JPH01162160A - Current measuring circuit - Google Patents
Current measuring circuitInfo
- Publication number
- JPH01162160A JPH01162160A JP32057287A JP32057287A JPH01162160A JP H01162160 A JPH01162160 A JP H01162160A JP 32057287 A JP32057287 A JP 32057287A JP 32057287 A JP32057287 A JP 32057287A JP H01162160 A JPH01162160 A JP H01162160A
- Authority
- JP
- Japan
- Prior art keywords
- load
- current
- amplifier
- switch
- voltage
- 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.)
- Pending
Links
- 239000003990 capacitor Substances 0.000 claims abstract description 17
- 238000005259 measurement Methods 0.000 claims abstract description 7
- 238000010586 diagram Methods 0.000 description 8
- 238000005516 engineering process Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
Landscapes
- Testing Electric Properties And Detecting Electric Faults (AREA)
- Measurement Of Current Or Voltage (AREA)
Abstract
Description
【発明の詳細な説明】
（ａ）発明の技術分野
この発明は、ＩＣなどの負荷に電流を流して、負荷の電
気特性を試験する場合などに使用する電流測定回路につ
いてのものである。DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a current measuring circuit used when testing the electrical characteristics of a load by passing a current through a load such as an IC.
（ｂ）従来技術と問題点 最初に、従来の電流測定回路図を第２図に示す。(b) Conventional technology and problems First, a conventional current measurement circuit diagram is shown in FIG.
第２図の５は入力電圧、６は負荷、７は抵抗、８１〜８
４は増幅器である。In Figure 2, 5 is the input voltage, 6 is the load, 7 is the resistance, 81 to 8
4 is an amplifier.
増幅器８１・８２は帰還増幅回路を構成し、入力電圧５
の電圧が負荷６にそのまま加えられる。Amplifiers 81 and 82 constitute a feedback amplifier circuit, and input voltage 5
voltage is applied to the load 6 as is.
例えば、入力端子５＝ＩＯＶ１抵抗７ ＝ １００００
ＭΩとすると、負荷６ ｉ： ハＩＯＶ ／ １１００
ＯＯＯ＝１ｎＡの電流が流れる。For example, input terminal 5 = IOV1 resistance 7 = 10000
Assuming MΩ, load 6 i: High IOV / 1100
A current of OOO=1 nA flows.
増幅器８３・８４は抵抗７の両端の電圧を取り出すため
の回路であり、端子９には抵抗７の両端の電圧が出てく
る。The amplifiers 83 and 84 are circuits for taking out the voltage across the resistor 7, and the voltage across the resistor 7 is output to the terminal 9.
したがって、端子９の電圧を測定すれば、負荷６に流れ
る電流Ｉを次式により算出することができる。Therefore, by measuring the voltage at the terminal 9, the current I flowing through the load 6 can be calculated using the following equation.
■＝抵抗７の両端の電圧／抵抗７の抵抗値しかし、負荷
６には浮遊容量などがあり、負荷６に入力電圧５が完全
に加わるまでには時間がかかるという問題がある。(2)=Voltage across the resistor 7/Resistance value of the resistor 7 However, there is a problem in that the load 6 has stray capacitance and the like, and it takes time for the input voltage 5 to be completely applied to the load 6.
負荷６がＩＣなどの場合は、電流測定のほか、他の性能
を調べるため、高速測定が要望されるが、第２図のよう
な従来回路では電流が定常状態になるまでに時間がかか
るという問題がある。If the load 6 is an IC or the like, high-speed measurement is required to check other performance in addition to current measurement, but with conventional circuits like the one shown in Figure 2, it takes time for the current to reach a steady state. There's a problem.
（ｃ）発明の目的
この発明は、負荷の諸特性を測定する場合に、負荷には
常時電流を供給しておき、負荷に流れる電流を測定する
場合でも、負荷に電流を供給したままで高速に電流を測
定することができる電流測定回路の提供を目的とする。(c) Purpose of the Invention This invention provides a method for measuring the various characteristics of a load by constantly supplying current to the load, and even when measuring the current flowing through the load, the current can be measured at high speed while the current is being supplied to the load. The purpose of the present invention is to provide a current measurement circuit that can measure current.
（ｄ）発明の実施例 次に、この発明の構成説明図を第１図に示す。(d) Examples of the invention Next, an explanatory diagram of the configuration of this invention is shown in FIG.
