JP2006064535A - Surge resistance measuring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surge resistance measuring apparatus suitable for continuous measurement. <P>SOLUTION: The surge resistance measuring apparatus comprises a voltage application section 1 for applying a voltage across a pair of connecting terminals 3 to which an element to be measured E is connected and a measuring section 2 for measuring a voltage value and a current value across the pair of connecting terminals 3. The voltage application section 1 comprises: a DC power source 5 of which the high-potential side is connected to one terminal 3a of the pair of connecting terminals 3 through an inductor 6 and of which the low-potential side is connected to the other terminal 3b of the pair of connecting terminals 3; a switching element 4 which has a source terminal 4b and a drain terminal 4c of which the continuity and opening are controlled by a control signal P inputted to a gate terminal 4a and of which a pair of terminals to be controlled 3 are connected to the pair of connecting terminals 3, respectively; and a control circuit 7 which inputs the control signal P, which allows a continuity between the source terminal 4b and the drain terminal 4c for a predetermined period of time, to the gate terminal 4a of the switching element 4. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a surge tolerance measuring apparatus for measuring a surge tolerance of an element.

  The characteristics of the device include a breakdown tolerance that indicates how much voltage or current can be withstood. The breakdown resistance includes electrostatic resistance against static electricity and surge resistance against surge. In recent years, it is necessary to evaluate surge resistance in high-speed switching elements such as power MOSFETs used in DC-DC converters. Has increased.

In order to measure the surge resistance, it is necessary to apply a voltage or current to the element for a short time. In Patent Document 1, in the method of measuring the surge resistance of a diode, the time for applying the surge is determined by the time until the fuse blows. The technology to be defined is disclosed.
Japanese Examined Patent Publication No. 6-14098

  According to the technique disclosed in Patent Document 1, it is useful because it can measure surge resistance with an inexpensive configuration, but it is necessary to replace with a fuse having different characteristics in order to measure under different conditions. It was not something that could be done.

  The present invention has been made in consideration of the above-described reasons, and an object of the present invention is to provide a surge tolerance measuring apparatus suitable for continuous measurement.

  In order to solve the above-described problem, the invention according to claim 1 includes a voltage application unit that applies a voltage between a pair of connection terminals to which a device under test is connected, and a voltage value and a current value between the pair of connection terminals. A voltage applying unit, the high potential side being connected to one terminal of the pair of connection terminals via an inductor, and the low potential side being the other of the pair of connection terminals. A DC power source connected to the terminal, and a pair of controlled terminals whose conduction and opening are controlled by a control signal input to the control terminal, and the pair of controlled terminals are connected to the pair of connection terminals, respectively. A switching element; and a control circuit for inputting a control signal for conducting the controlled terminal between the controlled terminals for a predetermined time to the control terminal of the switching element.

  Therefore, the control signal input to the control terminal of the switching element by the control circuit is used to change the time for conducting between the controlled terminals of the switching element, and to adjust the amount of magnetic energy accumulated in the inductor. The voltage applied to the measuring element can be changed.

  The invention according to claim 2 is the surge tolerance measuring apparatus according to claim 1, wherein the control circuit changes the predetermined time so as to monotonously increase.

  Therefore, since the control circuit monotonically increases the time during which the control signal conducts between the controlled terminals, it is possible to perform continuous measurement in which the voltage applied to the element to be measured is gradually increased.

  The invention according to claim 3 is the surge immunity measuring device according to claim 1 or 2, wherein the measuring section destroys the element under measurement based on the voltage value and the current value between the pair of connection terminals. Judging.

  Therefore, since it can be known that the element to be measured has been destroyed, it is possible to avoid applying a voltage after the element to be measured has been destroyed, for example, using this information.

  According to the present invention, it is possible to change the voltage applied to the element to be measured by changing the time for conduction between the controlled terminals of the switching element using the control signal input to the control terminal of the switching element by the control circuit. it can. Therefore, a surge tolerance measuring device suitable for continuous measurement can be provided.

