Driver for identifying emergency power and activating emergency lighting

Abstract

An emergency lighting system comprising a driver, a lighting device, a normal power source, and an emergency power source is provided. The driver includes a controller. The controller is configured to analyze an AC power signal to determine waveform characteristic data. The controller is further configured to analyze the waveform characteristic data. The waveform characteristic data is analyzed to identify a power mode from a plurality of power modes including at least a first power mode and a second power mode. The controller is further configured to adjust, based on the identified power mode, a dimming level of the lighting device. The AC power signal analyzed by the driver corresponds to the normal power signal or the emergency power signal. At least one waveform characteristic of the normal power signal differs from a corresponding waveform characteristic of the emergency power signal.

Description

[0001] 2025PF80058

[0002] 1

[0003] Driver for identifying emergency power and activating emergency lighting

[0004] FIELD OF THE DISCLOSURE

[0005] The present disclosure is generally directed to a driver for a lighting device, and, more particularly, to identifying emergency power provided by an emergency power source and activating emergency lighting.

[0006] BACKGROUND

[0007] Safety standards typically require dimmable lighting to return to full brightness output (also referred to 100% brightness or 100% dimming level) when powered by an emergency power source, such as a generator or an inverter. Accordingly, a wired emergency lighting system must provide a means to (1) monitor a normal power bus powering one or more non-emergency lights of the system and (2) send a signal to every emergency luminaire to indicate loss of normal power. When emergency lights detect the absence of normal power, they are typically configured to adjust their dimming levels to full brightness output. In some wired systems, both normal and emergency power is wired to every emergency light so that the emergency lights may monitor the normal power for power loss. In other systems, a dedicated device monitors normal power and provides a low voltage signal and / or power signal to all emergency lights.

[0008] In other emergency lighting systems, signal wiring between the normal power bus and the emergency lights is replaced with radio frequency (RF) beacons transmitted from the non-emergency lights to the emergency lights. If the RF beacons are not received by the emergency lights, this is interpreted as the non-emergency lighting being deactivated due to power failure. Accordingly, when the RF beacons are not received, the emergency lights enter emergency mode and produce 100% brightness output.

[0009] The above wired and wireless systems for triggering emergency lights to provide full brightness output when emergency power is provided present a number of challenges. The aforementioned wired systems are typically very expensive to design and install due to the complexity of the various wired connections. Further, the physical wiring renders these systems relatively inflexible following installation. Regarding the wireless systems, these systems are similarly complex as they require installers to purchase two2025PF80058

[0010] 2

[0011] different types of lighting fixtures: (1) non-emergency fixtures to connect to the normal power bus to transmit the RF beacons and (2) emergency fixtures to connected to the emergency power bus and to receive the beacons. Further, the wireless transmission of the RF beacons introduces additional time delays into the system which may trigger false emergencies.

[0012] SUMMARY OF THE DISCLOSURE

[0013] The present disclosure is generally directed to a driver for a lighting device, such as an emergency lighting device, for an emergency lighting system. Broadly, the driver analyzes an AC power signal provided by an unknown power source (AC mains supply, AC generator, AC inverter, etc.). The driver analyzes the AC power signal to determine waveform characteristic data, such as frequency data or wave shape data. The waveform characteristic data is then analyzed to identify a power mode from a plurality of power modes. The power modes include an emergency power mode and a normal power mode. The emergency power mode may correspond to the AC power signal being provided by an emergency power source, such as an AC generator or an AC inverter. The normal power mode may correspond to the AC power signal being provided by an AC mains supply. If the emergency power mode is detected, a dimming level of the lighting device is adjusted to an emergency level (such as 100%) to conform with safety standards and to enable safe passage in areas illuminated by the emergency lighting system during an emergency situation. If the normal power mode is detected, the dimming level may be set according to user preference or other settings.

[0014] As described above, the driver can determine whether the emergency lighting system is receiving the AC power signal from an emergency power source, and, if so, adjust the dimming level of the lighting device to provide the necessary light required in an emergency situation. Accordingly, these features eliminate any need for wired or wireless communication to the emergency lighting devices, as the drivers of the emergency lighting devices can automatically differentiate between the AC power signal corresponding to normal utility power provided by the AC mains supply and the AC power signal corresponding to emergency power provided by the emergency power source. The AC power signal provided by the emergency power source is sufficiently different from the AC power signal provided by the AC mains supply to quickly and reliably identify an emergency power situation, while being close enough to conventional power standards to also operate other lighting devices that may also be on the emergency power bus.2025PF80058

[0015] 3

[0016] The AC power signal provided by the emergency power source (also referred to as “emergency power signal”) may include a number of different waveform characteristics in order to differentiate the emergency power signal from the AC power signal provided by the AC mains supply (also referred to “normal power signal”). In some examples, where the only devices receiving the emergency power signal are lighting devices, the emergency power signal may have a higher frequency (such as 70 Hz or higher) than a normal power signal (60 Hz in North America or 50 Hz in Europe). Accordingly, the higher frequency emergency power signal may be identified based on an analysis of zero-crossings during a time period.

