JPS5449084A - Detector for abnormality of photo coupler circuit - Google Patents
Detector for abnormality of photo coupler circuitInfo
- Publication number
- JPS5449084A JPS5449084A JP11514777A JP11514777A JPS5449084A JP S5449084 A JPS5449084 A JP S5449084A JP 11514777 A JP11514777 A JP 11514777A JP 11514777 A JP11514777 A JP 11514777A JP S5449084 A JPS5449084 A JP S5449084A
- Authority
- JP
- Japan
- Prior art keywords
- output
- comparators
- coupling efficiency
- allowable limit
- abnormal
- 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)
Abstract
PURPOSE: To prevent malfunction by detecting the abnormal increase in dark current of a photo coupler circuit and abnormal decrease in coupling efficiency in their earily stages while carrying on the operation of the system.
CONSTITUTION: When the dark current of photo transistor 12 surpasses the highest allowable limit, output C of comparator 18 becomes low in potential L and an abnormal signal appears at output E of exclusive-OR 16. When the output of element 12 is more than a photo detection current and also above the lowest allowable limit value which corresponds to the lowest coupling efficiency, input erminals (a) of comparators 14 and 18 are both lower in potential than reference input terminals (b) and otuputs C are "L", so that circuit 16 will not output an abnormal signal. When the output of element 12 is below the lowest allowable limit value owing to a derease in coupling efficiency, the outputs of comparators 14 and 18 are "H" and "L" respectively, so that an abnormal signal will appear at output terminal E. By power supplies Vth and VR2, reference potentials of comparators are adjusted, and after abnormality is detected in its earily stage, a tolerant period is given, thereby making it possible to evade malfunction
COPYRIGHT: (C)1979,JPO&Japio
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11514777A JPS5449084A (en) | 1977-09-27 | 1977-09-27 | Detector for abnormality of photo coupler circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11514777A JPS5449084A (en) | 1977-09-27 | 1977-09-27 | Detector for abnormality of photo coupler circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5449084A true JPS5449084A (en) | 1979-04-18 |
| JPS5714573B2 JPS5714573B2 (en) | 1982-03-25 |
Family
ID=14655460
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11514777A Granted JPS5449084A (en) | 1977-09-27 | 1977-09-27 | Detector for abnormality of photo coupler circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5449084A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59101362U (en) * | 1982-12-27 | 1984-07-09 | 株式会社リコー | electrical connection device |
| JPS60111176U (en) * | 1983-12-27 | 1985-07-27 | カシオ計算機株式会社 | Liquid crystal display type small color television receiver |
| JPH0418301Y2 (en) * | 1987-10-01 | 1992-04-23 |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS51115872U (en) * | 1975-03-17 | 1976-09-20 | ||
| JPS5288579U (en) * | 1975-12-25 | 1977-07-01 |
-
1977
- 1977-09-27 JP JP11514777A patent/JPS5449084A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS51115872U (en) * | 1975-03-17 | 1976-09-20 | ||
| JPS5288579U (en) * | 1975-12-25 | 1977-07-01 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5714573B2 (en) | 1982-03-25 |
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