JPH0343680Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[Industrial Application Field] The present invention relates to an electrostatic discharge device that removes harmful static electricity from the human body or objects by discharging it, and is particularly useful in industries that handle MOS type semiconductors that are susceptible to high-voltage static electricity. It is related to a device. [Prior Art] Conventionally, in order to remove harmful static electricity induced in a human body or an object, the human body or object was electrically connected to a dedicated grounding terminal of an outlet, or connected to a grounding rod installed underground. It was necessary to electrically connect the body or article to an electrically connected ground wire. In addition, when using an outlet that does not have a dedicated grounding terminal, it is necessary to use a circuit meter etc. to detect the terminal on the grounding wire side of the outlet and electrically connect it to that terminal, and remove static electricity. The disadvantage is that it is complicated. [Problems to be solved by the invention] The invention is an electrostatic discharge device that can easily remove static electricity from the human body or objects without requiring grounding wire work or equipment such as an outlet with a special dedicated grounding terminal. The purpose is to provide [Means for solving the problem] The electrostatic discharge device according to the present invention includes a bridge type rectifier having a pair of power terminals and a pair of output terminals connected to a single-phase power line outlet, and a pair of the bridge type rectifiers. connected between the output terminals of the 2
It has a parallel circuit of two diode circuits connected in series in the same direction and a resistor, and these two diodes are connected in opposite polarity to the rectified voltage appearing on the resistor, and the interconnection point of the two diodes is The discharge terminal is connected to. [Operation] When a pair of power terminals of a bridge type rectifier are connected to a single-phase power line outlet, the direction of current flowing into and out of the pair of power terminals is determined according to the polarity of each single-phase AC half-wave applied to it. Although the current path in the bridge rectifier changes alternately, current always flows in a fixed direction through the resistor connected between the pair of output terminals of the bridge rectifier, and as a result, current flows from the pair of power supply terminals through the resistor. A current path is formed. A rectified voltage in a certain direction is generated in a resistor due to the current flowing in a certain direction through it, but the two series-connected diodes connected in parallel to the resistor are connected in the opposite polarity to the rectified voltage. Therefore, no current flows. If the discharge terminal connected to the interconnection point between the two diodes is electrically connected to an article that has accumulated a static charge, then if the article has a positive charge accumulated, the discharge terminal of the pair of power supply terminals will No matter which one is on the ground side, when the single-phase alternating current applied between these power supply terminals is a negative half-wave, the end of the resistor with the higher voltage where the rectified voltage is generated will be connected to the ground side power supply terminal. The formed current path connects them to the ground potential, which causes the current due to the positive charge on the article to flow from the discharge terminal through one of the two series diodes and the resistor to the non-grounded power supply terminal. Positive charges are discharged, and if negative charges are accumulated in the item, the single-phase alternating current applied between the pair of power terminals is a positive half-wave, regardless of which of the pair of power terminals is grounded. When , the lower voltage end of the resistor where the rectified voltage is generated is connected to the ground side power supply terminal by a current path and becomes close to the ground potential, and the potential of the other end of the resistor is lowered with respect to the ground potential. This causes the current due to the negative charge on the object to flow from the non-grounded power supply terminal through the current path formed, the resistor, and one of the two series diodes, and from the discharge terminal to the object. The negative charges are discharged. [Example] Fig. 1 is an electric circuit diagram of an electrostatic discharge device of the present invention, and a bridge type rectifier 1 is a bridge-connected rectifier of four silicon diodes D1 to D4.
The pair of power supply terminals A and B are connected to a single-phase 100V power line outlet (not shown), and the pair of output terminals 2 and 3 are connected to a series circuit of resistor R and two silicon diodes D5 and D6. connected to a parallel circuit consisting of Diodes D5 and D6
are connected in series in the same direction and in the opposite direction to the polarity of the rectified voltage appearing on the resistor R, so no current flows from the rectifier 1. The interconnection point 4 of these diodes D5, D6 is connected to a discharge terminal S, and the discharge terminal S is electrically connected (contacted) with a human body or an article (not shown) in order to discharge the static charge accumulated in the human body or article (not shown). be done. The operation will be explained with reference to the operation explanatory diagrams of FIGS. 2 and 3. In Figure 2, both a and b are power supply terminal A.
This is the case when is connected to the ground side terminal. Figure 2a
, a negative half-wave of single-phase AC is applied between power terminals A and B, and a positive charge (ground capacitance C) is applied to the article.
is accumulated, the negative half-wave v between the power supply terminals A and B causes the diode D of the rectifier 1 to
1, D3 (only related diodes are shown) causes a current io to flow through the resistor R in the direction shown, and the power supply terminal A
From diode D1, resistor R, diode D3
A current path from the terminal B to the power supply terminal B is formed. The direction of the current flowing through the resistor R is the same in the case of a positive half-wave, and a rectified voltage in a constant direction is generated.When the discharge terminal S is electrically connected to an article in which positive charges are accumulated, the positive charges C are From discharge terminal S to diode D
5, and is further discharged from the power supply terminal B through the resistor R and the diode D3. In this case, due to the negative half wave applied between power supply terminals A and B,
The end 5 of the higher rectified voltage generated in the resistor R is connected to the ground side power supply terminal A and the current path (diode D
1) to bring its potential close to ground potential, making it easier for positive charge from the article to flow through diode D5 to resistor R. Figure 2b shows a case where negative charges are accumulated in the article, and when a positive half-wave V is applied between a pair of power supply terminals A and B, a diode D is connected from power supply terminal B.
2. Current io flows to power supply terminal A through resistor R and diode D4. The lower end 6 of the rectified voltage in the resistor R is directly connected to the ground side power supply terminal A through a current path (diode D4), bringing the potential of the end 6 close to the ground potential, and the potential of the other end 5 to the ground potential. On the other hand, only the rectified voltage increases, and as a result, the diode D is connected from the power supply terminal B to the article in which negative charges are accumulated.
2. A current i flows from the discharge terminal S through the resistor R and the diode D6, and the negative charge is discharged. FIG. 3 shows the case where the power supply terminal B in both a and b is the ground terminal. In Figure 3a, when a positive charge is accumulated in the article, when a negative half-wave is applied between power supply terminals A and B, current io flows from power supply terminal B to diode D2, resistor R, and diode D4. through to power supply terminal A, and end 5 of resistor R communicates with ground side power supply terminal B. As a result, a current i flows from the article in which positive charges are accumulated to the power supply terminal A through the discharge terminal S, the diode D4, the resistor R, and the diode D4, and the positive charges are discharged. Figure 3b shows that a load charge is accumulated in the article, and when a positive half-wave is applied between the power supply terminals A and B, the current io flows from the power supply terminal A to the diode D1, the resistor R, Flows from diode D3 to power supply terminal B,
Further, a current i for discharging negative charges from the article flows from the power supply terminal A through the diode D1, the resistor R, and the diode D6, and from the discharge terminal S to the article. Figure 4 is an electrical circuit diagram of a test device for testing the discharge effect of the electrostatic discharge device of the present invention.
Using the input impedance switch 10 and making the DC power supply 20 variable, the DC voltage (charging voltage)
The discharge time to potential 0 was measured for 100V, 200V, 300V and 400V, and the following results were obtained.