[0017] In a further example where the only devices receiving the emergency power signal are lighting devices, the waveform emergency power signal may be a nonstandard wave shape, such as a square wave, rather than a standard sine wave. Accordingly, the wave shape of the nonstandard, emergency power signal could be compared to the wave shape of the standard, normal power signal to identify the emergency power signal.

[0018] In even further examples, the emergency power source may generate the emergency power signal by varying the frequency of the emergency power signal within a standard range. For example, the frequency of the emergency power signal could vary in the range of 60 Hz + / - 3.5% (from 57.9 to 62.1 Hz) over a 1.0 second period. By varying the frequency within a standard range, the emergency power signal may power devices (appliances, circuit breakers, etc.) other than lighting devices. The emergency power signal may be identified based on an analysis of zero-crossings during a time period.

[0019] Generally, in one aspect, a driver for a lighting device is provided. The driver includes a controller. The controller is configured to analyze an AC power signal to determine waveform characteristic data.

[0020] The controller is further configured to analyze the waveform characteristic data. The waveform characteristic data is analyzed to identify a power mode from a plurality of power modes including at least a first power mode and a second power mode.

[0021] The controller is further configured to adjust, based on the identified power mode, a dimming level of the lighting device.

[0022] According to an example, the first power mode may be an emergency power mode, and wherein the AC power signal may be generated by an emergency power source.

[0023] According to an example, the emergency power mode may adjust the dimming level to an emergency level.2025PF80058

[0024] 4

[0025] According to an example, the second power mode may be a normal power mode. The AC power signal may be generated by an AC mains supply.

[0026] According to an example, the waveform characteristic data includes frequency data of the AC power signal.

[0027] According to an example, determining the frequency data of the AC power signal includes (1) generating zero-crossing data for the AC power signal over a time period; and (2) calculating, based on the zero-crossing data, the frequency data over the time period.

[0028] According to an example, the power mode is identified based on the frequency data, a normal operation range, and a variation time threshold.

[0029] According to an example, the power mode is further identified based on a consistency time threshold.

[0030] According to an example, the waveform characteristic data comprises wave shape data, and wherein the power mode is identified based on a voltage threshold.

[0031] Generally, in another aspect, an emergency lighting system is provided. The emergency lighting system includes the driver, the lighting device coupled to the driver, a normal power source configured to generate a normal power signal, and an emergency power source configured to generate an emergency power signal. The AC power signal analyzed by the driver corresponds to the normal power signal or the emergency power signal. At least one waveform characteristic of the normal power signal differs from a corresponding waveform characteristic of the emergency power signal.

[0032] According to an example, the emergency power source is an AC inverter or an AC generator.

[0033] According to an example, the driver is arranged in a module arranged externally to the lighting device.

[0034] Generally, in a further aspect, a method for operating a lighting device is provided. The method includes: (1) analyzing an AC power signal to determine waveform characteristic data; (2) analyzing the waveform characteristic data to identify a power mode from a plurality of power modes comprising at least a first power mode and a second power mode; and (3) adjusting, based on the identified power mode, a dimming level of the lighting device.

[0035] According to an example, the first power mode is a normal power mode, and wherein the AC power signal is generated by an AC mains supply.

[0036] According to an example, the second power mode is an emergency power mode, and wherein the AC power signal is generated by an emergency power source.2025PF80058

[0037] 5

[0038] It should be appreciated that all combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not mutually inconsistent) are contemplated as being part of the inventive subject matter disclosed herein. In particular, all combinations of claimed subject matter appearing at the end of this disclosure are contemplated as being part of the inventive subject matter disclosed herein. It should also be appreciated that terminology explicitly employed herein that also may appear in any disclosure incorporated by reference should be accorded a meaning most consistent with the particular concepts disclosed herein.

[0039] In various implementations, a processor or controller may be associated with one or more storage media (generically referred to herein as “memory,” e.g., volatile and non-volatile computer memory such as RAM, PROM, EPROM, EEPROM, floppy disks, compact disks, optical disks, magnetic tape, SSD, etc.). In some implementations, the storage media may be encoded with one or more programs that, when executed on one or more processors and / or controllers, perform at least some of the functions discussed herein.

