JPH0786902A - Semiconductor photocoupler - Google Patents
Semiconductor photocouplerInfo
- Publication number
- JPH0786902A JPH0786902A JP22480693A JP22480693A JPH0786902A JP H0786902 A JPH0786902 A JP H0786902A JP 22480693 A JP22480693 A JP 22480693A JP 22480693 A JP22480693 A JP 22480693A JP H0786902 A JPH0786902 A JP H0786902A
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- light emitting
- power supply
- voltage
- supply 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.)
- Granted
Links
Landscapes
- Photo Coupler, Interrupter, Optical-To-Optical Conversion Devices (AREA)
- Electronic Switches (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は、半導体発行素子と半導
体受光素子とを光学的に結合させ、電気信号を光を媒体
として伝送する半導体フォト・カプラに関し、特に発光
素子側に発光素子駆動用の電気回路を内蔵した半導体フ
ォト・カプラに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor photo coupler that optically couples a semiconductor light emitting element and a semiconductor light receiving element and transmits an electric signal using light as a medium. The present invention relates to a semiconductor photo coupler having a built-in electric circuit.
【0002】[0002]
【従来の技術】発光素子と受光素子とを近接して配置
し、これを一体的に透光明樹脂等でパッケージ化した半
導体フォト・カプラが従来より知られている。この半導
体フォト・カプラは、発光回路側と受光回路側との信号
伝達特性を良好に保ちながら両回路間を電気的に絶縁す
ることができ、種々の用途に利用されている。例えば図
4に示すような発光素子を駆動するための電気回路を内
蔵したディジタル信号伝送用の半導体フォト・カプラも
ある。2. Description of the Related Art A semiconductor photo coupler in which a light emitting element and a light receiving element are arranged in close proximity to each other and integrally packaged with a transparent resin or the like has been known. This semiconductor photo coupler can be electrically insulated between the light emitting circuit side and the light receiving circuit side while maintaining good signal transmission characteristics, and is used for various purposes. For example, there is a semiconductor photo coupler for digital signal transmission which has an electric circuit for driving a light emitting element as shown in FIG.
【0003】図4は、従来の半導体フォト・カプラの構
成を示す概略ブロック図である。FIG. 4 is a schematic block diagram showing the structure of a conventional semiconductor photo coupler.
【0004】この半導体フォト・カプラは、LED10
1、及び該LED101駆動用の駆動集積回路(以下、
単に駆動回路という)102からなる発光部103と、
受光素子104、及び該受光素子104から出力される
電気信号を増幅する受光集積回路(以下、単に受光回路
という)105からなる受光部106とを有している。This semiconductor photo-coupler is based on the LED 10
1 and a driving integrated circuit for driving the LED 101 (hereinafter,
A light emitting portion 103 composed of 102)
It has a light receiving element 104 and a light receiving section 106 including a light receiving integrated circuit (hereinafter, simply referred to as a light receiving circuit) 105 that amplifies an electric signal output from the light receiving element 104.
【0005】発光部103側では、駆動回路102の入
力側が信号入力端子Vinに接続され、さらに駆動回路
102の電源側が発光側電源端子VCC1に、その接地
側がグランド端子E1にそれぞれ接続されている。そし
て、電源端子VCC1と駆動回路102の出力側との間
にはLED101が接続されている。ここで、発光部1
01の駆動回路102は、信号入力端子Vinに入力さ
れるディジタル入力信号の“1”または“0”に応じて
LED101を点滅させる。On the side of the light emitting portion 103, the input side of the drive circuit 102 is connected to the signal input terminal Vin, the power supply side of the drive circuit 102 is connected to the light emission side power supply terminal VCC1, and the ground side thereof is connected to the ground terminal E1. The LED 101 is connected between the power supply terminal VCC1 and the output side of the drive circuit 102. Here, the light emitting unit 1
The drive circuit 102 of 01 blinks the LED 101 according to "1" or "0" of the digital input signal input to the signal input terminal Vin.