  One embodiment of a surge tolerance measuring apparatus according to the present invention will be described with reference to FIGS. As shown in FIG. 1, the surge resistance measuring apparatus includes a voltage application unit 1 and a measurement unit 2. And this voltage application part 1 applies a voltage to a pair of connecting terminal 3 which connects the to-be-measured element E which should measure a surge tolerance, The switching element 4, DC power supply 5, Inductor 6, And a control circuit 7.

  The switching element 4 is, for example, a MOSFET, and includes a gate terminal 4a that is a control terminal, a drain terminal 4b that is a controlled terminal, and a source terminal 4c. The drain terminal 4 b is connected to one terminal 3 a of the connection terminal 3, and the source terminal 4 c is connected to the other terminal 3 b of the connection terminal 3. In the switching element 4, conduction and opening between the drain terminal 4 b and the source terminal 4 c are controlled by a control signal P input to the gate terminal 4 a. Here, when a positive voltage is applied to the gate terminal 4a, a current flows from the drain terminal 4b to the source terminal 4c.

  Here, the withstand voltage between the controlled terminals of the switching element 4 needs to be larger than the withstand voltage of the element E to be measured. This is because the measured element E and the controlled terminal of the switching element 4 are connected in parallel, and a voltage generated by the inductor 6 described later is applied to both, so that the resistance between the controlled terminals of the switching element 4 is temporarily assumed. This is because, if the voltage is smaller than the withstand voltage of the element E to be measured, the switching element 4 is destroyed first, and measurement cannot be performed.

  The DC power supply 5 has a high potential side connected to one terminal 3 a of the connection terminal 3 via an inductor 6 described later, and a low potential side connected to the other terminal 3 b of the connection terminal 3.

  The inductor 6 is formed by winding a conductive wire around a ferrite core as a core material, has a large inductance, and can store a large amount of magnetic energy. The inductor 6 can adjust the DC resistance, the inductance, and the time constant by changing the resistance value and the number of turns of the conducting wire and the material of the core material, and the current flowing through the inductor 6 when a DC voltage is applied to the inductor 6. The time characteristic can be changed. For example, when increasing the maximum current when a predetermined voltage is applied, decreasing the resistivity of the wire used for the conductive wire, increasing the cross-sectional area, reducing the number of turns and reducing the overall resistance of the conductive wire, etc. Can be adjusted.

  The control circuit 7 is an arbitrary waveform generator and is connected to the gate terminal 4a and the terminal 3b of the switching element 4 and inputs a rectangular and pulsed control signal P to the gate terminal 4a. When the control signal P is input to the gate terminal 4a, the switching element 4 is electrically connected between the source terminal 4b and the drain terminal 4c for a predetermined time. Here, the predetermined time is determined by the control signal P, and here is the same time as the pulse width. As shown in FIG. 4, the control signal P is continuously input as control signals P1, P2, P3, P4..., And the respective pulse widths T1, T2, T3, T4. <T4 <..., that is, the pulse width T monotonously increases (in this specification, the control signals P1, P2, P3, P4,. The pulse widths T1, T2, T3, T4... Are collectively referred to as pulse width T). The control circuit 7 starts operating when a start signal SS is input from the outside, and stops operating when a stop signal SE is input.

  The measurement unit 2 measures the voltage value between the connection terminals and the current value flowing through the connection terminal. As shown in FIG. 2, the voltage input unit 2d, the current input unit 2e, and the A / D converter 2f, a processing unit 2g, a storage unit 2h, and a display unit 2c.

  The voltage input unit 2d has a voltage input terminal 2a connected to the connection terminal 3, and inputs a voltage signal between the voltage input terminals 2a to the A / D converter 2f. On the other hand, the current input unit 2e has a current input coil 2b, and inputs a voltage signal induced in the current input coil 2b by the current flowing in the current input coil 2b to the A / D converter 2f. . The A / D converter 2f converts the input analog signal indicating the current value and voltage value into a digital signal at a constant time interval and inputs the digital signal to the processing unit 2g.