[0040] Various storage media may be fixed within a processor or controller or may be transportable, such that the one or more programs stored thereon can be loaded into a processor or controller so as to implement various aspects as discussed herein. The terms “program” or “computer program” are used herein in a generic sense to refer to any type of computer code (e.g., software or microcode) that can be employed to program one or more processors or controllers.

[0041] These and other aspects of the various embodiments will be apparent from and elucidated with reference to the embodiment s) described hereinafter.

[0042] BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In the drawings, like reference characters generally refer to the same parts throughout the different views. Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the various embodiments.

[0044] Fig. l is a schematic view of an emergency lighting system, in accordance with an example.

[0045] Fig. 2 is a schematic view of a variation of an emergency lighting system, in accordance with an example.

[0046] Fig. 3 is a schematic view of an emergency lighting device, in accordance with an example.2025PF80058

[0047] 6

[0048] Fig. 4 is a functional block diagram of an emergency lighting device, in accordance with an example.

[0049] Fig. 5A illustrates a normal power signal, in accordance with an example. Fig. 5B illustrates an emergency power signal oscillating at a higher frequency than the normal power signal of FIG. 5 A, in accordance with an example.

[0050] Fig. 6 is a functional block diagram of an emergency lighting device configured to detect an emergency power signal based on frequency data, in accordance with an example.

[0051] Fig. 7A illustrates a normal power signal, in accordance with an example. Fig. 7B illustrates an emergency power signal in the form of a square wave, in accordance with an example.

[0052] Fig. 8 is a functional block diagram of an emergency lighting device configured to detect an emergency power signal based on wave shape data, in accordance with an example.

[0053] Fig. 9A illustrates a normal power signal, in accordance with an example. Fig. 9B illustrates an emergency power signal oscillating according to a varying frequency, in accordance with an example.

[0054] Fig. 10 is a functional block diagram of an emergency lighting device configured to detect an emergency power signal based on varying frequency data, in accordance with an example.

[0055] Fig. 11 is a block diagram of a method for operating an emergency lighting device, in accordance with an example.

[0056] DETAILED DESCRIPTION OF EMBODIMENTS

[0057] The present disclosure is generally directed to a driver for a lighting device, such as an emergency lighting device, for an emergency lighting system. Broadly, the driver analyzes an AC power signal provided by an unknown power source (AC mains supply, AC generator, AC inverter, etc.). The driver analyzes the AC power signal to determine waveform characteristic data, such as frequency data or wave shape data. The waveform characteristic data is then analyzed to identify a power mode from a plurality of power modes. The power modes include an emergency power mode and a normal power mode. The emergency power mode may correspond to the AC power signal being provided by an emergency power source, such as an AC generator or an AC inverter. The normal power mode may correspond to the AC power signal being provided by an AC mains supply. If the2025PF80058

[0058] 7

[0059] emergency power mode is detected, a dimming level of the lighting device is adjusted to an emergency level (such as 100%) to conform with safety standards and to enable safe passage in areas illuminated by the emergency lighting system during an emergency situation. If the normal power mode is detected, the dimming level may be set according to user preference or other settings.

[0060] Turning now to the figures, FIG. 1 is an illustration of an emergency lighting system 1. Generally, in the non-limiting example of FIG. 1, the emergency lighting system 1 includes one or more lighting device 10a, 10b, an emergency power source 20, a normal power source 30 (shown as an AC mains supply), a power bus 50, and, optionally, one or more additional devices 60a, 60b. The lighting devices 10a, 10b may also be referred to as emergency lighting devices. Broadly, in non-emergency situations, the normal power source 30 provides an AC power signal 202a (also referred to as a normal power signal 202a) to the lighting devices 10a, 10b and the additional devices 60a, 60b via the power bus 50. If the normal power source 30 is interrupted, the power bus 50 switches to the emergency power source 20 to supply an AC power signal 202b (also referred to as an emergency power signal 202b) to the lighting devices 10a, 10b and the additional devices 60a, 60b. In some examples, the emergency power source 20 may be an AC generator or an AC inverter.

[0061] In the example of FIG. 1, the lighting devices 10a, 10b include drivers 100a, 100b to control the lighting output LI, L2 generated by the lighting device 10a, 10b. In this example, the lighting devices 10a, 10b may be referred to as emergency lighting devices 10a, 10b. As such, the emergency lighting devices 10a, 10b receive the emergency power signal 202b from the emergency power source 20 when the normal power source 30 is interrupted. When the emergency power signal 202b is being provided, the lighting devices 10a, 10b are configured to adjust their lighting output LI, L2 such that an area or egress may be safely illuminated during an emergency situation. In some examples, the drivers 100a, 100b of the emergency lighting devices 10a, 10b are configured to adjust a dimming level of the emergency lighting devices 10a, 10b to 100% when the emergency power signal 202b is being provided. Further, the additional devices 60a, 60b shown in FIG. 1 may include an exit sign 60a and a motor 60b.