【0006】一方、受光部106側は、受光素子104
の両端が受光回路105の入力側に接続され、その受光
回路105の出力側が出力端子VOUTに接続されてい
る。さらに、受光回路105の電源側が受光側電源端子
VCC2に、その接地側が受光側接地端子E2にそれぞ
れ接続されている。ここで、LED101より発光され
た光信号は、受光素子104で電気信号に変換された
後、受光回路105によって増幅されて出力端子VOU
Tへ出力される。On the other hand, on the side of the light receiving portion 106, the light receiving element 104 is provided.
Are connected to the input side of the light receiving circuit 105, and the output side of the light receiving circuit 105 is connected to the output terminal VOUT. Further, the power supply side of the light receiving circuit 105 is connected to the light receiving side power supply terminal VCC2, and the ground side thereof is connected to the light receiving side ground terminal E2. Here, the optical signal emitted from the LED 101 is converted into an electric signal by the light receiving element 104, and then amplified by the light receiving circuit 105 to be output terminal VOU.
Output to T.
【0007】しかし、この半導体フォト・カプラの発光
部103側の端子は、発光側電源端子VCC1、グラン
ド端子E、及び信号入力端子Vinの3端子のみなの
で、LED101に流れる電流を連続的に変化させるこ
とはできない。従って、製品の組立てが完了した時に行
われる出荷検査に際し、動作確認の検査は可能であるも
のの、発光部103と受光部106との結合効率などが
検査ができない。そのため、例えば、通常の測定が行わ
れる室温で正常動作の確認ができても、製品が使用され
る環境が高温であると、LED101の発光効率が減少
して光量が減るために受光部106が動作するのに十分
な光が得られず、動作不良の製品が出荷される恐れがあ
った。However, since the semiconductor photo coupler has only three terminals on the light emitting portion 103 side, that is, the light emitting side power supply terminal VCC1, the ground terminal E, and the signal input terminal Vin, the current flowing through the LED 101 is continuously changed. It is not possible. Therefore, in the shipping inspection performed when the product assembly is completed, the operation confirmation can be inspected, but the coupling efficiency between the light emitting unit 103 and the light receiving unit 106 cannot be inspected. Therefore, for example, even if normal operation can be confirmed at room temperature where normal measurement is performed, if the environment in which the product is used is at a high temperature, the light emitting efficiency of the LED 101 is reduced and the light amount is reduced. There was a possibility that a product with malfunction could be shipped because it could not obtain enough light to operate.
【0008】この問題を解決した従来の半導体フォト・
カプラを図5に示す。A conventional semiconductor photo
The coupler is shown in FIG.
【0009】図5において、このフォト・カプラは、図
4に示す上記のものに、LED101の特性を検査する
ための検査用端子107を設け、この検査用端子107
をLED101のカソード側に接続したものである。In FIG. 5, this photo coupler is provided with an inspection terminal 107 for inspecting the characteristics of the LED 101, in addition to the above-mentioned one shown in FIG.
Is connected to the cathode side of the LED 101.
【0010】例えば、発光部103と受光部106との
結合効率を検査する際には、検査装置を使用して、電源
端子VCC1と検査用端子107とを介してLED10
1の順方向に連続して直流電流を流す。このとき、電源
端子VCC1と検査用端子107との間に印加する電圧
を変化させて、直流電流を時間に比例して大きくなるよ
うに流し、受光部の出力状態が変化した時点のLED1
01に流れた電流を測定する。For example, when inspecting the coupling efficiency between the light emitting portion 103 and the light receiving portion 106, the LED 10 is inspected through the power supply terminal VCC1 and the inspection terminal 107 using an inspection device.
Direct current is continuously supplied in the forward direction of 1. At this time, the voltage applied between the power supply terminal VCC1 and the inspection terminal 107 is changed so that the direct current becomes larger in proportion to time, and the LED1 at the time when the output state of the light receiving unit changes.
The current flowing in 01 is measured.
