JP2002101664A - Isolated multi-channel power supply circuit. - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-channel power supply circuit capable of converting direct current into alternating current in the transmission system of a power supply for each channel and contriving miniaturization of the power supply circuit of the channel. SOLUTION: The isolated multi-channel power supply circuit is provided with an AC-AC converter obtaining remarkably low AC voltage on the basis of the commercial power, and a multi-channel input part having a transformer and a rectifying and filtering circuit and converting AC-DC by receiving AC voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply circuit for an insulated multi-channel measuring instrument or the like.

[0002]

2. Description of the Related Art FIG. 2 is a block diagram showing an example of a conventional power supply circuit of an insulated multi-channel measuring instrument. Since the input section of each channel is insulated, a DC input-DC output conversion mechanism (hereinafter, DC-DC
A converter) to supply power to the insulation.

[0003] This will be described in more detail. First, a 100 V AC voltage supplied from a commercial power supply is converted into a DC voltage (DC voltage) by an AC input-DC output conversion mechanism (hereinafter, referred to as an AC-DC converter) 10 having a transformer and a rectifying / smoothing circuit (both not shown). And converts the DC voltage to the input portions 20a, 20b,. . . Give to the common.

The input section 20a includes a capacitor 21 for input smoothing, a transformer 23, a drive circuit 22 for switchingly driving a current of a primary winding on an input side of the transformer 23, and a secondary circuit on an output side of the transformer 23. A generated on the side winding
The rectifying and smoothing circuit 24 rectifies and smoothes the C voltage and outputs a DC voltage. The input unit 20b has the same configuration as the input unit 20a.

With such a DC-DC converter,
The input part of each channel is insulated from the former part and the latter part by the transformer 23, and a DC voltage insulated from the input is obtained from the latter part.

[0006]

However, such a conventional power supply circuit has a DC-DC
There is a problem that the number of components and the mounting area are increased because of having the converter. In addition, there is a problem that the bobbin of the transformer must be large in order to secure a creepage distance for insulation required in safety standards.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and to change the transmission system of power supply to each channel from DC to AC, thereby making it possible to downsize the power supply circuit of each channel. A power supply circuit is provided.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, an invention of claim 1 is an insulated multi-channel power supply circuit which obtains a significantly low AC voltage based on a commercial power supply. A multi-channel input unit having an AC converter, a transformer and a rectifying / smoothing circuit, for receiving the AC voltage and performing AC-DC conversion.

The input section of each channel is composed of a transformer and a rectifying and smoothing circuit, and the transformer need only perform AC-AC conversion of a significantly low AC voltage, so that the circuit can be easily reduced in size. .

[0010] In this case, the AC-
The AC converter may be an insulation type, and the AC-AC converter may be a combination of an AC-DC converter and a DC input-AC output conversion mechanism (DC-AC converter).

[0011] The significantly low AC voltage may be defined by claim 4
The effective value is set to 42 V or less as shown in FIG. Further, the transformer is an insulation type. According to such a configuration, downsizing of the input unit is further facilitated.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a configuration diagram showing one embodiment of a multi-channel power supply circuit according to the present invention. In FIG. 1, reference numeral 100 denotes a power supply of 100 VAC (normal commercial power supply),
This is an AC-AC converter that converts the voltage (effective value is 42 V or less). The low output AC voltage is applied to the input portions 200a, 200b,. . . Is given in common.

The input section 200a comprises a transformer 201 and a rectifying / smoothing circuit 202. Transformer 201 is AC
Receiving the low AC voltage from the AC converter 100 into the primary winding on the input side and generating the AC voltage from the secondary winding on the output side; This AC voltage is rectified and smoothed by the rectification / smoothing circuit 202 and output as a DC power supply voltage. On the other hand, the input unit 200b has the same configuration as the input unit 200a.

Note that the AC-AC converter 100
It may be configured by a combination of a C-DC converter and a DC-AC converter. Further, the present invention is not limited to a measuring instrument, but can be widely applied to an insulated multi-channel electric device.

[0015]

As described above, according to the present invention, the following effects can be obtained. (1) The input section of each channel only requires a transformer and a rectifying / smoothing circuit, so that the number of components is reduced and the size can be reduced as compared with the conventional case. (2) Since the AC-AC converter is also insulated, the transformer 201 in the input section can be smaller than the transformer 23 used in the conventional input section in terms of safety standards.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a multi-channel power supply circuit according to the present invention.

FIG. 2 is a configuration diagram illustrating an example of a conventional multi-channel power supply circuit.

[Explanation of symbols]

 Reference Signs List 100 AC-AC converter 200a, 200b Input unit 201 Transformer 202 Rectifying smoothing circuit

Claims (5)

[Claims] 1. An insulated multi-channel power supply circuit comprising: an AC-AC converter for obtaining a significantly low AC voltage based on a commercial power supply; and a transformer and a rectifying / smoothing circuit for receiving the AC voltage.
An insulated multi-channel power supply circuit comprising a multi-channel input unit for performing C-DC conversion. 2. The insulated multi-channel power supply circuit according to claim 1, wherein said AC-AC converter is an insulated type. 3. An AC-DC converter, wherein:
2. The isolated multi-channel power supply circuit according to claim 1, wherein the isolated multi-channel power supply circuit is a combination of a converter and a DC-AC converter. 4. The significantly low AC voltage is 42 rms.
2. The isolated multi-channel power supply circuit according to claim 1, wherein the voltage is not more than V. 5. The insulated multi-channel power supply circuit according to claim 1, wherein said transformer is an insulated type.