JPH05119110A - Direct current measuring device - Google Patents
Direct current measuring deviceInfo
- Publication number
- JPH05119110A JPH05119110A JP3279553A JP27955391A JPH05119110A JP H05119110 A JPH05119110 A JP H05119110A JP 3279553 A JP3279553 A JP 3279553A JP 27955391 A JP27955391 A JP 27955391A JP H05119110 A JPH05119110 A JP H05119110A
- Authority
- JP
- Japan
- Prior art keywords
- voltage
- output
- main amplifier
- current
- load
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Landscapes
- Testing Of Individual Semiconductor Devices (AREA)
- Measurement Of Current Or Voltage (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明は例えばＩＣ試験装置の
直流試験に用いられ、設定した定電流又は定電圧を負荷
へ供給し、その時負荷に発生する電圧又は負荷に流れる
電流を測定するようになされ、かつその際に負荷に流れ
る電流を検出する電流検出用抵抗器をその負荷電流レン
ジに応じて切替えるようにした直流測定器に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used, for example, in a direct current test of an IC tester to supply a set constant current or constant voltage to a load and measure the voltage generated in the load at that time or the current flowing in the load. The present invention relates to a direct current measuring device which switches a current detecting resistor for detecting a current flowing through a load at that time according to the load current range.
【０００２】[0002]
【従来の技術】図３に従来の直流測定器を示す。設定用
ＤＡ変換器１１に対し印加しようとする電流又は電圧を
示すデジタル値が与えられ、そのデジタル値がアナログ
電圧に変換され、そのアナログ電圧が抵抗器１２を通じ
て主増幅器１３の反転入力端へ供給される。主増幅器１
３の非反転入力端は接地される。主増幅器１３の出力端
は電流レンジ切替えスイッチ１４1 〜１４n をそれぞれ
通じ、更に電流検出用抵抗器１５1 〜１５n を通じて出
力端子１６に接続され、出力端子１６は負荷１７を通じ
て接地される。スイッチ１４1 〜１４n はそれぞれリレ
ー１８1 〜１８n の接点であり、リレー１８1 〜１８n
はそれぞれ駆動用トランジスタ１９1 〜１９n により駆
動制御される。駆動用トランジスタ１９1 〜１９n の１
つがオンに制御され、対応するリレー１８1 〜１８n の
１つが付勢され、対応するスイッチ１４1 〜１４n の１
つがオンにされる。2. Description of the Related Art FIG. 3 shows a conventional DC measuring instrument. A digital value indicating a current or a voltage to be applied is given to the setting DA converter 11, the digital value is converted into an analog voltage, and the analog voltage is supplied to the inverting input terminal of the main amplifier 13 through the resistor 12. To be done. Main amplifier 1
The non-inverting input terminal of 3 is grounded. The output terminal of the main amplifier 13 through respective current range changeover switch 14 1 to 14 n, is connected to the output terminal 16 through further current detecting resistor 15 1 to 15 n, the output terminal 16 is grounded through the load 17. Switch 14 1 to 14 n are contacts of each relay 18 1 ~ 18 n, the relay 18 1 ~ 18 n
Are controlled by respective driving transistors 19 1 to 19 n . 1 of the driving transistors 19 1 to 19 n
One of the corresponding relays 18 1 to 18 n is activated and one of the corresponding switches 14 1 to 14 n is turned on.
One is turned on.
【０００３】主増幅器１３の出力端は差動増幅器２１の
一方の入力端に接続され、出力端子１６がバッファ回路
２２を通じて差動増幅器２１の他方の入力端に接続され
る。主増幅器１３と負荷１７との間に直列に挿入されて
いる電流検出用抵抗器１５i （ｉ＝１，２，…，ｎ）の
両端間の電圧が差動増幅器２１の出力として検出され、
この検出電圧が切替えスイッチ２３のＩＭ側を通じて主
増幅器１３の反転入力端へ負帰還される。このようにし
てＤＡ変換器１１に設定した電流が、負荷１７へ供給さ
れるように制御される。The output terminal of the main amplifier 13 is connected to one input terminal of the differential amplifier 21, and the output terminal 16 is connected to the other input terminal of the differential amplifier 21 through the buffer circuit 22. The voltage across the current detection resistor 15 i (i = 1, 2, ..., N) inserted in series between the main amplifier 13 and the load 17 is detected as the output of the differential amplifier 21,
This detected voltage is negatively fed back to the inverting input terminal of the main amplifier 13 through the IM side of the changeover switch 23. In this way, the current set in the DA converter 11 is controlled so as to be supplied to the load 17.
