JP3059098U - Electrostatic discharge generator - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To improve the test accuracy of an electrostatic discharge generator without the necessity of providing an element exclusively for static elimination outside or performing a sorting operation. A cock croft circuit rectifies an AC voltage and outputs a high voltage. When the relay switch S3 is operated to make contact with the contact 10b, a resistor R3 having a constant impedance is connected to the discharge chip 8a, which is the output terminal of the discharge gun unit 8, and the output voltage is set with the terminal of the discharge chip 8a as a constant impedance. Can be managed.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to an electrostatic discharge generator, and more particularly, to an electrostatic discharge generator having a configuration for discharging a charge charged in a charging element to a device under test according to a switch operation.

[0002]

[Prior art]

 Conventionally, an electrostatic discharge generator having a function of generating a high voltage of 30 kV or more, performing a contact discharge or an air discharge, and applying a high voltage pulse to the test object to test the electrostatic discharge immunity of the test object has been developed. Are known.

In the generation of the high voltage, generally, an oscillator is provided inside a main body of a high voltage power supply unit, an AC voltage is generated by the oscillator, and the AC voltage is rectified by a multi-stage cock / croft circuit to obtain 30 kV. The above high pressure has been obtained. This high voltage is applied to the device under test through a discharge gun (Electro Static Discharge Gun), and the discharge gun can turn on / off the discharge output from the charging element by operating a switch.

The above-described conventional electrostatic discharge generating device is designed with safety in mind, and is configured so that a user is not damaged by touching a high pressure. That is, the high voltage is discharged only when the user turns on the discharge start switch, and the high voltage pulse is applied to the DUT via the discharge gun. There is no direct contact with high pressure.

[0005]

[Problems to be solved by the invention]

 However, according to the above-mentioned conventional electrostatic discharge generator, the user does not inadvertently apply a high-voltage pulse or discharge a high-voltage pulse in an unexpected state, but can quickly stop the discharge output. There was a problem that there was not.

Further, the above-described apparatus has a problem that the test cannot be continued depending on the impedance characteristics and the test frequency of the device under test, and an individual switch is required to perform a safe and accurate test. There is a problem that the difference must be managed.

FIG. 2 is a circuit model diagram for explaining a further problem of an example of the conventional device. In FIG. 2, E indicates that a DC high voltage obtained by rectification is input. The charge stored in the capacitor C for energy storage through the charge resistor R1 is discharged from the discharge chip 20 as an output terminal to the device under test (not shown) through the discharge resistor R2 by closing the discharge start switch S2. Is done.

[0008] In the case where the device under test has a high insulation property, for example, a device having a housing made of a plastic cabinet, the former problem occurs. The charge stored in the capacitor C charges the floating capacitance of the DUT, but the housing has a very large insulation resistance, so the discharge time constant is large. Since it does not exist, its potential rises gradually.

Since the discharge is completely stopped when the discharge chip 20 and the DUT finally have the same potential, there is a conventional device which solves the above-mentioned problem by specially providing a relay exclusively for static elimination outside the electrostatic discharge generator.

[0010] The latter problem occurs except during use, and even when the discharge start switch S2 is open, a voltage is generated in the discharge chip 20 due to the capacitance between the contacts and the divided voltage due to the floating capacitance of the discharge chip 20. , The operator needs to be careful not to touch the discharge tip 20. Also, if the discharge chip 20 is brought close to the DUT in the voltage generation state, the discharge due to the stray capacitance occurs without operating the discharge start switch S2, and the intended test cannot be performed.

[0011] The voltage value generated at the output terminal other than during use is changed by complicated factors (atmospheric conditions, contamination of the discharge gun, storage location), and is difficult to manage. Further, even when the discharge start switch S2 is open, a leak current is generated in the switch, but it is difficult to manage the switch because the above-mentioned voltage value is different due to individual difference.

Therefore, in order to make the discharge output generated by the above-mentioned voltage value at the start of use to be the intended energy, it is necessary to limit the variation of the voltage value to a predetermined range by selecting the discharge start switch S2. Was needed.

In view of the above, the present invention has been made in view of the above points, and can solve the above-mentioned problems without providing an element dedicated to static elimination or performing a sorting operation. It is intended to provide a generator.

[0014]

[Means for Solving the Problems]

 In order to achieve the above object, an apparatus according to the present invention according to claim 1 includes a rectifier for outputting a DC high voltage based on an AC voltage, and a charging element, and the output DC high voltage is outputted. And a high-voltage discharging means for discharging the charge charged in the charging element to an external device, wherein a constant impedance element is provided inside the high-voltage discharging means. A first means for forming a discharge loop including the charging element and the external device, and discharging the charge charged in the charging element to the external device via the discharge loop; and forming the discharge loop. And a second means for connecting the constant impedance element to both ends of the external device.