【0011】[0011]
【発明が解決しようとする課題】しかしながら、図5に
示す従来の半導体フォト・カプラでは、上述の手法によ
って結合効率を測定することにより、結合効率不良の製
品を取り除くことはできるが、応用使用上は全く必要の
ない端子(検査用端子107)が増えることになり、パ
ッケージが大きくなるばかりか、コスト高になるという
問題があった。However, in the conventional semiconductor photocoupler shown in FIG. 5, the product having poor coupling efficiency can be removed by measuring the coupling efficiency by the above-mentioned method, but it is not suitable for practical use. The number of unnecessary terminals (inspection terminals 107) is increased, and there is a problem that not only the package becomes large, but also the cost becomes high.
【0012】本発明は、上述の如き従来の問題点を解決
するためになされたもので、その目的は、端子を増加す
ることなく結合効率の測定検査を行え、低コストで信頼
性の高い半導体フォト・カプラを提供することである。The present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to perform measurement and inspection of coupling efficiency without increasing the number of terminals, and to provide a low-cost and highly reliable semiconductor. It is to provide a photo coupler.
【0013】[0013]
【課題を解決するための手段】上記目的を達成するため
に、本発明の特徴は、ディジタル入力信号に応じた駆動
出力を送出する駆動回路、及びその駆動出力に基づいて
発光する発光素子を有する発光部と、前記発光素子から
の光を電気信号に変換する受光素子を有する受光部とを
備えた半導体フォト・カプラにおいて、前記発光部の電
源電圧を検出する電圧検出回路と、前記電圧検出回路に
より検出された電源電圧が動作保証電源電圧の範囲に達
していないときに前記駆動回路の作動を停止させる駆動
回路停止回路と、前記電圧検出回路により検出された電
源電圧が前記動作保証電源電圧に達していないときに前
記発光素子に電流を流す電流バイパス回路とを、前記発
光部に設けたことにある。To achieve the above object, a feature of the present invention is to have a drive circuit that sends out a drive output according to a digital input signal, and a light emitting element that emits light based on the drive output. In a semiconductor photo coupler including a light emitting section and a light receiving section having a light receiving element for converting light from the light emitting element into an electric signal, a voltage detecting circuit for detecting a power supply voltage of the light emitting section, and the voltage detecting circuit. The drive circuit stop circuit that stops the operation of the drive circuit when the power supply voltage detected by the voltage detection circuit does not reach the operation guarantee power supply voltage range, and the power supply voltage detected by the voltage detection circuit is the operation guarantee power supply voltage. And a current bypass circuit for supplying a current to the light emitting element when the light emitting element has not reached the light emitting element.
【0014】[0014]
【作用】上述の如き構成によれば、電源電圧が動作保証
電源電圧の範囲に達していないことを電圧検出回路によ
り検出し、その間は、駆動回路停止回路により駆動回路
の作動を停止させると共に、電流バイパス回路により発
光素子に電流が流れる状態を実現する。これにより、電
源電圧を変化させて発光素子に流れる電流を連続的に変
化させることができ、この時の受光部の出力状態の変化
を検出することにより、受発光部間の結合効率を測定検
査することが可能となる。According to the above configuration, the voltage detection circuit detects that the power supply voltage does not reach the range of the operation-guaranteed power supply voltage, and during that time, the drive circuit stop circuit stops the operation of the drive circuit and The current bypass circuit realizes a state in which current flows through the light emitting element. As a result, the power supply voltage can be changed to continuously change the current flowing through the light emitting element. By detecting the change in the output state of the light receiving part at this time, the coupling efficiency between the light receiving and emitting parts is measured and inspected. It becomes possible to do.
【0015】[0015]
【実施例】以下、本発明の一実施例を図面に基づいて説
明する。図1は、本発明を実施した半導体フォト・カプ
ラの概略構成を示すブロック図である。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a semiconductor photo coupler embodying the present invention.