[0062] FIG. 2 illustrates a variation of the emergency lighting system 1 of FIG. 1. In the non-limiting example of FIG. 2, the emergency lighting devices 10a, 10b are both controlled by an external module 40 with a single external driver 100. The external module 40 receives either the normal power signal 202a or the emergency power signal 202b via the power bus 50. The external module 40 then provides an external driver signal 42 to the2025PF80058

[0063] 8

[0064] emergency lighting devices 10a, 10b, thereby providing the emergency lighting devices 10a, 10b with power to generate their associated lighting outputs LI, L2.

[0065] FIG. 3 is a simplified schematic view of a lighting device 10. In the nonlimiting example of FIG. 3, the lighting device 10 includes a driver 100 and a light source LS. The lighting device 10 may also include a number of other hardware and / or software components or aspects. The light source LS may include one or more light emitting diodes (LEDs).

[0066] The driver 100 includes a controller 102 and a dimmer 117. The controller 102 includes a processor 150 and a memory 175. Broadly, the controller 102 uses the processor 150 and the memory 175 to control the dimmer 117, and therefore controls the lighting output generated by the light source LS. The processor 150 may take any suitable form, including, but not limited to a microcontroller, multiple microcontrollers, circuitry, a single processor, or plural processors. The memory 175 can take any suitable form, including a nonvolatile memory and / or RAM. The non-volatile memory may include read only memory (ROM), a hard disk drive (HDD), or a solid state drive (SSD). The memory 175 can store, among other things, operating system data corresponding to the AC power signal 202 received by the lighting device 10. The RAM is used by the processor 150 for the temporary storage of data. According to an embodiment, an operating system may contain code which, when executed by controller 102, controls the lighting output generated by the light source LS.

[0067] The dimmer 117 is configured to control the light output of the light source LS. The dimmer 117 may implement any appropriate type of dimming control, such as pulse width modulation dimming or phase cut dimming. As shown in FIG. 3, the dimmer 117 receives a dimming control signal from the controller 102 to control the dimmed power signal provided to the light source LS. In some examples, the driver 100 is configured to adjust the dimmer 117 to an emergency level (such as 100%) when an emergency power mode is detected. In further examples, the driver 100 may be configured to adjust the dimmer back to a level of less than 100% when normal power mode is detected. For example, a previous dimming level may be stored in memory and retrieved when the normal power mode is detected.

[0068] FIG. 4 illustrates a high-level functional block diagram of aspects of a lighting device 10. In the non-limiting example of FIG. 4, the lighting device 10 includes a driver 100 and a light source LS. The driver 100 includes a controller 102 and a dimmer 117. Aspects of2025PF80058

[0069] 9

[0070] the driver 100, including aspects of the controller 102 and / or the dimmer 117, may be performed with any practical combination of hardware and / or software.

[0071] In the non-limiting example of FIG. 4, the controller 102 includes a waveform analyzer 111, a power mode identifier 113, and a dimming adjuster 115. The waveform analyzer Ill is configured to receive an AC power signal 202, which may be a normal power signal 202a or an emergency power signal 202b. The waveform analyzer 111 generates waveform characteristic data 104 based on the AC power signal 202. The waveform characteristic data 104 may include any data corresponding to the AC power signal 202 which may be used to determine whether a normal power signal 202a or an emergency power signal 202b is being provided. The waveform characteristic data 104 may include data regarding waveform frequency, wave shape, amplitude, zero-crossing times, etc., collected over a period of time. The power mode identifier 113 then analyzes the waveform characteristic data 104 to determine whether the AC power signal 202 indicates that the emergency power system 1 is operating in a normal power mode 106a or an emergency power mode 106b.

[0072] The identified power mode 106 is then provided to the dimming adjuster 115. The dimming adjuster 115 generates a dimming control signal 126 based on the power mode 106. If the emergency power mode 106b is identified, the dimming control signal 126 may set a dimming level 108 of the dimmer 117 to an emergency level 124 stored in memory 175. The emergency level 124 may correspond to a factory setting, or it may correspond to a user defined level received via a user input. In some examples, the emergency level 124 may be 100% (or a maximum output level). In other examples, the emergency level 124 may be less than a maximum output level, such 90% or 95%. Additionally, if the dimming adjuster 115 receives notification of the emergency power mode 106b, the dimming adjuster 115 may ignore all other system or user inputs to adjust the dimming level 108 until the normal power mode 106a is detected.