According to a second aspect of the present invention, in the first aspect, a discharge resistor for discharging a charge charged in the charging element from a discharge output unit to the external device is provided in the charging element. The constant impedance element is a resistance element, and the first and second means include a first terminal connected to one end of a series circuit of the charging element and the discharge resistor, A second terminal connected to one end, a third terminal connected to one end of the discharge output unit, one end connected to the third terminal, and another end connected to one of the first terminal or the second terminal And a contact means connected to the second terminal, wherein the other end of the contact means is connected to the second terminal when the discharge loop is not formed.

According to a third aspect of the present invention, there is provided the device for generating an electrostatic discharge according to the first or second aspect, further comprising: an interrupting unit for interrupting an input voltage input to the rectifying unit. Provide equipment.

[0017]

[Embodiment of the invention]

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of an electrostatic discharge generator to which the present invention is applied.

In FIG. 1, a DC power supply unit 3 generates a DC voltage from a commercial AC voltage input from an AC plug 1 via a switch 2. The high-voltage power supply unit 4 receives the DC voltage, and outputs a predetermined level of AC voltage boosted to, for example, 5000 V or more by the step-up transformer TRF between the HV-H terminal and the HV-L terminal. Is variable. This AC voltage is input to the polarity switching unit 5 and rectified by a cock / croft circuit 6 of an odd-number doubler configuration provided inside the unit, and a high DC voltage is output.

As the polarity of the output high voltage, two different polarities can be selectively switched by a polarity reversing mechanism using the rotational driving force of the motor. In the polarity switching unit 5, reference numeral 7 denotes a feedback circuit. The panel & control unit 12 sets the output voltage level of the high-voltage power supply unit 4 and controls a motor drive circuit 13 for switching and controlling the output polarity.

The DC high voltage generated by the cock croft circuit 6 is applied from the polarity switching unit 5 to the discharge gun unit 8 and charged in the capacitor C provided in the unit via the resistor R1. The discharge gun unit 8 includes a discharge tip 8a. The discharge tip 8a is brought into contact with an external device under test (DUT) 11 or is separated by a predetermined distance to operate a discharge start switch (not shown). By operating the relay switch S3, the charged electric charge can be discharged to the device under test 11 through the resistor R2 by contact discharge or air discharge to test the electrostatic discharge immunity. R3 indicates a static elimination resistor, and the operation of the discharge start switch will be described later.

In the block configuration shown in FIG. 1, the switch 2 has a structure that can be instantly turned off by a one-touch push operation, and is provided for instantaneously stopping the discharge output in an emergency or the like. The AC input voltage to the DC power supply unit 3 can be instantaneously interrupted by pressing the switch (not shown) of the switch 2 quickly enough to touch lightly, and the DC output from the DC power supply unit 3 to the high-voltage power supply unit 4 Can be stopped instantaneously. As a result, the high voltage generation operation by the high voltage power supply unit 4 and the polarity switching unit 5 can be stopped, and the DC output voltage from the polarity switching unit 5 can be quickly reduced, so that emergency response can be promptly performed. .

The same purpose as described above can be achieved by providing a switch 2 for cutting off the input voltage at the input portion of the high-voltage power supply unit 4.

To reset (turn back on) the switch 2 from the off state after the emergency response is completed, a reset switch (not shown) provided around the pressing portion is mechanically turned clockwise. By rotating the AC power to the DC power supply unit 3 of the electrostatic discharge tester again or by inputting the DC voltage again to the high voltage power supply unit 4, a normal operation state is obtained. Can be restored. As described above, the reset switch is configured to perform a reset operation by performing the rotation operation by the operator after confirming that the cause of the emergency stop has been eliminated.

Next, details of the discharge gun unit 8 will be described.

The discharge gun unit 8 includes a resistor R1 to which one end receives the high DC voltage from the polarity switching unit 5, a capacitor C having both ends connected to the other end of the resistor R1 and the ground end, and a resistor R1. A resistor R2 having one end connected to a common connection point of the capacitor C and the capacitor C, and a resistor R3 having one end connected to the ground end. The resistor R2 is a discharge resistor, and the resistor R3 having a constant impedance characteristic is a high withstand voltage static elimination resistor. Further, the discharge gun unit 8 includes a relay switch S3. The relay switch S3 opens and closes by operating the discharge start switch provided in the discharge gun unit 8.

The relay switch S3 has contacts 9, 10a and 10b, and the contact 10a is connected to one end of a series circuit of a capacitor C and a resistor R2. The contact 10a is a contact that normally contacts when open, and the contact 10b is a contact that normally contacts when closed. The contact 10b is connected to the upper end of the resistor R3 in the drawing. The common contact 9 is connected to one end of the discharge chip 8a.