【０００４】出力端子１６の電圧はバッファ回路２４を
通じ、更に抵抗器２５を通じて電圧出力回路２６へ供給
され、電圧出力回路２６から出力端子１６の電圧が出力
される。つまり設定した電流を負荷１７へ供給し、その
時の負荷１７の電圧を測定する。負荷１７への供給電流
を大幅に変化する場合は、その電流レンジに応じて主増
幅器１３と負荷１７との間に挿入する電流検出用抵抗器
を１５1 〜１５n の何れかに切替える。The voltage at the output terminal 16 is supplied to the voltage output circuit 26 through the buffer circuit 24 and the resistor 25, and the voltage at the output terminal 16 is output from the voltage output circuit 26. That is, the set current is supplied to the load 17, and the voltage of the load 17 at that time is measured. Vary greatly supply current to the load 17, it switches the current detecting resistor inserted between the main amplifier 13 and the load 17 in accordance with the current range to any of the 15 1 to 15 n.
【０００５】またバッファ回路２４の出力を切替えスイ
ッチ２３のＶＭ側を通じて主増幅器１３の入力側へ負帰
還するようにすると、ＤＡ変換器１１で設定した電圧が
出力端子１６に発生し、従って設定電圧を負荷１７へ印
加し、その時の差動増幅器２１の出力により負荷１７に
流れる電流を測定することができる。この場合も負荷１
７に流れる電流の大きさに応じ、これが測定可能なよう
に電流検出用抵抗器を切替え接続する。When the output of the buffer circuit 24 is negatively fed back to the input side of the main amplifier 13 through the VM side of the changeover switch 23, the voltage set by the DA converter 11 is generated at the output terminal 16, and the set voltage is accordingly set. Is applied to the load 17, and the current flowing through the load 17 can be measured by the output of the differential amplifier 21 at that time. In this case as well, load 1
Depending on the magnitude of the current flowing through 7, the current detecting resistor is switched and connected so that it can be measured.
【０００６】[0006]
【発明が解決しようとする課題】負荷電流が比較的大き
な場合があり、また負荷電圧が比較的高い場合もある。
このため従来においては電流レンジ切替えスイッチ１４
1 〜１４n としてリレーの接点が用いられていた。しか
しリレーは動作速度が遅く、電流レンジの切替えに例え
ば０．２〜３ｍＳもかかった。またリレーは小形化が困
難であり、全体として大形になるという問題もあった。The load current may be relatively large and the load voltage may be relatively high.
Therefore, in the conventional case, the current range selector switch 14
The relay contact has been used as a 1 to 14 n. However, the operating speed of the relay was slow, and it took 0.2 to 3 mS, for example, to switch the current range. In addition, there is a problem that it is difficult to miniaturize the relay and it becomes large as a whole.
【０００７】前記電圧出力回路２６の出力の電圧測定、
差動増幅器２１の出力の電流測定は、例えばそれぞれデ
シタル値に変換して表示器に表示して行われる。Voltage measurement of the output of the voltage output circuit 26,
The current measurement of the output of the differential amplifier 21 is performed, for example, by converting it into a digital value and displaying it on a display.
【０００８】[0008]
【課題を解決するための手段】この発明によれば主増幅
器の出力側にフローティング電源が接続され、そのフロ
ーティング電源により、主増幅器の出力電位に対し一定
電圧高い電位と一定電圧低い電位とが出力され、電流レ
ンジ切替えスイッチはこのフローティング電源の出力が
動作電源電圧として供給されるアナログスイッチで構成
される。According to the present invention, a floating power supply is connected to the output side of the main amplifier, and the floating power supply outputs a constant high voltage and a constant low voltage with respect to the output potential of the main amplifier. The current range changeover switch is composed of an analog switch to which the output of the floating power supply is supplied as the operating power supply voltage.