  The processing unit 2g is a central processing unit, acquires digital signals of voltage values and current values from the A / D converter 2f, stores them in the storage unit 2f, and displays a graph on the display unit 2c. Here, the memory | storage part 2f is comprised by the hard disk, memory, etc., and the display part 2c is comprised by the liquid crystal display etc., for example.

  The processing unit 2g calculates a differential value dV / dt of the voltage waveform and a differential value di / dt of the current waveform from the obtained voltage waveform and current waveform, and based on which of these becomes negative first. Then, it is determined whether or not the device E to be measured is destroyed. This is because, as shown in FIG. 6, the point at which the differential value of the voltage waveform C5 when not broken appears negative is later than the point at which the differential value of the current waveform C7 becomes negative. The point where the differential value of the waveform C6 becomes negative is based on the fact that it appears earlier than the point where the differential value of the current waveform C7 becomes negative. When the processing unit 2g determines that the element E to be measured is destroyed, the processing unit 2g inputs a stop signal SE to the control circuit 7.

  Next, the appearance of the surge resistance measuring apparatus will be described with reference to FIG. In this surge resistance measuring device, a voltage application unit 1 and a measurement unit 2 are housed in a housing C formed of a conductor, and a display unit 2c and a terminal 3a which is a connection terminal 3 are provided on one surface of the housing C. , 3b are exposed and an operation button 7a is provided on the same surface. The operation button 7a is a push button for instructing start and end of measurement. When the operation button 7a is pressed, a start signal SS is input to the control circuit 7, and when pressed again in this state, a stop signal is input.

  Attachment of the device under test E to the connection terminal 3 is performed using the attachment 8. The attachment 8 is formed by combining an element side attachment 8a and a basic attachment 8b. The element side attachment 8a is formed in the shape of a rectangular parallelepiped with resin, and a hole into which a pin arrangement specific to the element can be inserted is opened on one surface thereof. And only the hole corresponding to two pins connected to the connection terminal 3 among those holes is connected to a predetermined position on the opposite surface by the conductor. Therefore, there are two terminals at a predetermined position on the surface opposite to the surface into which the element of the element side attachment 8a is inserted.

  On the other hand, the basic attachment 8b is formed in a rectangular parallelepiped shape with a resin, and has a concave portion for fitting the element side attachment 8a in the center of one surface thereof. The two terminals are in contact with the surface of the bottom of the recess, corresponding to the positions of the two terminals existing at predetermined positions on the surface opposite to the element E to be measured of the element side attachment 8a. Is provided. The two terminals existing in the recess are connected by conductors in the basic attachment 8b, and are attached to the surface opposite to the surface where the recess exists at the same distance as the terminals 3a and 3b. 8d is provided. Therefore, a specific pin of the measured element E can be connected to the connection terminal 3 by attaching the measured element E to the attachment 8 and inserting the attachment terminals 8c and 8d into the terminals 3a and 3b. Here, by preparing the element side attachment for each type of element and each pin number to be measured, it is easy to attach the element E to be measured, so that the measurement efficiency can be increased.

  Next, the operation of the surge resistance measuring device of the present invention will be described. The element to be measured E is connected to the attachment 8, and the attachment terminals 8c and 8d of the attachment 8 are inserted into the terminals 3a and 3b. When the measurer presses the operation button 7 a, the start signal SS is input to the control circuit 7. Then, the control circuit 7 inputs the control signal P shown in FIG. 4 to the gate terminal 4 a of the switching element 4. Then, while the voltage is given by the first control signal P1, the source terminal 4b and the drain terminal 4c of the switching element 4 become conductive, and the current from the DC power source 5 is changed between the inductor 6 and the switching element. Go through 4. At this time, magnetic energy is stored in the inductor 6. Then, when the voltage between pulses is not applied, the source terminal 4b and the drain terminal 4c of the switching element 4 are opened. Then, the inductor 6 works so as to keep the current flowing through itself, and as a result, a voltage corresponding to the current flowing through the inductor 6 is generated between the terminals 3a and 3b of the connection terminal 3.

