invention.

In the same figure, the transformer current input voltage side explained in FIG.
and the series connected circuits are connected in parallel. Therefore, a circuit suitable for a high-level DC input voltage and a circuit suitable for a low-level DC input voltage can be automatically selected to perform efficient operation. It is of course possible to perform efficient operation by selecting a high-level DC input voltage or a low-level DC input voltage as necessary, regardless of whether there is a power outage in the commercial power supply l. .

[Effects of the Invention] As described above, the present invention provides a switching circuit capable of handling both high-level DC input voltage and low-level DC input voltage, in which the input winding of a transformer is connected to a plurality of input windings. At the same time, a switching semiconductor element is connected in series to each of these human-powered windings, and for the above-mentioned high-level DC input voltage, the above-mentioned plurality of input windings and switching semiconductor elements are connected in series, and for the above-mentioned low-level DC input voltage, The switching circuit is characterized in that the plurality of input windings and switching semiconductor elements are connected in parallel for a DC input voltage of . Since the present invention has such characteristics, it is possible to automatically select a circuit suitable for high-level DC input voltage and a circuit suitable for low-level DC input voltage to perform efficient operation. .

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining one embodiment of the present invention, and FIG. 2 is a diagram for explaining a conventional switching circuit. l...Commercial power supply 2...Rectifier 312...Capacitor 4...DC power supply 5 14 15...Switch 6/Drive circuit 7.7゛...Switching semiconductor element 8/Transformer 9.10/ ...Diode 11...Inductor 13...Load 16...Power failure detection circuit

Claims (1)

[Claims] In a switching circuit that can handle both high-level DC input voltage and low-level DC input voltage, an input winding of a transformer is divided into a plurality of input windings, and each of these input windings is divided into a plurality of input windings. Switching semiconductor elements are connected in series to the windings, and the plurality of input windings and switching semiconductor elements are connected in series for the high level DC input voltage, and for the low level DC input voltage. A switching circuit characterized in that the plurality of input windings and switching semiconductor elements are connected in parallel.