In the above configuration, by connecting the common contact 9 to the output end side, the normally open contact 10a is connected to one end of a series circuit of the resistor R2 and the capacitor C, and the other end (ground level) of the series circuit is connected. ) Is connected to the ground end of the DUT 11 to form a loop. Therefore, when the discharge start switch is operated, a discharge output is given to the DUT 11 through the discharge loop.

Since the resistor R3, which is a constant impedance element, is connected to the normally closed contact 10b, when the operator does not operate the discharge start switch (does not discharge), the discharge loop is not formed, and the DUT is not tested. Both ends of the resistor 11 and the resistor R3 are connected to each other. At this time, the apparent insulation resistance of the discharge chip 8a can be controlled to a constant value determined by the resistance R3. As a result, the test can be performed continuously regardless of the impedance characteristics and test frequency of the DUT.Furthermore, even if there are individual differences in the discharge start switch, the voltage generated at the output terminal is managed to ensure safe and accurate A good test can be performed.

That is, even when the device under test 11 has a high insulation property such as a device having a cabinet as a housing during execution of the test, the discharge chip 8 a contacts the device under test 11 when not discharging. By doing so, a constant impedance is connected to the DUT 11 in parallel. This allows the charged stray capacitance of the DUT 11 to be quickly discharged, so that the above-described contact operation of the discharge gun unit 8 is performed every time discharge is performed to some extent, thereby preventing a voltage increase at the output terminal. It is not necessary to provide a special relay for static elimination outside the electrostatic discharge generator.

Further, even when the discharge gun unit 8 is left unattended without performing the test, the output terminal is not affected by the capacitance between the contacts of the relay switch S3, the leak current, the floating capacitance of the discharge chip 8a, and the like. The impedance can be controlled to a constant value according to the value of the resistor R3. Therefore, by selecting an appropriate value and using it, even if the selection range of the relay switch S3 is widened, it is easy to control the output voltage to a desired value. The test can be performed reliably, and an accurate test can be performed.

[0032]

[Effect of the invention]

 As described above, according to the present invention, the charging device is charged with the DC high voltage obtained based on the AC voltage, and the high voltage discharging means for discharging the charge charged in the charging device to the external device is provided. First means for forming a constant impedance element, a discharge loop including a charging element and an external device inside, and discharging the electric charge charged in the charging element to the external device via the discharge loop, and forming a discharge loop The second means for connecting a constant impedance element to both ends of the external device when not in use is provided, so that the external device can have a constant impedance when a discharge test is not performed via a discharge loop. It is easy to control the value of the test piece, and the output end is brought into contact with the test piece to obtain a constant impedance, regardless of the impedance characteristics and test frequency of the test piece. Test the effect can be performed.

Further, according to the device of the present invention provided with the input cutoff means, there is an effect that by interrupting the input voltage to the rectification means, the discharge output can be instantaneously stopped to perform an emergency response.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of an electrostatic discharge generator according to the present invention.

FIG. 2 is a circuit model diagram for explaining a problem of an example of a conventional device.

[Explanation of symbols]

 2, S2, S3 switch 5 Polarity switching unit 6 Cock / croft circuit 8 Discharge gun unit 12 Panel & control unit 13 Motor drive circuit

Claims (3)

[Utility model registration claims] A rectifier for outputting a DC high voltage based on an AC voltage; and a charging element, charging the charging element with the output DC high voltage, and charging the charging element. An electrostatic discharge generating device comprising: a high-voltage discharging unit that discharges to an external device, wherein a constant impedance element, a discharge loop including the charging element and the external device are formed inside the high-voltage discharging unit, First means for discharging the charge charged in the charging element to the external device via the discharge loop; and second means for connecting the constant impedance element to both ends of the external device when the discharge loop is not formed. An electrostatic discharge generator, further comprising: 2. The electrostatic discharge generating device according to claim 1, further comprising: a discharge resistor for discharging a charge charged in the charging element from a discharge output unit to the external device in series with the charging element; The constant impedance element is a resistance element, and the first and second means are connected to a first terminal connected to one end of a series circuit of the charging element and the discharge resistor, and to one end of the constant impedance element. A second terminal, a third terminal connected to one end of the discharge output section, and contact means having one end connected to the third terminal and the other end connected to one of the first terminal or the second terminal. And wherein the other end of the contact means is connected to the second terminal when the discharge loop is not formed. 3. The electrostatic discharge generating device according to claim 1, further comprising: a cutoff unit that cuts off an input voltage input to the rectifying unit.