[0073] If the emergency power system 1 is operating in normal power mode 106a, the dimming control signal 126 may set the dimming level 108 of the dimmer 117 to a lower dimming level, such as 25%, 50%, or 75%. In some examples, a stored dimming level 134 may be saved in memory 175. The dimming adjuster 115 may retrieve the stored dimming level 134 to generate the dimming control signal 126 when the normal power mode 106a is detected. The stored dimming level 134 may correspond to a default, factory setting dimming level, or it may correspond to a previous dimming level used by the lighting device 10 prior to the detection of the emergency power mode 106b, such as the most recent dimming level,2025PF80058

[0074] 10

[0075] or the most frequently used dimming level. Accordingly, the dimmer 117 receives both the dimming control signal 126 and the AC power signal 202. The dimming level 108 is adjusted based on the dimming control signal, and the AC power signal 202 is modified or modulated according to the dimming level 108. The dimmer 117 then provides a dimmed power signal 128 to the light source LS for illumination.

[0076] The emergency power signal 202b may be distinguished from the normal power signal 202a by a variety of waveform characteristics 203a, 203b. The waveform characteristics 203a, 203b may include frequency, wave shape, amplitude, and more. In the examples of FIGS. 5 A and 5B, the normal power signal 202a has a frequency of 60 Hz, typical for AC mains supplies 30 in North America. By contrast, the emergency power source 20 has been configured to configure the emergency power signal 202b to have a constant frequency of approximately 70 Hz. As will be demonstrated, the frequency of the normal power signal 202a or the emergency power signal 202b may be determined according to the amount of time between zero-crossings, i.e., when the signal 202a, 202b crosses the horizontal axis. For example, if the time between two zero-crossing points is 20 milliseconds, the frequency of the signal 202a, 202b between those two zero-crossing points is 50 Hz. The emergency power signal 202b illustrated in FIG. 5B may be particularly applicable to lighting devices using LEDs, as other types of electrical or electronic devices may not be able to operate at a frequency of 70 Hz.

[0077] FIG. 6 illustrates a specific implementation of the functional block diagram of FIG. 4. In this example, the waveform characteristic data 104 generated by the waveform analyzer 111 includes frequency data 110. In particular, the frequency data 110 includes zero-crossing data 112 over a time period 114. The power mode identifier 113 then analyzes the zero-crossing data 112 to determine if the frequency of the AC power signal 202 is outside of a normal operation range 116 (such as from 58 Hz to 62 Hz or from 48 Hz to 52 Hz) for a variation time threshold 118 (such as at least 4 seconds). Thus, if the AC power signal 202 is determined to maintain a frequency of 70 Hz (as shown in FIG. 5B) for 4 seconds, the emergency power mode 106b is detected. Following the detection of the emergency power mode 106b, normal power mode 106a may be detected if the AC power signal 202 maintains a frequency within the normal operation range 116 for a secondary time threshold 136 (such as at least 10 seconds). Accordingly, if the AC power signal 202 has a frequency of 60 Hz for 8 seconds, the normal power mode 106b is detected.

[0078] FIGS. 7A and 7B illustrate a variation of FIGS. 5A and 5B. While FIG. 7A illustrates a conventional normal power signal 202a as a sine wave, the FIG. 7B illustrates an2025PF80058

[0079] 11

[0080] emergency power signal 202b configured as a square wave. Thus, the emergency power signal 202b may be detected by analyzing the wave shape of the signal 202a, 202b. As can be seen in FIG. 7A, the normal power signal 202a is above an amplitude threshold 130 for 35% of a cycle. By contrast, the emergency power signal 202b is above the same amplitude threshold 130 for 50% of a cycle. Accordingly, the normal and emergency power signals 202a, 202b can be identified by analyzing the individual cycles of the signals 202a, 202b against the amplitude threshold 130.

[0081] FIG. 8 illustrates another specific implementation of the functional block diagram of FIG. 4. In this example, the waveform characteristic data 104 generated by the waveform analyzer 111 includes wave shape data 122. In particular, the wave shape data 122 may track the amplitude of the AC power signal 202 over time. The wave shape data 122 is then provided to the power mode identifier 113. The power mode identifier 113 compares the amplitude of the wave shape data 122 corresponding to each cycle of the AC power signal 202 to the amplitude threshold 130 to determine an over-threshold percentage for each cycle. For example, the over-threshold percentage of the first cycle of the normal power signal 202a of FIG. 7 A is 35%, and the over-threshold percentage of the first cycle of the emergency power signal 202b of FIG. 7B is 50%. The over-threshold percentage is then compared to a percentage threshold 132. For example, in the example of FIGS. 7A and 7B, the percentage threshold 132 is 45%. If the over-threshold percentage exceeds the percentage threshold 132 for a time period exceeding the variation time threshold 118 (such as at least four seconds), the emergency power mode 106b is detected, and the dimming level 108 is set according to an emergency level 124. Similarly, if the over-threshold percentage fails to exceed the percentage threshold 132 for a time period exceeding the secondary time threshold 136 (such as at least ten seconds), the normal power mode 106a is detected.

