JPH064575Y2 - Power supply current detection circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a current detection circuit of a power supply device, and more particularly to an improved current detection circuit when an excessive current flows.

(Prior Art) FIG. 4 is a configuration block diagram of a conventional power supply circuit. In the figure, 10 is a switching power supply circuit, which is used, for example, as a stabilized DC power supply. Reference numeral 20 is a current detection circuit that detects the output current I of the power supply circuit 10, and a transformer is used here. 30 is a signal V detected by the current detection circuit 20
Is a current limiting circuit that controls so that an excessive current does not flow from the power supply circuit 10.

FIG. 5 is a block diagram of a transformer used in the current detection circuit 20. Reference numeral 21 is a primary coil, 22 is a secondary coil, and 23 is a main body that houses the coils 21 and 22 and is made of an insulating resin or the like. It has a box shape.

In the device thus configured, the primary coil 2
1, the output signal I from the power supply circuit 10 is supplied, the secondary side coil 22 boosts the voltage to convert it into a voltage signal V, and the current limiting circuit 3
It outputs to 0. The winding ratio is, for example, 1: 100.

(Problems to be Solved by the Invention) However, if the current flowing through the primary coil 21 becomes excessive, the following problems will occur.

Since the coil generates heat, the main body 23 is adversely affected if it is not sufficiently cooled.

If the coil breaks, the current cannot be detected, and the reliability of the operation of the current limiting circuit 30 decreases.

Since the coil generates heat, electric energy becomes useless thermal energy, and the load on the power supply circuit 10 becomes excessive.

Unless the overcurrent is quickly limited, the fuse of the power supply circuit 10 may blow or the parts may be destroyed.

Therefore, it is conceivable to use a thick copper wire for the primary coil 21, but there is a drawback that assembly work such as electrical connection with the terminal becomes complicated.

The present invention solves the above-mentioned problems, and an object thereof is to provide a current detection circuit having a large current capacity and easy to assemble.

(Means for Solving the Problems) The present invention which achieves such an object is to limit the current by flowing a current into the power supply circuit into a primary side coil and a current flowing through the primary side coil into a voltage signal. A secondary side coil for sending to a circuit, wherein the output current of the power source circuit is limited to a predetermined value or less, in a power supply device, the winding is attached to surround the winding of the primary side coil, It is characterized in that an auxiliary coil made of a substantially U-shaped conductive material connected in parallel is provided.

(Operation) Since the auxiliary coil increases the current capacity flowing in the primary coil, the width of the input current for operating the current detection circuit is increased.

(Example) The present invention will be described below with reference to the drawings.

FIG. 1 is a configuration block diagram showing an embodiment of the present invention, and FIG.
FIG. 1A is a front view and FIG. 1B is a side view showing a configuration of essential parts of a concrete example of the present invention. It should be noted that in these figures, the elements having the same functions as those in FIG. 1 and FIG.

In the figure, reference numeral 24 is an auxiliary coil connected in parallel with the primary coil 21, and is attached so as to surround the winding of the primary coil 21.

FIG. 3 is a perspective view showing the structure of the auxiliary coil 24. The leg portion 24a is thinned to avoid interference with the winding. Auxiliary coil 2
No. 4 has a larger cross-sectional area than a winding such as a copper plate, and a conductive material is used. When the auxiliary coil 24 is housed inside the box-shaped body 23, the auxiliary coil 24 retains its function without insulation, but may be coated with insulation.

(Effect of the Invention) As described above, according to the present invention, since the auxiliary coil 24 increases the cross-sectional area, the current capacity of the primary side coil increases, so that the following effect is obtained.

Since there is no fear of breaking the coil, the current limiting circuit 30
Highly reliable operation.

Since the coil does not generate heat, the load on the power supply circuit 10 is small.

Since the coil is highly resistant to overcurrent, the reliability of the power supply circuit 10 is increased.

[Brief description of drawings]

FIG. 1 is a configuration block diagram showing an embodiment of the present invention, and FIG.
FIG. 3 and FIG. 3 are main part configuration diagrams, and FIGS. 4 and 5 are explanatory views of a conventional device. 10 ... Power supply circuit, 20 ... Current detection circuit, 21 ... Primary side coil, 22 ... Secondary side coil, 24 ... Auxiliary coil, 30 ...
Current limiting circuit.

Claims (1)

[Scope of utility model registration request] 1. An output current of the power supply circuit, comprising: a primary side coil for inputting a current flowing through the power supply circuit; and a secondary side coil for converting the current flowing through the primary side coil into a voltage signal and sending the voltage signal to a current limiting circuit. In a power supply device, wherein the auxiliary coil is attached so as to surround the winding of the primary coil and is connected in parallel with the winding and is made of a substantially U-shaped conductive material. A current detection circuit characterized by being provided.