【0016】この半導体フォト・カプラは、ディジタル
入力信号に応じた光信号を発光する発光部10と、該発
光部10に近接して配置され発光部10からの点滅光信
号を電気信号に変換して“1”または“0”の信号を出
力する受光部20とを備えている。これら発光部10と
受光部20は従来装置と同様に透明樹脂などによって一
体的にパッケージ化されている。This semiconductor photo-coupler is a light emitting section 10 which emits an optical signal corresponding to a digital input signal, and a flashing optical signal from the light emitting section 10 which is arranged close to the light emitting section 10 and is converted into an electric signal. And a light receiving unit 20 that outputs a signal of "1" or "0". The light emitting unit 10 and the light receiving unit 20 are integrally packaged with a transparent resin or the like as in the conventional device.
【0017】発光部10は、LED1を有し、そのアノ
ード側が電源端子VCC1に接続される一方、そのカソ
ード側が抵抗2を介して駆動回路3に接続されている。
この駆動回路3は、信号入力端子Vinに供給されるデ
ィジタル入力信号の“1”または“0”に応じて、該L
ED1に一定の電流を流すか、あるいはその電流を切る
かしてLED1を点滅させる。The light emitting section 10 has an LED 1, the anode side of which is connected to the power supply terminal VCC1 and the cathode side of which is connected to the drive circuit 3 via the resistor 2.
The drive circuit 3 operates in response to the digital input signal “1” or “0” supplied to the signal input terminal Vin,
The LED 1 is made to blink by flowing a constant current to the ED 1 or cutting off the current.
【0018】このような機能を有する駆動回路3を内蔵
した本実施例の発光部10は、最小の端子数(電源端子
VCC1、信号入力端子Vin、及び接地端子E1)で
発光部10と受光部20との結合効率を測定するため、
結合効率測定時にはLED1に流れる電流を連続的に変
化しうるように、電圧検出回路4、駆動回路停止回路
5、及び電流バイパス回路6の各手段を設けている。The light emitting section 10 of this embodiment having the drive circuit 3 having such a function built therein has the minimum number of terminals (power supply terminal VCC1, signal input terminal Vin, and ground terminal E1) and the light emitting section 10 and the light receiving section. To measure the binding efficiency with 20,
Each unit of the voltage detection circuit 4, the drive circuit stop circuit 5, and the current bypass circuit 6 is provided so that the current flowing through the LED 1 can be continuously changed when the coupling efficiency is measured.
【0019】前記電圧検出回路4は電源端子VCC1と
接地端子E1との間に接続され、この電圧検出回路4に
よって電源電圧を検出する。そして、電圧検出回路4の
出力側には、駆動回路停止回路5と電流バイパス回路6
とが接続されている。駆動回路停止回路5は、接地端子
E1に接続されると共にその出力側が駆動回路3に接続
され、電流バイパス回路6は、LED1のカソード側に
抵抗2を介して接続されると共に接地端子E1に接続さ
れている。The voltage detection circuit 4 is connected between the power supply terminal VCC1 and the ground terminal E1, and the voltage detection circuit 4 detects the power supply voltage. The drive circuit stop circuit 5 and the current bypass circuit 6 are provided on the output side of the voltage detection circuit 4.
And are connected. The drive circuit stop circuit 5 is connected to the ground terminal E1 and its output side is connected to the drive circuit 3, and the current bypass circuit 6 is connected to the cathode side of the LED 1 via the resistor 2 and also connected to the ground terminal E1. Has been done.
【0020】駆動回路停止回路5は、電圧検出回路4に
より検出された電源電圧が通常動作における動作保証電
源電圧の範囲(例えば4.5V〜5.5V)に達してい
ないときに駆動回路3の作動を停止させる。また、電流
バイパス回路6は、電源電圧が前記動作保証電源電圧に
達していないときに作動してLED1のカソードと接地
端子E1との間を導通状態にする。なお、電圧検出回路
4により検出された電源電圧が前記動作保証電源電圧の
範囲内にあるときは、駆動回路停止回路5及び電流バイ
パス回路6の動作は停止される。The drive circuit stop circuit 5 is provided for the drive circuit 3 when the power supply voltage detected by the voltage detection circuit 4 has not reached the operation-guaranteed power supply voltage range (for example, 4.5 V to 5.5 V) in the normal operation. Stop operation. Further, the current bypass circuit 6 operates when the power supply voltage does not reach the operation-guaranteed power supply voltage, and brings the cathode of the LED 1 and the ground terminal E1 into conduction. When the power supply voltage detected by the voltage detection circuit 4 is within the operation-guaranteed power supply voltage range, the operation of the drive circuit stop circuit 5 and the current bypass circuit 6 is stopped.
