JPS609329A - Rush current preventing system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (al) Technical Field of the Invention The present invention is implemented in a printed circuit board package, and when a circuit equipped with a power supply bypass capacitor is inserted into a connector, DC power supplied from the outside causes a current to flow to the capacitor. This invention relates to an inrush current prevention method that prevents connector terminals from being destroyed by charging current.

(bl) Prior Art and Problems FIG. 1 is a diagram showing an example of a circuit to which the present invention is applied. In FIG. 1, a subscriber circuit 2 constituting an electronic exchange is mounted on a printed circuit board package 1. The printed board hanger is inserted into a connector 4 fixed to a bank panel (not shown), and is supplied with a DC voltage of, for example, -48 volts from a DC power supply 5.Inside the printed board hanger 1, there are A power supply bypass capacitor 6 is provided in parallel with the DC power supply 5. Therefore, when the printed board pancake 1 is inserted into the connector 4, a charging current flows transiently from the DC power supply 5 to the capacitor 6 (hereinafter referred to as an inrush current). If the power terminals 7 of the rear connector 3 and the connector 4 are repeatedly disconnected and disconnected, the power terminals 7 will be damaged.

Although it is known to insert a current limiting resistor in series with the capacitor 6 in order to limit such inrush current, there is a drawback that the effect of the capacitor 6 is reduced if the resistor is not inserted.

(C1 Purpose of the Invention The purpose of the present invention is to eliminate the drawbacks of the conventional inrush current prevention method as described above, and to prevent power terminals from being damaged due to inrush current flowing through the capacitor when a printed circuit board package is inserted into a connector. The goal is to realize a means to prevent this.

(dl) Structure of the Invention This object is to provide a circuit having a power supply bypass capacitor mounted in a printed board pancase and connected in parallel to a DC power supply supplied from the outside, in which the circuits other than the power supply bypass capacitor are mounted in the printed board pancase. This is achieved by mounting and connecting the power supply bypass capacitor between the terminals supplying the DC power of the connector into which the printed board pancage is inserted, and also connecting all the circuits including the power supply bypass capacitor to the printed board package. This is accomplished by installing a current limiting resistor in series with the power supply bypass capacitor, and providing means for short-circuiting the resistor by operating it from the front of the printed circuit board package.

(Q) Examples of the invention An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a diagram showing a rush current prevention method according to one embodiment of the present invention, and FIG. 3 is a diagram showing a rush current prevention method according to another embodiment of the present invention. Note that the same reference numerals refer to the same objects throughout the plan. In FIG. 2, the capacitor 6 is not mounted within the printed circuit board package 1, but is instead connected between the lead wires on the back side of the power terminal 7 of the connector 4.

As a result, the capacitor 6 is charged by the DC power supply 5 regardless of whether the printed board package 1 is attached or detached, and no rush current flows through the power supply terminal 7 of the back connector 3 and the connector 4. In addition, in FIG. 3, a current limiting resistor 8 is inserted in series with the capacitor 6.
Both ends of the resistor 8 are connected to a shorting terminal 9 provided on the front surface of the printed circuit board package 1. When the printed circuit board cage 1 is inserted into the connector 4, the DC power supply 5
The inrush current flowing from the capacitor 6 to the capacitor 6 is restricted by the resistor 8, and the power supply terminal 7 of the back connector 3 and connector 4
It will not cause any damage. After the printed circuit board package 1 is inserted into the connector 4 and the inrush current has sufficiently attenuated, the shorting plug 10 is attached to the shorting terminal 9 on the front of the printed circuit board pancage 1. From then on, the resistor 8 becomes short-circuited, and the capacitor 6 Loss of effectiveness is prevented.

Note that FIGS. 2 and 3 are only one embodiment of the present invention, and for example, the means for short-circuiting the resistor 8 is a short-circuiting plug 10.
However, in any case, the invention is not limited to this, and there are many variations such as short-circuiting using empty terminals of the front connector attached to the front of the printed board package 1. The effect remains the same. Furthermore, the circuit mounted on the printed circuit board Nomanocage 1 is not limited to the subscriber circuit 2.
There's no need to say so.

(fl　Effects of invention As described above, according to the present invention, the above circuit is provided.

When inserting the lint board package into the connector, damage to the power terminal due to rush current flowing through the capacitor is prevented.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of a circuit to which the present invention is applied, and FIG.
This figure shows a rush current prevention method according to one embodiment of the present invention, and FIG. 3 is a diagram showing a rush current prevention method according to another embodiment of the present invention. In the figure, 1 is a printed board package, 2 is a subscriber circuit, 3 is a back connector, 4 is a connector, and 5 is a DC power supply (
E), 6 is a capacitor (C), 7 is a power supply terminal, 8-
9 indicates a resistor, 9 indicates a short-circuit terminal, and 104 indicates each short thread plug.

Claims (2)

[Claims] (1) In a circuit having a power supply bypass capacitor mounted in a printed board package and connected in parallel to a DC power supply supplied from the outside, the circuit other than the power supply bypass capacitor is mounted in the printed board package,
An inrush current prevention method characterized in that the power supply bypass capacitor is connected between terminals for supplying the DC power of a connector into which the printed board package is inserted. (2) In a circuit having a power supply bypass capacitor mounted in a printed board package and connected in parallel to a DC power supply supplied from the outside, all the circuits including the power supply bypass capacitor are connected to the printed circuit board package. An inrush current prevention method, characterized in that a current limiting resistor is inserted in series with the power supply bypass capacitor, and means is provided for short-circuiting the resistor by operating it from the front of the printed board pancase.