[0082] FIGS. 9A and 9B illustrate a further variation of FIGS. 5A and 5B. While FIG.

[0083] 9A illustrates a conventional normal power signal 202a as a sine wave with a constant frequency of 60 Hz, FIG. 7B illustrates an emergency power signal 202b configured as a sine wave having a frequency varying from 57.9 Hz to 62.1 Hz and back to 57.9 Hz within a one second sweep. This variation may also be defined at 60 Hz + / -3.5%. In some examples, the emergency power source 20 providing the emergency power signal 202b could be a mechanical generator with a gear arrangement designed to vary transmission speed over a fixed time period. Further, the emergency power source 20 could be an AC inverter with digitally controlled firmware to provide this frequency variation. Thus, the emergency power signal 202b may be identified by detecting these shifts in frequency. Notably, the frequency2025PF80058

[0084] 12

[0085] range of the emergency power signal 202b is within frequency variations accepted by most electrical devices, including lighting devices, motors, circuit breakers, etc. By contrast, nonlighting electrical devices may not be configured to function with the emergency power signals 202b shown in FIGS. 5B and 7B.

[0086] FIG. 10 illustrates another specific implementation of the functional block diagram of FIG. 4. In this example, the waveform analyzer 111, as with the example of FIG.

[0087] 6, generates waveform characteristic data 104 in the form of frequency data 110 including zero-crossing data 112 over a time period 114. The power mode identifier 113 then analyzers the frequency data 110 to determine if the AC power signal 202 is a frequency varying emergency power signal 202b. First, the power mode identifier 113 determines if the frequency of the AC power signal 202 is outside of a normal operation range 116 during a variation time threshold 118. In some examples, the variation time threshold is 4 seconds or more, corresponding to 240 cycles or more for a 60 Hz waveform. Referencing FIG. 9B, if the frequency of the emergency power signal 202b sweeps at 60 Hz + / - 3.50% (i.e., from 57.90 Hz to 62.10 Hz), the normal operation range 116 may be defined as 60 Hz + / - 2.45% (i.e., from 58.53 Hz to 61.47 Hz).

[0088] While the frequency of the AC power signal 202 being outside of the normal operation range 116 may be a sign of the emergency power signal 202b, in some circumstances, it may be indicative of noise or other brief anomalies occurring on the normal power signal 202a. Accordingly, a consistency time threshold 120 and a consistency count threshold 138 may be used to distinguish the emergency power signal 202b from a noisy or anomalous normal power signal 202a. In some examples, the zero-crossing data 112 may indicate that the current frequency of the of the AC power signal 202 is 58.00 Hz, and therefore outside of the normal operation range 116 of 60 Hz + / - 2.45%. Using subsequent zero-crossing data 112, the power mode identifier 113 then determines if the next frequency of the AC power signal 202 determined outside of the normal operation range 116 is within the consistency time threshold 120 (for example, 0.3 seconds). Accordingly, if two frequencies of the AC power signal 202 are determined to be outside of the normal operation range 116 within the consistency time threshold 120, a consistency count may be incremented by the power mode identifier 113. If the consistency count value exceeds the consistency count threshold 138 (such as at least 3 counts) during the variation time threshold 118 (such as 4 seconds), the power mode identifier 113 identifies the emergency power signal 202b and informs the dimming adjuster 115 of the emergency power mode 106b. The2025PF80058

[0089] 13

[0090] dimming adjuster 115 may then use the dimming control signal 126 to set the dimming level 108 of the dimmer 117 to an emergency power level 124.

[0091] Once the emergency power mode 106b has been identified, normal power mode 106a may be detected by determining if the frequency of the AC power signal 202 is within the normal operation range 116 for the secondary time threshold 136 (such as at least 10 seconds). The dimming adjuster 115 may then adjust the dimming level 108 of the dimmer 117 according to a stored dimming level 134.

[0092] FIG. 11 is a block diagram of a method 900 for operating an emergency lighting device 10. The method 900 includes, in step 902, analyzing an AC power signal 202 to determine waveform characteristic data 104.

