JPH0642627B2 - Logic circuit - Google Patents
Logic circuitInfo
- Publication number
- JPH0642627B2 JPH0642627B2 JP61300776A JP30077686A JPH0642627B2 JP H0642627 B2 JPH0642627 B2 JP H0642627B2 JP 61300776 A JP61300776 A JP 61300776A JP 30077686 A JP30077686 A JP 30077686A JP H0642627 B2 JPH0642627 B2 JP H0642627B2
- Authority
- JP
- Japan
- Prior art keywords
- transistor
- circuit
- emitter
- emitter follower
- base
- 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.)
- Expired - Lifetime
Links
Landscapes
- Logic Circuits (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、半導体集積回路（以下、ＩＣと記す）に関
し、特にエミッタホロア回路を有するＥＣＬ回路に関す
るものである。The present invention relates to a semiconductor integrated circuit (hereinafter referred to as an IC), and more particularly to an ECL circuit having an emitter follower circuit.
従来のＥＣＬ回路は、第３図に示すように、トランジス
タ１の定電流源にトランジスタ２と３とのエミッタを接
続し、一方のトランジスタ２のベースに入力端子５を接
続し、他方のトランジスタ３のベースに基準電圧Vrefを
与え、このトランジスタ３のコレクタにトランジスタ４
で構成されるエミッタホロア回路を接続し、トランジス
タ４のエミッタに出力端子６を接続している。このエミ
ッタホロア回路を有するＥＣＬ回路では、定電流回路
（トランジスタ１）により決定される差動回路部の動作
電流を入力信号の信号レベルにより、その流通経路を切
り替えるカレントスイッチ部分（トランジスタ２，３）
と差動回路の出力信号をエミッタホロア接続で次段に伝
えるエミッタホロア回路（トランジスタ４）とから構成
されている。In the conventional ECL circuit, as shown in FIG. 3, the emitters of the transistors 2 and 3 are connected to the constant current source of the transistor 1, the input terminal 5 is connected to the base of one transistor 2, and the other transistor 3 is connected. The reference voltage Vref is applied to the base of the
Is connected to the emitter follower circuit, and the output terminal 6 is connected to the emitter of the transistor 4. In the ECL circuit having this emitter follower circuit, the current switch portion (transistors 2 and 3) that switches the flow path of the operating current of the differential circuit portion determined by the constant current circuit (transistor 1) according to the signal level of the input signal.
And an emitter follower circuit (transistor 4) for transmitting the output signal of the differential circuit to the next stage through an emitter follower connection.
しかし、かかる従来のＥＣＬ回路では、エミッタホロア
回路（トランジスタ４）の出力端子６と、エミッタホロ
ア抵抗（ＲEF）の接続点１０が何らかの原因で開放とな
った場合でも、低速動作であれば充分動作可能なことか
ら、その不良箇所の発見が高速動作試験を実施しなけれ
ば発見できないという問題点があった。However, in such a conventional ECL circuit, even if the output terminal 6 of the emitter follower circuit (transistor 4) and the connection point 10 of the emitter follower resistor (R EF ) are opened for some reason, they can operate at a low speed. Therefore, there is a problem in that the defective portion cannot be found without performing the high-speed operation test.
本発明によれば、定電流源から共通にエミッタに定電流
を受ける第１および第２のトランジスタと、第１又は第
２のトランジスタのコレクタにベースが接続され、その
エミッタに出力端子とエミッタ抵抗とが接続された第３
のトランジスタと、この第３のトランジスタのベースに
アノードが接続されたダイオードと、このダイオードの
カソード端子にエミッタが接続され、ベースがエミッタ
抵抗の適当な個所に接続され、コレクタが電源に接続さ
れた第４のトランジスタとを有するエミッタホロア回路
を備えた論理回路を得る。According to the present invention, the first and second transistors commonly receiving a constant current from the constant current source to the emitter and the bases of the collectors of the first and second transistors are connected to the output terminal and the emitter resistance of the emitter. The third where and are connected
, A diode whose anode is connected to the base of this third transistor, an emitter is connected to the cathode terminal of this diode, the base is connected to an appropriate point of the emitter resistor, and the collector is connected to the power supply. A logic circuit having an emitter follower circuit having a fourth transistor is obtained.
次に、図面を参照して本発明を説明する。 Next, the present invention will be described with reference to the drawings.