【0021】一方、受光部20は、受光素子であるフォ
トダイオード21のアノード、カソード両端が受光回路
22の入力側に接続され、その受光回路22の出力側が
出力端子VOUTに接続されている。さらに、受光回路
22の電源側が受光側電源端子VCC2に、その接地側
が受光側接地端子E2にそれぞれ接続されている。On the other hand, in the light receiving section 20, both ends of the anode and the cathode of the photodiode 21, which is a light receiving element, are connected to the input side of the light receiving circuit 22, and the output side of the light receiving circuit 22 is connected to the output terminal VOUT. Further, the power supply side of the light receiving circuit 22 is connected to the light receiving side power supply terminal VCC2, and the ground side thereof is connected to the light receiving side ground terminal E2.
【0022】LED1より点滅発光された光信号は、フ
ォトダイオード21で電気信号に変換された後、受光回
路22によって増幅されて出力端子VOUTへ出力され
る。図2は、図1に示すフォトカプラにおける発光部1
0の回路図である。The optical signal flashing and emitted from the LED 1 is converted into an electric signal by the photodiode 21, amplified by the light receiving circuit 22, and output to the output terminal VOUT. FIG. 2 shows a light emitting unit 1 in the photocoupler shown in FIG.
It is a circuit diagram of 0.
【0023】同図において、駆動回路3は、NPNトラ
ンジスタ3−1〜3−9、PNPトランジスタ3−1
0、及び抵抗3−11〜3−17からなる入力段と、N
PNトランジスタ3−21〜3−23、PNPトランジ
スタ3−24、及び抵抗3−25〜3−29からなる出
力段とで構成されている。また、電圧検出回路4は、N
PNトランジスタ4−1〜4−8と、抵抗4−9,4−
10とで構成され、駆動回路停止回路5はNPNトラン
ジスタ5−1で構成されている。さらに、電流バイパス
回路6はマルチエミッタトランジスタ6−1で構成され
ている。In the figure, the drive circuit 3 includes NPN transistors 3-1 to 3-9 and a PNP transistor 3-1.
0 and an input stage consisting of resistors 3-11 to 3-17, and N
The output stage includes PN transistors 3-21 to 3-23, a PNP transistor 3-24, and resistors 3-25 to 3-29. Further, the voltage detection circuit 4 is
PN transistors 4-1 to 4-8 and resistors 4-9 and 4-
10 and the drive circuit stop circuit 5 is composed of an NPN transistor 5-1. Further, the current bypass circuit 6 is composed of a multi-emitter transistor 6-1.
【0024】図2に示す回路によれば、電圧検出回路4
のトランジスタ4−8は、ベース、エミッタ間のダイオ
ード順電圧を利用し、電源端子VCC1に印加される電
源電圧が約3.7Vでオンする。一方、電源電圧が約
3.7V以下(動作保証電源電圧の範囲よりも小さい)
ときには、前記トランジスタ4−8はオフ状態となり、
抵抗4−9を通して、駆動回路停止回路5を構成するト
ランジスタ5−1と、電流バイパス回路6を構成するト
ランジスタ6−1とにベース電流が流れ、これらのトラ
ンジスタ5−1,6−1が共にオンして導通状態とな
る。その結果、トランジスタ5−1のオンによって駆動
回路3の動作は停止し、トランジスタ6−1のオンによ
ってLED1に電流IF が流れる。According to the circuit shown in FIG. 2, the voltage detection circuit 4
Transistor 4-8 uses the diode forward voltage between the base and emitter, and turns on when the power supply voltage applied to the power supply terminal VCC1 is about 3.7V. On the other hand, the power supply voltage is approximately 3.7 V or less (smaller than the guaranteed operating power supply voltage range)
Sometimes the transistor 4-8 is turned off,
Through the resistor 4-9, a base current flows through the transistor 5-1 forming the drive circuit stop circuit 5 and the transistor 6-1 forming the current bypass circuit 6, so that these transistors 5-1 and 6-1 are both connected. It turns on and becomes conductive. As a result, the operation of the drive circuit 3 is stopped by turning on the transistor 5-1 and the current IF flows through the LED 1 by turning on the transistor 6-1.