[0093] The method 900 further includes, in step 904, analyzing the waveform characteristic data 104 to identify a power mode 106 from a plurality of power modes comprising at least a first power mode 106a and a second power mode 106b.

[0094] The method 900 further includes, in step 906, adjusting, based on the identified power mode 106, a dimming level 108 of the lighting device 10.

[0095] According to an example, the first power mode 106a is a normal power mode, and wherein the AC power signal 202 is generated by an AC mains supply.

[0096] According to an example, the second power mode 106b is an emergency power mode. The AC power signal 202 is generated by an emergency power source 20.

[0097] All definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and / or ordinary meanings of the defined terms.

[0098] The indefinite articles “a” and “an,” as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean “at least one.”

[0099] The phrase “and / or,” as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with “and / or” should be construed in the same fashion, i.e., “one or more” of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the “and / or” clause, whether related or unrelated to those elements specifically identified.

[0100] As used herein in the specification and in the claims, “or” should be understood to have the same meaning as “and / or” as defined above. For example, when2025PF80058

[0101] 14

[0102] separating items in a list, “or” or “and / or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of’ or “exactly one of,” or, when used in the claims, “consisting of,” will refer to the inclusion of exactly one element of a number or list of elements. In general, the term “or” as used herein shall only be interpreted as indicating exclusive alternatives (i.e. “one or the other but not both”) when preceded by terms of exclusivity, such as “either,” “one of,” “only one of,” or “exactly one of.”

[0103] As used herein in the specification and in the claims, the phrase “at least one,” in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified.

[0104] It should also be understood that, unless clearly indicated to the contrary, in any methods claimed herein that include more than one step or act, the order of the steps or acts of the method is not necessarily limited to the order in which the steps or acts of the method are recited.

[0105] In the claims, as well as in the specification above, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” “composed of,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of’ and “consisting essentially of’ shall be closed or semi-closed transitional phrases, respectively.

[0106] The above-described examples of the described subject matter can be implemented in any of numerous ways. For example, some aspects may be implemented using hardware, software, or a combination thereof. When any aspect is implemented at least in part in software, the software code can be executed on any suitable processor or collection of processors, whether provided in a single device or computer or distributed among multiple devices / computers.

[0107] The present disclosure may be implemented as a system, a method, and / or a computer program product at any possible technical detail level of integration. The computer program product may include a computer readable storage medium (or media) having2025PF80058

[0108] 15

[0109] computer readable program instructions thereon for causing a processor to carry out aspects of the present disclosure.

[0110] The computer readable storage medium can be a tangible device that can retain and store instructions for use by an instruction execution device. The computer readable storage medium may be, for example, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of the computer readable storage medium includes the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanically encoded device such as punch-cards or raised structures in a groove having instructions recorded thereon, and any suitable combination of the foregoing. A computer readable storage medium, as used herein, is not to be construed as being transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission media (e.g., light pulses passing through a fiber-optic cable), or electrical signals transmitted through a wire.

[0111] Computer readable program instructions described herein can be downloaded to respective computing / processing devices from a computer readable storage medium or to an external computer or external storage device via a network, for example, the Internet, a local area network, a wide area network and / or a wireless network. The network may comprise copper transmission cables, optical transmission fibers, wireless transmission, routers, firewalls, switches, gateway computers and / or edge servers. A network adapter card or network interface in each computing / processing device receives computer readable program instructions from the network and forwards the computer readable program instructions for storage in a computer readable storage medium within the respective computing / processing device.

[0112] Computer readable program instructions for carrying out operations of the present disclosure may be assembler instructions, instruction-set-architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state-setting data, configuration data for integrated circuitry, or either source code or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, C++, or the like, and2025PF80058

[0113] 16

[0114] procedural programming languages, such as the “C” programming language or similar programming languages. The computer readable program instructions may execute entirely on the user’s computer, partly on the user's computer, as a stand-alone software package, partly on the user’s computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). In some examples, electronic circuitry including, for example, programmable logic circuitry, field-programmable gate arrays (FPGA), or programmable logic arrays (PLA) may execute the computer readable program instructions by utilizing state information of the computer readable program instructions to personalize the electronic circuitry, in order to perform aspects of the present disclosure.

[0115] Aspects of the present disclosure are described herein with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to examples of the disclosure. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer readable program instructions.

[0116] The computer readable program instructions may be provided to a processor of a, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions / acts specified in the flowchart and / or block diagram block or blocks. These computer readable program instructions may also be stored in a computer readable storage medium that can direct a computer, a programmable data processing apparatus, and / or other devices to function in a particular manner, such that the computer readable storage medium having instructions stored therein comprises an article of manufacture including instructions which implement aspects of the function / act specified in the flowchart and / or block diagram or blocks.