【０００９】[0009]
【実施例】図１にこの発明の実施例を示し、図３と対応
する部分に同一符号を付けてある。この発明では主増幅
器１３の出力端にフローティング電源３１が接続され、
フローティング電源３１は主増幅器１３の出力電位より
も一定電圧高い電位＋Ｆｖと一定電圧低い電位−Ｆｖと
を出力する。電源レンジ切替えスイッチとしてアナログ
スイッチ３２1 〜３２n が用いられ、アナログスイッチ
３２1 〜３２n の各一端は主増幅器１３の出力端に接続
され、各他端はそれぞれ電流検出用抵抗器１５1 〜１５
n を通じて出力端子１６に接続される。FIG. 1 shows an embodiment of the present invention, in which parts corresponding to those in FIG. 3 are designated by the same reference numerals. In the present invention, the floating power supply 31 is connected to the output terminal of the main amplifier 13,
The floating power supply 31 outputs a potential + Fv higher than the output potential of the main amplifier 13 by a constant voltage and a potential −Fv lower by a constant voltage. Analog switches 32 1 to 32 n are used as power supply range changeover switches, one end of each of the analog switches 32 1 to 32 n is connected to an output end of the main amplifier 13, and each other end thereof is a current detection resistor 15 1 to. 15
It is connected to the output terminal 16 through n .
【００１０】アナログスイッチ３２1 〜３２n はそれぞ
れ駆動回路３３1 〜３３n の出力によりオン・オフ制御
される。アナログスイッチ３２1 〜３２n 及びその駆動
回路３３1 〜３３n はフローティング電源３１の出力電
位＋Ｆｖ、−Ｆｖが電源電圧として印加されて動作す
る。駆動用トランジスタ１９1〜１９n の各出力はそれ
ぞれレベルシフト回路３４でフローティング電源３１の
出力のレベルはシフトされて駆動回路３３1 〜３３n に
それぞれ供給される。The analog switches 32 1 to 32 n are on / off controlled by the outputs of the drive circuits 33 1 to 33 n , respectively. The analog switches 32 1 to 32 n and their drive circuits 33 1 to 33 n operate by applying the output potentials + Fv and −Fv of the floating power supply 31 as power supply voltages. The output of each of the driving transistors 19 1 to 19 n is level-shifted by the level shift circuit 34 and supplied to the drive circuits 33 1 to 33 n .
【００１１】この例ではアナログスイッチ３２1 〜３２
n における降下電圧の影響を小さくするために、電流検
出用抵抗器１５1 〜１５n の各一端がバッファ回路２２
に接続されると共に、各他端はアナログスイッチ３５1
〜３５n をそれぞれ通じてバッファ回路３６に接続さ
れ、バッファ回路３６の出力とバッファ回路２２の出力
との差が差動増幅器２１で取出される。アナログスイッ
チ３５1 〜３５n はそれぞれ駆動回路３７1 〜３７n の
出力でオン・オフ制御される。アナログスイッチ３５1
〜３５n 及び駆動回路３７1 〜３７n も電位＋Ｆｖ、−
Ｆｖで動作される。また駆動回路３７1 〜３７n の各入
力側はそれぞれ駆動回路３３1 〜３３n の各入力側と接
続され、対応するものが同時にオン・オフ制御される。In this example, analog switches 32 1 to 32
In order to reduce the influence of the voltage drop in n , one end of each of the current detection resistors 15 1 to 15 n has a buffer circuit 22.
Is connected to the analog switch 35 1 at the other end.
.About.35 n are connected to the buffer circuit 36, and the difference between the output of the buffer circuit 36 and the output of the buffer circuit 22 is taken out by the differential amplifier 21. The analog switches 35 1 to 35 n are on / off controlled by the outputs of the drive circuits 37 1 to 37 n , respectively. Analog switch 35 1
To 35 n and the drive circuit 37 1 to 37 n is also the potential + Fv, -
It is operated in Fv. The respective input side of the drive circuit 37 1 to 37 n is connected to the input side of the drive circuit 33 1 ~ 33 n respectively, a corresponding is on-off controlled at the same time.
