Power limit circuit for computer system
US5801522A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 26, 1996 |
| Grant date | Sep 1, 1998 |
| Priority date | — |
| Expiry date | Sep 26, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F1/26
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method for controlling the power level of a computer system or the like provides a dual power range feature which allows a power supply to be used over a wide range of AC input voltages. The power control circuit employs a detector for the RMS voltage of the input power line, and a detector for the AC input current at the power line. These detected levels are applied to a multiplier to provide an indication of power input, multiplier output is compared with a reference to produce a control for the output power of the power supply. The duty cycle of an oscillator for an AC-to-DC conversion for a power factor control circuit within the power supply is the controlled element, using pulse width modulation. A dual power range is provided so that for low AC line voltages, where the AC line current would tend to be high, a lower power limit is in effect, then for higher AC line voltages, where AC line current is proportionally lower for a given power level, a higher power limit is allowed. This is accomplished by a simple and efficient circuit, in an example embodiment; when the RMS voltage of the AC input exceeds a certain level, the values of resistors in a voltage divider within the …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.