〔Effect of the invention〕

The electrostatic discharge device of the present invention can be manufactured with a simple circuit configuration using a low-cost bridge rectifier, resistor, and silicon diode, and can be manufactured even in locations where no grounding wire work is being performed, or with dedicated grounding terminal equipment. Even if you do not have one, you can easily use it by simply connecting it to a two-outlet outlet for single-phase power lines, and it can reliably remove harmful static electricity from the human body or objects. Furthermore, when a circuit meter or the like is used to detect a grounding wire from an outlet that does not have a dedicated grounding terminal and the grounding wire is used for electrostatic discharge, it is possible to prevent the danger of erroneous connection between a grounding wire and a live wire.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of the electrostatic discharge device of the present invention,
2 and 3 are explanatory diagrams of the operation of the device in FIG. 1, FIG. 4 is a connection diagram for testing the device of the present invention, and FIG. 5 is an external perspective view of the device of the present invention. be. 1... Bridge type rectifier, A, B... Power supply terminal, R... Resistor, S... Discharge terminal.

Claims (1)

[Claims for Utility Model Registration] A bridge-type rectifier having a pair of power terminals and a pair of output terminals connected to a single-phase power line outlet; and a bridge-type rectifier connected between the pair of output terminals of the bridge-type rectifier. a parallel circuit of a resistor and two diodes connected in series in the same direction with opposite polarity to the rectified voltage appearing across the resistor; and a discharge terminal connected to the interconnection point of the two diodes. Electrostatic discharge device consisting of.