【0025】また、電源端子VCC1に印加される電源
電圧が動作保証電源電圧の範囲(4.5〜5.5V)に
なったときには、電圧検出回路4のトランジスタ4−8
がオンして導通状態となり、前記トランジスタ5−1,
6−1のベース電流が断たれるため、駆動回路3は正常
に動作する。Further, when the power supply voltage applied to the power supply terminal VCC1 becomes within the operation-guaranteed power supply voltage range (4.5 to 5.5 V), the transistor 4-8 of the voltage detection circuit 4 is detected.
Turns on and becomes conductive, and the transistors 5-1 and
Since the base current of 6-1 is cut off, the drive circuit 3 operates normally.
【0026】なお、図2の駆動回路3ではバイポーラト
ランジスタを用いて構成したが、これに代えてMOSF
ETやジャンクションFET等を使用しても構成できる
ことは言うまでもない。Although the drive circuit 3 shown in FIG. 2 is constructed by using the bipolar transistor, it is replaced by a MOSF.
Needless to say, it can be configured by using an ET, a junction FET, or the like.
【0027】次に、本実施例の結合効率測定手法を説明
する。Next, the coupling efficiency measuring method of this embodiment will be described.
【0028】本実施例の結合効率測定は、通常動作にお
ける動作保証電源電圧の範囲(例えば4.5V〜5.5
V)より低い電圧を使用して行われる。これは、前述し
たように、ディジタル伝送では、駆動回路3により、デ
ィジタル入力信号の“1”または“0”に対して、一定
の電流を流すか、あるいはその電流を切るかしてLED
1を点滅させており、このような通常動作時における動
作保証電源電圧の範囲に結合効率測定時の電源電圧を設
定した場合は連続的に変化する電流をLED1に流すこ
とはできず、発光部10、受光部20間の結合効率を測
定することができないためである。The coupling efficiency of this embodiment is measured in the range of the power supply voltage guaranteed for normal operation (for example, 4.5 V to 5.5 V).
V) is used. As described above, this is because in the digital transmission, by the drive circuit 3, a constant current is made to flow to the digital input signal "1" or "0", or the current is cut off.
When the power supply voltage at the time of coupling efficiency measurement is set within the range of the operation-guaranteed power supply voltage during such normal operation, a continuously changing current cannot be passed through the LED 1 and the light emitting unit This is because the coupling efficiency between the light receiving unit 20 and the light receiving unit 20 cannot be measured.
【0029】電圧検出回路4によって検出された電源電
圧が前記動作保証電源電圧に達していないときは、駆動
回路停止回路5により駆動回路3の作動が停止し、且つ
電流バイパス回路6によりLED1のカソードと接地端
子E1との間が導通状態になる。When the power supply voltage detected by the voltage detection circuit 4 has not reached the operation guarantee power supply voltage, the drive circuit stop circuit 5 stops the operation of the drive circuit 3 and the current bypass circuit 6 causes the cathode of the LED 1 to operate. And the ground terminal E1 are electrically connected.
【0030】この状態で、電源端子VCC1に印加する
電源電圧を前記動作保証電源電圧の範囲より低い電圧で
徐々に増加させるていくと、LED1に流れる電流IF
は、図3に示すように増加し、電源電圧が4V近辺に近
付くと、急激に0となる。このように、LED1に連続
的に変化する電流IF を流すことができる。なお、電流
IF の変化の傾きは抵抗2の抵抗値で決定され、この抵
抗値を変更すれば電流IF の変化量を変えることができ
る。また、この抵抗2は、本実施例において回路内に内
蔵したが、測定時に外付けするようにしてもよい。In this state, when the power supply voltage applied to the power supply terminal VCC1 is gradually increased at a voltage lower than the operation guaranteed power supply voltage range, the current IF flowing in the LED1 is increased.