第１図は、本発明の一実施例を示すエミッタホロア回路
を有するＥＣＬ回路であり、従来同様トランジスタ１，
２，３，４でＥＣＬ回路およびエミッタホロア回路を形
成している。ダイオード７のアノード端子をエミッタホ
ロアトランジスタ４のベースに接続し、ダイオード７の
カソード端子をトランジスタ８のエミッタに接続し、こ
のトランジスタ８のベースを、エミッタホロア回路中の
エミッタホロア抵抗ＲEFの適当な分圧点に接続し、トラ
ンジスタ８のコレクタを電源端子に接続したものであ
る。図中１０で示した接続部分が接続されている正常状
態の場合は、トランジスタ８は、オフ状態となり、通常
のＥＣＬ動作を保つ。接続部分１０が何らかの原因でオ
ーブン状態となった場合、トランジスタ８は、オン状態
となり出力端子６に得られるＥＣＬ回路の出力レベル
は、“Ｌ”レベルに固定される。このため、出力端子６
の電位を観察すれば、接続部分１０が接続されているか
どうかはすぐに判別できる。FIG. 1 shows an ECL circuit having an emitter follower circuit according to an embodiment of the present invention.
2, 3, 4 form an ECL circuit and an emitter follower circuit. The anode terminal of the diode 7 is connected to the base of the emitter follower transistor 4, the cathode terminal of the diode 7 is connected to the emitter of the transistor 8, and the base of this transistor 8 is connected to the emitter follower resistor R EF in the emitter follower circuit. It is connected to the pressure point and the collector of the transistor 8 is connected to the power supply terminal. In the normal state where the connection portion shown by 10 in the figure is connected, the transistor 8 is turned off and the normal ECL operation is maintained. When the connecting portion 10 is in the oven state for some reason, the transistor 8 is turned on and the output level of the ECL circuit obtained at the output terminal 6 is fixed to the “L” level. Therefore, the output terminal 6
By observing the potential of, it is possible to immediately determine whether or not the connecting portion 10 is connected.
以上説明したように、本発明は、エミッタホロア回路を
備えたＥＣＬ回路を含むＩＣにおいて、エミッタホロア
回路の断線を出力端子で通常動作試験にて、発見できる
効果があり、ＥＣＬ回路の信頼性を大幅に向上させるも
のである。As described above, the present invention has the effect of being able to find a disconnection of the emitter follower circuit at the output terminal in the normal operation test in the IC including the ECL circuit having the emitter follower circuit, and greatly improves the reliability of the ECL circuit. To improve.
第１図は本発明の一実施例を示す回路図、第２図は従来
例を示す回路図である。 １，２，３，４，８……トランジスタ、７……ダイオー
ド、５……入力端子、６……出力端子、１０……接続部
分。FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIG. 2 is a circuit diagram showing a conventional example. 1, 2, 3, 4, 8 ... Transistor, 7 ... Diode, 5 ... Input terminal, 6 ... Output terminal, 10 ... Connection part.
Claims (1)
スに受ける一導電型のエミッタホロアトランジスタであ
って電源端子との間にエミッタ抵抗を有するエミッタホ
ロアトランジスタと、アノードが前記エミッタホロアト
ランジスタのベースに接続されたダイオードと、このダ
イオードのカソードにエミッタが接続され、ベースが前
記エミッタ抵抗の分圧点に接続され、コレクタが前記電
源端子に接続された逆導電型の付加トランジスタとを有
することを特徴とする論理回路。1. An ECL circuit, an emitter follower transistor of one conductivity type which receives an output of the ECL circuit as a base, and which has an emitter resistance between a power supply terminal, and an anode of the emitter follower transistor. A diode connected to the base of the transistor, an emitter connected to the cathode of the diode, a base connected to the voltage dividing point of the emitter resistor, and a collector connected to the power supply terminal with a reverse conductivity type additional transistor; A logic circuit having:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61300776A JPH0642627B2 (en) | 1986-12-16 | 1986-12-16 | Logic circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61300776A JPH0642627B2 (en) | 1986-12-16 | 1986-12-16 | Logic circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63152221A JPS63152221A (en) | 1988-06-24 |
| JPH0642627B2 true JPH0642627B2 (en) | 1994-06-01 |
Family
ID=17888951
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61300776A Expired - Lifetime JPH0642627B2 (en) | 1986-12-16 | 1986-12-16 | Logic circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0642627B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5291075A (en) * | 1990-10-01 | 1994-03-01 | Motorola, Inc. | Fault detection circuit |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59193626A (en) * | 1983-04-18 | 1984-11-02 | Mitsubishi Electric Corp | Transistor logical circuit |
| JPS61163718A (en) * | 1985-01-16 | 1986-07-24 | Mitsubishi Electric Corp | integrated circuit device |
-
1986
- 1986-12-16 JP JP61300776A patent/JPH0642627B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63152221A (en) | 1988-06-24 |
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