Overload protection circuit
US5299087A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 17, 1991 |
| Grant date | Mar 29, 1994 |
| Priority date | — |
| Expiry date | Jul 17, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2200/426
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The overload protection circuit 12 comprises a resistor bridge 20 with a low impedance sensing resistor r and high impedance resistors R1 to R4 which generates voltages Va and Vb at the inputs 32 and 34 of a comparator 22. Voltage Vb depend upon the value of the load current so that the comparator provides at its output 36 a control signal for opening the switching device 24 comprising a field effect transistor when the load current exceeds a maximum value. Resistor R5 reinforces the effect of the control signal. This circuit can be used in a system which comprises a central power supply unit 8 which powers a plurality of devices such as 4. The status of the circuit 12 is reported to the system 8 though line 14 and circuit 12 comprises a control circuit 26 which is responsive to set and reset control signals on lines 14 and 18 from the unit 8 to close or open the switch 26.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.