Electricity: power supply or regulation systems – Input level responsive – Using a linearly acting final control device
Patent
1996-09-26
1998-09-01
Berhane, Adolf
Electricity: power supply or regulation systems
Input level responsive
Using a linearly acting final control device
G05F 508
Patent
active
058015221
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 RMS voltage detector circuit are changed so that a different power limit is provided which is in excess of the first power limit. The switchover from one power limit to another is done by a non-linear switch device such as a diode turning on and adding a resistor in the voltage divider.
REFERENCES:
patent: 4876637 (1989-10-01), Mose et al.
patent: 5105182 (1992-04-01), Shindo
patent: 5297015 (1994-03-01), Miyazaki et al.
patent: 5568373 (1996-10-01), Small
Berhane Adolf
Compaq Computer Corporation
LandOfFree
Power limit circuit for computer system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Power limit circuit for computer system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Power limit circuit for computer system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-272989