Programmable current limiting using a shunt resistor
US6917503B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 29, 2003 |
| Grant date | Jul 12, 2005 |
| Priority date | — |
| Expiry date | Oct 29, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H9/004
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An overcurrent protection circuit using a shunt resistor and the voltage drop across a switch to program a user-defined current limiting level. This protects the switch and the input power supply, as well as the load. The shunt resistor is connected to the input or output of the switch, and a temperature dependent current source, so that a voltage drop is generated across the shunt resistor. An amplifier is used to sense the voltage across the shunt resistor and the voltage drop across the switch. When the voltage drop across the switch exceeds the voltage drop across the shunt resistor, the amplifier will regulate the switch so that a voltage drop across the switch is equal to the voltage drop across the shunt resistor. In this way, a constant current through the switch can be achieved. A constant ratio between the current limiting level to the shunt resistor value can be achieved with this method, so the current limiting level is programmable by selecting the resistor value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.