【００１２】フローティング電源３１は例えば図２Ａに
示すように主増幅器１３の出力端にツェナーダイオード
３８のアノードとツェナーダイオード３９のカソードと
が接続され、ツェナーダイオードのカソードはｎｐｎト
ランジスタ４１のベースに接続されると共に定電流源４
２を通じて電源端子４３に接続され、トランジスタ４１
のコレクタが電源端子４３に接続され、トランジスタ４
１のエミッタから主増幅器１３の出力電位に対し、ほぼ
ツェナー電圧だけ高い電圧＋Ｆｖが得られる。同様にツ
ェナーダイオード３９のアノードはｐｎｐトランジスタ
４４のベースに接続されると共に定電流源４５を通じて
電源端子４６に接続され、トランジスタ４４のコレクタ
は電源端子４６に接続され、エミッタから主増幅器１３
の出力電位よりもほぼツェナー電圧だけ低い電圧−Ｆｖ
が得られる。2A, the anode of the Zener diode 38 and the cathode of the Zener diode 39 are connected to the output terminal of the main amplifier 13, and the cathode of the Zener diode is connected to the base of the npn transistor 41, as shown in FIG. 2A. And constant current source 4
2 is connected to the power supply terminal 43 through the transistor 41
The collector of is connected to the power supply terminal 43, and the transistor 4
A voltage + Fv higher than the output potential of the main amplifier 13 from the emitter of 1 by a Zener voltage is obtained. Similarly, the anode of the Zener diode 39 is connected to the base of the pnp transistor 44 and also connected to the power supply terminal 46 through the constant current source 45, the collector of the transistor 44 is connected to the power supply terminal 46, and the emitter to the main amplifier 13 is connected.
-Fv, which is lower than the output potential of
Is obtained.
【００１３】アナログスイッチ３２1 に対する駆動系の
例を図２Ｂに示す。駆動トランジスタ１９1 のコレクタ
に発光ダイオード４７が挿入され、発光ダイオード４７
の光を受光するフォトトランジスタ４８のコレクタは抵
抗器を通じて＋Ｆｖの電源端子に接続され、エミッタは
抵抗器を通じて−Ｆｖの電源端子に接続される。発光ダ
イオード４７とフォトトランジスタ４８とはフォトカプ
ラを構成しており、図１中のレベルシフト回路３４内の
アナログスイッチ３２1 に対する駆動系である。フォト
トランジスタ４８のコレクタは駆動回路３３1 の入力側
に接続される。駆動回路３３1 の出力側はアナログスイ
ッチ３２1 としてのＣＭＯＳを構成する一対のＦＥＴ４
９、５１のゲートに接続される。その他のアナログスイ
ッチ及びそれに対する駆動系も同様に構成される。An example of a drive system for the analog switch 32 1 is shown in FIG. 2B. The light emitting diode 47 is inserted in the collector of the driving transistor 19 1 ,
The collector of the phototransistor 48 for receiving the light is connected to the + Fv power supply terminal through the resistor, and the emitter is connected to the -Fv power supply terminal through the resistor. The light emitting diode 47 and the phototransistor 48 form a photocoupler, which is a drive system for the analog switch 32 1 in the level shift circuit 34 in FIG. The collector of the phototransistor 48 is connected to the input side of the drive circuit 33 1 . The output side of the drive circuit 33 1 is a pair of FETs 4 forming a CMOS as an analog switch 32 1.
It is connected to the gates of 9, 51. The other analog switches and the drive system for them are similarly constructed.
【００１４】なお差動増幅器２１及び電圧出力回路２６
には通常の電源電圧＋Ｖ１、−Ｖ１が動作電源電圧とし
て与えられ、主増幅器１３にはＶ１より高い電圧＋Ｖ
２、−Ｖ２が動作電源電圧として与えられる。図１の実
施例ではバッファ回路２２、２４、３６の各動作電源電
圧として＋Ｆｖ、−Ｆｖを与え、バッファ回路２２、２
４、３６を各構成素子として比較的耐圧の低いもので構
成できるようにした場合である。The differential amplifier 21 and the voltage output circuit 26
Are supplied with normal power supply voltages + V1 and -V1 as operating power supply voltages, and the main amplifier 13 has a voltage + V higher than V1.
2, -V2 is applied as the operating power supply voltage. In the embodiment of FIG. 1, + Fv and −Fv are given as the operating power supply voltages of the buffer circuits 22, 24 and 36, respectively.
This is a case where each of the constituent elements 4 and 36 can be configured with a relatively low breakdown voltage.
