JPS62206467A - Output inspection circuit for digital circuit - Google Patents
Output inspection circuit for digital circuitInfo
- Publication number
- JPS62206467A JPS62206467A JP61049717A JP4971786A JPS62206467A JP S62206467 A JPS62206467 A JP S62206467A JP 61049717 A JP61049717 A JP 61049717A JP 4971786 A JP4971786 A JP 4971786A JP S62206467 A JPS62206467 A JP S62206467A
- Authority
- JP
- Japan
- Prior art keywords
- output
- constant current
- current source
- voltage
- comparator
- 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.)
- Granted
Links
- 238000007689 inspection Methods 0.000 title description 2
- 238000011990 functional testing Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 230000000295 complement effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
Landscapes
- Tests Of Electronic Circuits (AREA)
- Test And Diagnosis Of Digital Computers (AREA)
- Testing Of Individual Semiconductor Devices (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明はディジタル回路の出力検査回路に係わシ、特に
、ディジタル回路の負荷駆動能力を検査する出力検査回
路に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an output testing circuit for a digital circuit, and more particularly to an output testing circuit for testing the load driving ability of a digital circuit.
一般にディジタル回路、特に集積化されたディジタル回
路の検査は、直流的には汎用のＩＣ，デスクを用いたレ
ベルチェックを行なっておシ、機能テストにおいても対
象となる回路部分のみＬＳＩテスタ、または、専用の検
査治具によりその出力値を出力期待値と比較していた。In general, digital circuits, especially integrated digital circuits, are tested by level checking using general-purpose ICs and desks for direct current, and for functional testing, only the target circuit parts are tested using an LSI tester or The output value was compared with the expected output value using a special inspection jig.
この機能テストにおいてもレベルチェックは行なわれる
が、出力段の負荷駆動能力の検査までは行なわれなかっ
た。Although a level check was also performed in this functional test, the load driving ability of the output stage was not tested.
しかしガから、ディジタル回路の場合、その負荷駆動能
力は重要な特性でめるにもかかわらず、その出力検査に
おいては単にレベルチェックしかなされず、負荷駆動能
力の検査はなされていなかった０
それで、本発明は簡単な構成でディジタル回路の負荷駆
動能力を検査できる出力検査回路を提供することを目的
としている。However, in the case of digital circuits, although the load driving ability can be determined as an important characteristic, when testing the output, only a level check was performed, and the load driving ability was not tested. An object of the present invention is to provide an output test circuit that can test the load driving ability of a digital circuit with a simple configuration.
〔問題点を解決するだめの手段、作用および効果〕本発
明に係わる出力検査回路においては、機能テスト時に出
力ノードの電圧が変化すると、コンパレータが出力ノー
ドの電圧と参照電圧とを比較し、出力ノードの電圧が参
照電圧を横切るとその方向に対応してコンパレータの出
力が変化する。[Means, operations, and effects for solving the problem] In the output test circuit according to the present invention, when the voltage at the output node changes during a functional test, the comparator compares the voltage at the output node with the reference voltage, and When the voltage at the node crosses the reference voltage, the output of the comparator changes in accordance with the direction.
このコンパレータの出力に応じて第１定電流源または第
２定電流源が機能し、出力段の基準電位側ノードまたは
接地電位側ノードに電流を供給する。The first constant current source or the second constant current source functions depending on the output of the comparator, and supplies a current to the reference potential side node or the ground potential side node of the output stage.
その結果、出力段の負荷状態が変化し、判定部は変化し
た負荷状態のもとての出力ノード電圧に基づき出力段の
負荷駆動能力を判定する。したがって、本発明によれば
、簡単な構成の付加によυ通常の機能テスト時に負荷駆
動能力を検査することができ、ディジタル回路の信頼性
を高めることができる。As a result, the load state of the output stage changes, and the determining section determines the load driving ability of the output stage based on the original output node voltage of the changed load state. Therefore, according to the present invention, the load driving ability can be tested during a normal functional test by adding a simple configuration, and the reliability of the digital circuit can be improved.
