Patent Description:
The tunable white circuit may utilize two separate LEDs that operate at different lighting temperatures (e.g., measured in Kelvin (K)). The combined illumination effect of the two separate LEDs in the tunable white circuit generates a dynamically selectable luminance output through decreasing and increasing an intensity of the individual LEDs as well as modifying the lighting temperature. The tunable white circuit may include a cool white channel as the first LED and a warm white channel as the second LED. The control parameters may be brightness and color temperature. The tunable white circuit may utilize dimming information that is carried in a voltage waveform and delivered current to select the control parameters. Thus, the design of the tunable white circuit utilizes a controlled interaction between the two LEDs.

A conventional approach to design a tunable white circuit involves a current source, the plurality of LEDs, and a plurality of semiconductors (e.g., metal-oxide semiconductor field-effect transistor (MOSFET)) that manage LED operation. By controlling a current, the LEDs may be powered at a selected lighting temperature and a selected luminance may be achieved where a mixed light color temperature is determined by a ratio of warm light and cool light. This conventional approach switches the warm LED and the cool LED on and off alternatively, which will be described in further detail below. However, in view of the interaction between the two LEDs to generate the selected luminance, the conventional approach may be modified for a more controlled operation in generating a selected luminance.

<FIG> shows an exemplary lighting device <NUM> that is a tunable white circuit that dynamically selects control parameters for a plurality of LEDs utilizing a further control mechanism. For example, the lighting device <NUM> represents an electronic device including a circuit arrangement for a conventional tunable white circuit. As illustrated, the lighting device <NUM> includes a current source <NUM>, an inductor <NUM>, a lighting load <NUM>, a lighting load <NUM>, a semiconductor <NUM> associated with the lighting load <NUM>, and a semiconductor <NUM> associated with the lighting load <NUM>. The loads <NUM>, <NUM> may each be a LED that operates at a selected lighting temperature (the terms "load" and "LED" to be used interchangeably herein). For example, the LED <NUM> may be a cool LED operating at a lighting temperature of <NUM> while the LED <NUM> may be a warm LED operating at a lighting temperature of <NUM>. The semiconductors <NUM>, <NUM> may each be a MOSFET configured to switch or amplify signals (the terms "semiconductor" and "MOSFET" to be used interchangeably herein). The inductor <NUM> is introduced and positioned in the tunable white circuit to balance the current between the cool LED and the warm LED when forward voltage of the two LEDs is not exactly the same. In this manner, the inductor <NUM> provides a further control mechanism for the tunable white circuit.

In the lighting device <NUM>, the current source <NUM> may generate a constant voltage V0. The average current in the inductor <NUM> may be the same as the current source <NUM>. In a steady operating state, when a forward voltage of the two LEDs (e.g., denoted as VF1 for the LED <NUM> and VF2 for the LED <NUM>) are different, the voltage for the constant current power source V0 may be an average voltage of the two LED strings. For example, V0 may be calculated as a sum of the product of an on duty cycle at VF1 and the product of an on duty cycle of VF2 (e.g., V0=D·VF1+(<NUM>-D)·VF2), where D is the on duty cycle of the cool LED during an overall cycle, <NUM>-D is the other on duty cycle of the warm LED during the overall cycle). The voltage waveform at a positive end of the two LEDs <NUM>, <NUM> may result in a square wave repeatedly alternating between VF1 and VF2 for the respective duration D and <NUM>-D. The inductor <NUM> may provide the additional control in maintaining the voltage waveform of the two LEDs <NUM>, <NUM>.

<NPL> discloses a lighting device comprising first and second loads and a voltage controller configured to adjust a setting for a current generated by a current source based on a reading of a voltage peak of the first and second loads. <CIT> discloses a multi-output DC-DC converter comprising first and second loads, a first and second semiconductor adapted to manage current flowing through the first and second loads, and a semiconductor controller configured to deactivate the first and second semiconductors based on a reading of a voltage peak of the first and second loads.