【００１５】以上の構成において、負荷電源の検出を、
その電源レンジに応じてアナログスイッチ３２1 〜３２
n の何れかをオンにすると、アナログスイッチ３７1 〜
３７ n の対応するものもオンになり、主増幅器１３及び
負荷１７間に接続された電流検出用抵抗器の両端間電圧
が差動増幅器２１で検出され、正しい測定を行うことが
できる。アナログスイッチ３２1 〜３２n 、３５1 〜３
５n としてはＣＭＯＳに限らず、ＮＭＯＳ、バイポーラ
トランジスタなどを用いてもよい。In the above configuration, the load power source is detected by
Analog switch 32 according to the power range1~ 32
nWhen any one of them is turned on, the analog switch 371~
37 nThe corresponding one of is also turned on and the main amplifier 13 and
Voltage across the resistor for current detection connected between load 17
Is detected by the differential amplifier 21 and correct measurement can be performed.
it can. Analog switch 321~ 32n, 351~ 3
5nIs not limited to CMOS, NMOS, bipolar
A transistor or the like may be used.
【００１６】[0016]
【発明の効果】以上述べたようにこの発明によれば電流
レンジ切替えスイッチとしてアナログスイッチを用いて
おり、アナログスイッチは例えば１μＳ以下で動作する
ことができ、電流レンジの切替えを高速に行うことがで
きる。またアナログスイッチは半導体スイッチにより小
形に構成でき、特に複数のアナログスイッチを１つのＩ
Ｃとすることにより、非常に小形化することができ、し
かもそのようにＩＣ化したアナログスイッチが市販され
ているため安価に構成できる。As described above, according to the present invention, the analog switch is used as the current range changeover switch, and the analog switch can operate at 1 μS or less, for example, and the current range changeover can be performed at high speed. it can. Also, the analog switch can be made small by a semiconductor switch, and in particular, a plurality of analog switches can be combined into one I switch.
By adopting C, it is possible to make the size very small, and further, since an analog switch made into such an IC is commercially available, it can be constructed at low cost.
【００１７】更にアナログスイッチ、及びその駆動回路
の動作電源電圧としてフローティング電源の出力電圧を
用いているため、主増幅器１３の出力電圧に拘わらず、
一定の低い動作電圧で済み、耐圧の低い素子で構成する
ことができ、この点でも安価に構成できる。つまり通常
のＩＣ化された演算増幅器の動作電圧±Ｖ１（約±１０
Ｖ）よりも高い電圧を負荷１７に印加することがある場
合に、主増幅器１３から高い電圧が出力されてもアナロ
グスイッチ３２1 〜３２n が破壊されるおそれはない。Furthermore, since the output voltage of the floating power supply is used as the operating power supply voltage of the analog switch and its drive circuit, regardless of the output voltage of the main amplifier 13,
It is possible to form an element having a low withstand voltage and a low breakdown voltage, and in this respect as well, it is possible to form at a low cost. That is, the operating voltage of a normal IC operational amplifier ± V1 (about ± 10
When a voltage higher than V) may be applied to the load 17, the analog switches 32 1 to 32 n are not damaged even if a high voltage is output from the main amplifier 13.
【００１８】アナログスイッチはオン抵抗が比較的大き
い場合があるが、前述したようにアナログスイッチ３５
1 〜３５n を用いれば、アナログスイッチ３２1 〜３２
n に影響されることなく電流検出用抵抗器の降下電圧を
正しく検出することができる。The on resistance of the analog switch may be relatively large, but as described above, the analog switch 35 is used.
If 1 to 35 n are used, analog switches 32 1 to 32
It is possible to correctly detect the voltage drop of the current detection resistor without being affected by n .
【図１】この発明の実施例を示すブロック図。FIG. 1 is a block diagram showing an embodiment of the present invention.
【図２】Ａはフローティング電源３１の具体例を示す接
続図、Ｂはアナログスイッチ３２1 、その駆動系の具体
例を示す接続図である。FIG. 2A is a connection diagram showing a specific example of a floating power supply 31, and B is a connection diagram showing a specific example of an analog switch 32 1 and its drive system.
【図３】従来の直流測定器を示すブロック図。FIG. 3 is a block diagram showing a conventional DC measuring device.