  Since the second control signal P2 has a pulse width T larger than that of the first control signal P1, the time during which the source terminal 4b and the drain terminal 4c of the switching element 4 are conducted is increased. Then, the current flowing through the inductor 6 is larger in the second control signal P2 than in the first control signal P1 within the range of the transient phenomenon. Therefore, the voltage applied between the terminals 3a and 3b of the connection terminal 3 is also larger at the second control signal P2 than at the first control signal P1. The same applies to the third and subsequent control signals P3.

  On the other hand, in each control signal P, the processing unit 2g determines the voltage waveform differential value dV / dt at each time and the current waveform differentiation from the voltage waveform and the current waveform stored in the storage unit 2h. The value di / dt is calculated, and it is determined whether the device under test E has been destroyed based on which of these values is negative first. When the processing unit 2g determines that the element E to be measured has been destroyed, it sends a stop signal SE to the control circuit 7, so that the control circuit 7 stops inputting the control signal P to the gate terminal 4a.

  The measurement result of the surge resistance obtained in this way is, for example, as shown in FIG. FIG. 5 shows the case where the device under test E is destroyed by the fourth control signal P4. From the resulting characteristics C1 to C4, it is possible to know the voltage and current at which the element E to be measured is destroyed.

  As described above, in the surge tolerance measuring apparatus according to the present invention, the source signal 4b and the drain terminal 4c of the switching element 4 using the control signal P input to the gate terminal 4a that is the control terminal of the switching element 4 by the control circuit 7. The voltage applied to the element E to be measured can be changed by changing the time for conducting the current between the two and adjusting the amount of magnetic energy accumulated in the inductor 6. In addition, since the time for conducting between the source terminal 4b and the drain terminal 4c of the switching element 4 is monotonously increased, the surge resistance measurement suitable for continuous measurement in which the voltage applied to the element E to be measured is gradually increased. An apparatus can be provided. Moreover, since it can be known that the element E to be measured has been destroyed, it is possible to avoid applying a voltage after the destruction, for example, using this information.

  In the embodiment, an example in which a MOSFET is used as the switching element 4 has been described. However, the present invention is not limited to this, and a control signal P input to a control terminal such as an FET, a transistor, or a thyristor having another configuration is used. Any device having a pair of controlled terminals whose conduction and release are controlled can be used.

  In addition, although the case where the control signal P is a rectangular pulse signal has been described, the present invention is not limited to this, and any waveform may be used as long as it allows conduction between controlled terminals for a predetermined time.

It is a circuit diagram which shows the structure of the surge tolerance measuring apparatus of this invention. It is a block diagram which shows the structure of the measurement part of the surge tolerance measuring apparatus of this invention. It is a perspective view which shows the external appearance of the surge tolerance measuring apparatus of this invention. It is a wave form diagram which shows the control signal which a control circuit outputs. It is a graph which shows the measurement result of surge tolerance. It is a graph which shows the change of the voltage value between connection terminals with respect to one control signal input, and an electric current value.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Voltage application part 2 Measuring part 3 Connection terminal 4 Switching element 4a Gate terminal (control terminal)
4b Source terminal (controlled terminal)
4c Drain terminal (controlled terminal)
5 DC power supply 6 Inductor 7 Control circuit

Claims (3)

  A voltage application unit that applies a voltage between a pair of connection terminals to which a device under test is connected; and a measurement unit that measures a voltage value and a current value between the pair of connection terminals. The high-potential side is connected to one terminal of the pair of connection terminals via an inductor, and the low-potential side is connected to the other terminal of the pair of connection terminals, and the control is input to the control terminal. A switching element having a pair of controlled terminals whose conduction and opening are controlled by a signal, and the pair of controlled terminals connected to the pair of connection terminals, respectively, and the control terminal of the switching element between the controlled terminals A surge tolerance measuring apparatus comprising: a control circuit for inputting a control signal for conducting for a predetermined time.   The surge resistance measuring apparatus according to claim 1, wherein the control circuit changes the predetermined time so as to monotonously increase.   The surge withstand measuring apparatus according to claim 1 or 2, wherein the measuring unit determines whether the element to be measured is broken based on a voltage value and a current value between the pair of connection terminals.

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