以下、本発明を図面に基づき説明する。図は本発明の一
実施例の構成を示す電気回路図であシ、被検査体である
ディジタル回路の出力段１は、電源電位Ｖ。Ｃと接地電
位との間に直列に配された１対のバイポーラトランジス
タ３，５を有しておシ、これらのバイポーラトランジス
タ３，５は図示していない論理回路の出力によシ相補的
にオン、オフし、出力端子７を略電源電位■。Ｃまたは
接地電位に切換える。この出力端子７は判定回路９の入
力端子、コンパレータ１１の正相入力端子および１対の
アナログスイッチ１３．１５に接続されてお多、コンパ
レータ１１の逆相入力端子には参照電圧発生源１７から
参照電圧ＶＴＨＲＩＪＨが印加されている。コンパレー
タ１１は出力端子７の電圧Ｖ。ＵＴと参照電圧Ｖ ＴＨ
ＲＥＳＨとを比較し、出力端子電圧ＶＯＵＴが参照電圧
Ｖ ＴＨＲＥＳＨよシ高いとコンパレータ１１の出力が
アナログスイッチ１５をオンさせ定電流源１９によシン
−スミ流を引っ張る。これに対して、出力端子電圧ＶＯ
ＵＴが参照電圧ＶＴＨＲ１ｉ、Ｓ□よシ低いと、インバ
ータ２１によるコンノ（レータ１１の反転出力をアナロ
グスイッチ１３に送出してアナログスイッチ１５をオン
させ、定電流源２３からシンク電流を流す。こうして、
負荷状態での出力端子電圧■。ＵＴを判定部９にて判断
し、出力段１の負荷駆動能力を判定する。Hereinafter, the present invention will be explained based on the drawings. The figure is an electric circuit diagram showing the configuration of an embodiment of the present invention, and the output stage 1 of the digital circuit to be tested is at the power supply potential V. It has a pair of bipolar transistors 3 and 5 arranged in series between C and ground potential, and these bipolar transistors 3 and 5 are complementary to the output of a logic circuit (not shown). Turn on and off, and set output terminal 7 to approximately power supply potential■. Switch to C or ground potential. This output terminal 7 is connected to the input terminal of the judgment circuit 9, the positive phase input terminal of the comparator 11, and a pair of analog switches 13.15. A reference voltage VTHRIJH is applied. The comparator 11 receives the voltage V at the output terminal 7. UT and reference voltage V TH
RESH, and if the output terminal voltage VOUT is higher than the reference voltage VTHRESH, the output of the comparator 11 turns on the analog switch 15, and the constant current source 19 pulls the thin-sumi current. On the other hand, the output terminal voltage VO
When UT is lower than the reference voltage VTHR1i, S□, the inverter 21 sends the inverted output of the converter 11 to the analog switch 13, turning on the analog switch 15, and causing a sink current to flow from the constant current source 23.
Output terminal voltage under load condition ■. The determination unit 9 determines the UT and determines the load driving ability of the output stage 1.
また、上記参照電圧発生源１７と定電流源１９゜２３は
それぞれ出力可変型であシ、検査するディジタル回路に
合わせて調整可能である。Further, the reference voltage generation source 17 and the constant current source 19, 23 are each of variable output type, and can be adjusted according to the digital circuit to be tested.
図は本発明の一実施例の構成を示す電気回路図である。
１・・・・・・出力段、７・・・・・・出力ノード（出
力端子）、９・・・・・・判定Ｌ １１・・・・・・
コンパレータ、１９・−・・・・第２定電流源、２３・
・・・−・第１定電流源。The figure is an electrical circuit diagram showing the configuration of an embodiment of the present invention. 1... Output stage, 7... Output node (output terminal), 9... Judgment L 11...
Comparator, 19...Second constant current source, 23.
...--First constant current source.
Claims (3)
有するディジタル回路の負荷駆動能力を検査する出力検
査回路において、上記出力段の出力ノードと該出力段の
基準電位側ノードとの間に設けられた第１定電流源と、
上記出力段の出力ノードと該出力段の接地電位側ノード
との間に設けられた第２定電流源と、上記出力段の出力
ノードの電圧を参照電圧と比較し該比較結果に応じて上
記第１定電流源または第２定電流源を機能させるコンパ
レータと、上記第１定電流源および第２定電流源を機能
させた状態での上記出力ノードの電圧に基づき出力段の
負荷駆動能力を判定する判定部とを具えたことを特徴と
するディジタル回路の出力検査回路。(1) In an output test circuit that tests the load driving ability of a digital circuit having an output stage provided between a reference potential and a ground potential, the connection between the output node of the output stage and the reference potential side node of the output stage is a first constant current source provided between;
A second constant current source provided between the output node of the output stage and the ground potential side node of the output stage compares the voltage of the output node of the output stage with a reference voltage, and A comparator that makes the first constant current source or the second constant current source function, and a load driving capacity of the output stage based on the voltage of the output node with the first constant current source and the second constant current source functioning. 1. An output testing circuit for a digital circuit, comprising a determining section for making a determination.
記載の出力検査回路。(2) The output test circuit according to claim 1, wherein the reference voltage is made variable.
範囲第１項記載の出力検査回路。(3) The output test circuit according to claim 1, wherein the output current of the constant current source is made variable.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61049717A JPH0664127B2 (en) | 1986-03-06 | 1986-03-06 | Output inspection circuit of digital circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61049717A JPH0664127B2 (en) | 1986-03-06 | 1986-03-06 | Output inspection circuit of digital circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62206467A true JPS62206467A (en) | 1987-09-10 |
| JPH0664127B2 JPH0664127B2 (en) | 1994-08-22 |
Family
ID=12838938
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61049717A Expired - Lifetime JPH0664127B2 (en) | 1986-03-06 | 1986-03-06 | Output inspection circuit of digital circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0664127B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005156341A (en) * | 2003-11-26 | 2005-06-16 | Yokogawa Electric Corp | Tester simulation system and tester simulation method |
-
1986
- 1986-03-06 JP JP61049717A patent/JPH0664127B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005156341A (en) * | 2003-11-26 | 2005-06-16 | Yokogawa Electric Corp | Tester simulation system and tester simulation method |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0664127B2 (en) | 1994-08-22 |
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