Increases as shown in FIG. 3, and becomes 0 rapidly when the power supply voltage approaches 4V. In this way, a continuously changing current IF can be passed through the LED 1. The slope of the change of the current IF is determined by the resistance value of the resistor 2, and the change amount of the current IF can be changed by changing the resistance value. Although the resistor 2 is built in the circuit in this embodiment, it may be externally attached at the time of measurement.
【0031】そして、このように、LED1に流れる電
流IF を連続的に変化させながら、受光部20の出力端
子VOUTから送出される出力信号の状態変化を監視
し、その出力状態が“H”レベルから“L”レベル(ま
たは“L”レベルから“H”レベル)へ変化した時のL
ED1に流れる電流IF を測定することにより、発光部
10と受光部20との結合効率を求めることができる。As described above, while continuously changing the current IF flowing through the LED 1, the state change of the output signal sent from the output terminal VOUT of the light receiving section 20 is monitored, and the output state is at "H" level. From the low level to the "L" level (or from the "L" level to the "H" level)
By measuring the current IF flowing in ED1, the coupling efficiency between the light emitting section 10 and the light receiving section 20 can be obtained.
【0032】以上の如く本実施例では、電圧検出回路
4、駆動回路停止回路5、及び電流バイパス回路6の各
手段を設けて、LED1を流れる電流が連続的に変化し
うるようにしたので、必要最小限の端子数で結合効率の
測定が行え、従来のように、検査用端子を設ける必要が
なく、その分パッケージを小型にすることができ、低コ
スト化することができる。As described above, in this embodiment, the voltage detecting circuit 4, the driving circuit stopping circuit 5, and the current bypass circuit 6 are provided so that the current flowing through the LED 1 can be continuously changed. The coupling efficiency can be measured with the minimum required number of terminals, and it is not necessary to provide an inspection terminal as in the conventional case, so that the package can be downsized and the cost can be reduced.
【0033】[0033]
【発明の効果】以上に説明したように、発光部の電源電
圧を検出する電圧検出回路と、この電圧検出回路により
検出された電源電圧が動作保証電源電圧の範囲に達して
いないときに発光素子駆動用の駆動回路の作動を停止さ
せる駆動回路停止回路と、電源電圧が前記動作保証電源
電圧に達していないときに前記発光素子に電流を流す電
流バイパス回路とを前記発光部に設けたので、特別に検
査用端子を設けなくとも、結合効率の測定検査が可能と
なる。従って、発光部及び受光部共に最少端子数(3端
子)で構成でき、従来の3端子型よりも信頼性が高く、
また検査用端子を設けたものよりもパッケージが小形化
され且つ低コストとなる。As described above, the voltage detection circuit for detecting the power supply voltage of the light emitting portion, and the light emitting element when the power supply voltage detected by the voltage detection circuit does not reach the operation guaranteed power supply voltage range. Since the drive circuit stop circuit for stopping the operation of the drive circuit for driving and the current bypass circuit for supplying a current to the light emitting element when the power supply voltage does not reach the operation guaranteed power supply voltage are provided in the light emitting unit, It is possible to measure and inspect the coupling efficiency without providing a special inspection terminal. Therefore, both the light emitting part and the light receiving part can be configured with the minimum number of terminals (3 terminals), which is more reliable than the conventional 3 terminal type,
In addition, the package is smaller and less expensive than the one provided with the inspection terminals.
【図1】本発明を実施した半導体フォト・カプラの概略
構成を示すブロック図である。FIG. 1 is a block diagram showing a schematic configuration of a semiconductor photo coupler embodying the present invention.
【図2】図1に示すフォトカプラにおける発光部10の
回路図である。FIG. 2 is a circuit diagram of a light emitting unit 10 in the photocoupler shown in FIG.