The lighting device <NUM> may also be a commercially available product or used in an environment such that the design is to follow certain operating standards. For example, an operating standard set for North America may be a requirement that linear indoor LED drivers are to comply with class <NUM>. Accordingly, in a particular implementation, the current source <NUM> may be an Underwriter Laboratories (UL) class <NUM> compliant current source. However, the operating standard may not extend to other components of the lighting device <NUM>. For example, despite the voltage V0 generated by the current source <NUM> being class <NUM> compliant, when one of the LEDs <NUM>, <NUM> fails resulting in an open circuit along a circuit pathway including the failed LED (e.g., the LED <NUM>), the voltage peak Vp at the remaining operating one of the LEDs <NUM>, <NUM> having the closed circuit (e.g., the LED <NUM>) becomes significantly higher due to the inductor <NUM> operating in a free-wheeling manner. When this occurs, the operating one of the LEDs <NUM>, <NUM>, the inductor <NUM>, etc. may not be class <NUM> compliant (e.g., exceeding the class <NUM> standard may result in a higher probability of causing a shock to a user). Thus, the introduction of the inductor <NUM> may provide an increased performance control of the tunable white circuit under normal operating conditions but also introduces a warm/cool problem when at least one of the LEDs <NUM>, <NUM> fails.

The exemplary embodiments are directed to a lighting device having circuit protection. The lighting device comprises a current source generating a current and a first load and a second load receiving the current. The lighting device comprises an inductor positioned between the current source and the first and second loads that balances the current powering the first and second loads. The lighting device comprises a detector monitoring a voltage peak of the first and second loads. The lighting device comprises a voltage controller receiving a reading of the voltage peak from the detector and determining when the voltage peak is at least a voltage peak threshold. The voltage controller is configured to adjust a setting for the current generated by the current source based on the reading of the voltage peak.

The exemplary embodiments are directed to a lighting device having circuit protection. The lighting device comprises a current source generating a current and a first load and a second load receiving the current. The lighting device comprises an inductor positioned between the current source and the first and second loads that balances the current powering the first and second loads. The lighting device comprises a first semiconductor and a second semiconductor managing the current flowing to the first load and the second load, respectively. The lighting device comprises a detector monitoring the voltage peak of the first and second loads. The lighting device comprises a comparator receiving a reading of the voltage peak from the detector and determining when the voltage peak is at least a comparator threshold. The comparator is configured to generate a signal when the voltage peak is at least the comparator threshold. The lighting device comprises a semiconductor controller configured to receive the signal and deactivate the first and second semiconductors.

The exemplary embodiments are directed to a lighting device having circuit protection. The lighting device comprises a current source generating a current and a first load and a second load receiving the current. The lighting device comprises an inductor positioned between the current source and the first and second loads that balances the current powering the first and second loads. The lighting device comprises a first semiconductor and a second semiconductor managing the current flowing to the first load and the second load, respectively. The lighting device comprises a first protection mechanism and a second protection mechanism. The first protection mechanism comprises a detector monitoring a voltage peak of the first and second loads. The first protection mechanism comprises a voltage controller receiving a reading of the voltage peak from the detector and determining when the voltage peak is at least a voltage peak threshold. The voltage controller is configured to adjust a setting for the current generated by the current source based on the reading of the voltage peak. The second protection mechanism comprises a further detector monitoring the voltage peak of the current. The second protection mechanism comprises a comparator receiving a further reading of the voltage peak from the further detector and determining when the voltage peak is at least a comparator threshold. The comparator is configured to generate a signal when the voltage peak is at least the comparator threshold. The second protection mechanism comprises a semiconductor controller configured to receive the signal and deactivate the first and second semiconductors.

The exemplary embodiments may be further understood with reference to the following description and the related appended drawings, wherein like elements are provided with the same reference numerals. The exemplary embodiments are related to a device, a system, and a method for protecting a class <NUM> circuit of an electronic device configured as a tunable white circuit including a plurality of loads. The exemplary embodiments provide a protection mechanism that addresses an open circuit high voltage issue on a first load resulting from a second load failing. Through using the exemplary embodiments to address this scenario, the class <NUM> circuit may remain class <NUM> compliant. The protection mechanism according to the exemplary embodiments provides a first protector based on a voltage control and a second protector based on a semiconductor control.

The exemplary embodiments are described with regard to particular circuitry components that are interconnected within the tunable white circuit of the electronic device. The exemplary embodiments are also described with regard to these particular circuitry components being arranged in a specific configuration. However, the types of circuitry components and the specific arrangement are only for illustrative purposes. Different types of circuitry components and different arrangements may also be used within the scope of the exemplary embodiments to achieve a substantially similar protection to the above noted scenario where voltage peaks on functioning loads exceeds class <NUM> compliance standards. In a first example, the load of the electronic device is described as a diode such as a light emitting diode (LED). However, the load may be any sub-component that draws power to activate the sub-component or stops drawing power to deactivate the sub-component. In a second example, the semiconductor of the electronic device is described as a metal oxide semiconductor field effect transistor (MOSFET). However, the semiconductor may be any component that is configured to control the operation of the respective load for which it is responsible.

