Equipment and methods for emergency lighting that provides brownout detection and protection

• US 20070086128A1
• Filed: 12/06/2006
• Published: 04/19/2007
• Est. Priority Date: 09/28/2004
• Status: Active Grant

• Current Assignee: ABL IP Holding LLC (Acuity Brands, Inc.)
• Original Assignee: Acuity Brands, Inc.
• Inventors: Zulim, Don, Lane, John
• Granted Patent: US 7,501,768 B2
• Time in Patent Office: Days
• US Class Current: 361/42
• CPC Class Codes: H02J 9/065 for lighting purposes
• CPC Class Codes: H05B 41/28 using static converters
• CPC Class Codes: H05B 45/375 using buck topology

Abstract

The present invention relates to systems, equipment and methods that provide emergency lighting and allow the detection of brownout conditions. One aspect of the present invention is an emergency lighting system with an input voltage interface for receiving an input voltage, a brownout detection component for detecting a brownout condition on the input voltage and generating a brownout signal, a switch mode power converter for altering the input voltage; and an emergency lighting control and battery charging component for controlling the charging of a battery pack and receiving the brownout signal. Another aspect of the invention is a method of providing emergency lighting performed by receiving an input voltage; automatically establishing a brownout threshold relative to the input voltage; and detecting a brownout condition.

Claims

1. A method of determining a brownout threshold for use in providing emergency lighting comprising:

providing a circuit configured to operate over a wide range of input voltages;

connecting the circuit to an input voltage with an expected voltage level, wherein the expected voltage level is a discrete voltage level within the wide range of voltages;

sampling an actual voltage level of the input voltage; and

in response to sampling the actual input voltage level, automatically establishing a brownout threshold based on the sampled input voltage level and not based on the expected voltage level.

2. The method of claim 1 further comprising transforming the input voltage using a switch mode power converter.

3. The method of claim 1 further comprising transforming the input voltage to charge a battery.

4. The method of claim 1 further comprising altering the input voltage to power an emergency lighting control component.

5. The method of claim 1 further comprising detecting a brownout condition using the brownout threshold.

6. The method of claim 1 wherein the brownout threshold is proportional to the input voltage.

7. The method of claim 1 wherein the brownout threshold is determined independent of the frequency of the AC line input.

8. The method of claim 1 further comprising sending a brownout signal to activate a lighting device.

9. The method of claim 1 further comprising activating an isolated lighting device.

10. The method of claim 1 wherein receiving an input voltage comprises receiving an input voltage is in the range from 85 to 305 Volts.

11. A method of providing emergency lighting comprising:

receiving an input voltage;

determining a brownout condition threshold voltage based at least in part on an actual level of the input voltage;

monitoring the input voltage for a brownout condition, wherein a brownout condition is determined to exist when the input voltage drops below the brownout condition threshold voltage;

if a brownout condition exists, sending a brownout signal to activate emergency lighting; and

if a brownout condition does not exist, using a switch mode power converter to provide power.

12. The method of claim 11 wherein the switch mode power converter provides power to charge a battery.

13. The method of claim 11 wherein the switch mode power converter supplies power to charge an emergency lighting control component.

14. An emergency lighting unit comprising:

a converter capable of receiving a wide range of input voltages; and

a brownout detection component capable of detecting a brownout condition by comparing the input voltage with a brownout threshold value determined using a sample actual voltage level of the input voltage.

15. The system of claim 14 wherein the converter is a switch mode power converter.

16. The system of claim 14 wherein the converter operates over a range between 85 and 305 VAC.

17. The system of claim 14 wherein the converter does not have voltage specific taps.

18. The system of claim 14 wherein the converter accepts one or more odd voltage and frequency inputs.

19. The system of claim 14 wherein the brownout detection component determines one or more brownout thresholds.

20. The system of claim 14 wherein the brownout detection component determines the one or more brownout thresholds using the wide range of input voltages.