Claims (1)
給され、 電流レンジ切替えスイッチにより、複数の電流検出用抵
抗器が切替えられて上記主増幅器と負荷との間に直列に
挿入接続され、 その挿入接続された電流検出用抵抗器の両端間電圧が差
動増幅器で検出される直流測定器において、 上記主増幅器の出力が供給され、その出力電位より一定
電圧高い電位及び一定電圧低い電位を出力するフローテ
ィング電源が設けられ、 上記電流レンジ切替えスイッチは、上記フローティング
電源の出力が動作電源電圧として供給されるアナログス
イッチで構成されていることを特徴とする直流測定器。1. An output of a setting DA converter is supplied to a main amplifier, and a plurality of current detection resistors are switched by a current range changeover switch to be inserted and connected in series between the main amplifier and a load. In a DC measuring instrument in which the voltage across the inserted current detecting resistor is detected by a differential amplifier, the output of the main amplifier is supplied, and a potential higher by a constant voltage and a potential lower by a constant voltage than the output potential. The DC measuring instrument is characterized in that a floating power supply for outputting is output, and the current range changeover switch is composed of an analog switch to which the output of the floating power supply is supplied as an operating power supply voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3279553A JPH05119110A (en) | 1991-10-25 | 1991-10-25 | Direct current measuring device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3279553A JPH05119110A (en) | 1991-10-25 | 1991-10-25 | Direct current measuring device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH05119110A true JPH05119110A (en) | 1993-05-18 |
Family
ID=17612572
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3279553A Withdrawn JPH05119110A (en) | 1991-10-25 | 1991-10-25 | Direct current measuring device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH05119110A (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003057270A (en) * | 2001-08-10 | 2003-02-26 | Advantest Corp | Voltage-applied current measuring apparatus and semiconductor tester |
| US7141984B2 (en) | 2004-06-25 | 2006-11-28 | Agilent Technologies, Inc. | Switching circuit for current measurement range resistor and current measurement apparatus including switching circuit |
| US7352193B2 (en) | 2002-12-11 | 2008-04-01 | Advantest Corporation | Voltage-impressed current measuring apparatus and current buffers with switches used therefor |
| JP2008190973A (en) * | 2007-02-05 | 2008-08-21 | Yokogawa Electric Corp | Dc module apparatus |
| JP2008298467A (en) * | 2007-05-29 | 2008-12-11 | Imv Corp | Board inspecting device |
| US7482829B2 (en) | 2006-04-28 | 2009-01-27 | Advantest Corporation | Electric power applying circuit and test apparatus |
| US7576345B2 (en) | 2007-03-28 | 2009-08-18 | Advantest Corp. | Semiconductor relay |
| CN105259403A (en) * | 2015-11-06 | 2016-01-20 | 上海大众汽车有限公司 | Special current test system and current switching method for vehicle information system test bench |
-
1991
- 1991-10-25 JP JP3279553A patent/JPH05119110A/en not_active Withdrawn
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003057270A (en) * | 2001-08-10 | 2003-02-26 | Advantest Corp | Voltage-applied current measuring apparatus and semiconductor tester |
| JP4511771B2 (en) * | 2001-08-10 | 2010-07-28 | 株式会社アドバンテスト | Voltage applied current measuring device and semiconductor test device |
| US7352193B2 (en) | 2002-12-11 | 2008-04-01 | Advantest Corporation | Voltage-impressed current measuring apparatus and current buffers with switches used therefor |
| US7141984B2 (en) | 2004-06-25 | 2006-11-28 | Agilent Technologies, Inc. | Switching circuit for current measurement range resistor and current measurement apparatus including switching circuit |
| US7482829B2 (en) | 2006-04-28 | 2009-01-27 | Advantest Corporation | Electric power applying circuit and test apparatus |
| JP2008190973A (en) * | 2007-02-05 | 2008-08-21 | Yokogawa Electric Corp | Dc module apparatus |
| US7576345B2 (en) | 2007-03-28 | 2009-08-18 | Advantest Corp. | Semiconductor relay |
| JP2008298467A (en) * | 2007-05-29 | 2008-12-11 | Imv Corp | Board inspecting device |
| CN105259403A (en) * | 2015-11-06 | 2016-01-20 | 上海大众汽车有限公司 | Special current test system and current switching method for vehicle information system test bench |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A300 | Application deemed to be withdrawn because no request for examination was validly filed |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 19990107 |