Voltage threshold circuit for power conditioner

• US 6,359,426 B1
• Filed: 11/24/1999
• Issued: 03/19/2002
• Est. Priority Date: 11/24/1999
• Status: Expired due to Term

• Current Assignee: Extreme Networks, Inc.
• Original Assignee: Enterasys Networks Incorporated (Extreme Networks, Inc.)
• Inventors: DeGregorio, John Anthony, Sarles, F. Williams
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): Laxton, Gary L.
• Application Number:
  US09/449,439
• Time in Patent Office: 846 Days
• Field of Search: 323/901, 323/908, 323/280, 323/281, 363/49
• US Class Current: 323/281
• CPC Class Codes: H02M 1/4208 Arrangements for improving power factor of AC input
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
• CPC Class Codes: Y02P 80/10 Efficient use of energy, e.g. using compressed air or pressurized fluid as energy carrier
• CPC Class Codes: Y10S 323/901 Starting circuits

Abstract

A voltage threshold circuit for the power factor correction stage of a power conversion system is provide. The circuit features a voltage threshold circuit with a comparator for (i) comparing a predetermined threshold voltage to the output voltage of a power factor correction stage of a power conditioner and (ii) outputting a signal if the output voltage is at least equal to the predetermined threshold voltage. The presence of the signal decreases the predetermined threshold voltage, thereby effectively changing the output voltage above which the comparator continues to output the signal.

Claims

1. In a power conditioner characterized by the use of a power factor correction stage having an output voltage, a voltage threshold circuit comprising:

a comparator with inputs and an output;

a predetermined threshold voltage connected to a first comparator input and providing a first value to the first comparator input;

a first signal corresponding to the output voltage of the power factor correction stage connected to a second comparator input and providing a second value to the second comparator input;

a second signal corresponding to the output of the comparator and determined by a comparison of values of first and second comparator inputs; and

a responsive means for altering one value in the group of first value and second value, in response to the second signal, changing the comparison of values of first and second comparator inputs.

2. The voltage threshold circuit of claim 1 wherein the comparator has an inverting input and a non-inverting input, the first comparator input being the non-inverting input of the comparator and the second comparator input being the inverting input of the comparator.

3. The voltage threshold circuit of claim 1 wherein the responsive means comprises an adjustable voltage divider.

4. The voltage threshold circuit of claim 3 wherein the voltage divider circuit receives the first signal and receives the second signal and transmits a third signal to the second comparator input, thereby the voltage divider is altering the second value provided to the second comparator input in response to the second signal.

5. The voltage threshold circuit of claim 1 wherein the responsive means further comprises a buffer circuit.

6. The voltage threshold circuit of claim 5 wherein the buffer circuit receives the second signal from the comparator and outputs a fourth signal which corresponds to the second signal but may be voltage translated, scaled or inverted with respect to the second signal.

7. The voltage threshold circuit of claim 6 wherein the responsive means further comprises a voltage divider circuit which intercepts the first signal and receives the fourth signal from the buffer and transmits a third signal to the second comparator input.

8. The voltage threshold circuit of claim 7 wherein the voltage divider receives the fourth and first signals, modifying and combining them to produce the third signal.

9. The voltage threshold circuit of claim 1 further comprising:

an applied power signal;

a signal generating means receiving both the applied power signal and the second signal; and

a control signal transmitted by the signal generating means for enabling and disabling at least one downstream device.

10. The voltage threshold circuit of claim 9 wherein the signal generating means comprises a transistor.

11. In a power conditioner characterized by the use of a power factor correction stage having an output voltage, a voltage threshold circuit comprising:

a comparison means for comparing a predetermined threshold voltage to a first signal corresponding to the output voltage of the power factor correction stage and outputting a second signal in response to the first signal being a value at least equal to the predetermined threshold voltage; and

a responsive means responsive to the second signal for decreasing the predetermined threshold voltage, effectively changing the threshold voltage above which the comparison means continues to output the second signal.

12. In a power conditioner characterized by the use of a power factor correction stage having an output voltage, a voltage threshold circuit comprising:

a first signal corresponding to the output voltage of the power factor correction stage;

a voltage divider circuit, with at least two inputs and at least one output, which receives said first signal;

a comparator with inputs and an output;

a predetermined threshold voltage connected to a first comparator input and providing a first value to the first comparator input;

a third signal transmitted from the voltage divider circuit connected to a second comparator input and providing a second value to the second comparator input;

a second signal corresponding to the output of the comparator and determined by a comparison of values of the first and second comparator inputs;

a buffer circuit receiving the second signal;

a fourth signal transmitted by the buffer circuit corresponding to the second signal with signal alterations made by the buffer, and received by the voltage divider circuit, the voltage divider circuit is thereby modifying the first signal to create the third signal received by the comparator.