Low voltage current limit circuit with temperature insensitive foldback network
US5804955A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 30, 1996 |
| Grant date | Sep 8, 1998 |
| Priority date | — |
| Expiry date | Oct 30, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05F1/468
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A voltage regulator with a current limit circuit for limiting pass current in a pass transistor below a current limit threshold and a foldback circuit for lowering the current limit threshold when the voltage differential between the input and output terminals of the voltage regulator exceeds a foldback threshold, where the current limit threshold has a negative temperature coefficient, the current limit circuit comprising two transistors coupled to a sense resistor such that the difference in emitter-to-base voltages of the transistors is equal to the voltage drop of the sense resistor, where the collectors of the two transistors provides first and second currents to first and second resistors, respectively, where the first current is responsive to a pass current flowing through the sense resistor and decreases when the pass current increases, where the second current is independent of the pass current, and the foldback circuit provides a third current to the second resistor when the voltage differential between the input and output terminals of the voltage regulator exceeds the foldback threshold. A comparator circuit compares a first voltage drop developed across the first resis…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.