第１図の１と２は増幅器、３１〜３３はスイッチ、４は
コンデンサである。1 and 2 are amplifiers, 31 to 33 are switches, and 4 is a capacitor.
第１図では、入力電圧５を増幅器１の入力端子１１に加
え、増幅器１の入力端子１２と出力端子１３を接続し、
増幅器１の入力端子１２と負荷６の間にスイッチ３１を
接続する。In FIG. 1, input voltage 5 is applied to input terminal 11 of amplifier 1, input terminal 12 and output terminal 13 of amplifier 1 are connected,
A switch 31 is connected between the input terminal 12 of the amplifier 1 and the load 6.
また、入力電圧５を増幅器２の入力端子２１に加え、増
幅器２の入力端子２２と出力端子２３との間にスイッチ
３２とコンデンサ４を並列に接続する。Further, the input voltage 5 is applied to the input terminal 21 of the amplifier 2, and the switch 32 and the capacitor 4 are connected in parallel between the input terminal 22 and the output terminal 23 of the amplifier 2.
そして、増幅器２の入力端子２２と負荷６の間にスイッ
チ３３を接続する。Then, a switch 33 is connected between the input terminal 22 of the amplifier 2 and the load 6.
次に、第１図の作用を説明する。Next, the operation of FIG. 1 will be explained.
第１図で、負荷６に流れる電流を測定しないときは、ス
イッチ３１とスイッチ３２を接にし、スイッチ３３を断
にして負荷６に入力電圧５を加える。In FIG. 1, when the current flowing through the load 6 is not being measured, the switches 31 and 32 are connected, the switch 33 is turned off, and the input voltage 5 is applied to the load 6.
この状態では、増幅器１の入力端子１１・１２は同電位
なので、入力電圧５はそのまま負荷６に加えられる。In this state, the input terminals 11 and 12 of the amplifier 1 are at the same potential, so the input voltage 5 is applied to the load 6 as is.
第１図で、負荷８に流れる電流を測定するときは、スイ
ッチ３１とスイッチ３２を断にし、スイッチ３３を接に
する。In FIG. 1, when measuring the current flowing through the load 8, the switches 31 and 32 are turned off and the switch 33 is turned on.
この状態では、増幅器２の入力端子２１からの入力電圧
５はコンデンサ４を充電しながら負荷６に電流を供給す
る。In this state, the input voltage 5 from the input terminal 21 of the amplifier 2 supplies current to the load 6 while charging the capacitor 4.
コンデンサ４の容量を０１コンデンサ４の充電電圧をＥ
ｃ ｓ充電時間をＴｃとすると、次式が成立する。The capacitance of capacitor 4 is 01 The charging voltage of capacitor 4 is E
cs If the charging time is Tc, the following equation holds true.
Ｅｃ＝ （１／Ｃ）ＸＴｃ・・・・・・・・・・・・・
・・・・・・・・（１）容量Ｃは既知なので、ＥｃとＴ
ｃが分かれば、負荷６に流れる電流■を式（１）から算
出することができる。Ec= (1/C)XTc・・・・・・・・・・・・
・・・・・・・・・(1) Since the capacitance C is known, Ec and T
If c is known, the current ■ flowing through the load 6 can be calculated from equation (1).
第１図の入力電圧５の電圧をＥｌ、増幅器２の出力電圧
をＥ２とすれば、次の関係が成立する。If the voltage of the input voltage 5 in FIG. 1 is El, and the output voltage of the amplifier 2 is E2, the following relationship holds true.
Ｅｃ＝Ｅ２−Ｅｌ 次に、式（＋）の関係説明図を第３図に示す。Ec=E2-El Next, an explanatory diagram of the relationship of equation (+) is shown in FIG.
第３図の横軸は時間を示し、縦軸はコンデンサ４の充電
電圧を示す。The horizontal axis in FIG. 3 indicates time, and the vertical axis indicates the charging voltage of the capacitor 4.
時刻Ｔ１以前では、スイッチ３１とスイッチ３２を接に
し、スイッチ３３を断にしておく。Before time T1, the switches 31 and 32 are connected, and the switch 33 is disconnected.
時刻Ｔ１で、スイッチ３１とスイッチ３２を断にし、ス
イッチ３３を接にする。At time T1, switches 31 and 32 are turned off and switch 33 is turned on.