【図3】電源端子VCCに加える電圧とLED1に流れ
る電流の関係を示す図である。FIG. 3 is a diagram showing a relationship between a voltage applied to a power supply terminal VCC and a current flowing through the LED 1.
【図4】従来の半導体フォト・カプラの構成を示す概略
ブロック図である。FIG. 4 is a schematic block diagram showing a configuration of a conventional semiconductor photo coupler.
【図5】従来の他の半導体フォト・カプラの構成を示す
概略ブロック図である。FIG. 5 is a schematic block diagram showing the configuration of another conventional semiconductor photo coupler.
1 LED 3 駆動回路 4 電圧検出回路 5 駆動回路停止回路 6 電流バイパス回路 10 発光部 20 受光部 21 フォトダイオード VCC1,VCC2 電源端子 Vin 信号入力端子 E1,E2 接地端子 VOUT 出力端子 1 LED 3 Drive Circuit 4 Voltage Detection Circuit 5 Drive Circuit Stop Circuit 6 Current Bypass Circuit 10 Light Emitting Section 20 Light Receiving Section 21 Photodiode VCC1, VCC2 Power Supply Terminal Vin Signal Input Terminal E1, E2 Ground Terminal VOUT Output Terminal
Claims (1)
送出する駆動回路、及びその駆動出力に基づいて発光す
る発光素子を有する発光部と、前記発光素子からの光を
電気信号に変換する受光素子を有する受光部とを備えた
半導体フォト・カプラにおいて、 前記発光部の電源電圧を検出する電圧検出回路と、 前記電圧検出回路により検出された電源電圧が動作保証
電源電圧の範囲に達していないときに前記駆動回路の作
動を停止させる駆動回路停止回路と、 前記電圧検出回路により検出された電源電圧が前記動作
保証電源電圧に達していないときに前記発光素子に電流
を流す電流バイパス回路とを、 前記発光部に設けたことを特徴とする半導体フォト・カ
プラ。1. A drive circuit which sends out a drive output according to a digital input signal, a light emitting section having a light emitting element which emits light based on the drive output, and a light receiving element which converts light from the light emitting element into an electric signal. In a semiconductor photo coupler including a light receiving unit having a voltage detecting circuit for detecting the power supply voltage of the light emitting unit, and the power supply voltage detected by the voltage detecting circuit is not within the operation guaranteed power supply voltage range. A drive circuit stop circuit for stopping the operation of the drive circuit, and a current bypass circuit for supplying a current to the light emitting element when the power supply voltage detected by the voltage detection circuit does not reach the operation guaranteed power supply voltage, A semiconductor photo coupler provided in the light emitting unit.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP22480693A JP3367718B2 (en) | 1993-09-09 | 1993-09-09 | Semiconductor photo coupler |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP22480693A JP3367718B2 (en) | 1993-09-09 | 1993-09-09 | Semiconductor photo coupler |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH0786902A true JPH0786902A (en) | 1995-03-31 |
JP3367718B2 JP3367718B2 (en) | 2003-01-20 |
Family
ID=16819501
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP22480693A Expired - Fee Related JP3367718B2 (en) | 1993-09-09 | 1993-09-09 | Semiconductor photo coupler |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP3367718B2 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7642494B2 (en) | 2007-04-24 | 2010-01-05 | Kabushiki Kaisha Toshiba | Light emitting apparatus and method for inspecting same |
US7859810B2 (en) | 2007-09-14 | 2010-12-28 | Kabushiki Kaisha Toshiba | Photocoupler |
-
1993
- 1993-09-09 JP JP22480693A patent/JP3367718B2/en not_active Expired - Fee Related
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7642494B2 (en) | 2007-04-24 | 2010-01-05 | Kabushiki Kaisha Toshiba | Light emitting apparatus and method for inspecting same |
US7859810B2 (en) | 2007-09-14 | 2010-12-28 | Kabushiki Kaisha Toshiba | Photocoupler |
Also Published As
Publication number | Publication date |
---|---|
JP3367718B2 (en) | 2003-01-20 |
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