JPS63287325A - Rush current preventing element - Google Patents

Abstract

PURPOSE:To improve response and to reduce the size by preparing a planar thermister having a through-hole then placing thermister elements having reverse polarities in the through-hole and electrically connecting in parallel to each other thereby improving thermal coupling between elements. CONSTITUTION:A positive characteristic thermister 7 is formed into ring shape having a through-hole in the center, and electrodes 7a, 7b are provided on the opposite faces. A negative characteristic thermister element 6 is formed into such shape that the element 6 can be contained in the through-hole, and electrodes 6a, 6b are provided on the opposite faces. Then the negative characteristic thermister element 6 is assembled in the through-hole of the positive characteristic thermister element 7, thereafter electrodes at the opposite faces are connected electrically in parallel to each other so as to provide a rush current preventing element. Positional relation between the negative characteristic thermister 6 and the positive characteristic thermister 7 may be reversed. Consequently, starting performance and restarting performance of power source can be improved and mounting area can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an inrush current prevention element used for controlling inrush current when a switch is turned on in various power supplies.

2. Description of the Related Art Hereinafter, a conventional inrush current prevention element will be explained with reference to the drawings.

As shown in Fig. 3, conventional inrush current prevention elements include a negative characteristic thermistor element (hereinafter referred to as an NTC thermistor element) 1 which is fired into a disc shape and has electrodes 1a and 1b formed on both sides, and a negative characteristic thermistor element (hereinafter referred to as an NTC thermistor element) 1 which is fired into a disc shape and has electrodes 1a and 1b formed on both sides. An electrode plate 3 is sandwiched in the center by a positive temperature coefficient thermistor element (hereinafter referred to as a PTC thermistor element) 2 having electrodes 2a and 2b formed thereon, and the NTC thermistor element 1 and the PTC thermistor element 2 with the electrode plate 3 sandwiched therebetween. However, in such a conventional configuration, the NTC thermistor element 1 is held between the spring electrode plates 41L and 4b, and the PTC thermistor element 1 is held in the case 6.
Since the PTC thermistor element 2 and PTC thermistor element 2 are present with the electrode plate 3 interposed, the thermal coupling between the NTC thermistor element 1 and the PTC thermistor element 2 is poor, and it takes time for the resistance value of the inrush current prevention element to change when the power is turned on. The starting characteristics of the power supply were poor. In addition, NTC thermistor element 1 and PT
In order to improve the thermal coupling of the Ci thermistor element 2, if both thermistor elements 1 and 2 are housed in the case 5, heat dissipation will be poor, the allowable current will be small, and the power supply will have to be restarted until the power supply can be restarted. It also took a long time to cool down. Furthermore, when mounted on a printed circuit board, the area occupied was large.

The present invention solves these conventional problems and aims to provide a high-performance, highly reliable inrush current prevention element.

Means for Solving the Problem In order to solve this problem, the inrush current prevention element of the present invention is an NTC thermistor element (or PTC thermistor element) which is fired into a plate shape and has electrodes formed on both sides.
A PTC thermistor element (or NTC thermistor element) is fired into a plate having a through hole in which a C thermistor element (or a P'RC thermistor element) can be accommodated, and electrodes are formed on both sides. N.T.C.
Lead wires are connected so that the thermistor element and the PTC thermistor element are connected in parallel.

Function: Since the inrush current prevention element of the present invention houses the NTC thermistor in the through hole of the PTC thermistor element, the thermal coupling between the pixel elements is improved, the resistance value changes quickly when the power is turned on, and the allowable current is large. Therefore, it is possible to provide an inrush current prevention element that has a short cooling time and also occupies a small area when mounted on a printed circuit board.

EXAMPLE Hereinafter, an inrush current prevention element according to an example of the present invention will be described with reference to the drawings.

FIG. 1 is a front view showing an embodiment of the inrush current prevention element according to the present invention, and FIG. 2 is a side view of the same.

As shown in FIGS. 1 and 2, an NTC thermistor element 6 is fired into a disk shape and has electrodes ea and 6b formed on both sides, and has a circular through hole slightly larger than the diameter of the NTC thermistor element 6. Electrode 71L fired to the same thickness
, 7b is housed in the through hole of the PTC thermistor element 7, and the lead wire 82L is housed in the through hole of the PTC thermistor element 7 in which the NTC thermistor elements and the PTC thermistor element 7 are connected in parallel.

8b are connected with solder 9 and further coated with exterior resin 1o.

Effects of the Invention The present invention configured as described above has the following effects.

(i) Since the NTC thermistor element is housed within the PTC thermistor element, the thermal coupling between the pixel elements is good, the response of the resistance value when the power is turned on is quick, and the start-up performance of the power supply is excellent.

(ii) Thermal coupling between the NTC thermistor element and the p'rc thermistor element is good, and there is no need to store it in a case.
The heat dissipation of the element is improved, the allowable current is increased, and the cooling time until the power supply can be restarted is shortened.

(iii) Since the NTC thermistor element is housed within the PTC thermistor element, the occupied area can be reduced when mounted on a printed circuit board.

In addition, in the above embodiment, the NTG thermistor element and the PTC
The present invention is still effective even if the relationship between the thermistor elements is reversed.

[Brief explanation of the drawing]

FIG. 1 is a front view of an inrush current prevention element according to an embodiment of the present invention, FIG. 2 is a side view of the same, and FIG. 3 is a side view of a conventional inrush current prevention element. 6...NTC thermistor element (negative characteristic thermistor element), 7...PTC thermistor element (positive characteristic thermistor element), 62L, 6b, 7N, 7b
--- Electrode, 82L, 8b... Publication wire, 9
... Solder, 10 ... Exterior resin.

Claims (1)

[Claims] A negative temperature thermistor element (or positive temperature thermistor element) is fired into a plate shape and has electrodes formed on both sides.The negative temperature thermistor element (or positive temperature thermistor element) is fired into a plate shape having a through hole that can accommodate the negative temperature thermistor element (or positive temperature thermistor element), and both sides are fired. A positive characteristic thermistor element (or a negative characteristic thermistor element) having an electrode formed thereon is housed in the through hole, and a lead wire is connected so that the negative characteristic thermistor element and the positive characteristic thermistor element are connected in parallel. Current prevention element.