第３図の傾斜線は、コンデンサ４の充電曲線であり、時
刻の経過とともに充電電圧が増えていく。The slope line in FIG. 3 is a charging curve of the capacitor 4, and the charging voltage increases as time passes.
時刻Ｔ２のときの充電電圧Ｅｃと、時刻Ｔ２−時刻時刻
＝時間Ｔｃがわかれば、式（１）から電流■を求めるこ
とができる。If the charging voltage Ec at time T2 and time T2 - time = time Tc are known, the current ■ can be determined from equation (1).
例えば、コンデンサ４の容量＝ １ｏｏｏｐＦ 、電圧
ＥＣ＝ ｌ Ｏｍ Ｖ ％時間Ｔ ｃ ＝ ｌｏｍ ｓ
とすれば、式（１）電流１＝ （ＥｃＸＣ）／Ｔ＝ｌｎ
Ａとなる。For example, capacitance of capacitor 4 = 1ooopF, voltage EC = l Om V % time T c = lom s
Then, equation (1) current 1= (EcXC)/T=ln
It becomes A.
次に、負荷６の電流を測定しなくなったときは、スイッ
チ３１とスイッチ３２を接にし、スイッチ３３を断にし
て負荷８に入力電圧５を加える。Next, when the current of the load 6 is no longer measured, the switches 31 and 32 are connected, the switch 33 is turned off, and the input voltage 5 is applied to the load 8.
この状態では、入力電圧５が負荷６に加えられ、コンデ
ンサ４の両端は短絡されるので、コンデンサ４の電荷は
放電される。In this state, the input voltage 5 is applied to the load 6 and both ends of the capacitor 4 are short-circuited, so that the charge in the capacitor 4 is discharged.
すなわち、第１図では、常時負荷６に電流を供給しなが
ら、電流側定時以外は増幅器１を使用し、電流測定時に
は増幅器２を使用するようにしたものである。That is, in FIG. 1, while supplying current to the load 6 at all times, the amplifier 1 is used except when the current side is fixed, and the amplifier 2 is used when measuring the current.
次に、第１図の実施例の構成図を第４図に示す。Next, a configuration diagram of the embodiment shown in FIG. 1 is shown in FIG. 4.
第４図の８５は増幅器、８６はサンプルホールド回路、
８７はダイオードである。85 in FIG. 4 is an amplifier, 86 is a sample and hold circuit,
87 is a diode.
増幅器８５は第３図の電圧Ｅｃを検出するための差動増
幅器で、あり、サンプルホールド回路８６は、第３図の
時刻Ｔ２で電圧Ｅｃをホールドするためのものである。The amplifier 85 is a differential amplifier for detecting the voltage Ec in FIG. 3, and the sample hold circuit 86 is for holding the voltage Ec at time T2 in FIG.
第４図の増幅器８５とサンプルホールド回路８６の代わ
りに、増幅器８５の２人力にそれぞれサンプルホールド
回路を接続してもよい。Instead of the amplifier 85 and the sample-and-hold circuit 86 in FIG. 4, a sample-and-hold circuit may be connected to each of the two amplifiers 85.
ダイオード８７はツェナダイオードであり、増幅器２に
過大入力が加わらないようにするためのものである。The diode 87 is a Zener diode and is used to prevent excessive input from being applied to the amplifier 2.
第４図の実施例回路によれば、ｌｎＡ程度の微小電流を
測定することができる。According to the embodiment circuit shown in FIG. 4, it is possible to measure a minute current of about lnA.
（ｅ）発明の効果
この発明によれば、電流側定時以外は増幅器１で電流を
負荷に供給し、電流測定時は増幅器２に切り換えて電流
を負荷に供給し、このときのコンデンサに対する充電時
間と充電電流から負荷に供給される電流を求めるように
しているので、負荷の諸特性を測定する場合に、負荷に
電流を供給したままで高速に電流を測定することができ
る。(e) Effect of the Invention According to this invention, the amplifier 1 supplies current to the load except when the current side is fixed, and when measuring the current, switches to the amplifier 2 to supply current to the load, and the charging time for the capacitor at this time Since the current supplied to the load is determined from the charging current and the charging current, when measuring various characteristics of the load, the current can be measured at high speed while the current is being supplied to the load.