[0117] The computer readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other device to produce a computer implemented process, such that the instructions which execute2025PF80058

[0118] 17

[0119] on the computer, other programmable apparatus, or other device implement the functions / acts specified in the flowchart and / or block diagram block or blocks.

[0120] The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various examples of the present disclosure. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the blocks may occur out of the order noted in the Figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and / or flowchart illustration, and combinations of blocks in the block diagrams and / or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts or carry out combinations of special purpose hardware and computer instructions.

[0121] Other implementations are within the scope of the following claims and other claims to which the applicant may be entitled.

[0122] While various examples have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and / or structures for performing the function and / or obtaining the results and / or one or more of the advantages described herein, and each of such variations and / or modifications is deemed to be within the scope of the examples described herein. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and / or configurations will depend upon the specific application or applications for which the teachings is / are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific examples described herein. It is, therefore, to be understood that the foregoing examples are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, examples may be practiced otherwise than as specifically described and claimed. Examples of the present disclosure are directed to each individual feature, system, article, material, kit, and / or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and / or methods, if such features, systems, articles, materials,2025PF80058

[0123] 18

[0124] kits, and / or methods are not mutually inconsistent, is included within the scope of the present disclosure.

Claims

2025PF8005819CLAIMS:

1. A driver (100) of a lighting device (10), the driver (100) comprising a controller (102) configured to:analyze an AC power signal (202) to determine waveform characteristic data (104);analyze the waveform characteristic data (104) by comparing the waveform characteristic data to a threshold for the waveform characteristic data;identify, responsive to the comparison to the threshold, a power mode (106) from a plurality of power modes comprising at least a first power mode (106a) and a second power mode (106b); andadjust, based on the identified power mode, a dimming level (108) of the lighting device (10).

2. The driver (100) of claim 1, wherein the first power mode (106a) is a normal power mode, and wherein the AC power signal (202) is generated by an AC mains supply (30).

3. The driver (100) of claim 1, wherein the second power mode (106b) is an emergency power mode, and wherein the AC power signal (202) is generated by an emergency power source (20).

4. The driver (100) of claim 3, the emergency power mode adjusts the dimming level (108) to an emergency level (124).

5. The driver (100) of claim 1, wherein the waveform characteristic data (104) comprises frequency data (110) of the AC power signal (202).

6. The driver (100) of claim 5, wherein determining the frequency data (110) of the AC power signal (202) comprises:2025PF8005820generating zero-crossing data (112) for the AC power signal (202) over a time period (114); andcalculating, based on the zero-crossing data (112), the frequency data (110) over the time period (114).

7. The driver (100) of claim 6, wherein the power mode (106) is identified based on the frequency data (110), a normal operation range (116), and a variation time threshold (H8).

8. The driver (100) of claim 7, wherein the power mode (106) is further identified based on a consistency time threshold (120).

9. The driver (100) of claim 1, wherein the waveform characteristic data (104) comprises wave shape data (122), and wherein the power mode (106) is identified based on a voltage threshold (130).

10. An emergency lighting system (1), comprising:the driver (100) of claim 1;the lighting device (10) coupled to the driver (100);a normal power source (30) configured to generate a normal power signal (202a); and an emergency power source (20) configured to generate an emergency power signal (202b), wherein the AC power signal (202) analyzed by the driver (100) corresponds to the normal power signal (202a) or the emergency power signal (202b), and wherein at least one waveform characteristic (203 a) of the normal power signal (202a) differs from a corresponding waveform characteristic (203b) of the emergency power signal (202b).

11. The emergency lighting system (1) of claim 10, wherein the emergency power source (20) is an AC inverter (20a) or an AC generator (20b).

12. The emergency lighting system (1) of claim 10, wherein the driver (100) is arranged in a module (40) arranged externally to the lighting device (10).

13. A method (900) for operating a lighting device, comprising:2025PF8005821analyzing (902), by a controller of a driver of the lighting device, an AC power signal to determine waveform characteristic data;analyzing (904) the waveform characteristic data by comparing the waveform characteristic data to a threshold for the waveform characteristic data;identifying, responsive to the comparison to the threshold, a power mode from a plurality of power modes comprising at least a first power mode and a second power mode; andadjusting (906), based on the identified power mode, a dimming level of the lighting device.

14. The method (900) of claim 13, wherein the first power mode is an emergency power mode, and wherein the AC power signal is generated by an emergency power source.

15. The method (900) of claim 13, wherein the second power mode is a normal power mode, and wherein the AC power signal is generated by an AC mains supply.

Images