Power surge protection circuit
First Claim
1. Apparatus for protecting electronic equipment from a line voltage transient resulting from a temporary power line interruption comprising:
- power input means for receiving alternating current line voltage and providing first and second signals derived from the line voltage;
power output means operatively connected to said power input means for connecting the line voltage to the protected electronic equipment, said power output means including a normally open switch responsive to said first signal for connecting the electronic equipment to the power line and responsive to the interruption of said first signal for disconnecting the protected electronic equipment from the power line;
signal comparing means responsive to said second signal and a reference signal for providing a gate signal when said second signal has a predetermined relationship to said reference signal;
gated switch means responsive to said first signal and said gate signal for transmitting said first signal to said power output means and to said signal comparing means such that said first signal, when so transmitted, constitutes the reference signal; and
energy storage means coupled to said signal comparing means and responsive to said first signal such that (a) said energy storage means is charged up to the level of said first signal when said first signal is transmitted to said signal comparing means, and (b) said energy storage means is discharged at a preselected rate so as to provide the reference signal after a power line interruption when said second signal is interrupted from said signal comparing means;
said discharge rate being selected to provide a time delay after the power line interruption during which the electronic equipment is maintained disconnected from the power line.
1 Assignment
0 Petitions
Accused Products
Abstract
A circuit for protecting electronic equipment such as computers, laser printers, fax machines, and the like from damage due to electrical transients associated with a temporary power interruption is connectable between a source of A.C. power and the electronic equipment. The circuit disconnects the equipment from the power source during a temporary power outage and maintains the equipment disconnected from the A.C. power until transients in the line voltage have abated. The circuit reconnects the equipment to the A.C. power source after a preselected time delay from the initial power interruption. The circuit keeps track of time during a power interruption without the use of batteries.
37 Citations
11 Claims
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1. Apparatus for protecting electronic equipment from a line voltage transient resulting from a temporary power line interruption comprising:
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power input means for receiving alternating current line voltage and providing first and second signals derived from the line voltage; power output means operatively connected to said power input means for connecting the line voltage to the protected electronic equipment, said power output means including a normally open switch responsive to said first signal for connecting the electronic equipment to the power line and responsive to the interruption of said first signal for disconnecting the protected electronic equipment from the power line; signal comparing means responsive to said second signal and a reference signal for providing a gate signal when said second signal has a predetermined relationship to said reference signal; gated switch means responsive to said first signal and said gate signal for transmitting said first signal to said power output means and to said signal comparing means such that said first signal, when so transmitted, constitutes the reference signal; and energy storage means coupled to said signal comparing means and responsive to said first signal such that (a) said energy storage means is charged up to the level of said first signal when said first signal is transmitted to said signal comparing means, and (b) said energy storage means is discharged at a preselected rate so as to provide the reference signal after a power line interruption when said second signal is interrupted from said signal comparing means; said discharge rate being selected to provide a time delay after the power line interruption during which the electronic equipment is maintained disconnected from the power line. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification