JPS57144469A - Overcurrent detecting circuit - Google Patents
Overcurrent detecting circuitInfo
- Publication number
- JPS57144469A JPS57144469A JP3033481A JP3033481A JPS57144469A JP S57144469 A JPS57144469 A JP S57144469A JP 3033481 A JP3033481 A JP 3033481A JP 3033481 A JP3033481 A JP 3033481A JP S57144469 A JPS57144469 A JP S57144469A
- Authority
- JP
- Japan
- Prior art keywords
- voltage
- input
- waveform
- comparator
- current
- 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
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/165—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
- G01R19/16566—Circuits and arrangements for comparing voltage or current with one or several thresholds and for indicating the result not covered by subgroups G01R19/16504, G01R19/16528, G01R19/16533
- G01R19/16571—Circuits and arrangements for comparing voltage or current with one or several thresholds and for indicating the result not covered by subgroups G01R19/16504, G01R19/16528, G01R19/16533 comparing AC or DC current with one threshold, e.g. load current, over-current, surge current or fault current
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Current Or Voltage (AREA)
- Emergency Protection Circuit Devices (AREA)
Abstract
PURPOSE:To answer without delay by a regular current waveform without answering by a spike current component of an input current waveform, by comparing the reference voltage on which differential voltage of detection voltage has been superposed, with the detection voltage. CONSTITUTION:A detection current transformed by a transformer T1 is shunted by resistnaces R1, R2, and a voltage waveform almost similar to a current waveform is generated across the resistance R2. This voltage waveform is applied to not only one input termianl of a comparator CP but also a differentiating circuit constituted of a capacitor C3 and a resistance R3, and to the reference side input terminal of the comparator CP, superposed reference voltage obtained by superposing the differential voltage on the reference voltage is applied. In this way, even if input voltage has been raised by a spike current component of the input current waveform, input voltage of the reference side is also raised in accordance with said rise, and the comparator is capable of exactly detecting an overcurrent without answering by the spike current component.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3033481A JPS57144469A (en) | 1981-03-03 | 1981-03-03 | Overcurrent detecting circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3033481A JPS57144469A (en) | 1981-03-03 | 1981-03-03 | Overcurrent detecting circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS57144469A true JPS57144469A (en) | 1982-09-07 |
| JPH023947B2 JPH023947B2 (en) | 1990-01-25 |
Family
ID=12300912
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3033481A Granted JPS57144469A (en) | 1981-03-03 | 1981-03-03 | Overcurrent detecting circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS57144469A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007147538A (en) * | 2005-11-30 | 2007-06-14 | Ricoh Co Ltd | Device for detecting light-emitting drive current, and image forming apparatus |
-
1981
- 1981-03-03 JP JP3033481A patent/JPS57144469A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007147538A (en) * | 2005-11-30 | 2007-06-14 | Ricoh Co Ltd | Device for detecting light-emitting drive current, and image forming apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH023947B2 (en) | 1990-01-25 |
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