第１図はこの発明の構成説明図、第２図は従来の電流測
定回路図、第３図は式（１）の関係説明図、第４図は第
１図の実施例の構成図である。
ｌ・・・・・・増幅器、２・・・・・・増幅器、４・・
・・・・コンデンサ、５・・・・・・入力電圧、６・・
・・・・負荷、７・・・・・・抵抗、９・・・・・・端
子、１１〜１３・・・・・・増幅器１の端子、２１〜２
３・・・・・・増幅器２の端子、３１〜３３・・・・・
・スイッチ、８１〜８５・・・・・・増幅器、８６・・
・・・・サンプルホールド回路、８７・・・・・・ダイ
オード。
代理人 弁理士 小 俣 欽 司Fig. 1 is an explanatory diagram of the configuration of the present invention, Fig. 2 is a conventional current measurement circuit diagram, Fig. 3 is an explanatory diagram of the relationship of formula (1), and Fig. 4 is a diagram of the configuration of the embodiment of Fig. 1. . l...Amplifier, 2...Amplifier, 4...
...Capacitor, 5...Input voltage, 6...
...Load, 7...Resistance, 9...Terminals, 11-13...Terminals of amplifier 1, 21-2
3...Terminals of amplifier 2, 31-33...
・Switch, 81-85...Amplifier, 86...
...Sample and hold circuit, 87...Diode. Agent Patent Attorney Kinji Komata
Claims (1)
第２の入力端子（１２）と第１の出力端子（１３）を接
続する第１の増幅器（１）と、 第１の増幅器（１）の第２の入力端子（１２）と負荷（
６）の間に接続する第１のスイッチ（３１）と、入力電
圧（５）を第３の入力端子（２１）に加え、第４の入力
端子（２２）と第２の出力端子（２３）との間に第２の
スイッチ（３２）とコンデンサ（４）を並列接続する第
２の増幅器（２）と、 第２の増幅器（２）の第４の入力端子（２２）と負荷（
６）の間に接続する第３のスイッチ（３３）とを備え、 負荷（６）に流れる電流を測定しないときは、第１のス
イッチ（３１）と第２のスイッチ（３２）を接にし、第
３のスイッチ（３３）を断にして負荷（６）に入力電圧
（５）を加え、 負荷（６）に流れる電流を測定するときには、第１のス
イッチ（３１）と第２のスイッチ（３２）を断にし、第
３のスイッチ（３３）を接にして負荷（６）に入力電圧
（５）を加え、コンデンサ（４）の充電時間に対する充
電電圧を測定することにより、負荷（６）に流れる電流
を測定する電流測定回路。[Claims] 1. Applying an input voltage (5) to a first input terminal (11),
A first amplifier (1) that connects a second input terminal (12) and a first output terminal (13), and a second input terminal (12) of the first amplifier (1) and a load (
A first switch (31) connected between 6), which applies an input voltage (5) to a third input terminal (21), and a fourth input terminal (22) and a second output terminal (23). a second amplifier (2) with a second switch (32) and a capacitor (4) connected in parallel between the fourth input terminal (22) of the second amplifier (2) and the load (
6), and when not measuring the current flowing through the load (6), the first switch (31) and the second switch (32) are connected, When measuring the current flowing through the load (6) by applying the input voltage (5) to the load (6) with the third switch (33) turned off, turn off the first switch (31) and the second switch (32). ) is turned off, the third switch (33) is connected, the input voltage (5) is applied to the load (6), and the charging voltage is measured with respect to the charging time of the capacitor (4). A current measurement circuit that measures the flowing current.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32057287A JPH01162160A (en) | 1987-12-18 | 1987-12-18 | Current measuring circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32057287A JPH01162160A (en) | 1987-12-18 | 1987-12-18 | Current measuring circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01162160A true JPH01162160A (en) | 1989-06-26 |
Family
ID=18122930
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP32057287A Pending JPH01162160A (en) | 1987-12-18 | 1987-12-18 | Current measuring circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01162160A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5466914A (en) * | 1992-04-24 | 1995-11-14 | Olympus Optical Co., Ltd. | Recording-reproducing apparatus with a mechanism for preventing successive insertion of two cards |
-
1987
- 1987-12-18 JP JP32057287A patent/JPH01162160A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5466914A (en) * | 1992-04-24 | 1995-11-14 | Olympus Optical Co., Ltd. | Recording-reproducing apparatus with a mechanism for preventing successive insertion of two cards |
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