The exemplary embodiments are further described with regard to certain values of the components in the tunable white circuit. For example, the values may be lighting temperatures. However, these exemplary values pertain to selected lighting temperatures of LEDs such that an interaction of the LEDs generates a selected luminance. In another example, the values may be a voltage peak that is monitored. However, these exemplary values pertain to a design selection based on class <NUM> compliance standards. Accordingly, if a different standard were selected or a tolerance range within the compliance standard were selected, a threshold associated with the voltage peak may be modified. Thus, any values used to describe the operation of the tunable white circuit according to the exemplary embodiments is only for illustrative purposes and other values may be used within the scope of the exemplary embodiments.

The exemplary embodiments provide a protection mechanism in a tunable white circuit lighting device that provides protection against conditions resulting in a voltage peak that exceeds an acceptable threshold. The protection mechanism may be embodied in a first protector that is configured with a voltage control. The voltage control may detect when the voltage peak exceeds the acceptable threshold and adjust the voltage or current being output to the loads. The protection mechanism may also be embodied in a second protector that is configured with a semiconductor control. The semiconductor control may receive a signal that triggers the semiconductor control to deactivate the semiconductors that results in the loads from receiving further power. The protection mechanism may also incorporate both the first protector and the second protector (e.g., in view of class <NUM> compliance requirements for a redundant protection circuit).

<FIG> shows an exemplary lighting device <NUM> according to the exemplary embodiments. The lighting device <NUM> includes a power source <NUM> and a plurality of loads <NUM>, <NUM>. The loads <NUM>, <NUM> may be any type of component that draws power (e.g., a LED, a light bulb, an audio output component, etc.). For illustrative purposes, the loads <NUM>, <NUM> are described in the exemplary embodiments as LEDs (the terms "load" and "LED" being used interchangeably herein). The lighting device <NUM> also includes a plurality of semiconductors <NUM>, <NUM> corresponding to each load <NUM>, <NUM>. For example, the semiconductor <NUM> may be associated with the load <NUM> and the semiconductor <NUM> may be associated with the load <NUM>. The semiconductors <NUM>, <NUM> may be any type of component that manages the operation of the loads <NUM>, <NUM>. For example, the semiconductors <NUM>, <NUM> may control a current that is supplied to the loads <NUM>, <NUM>. For illustrative purposes, the semiconductors <NUM>, <NUM> are described in the exemplary embodiments as MOSFETs (the terms "semiconductor" and "MOSFET" being used interchangeably herein). The lighting device may also include an inductor <NUM> that provides an additional performance control mechanism for the operation of the loads <NUM>, <NUM>. The lighting device <NUM> may include a protection mechanism <NUM> that dynamically protects the LEDs <NUM>, <NUM> and the corresponding LED strings including the LEDs <NUM>, <NUM>.

As a tunable white circuit, the LEDs <NUM>, <NUM> may operate at a selected lighting temperature. For example, the LED <NUM> may be a cool LED operating at <NUM> and the LED <NUM> may be a warm LED operating at <NUM>. When in operation, the LEDs <NUM>, <NUM> may alternate between an on period and an off period. Accordingly, while the LED <NUM> is on, the LED <NUM> may be off and vice versa. To achieve a particular luminance based on the selected lighting temperatures of the LEDs <NUM>, <NUM>, the LEDs <NUM>, <NUM> may operate using an overall cycle in which a portion of the overall cycle is devoted to an on duty cycle of the LED <NUM> and a remaining portion of the overall cycle is devoted to an on duty cycle of the LED <NUM>. The overall cycle may have a voltage waveform that is a square wave alternating between a forward voltage across each of the LEDs <NUM>, <NUM> for a duration corresponding to the respective on duty cycle. The inductor <NUM> may enable the square wave to be maintained at the intended voltage and duration to provide the performance control.

The protection mechanism <NUM> may include a detector <NUM> associated with a voltage controller <NUM>. The detector <NUM> and the voltage controller <NUM> may be the first protector of the protection mechanism <NUM>. The detector <NUM> may detect or monitor a voltage peak in the tunable white circuit. The detected voltage peak may be fed back to the voltage controller <NUM>. The voltage controller <NUM> may be configured to adjust the current output by the power source <NUM>. For example, the voltage controller <NUM> may determine a setting that the power source <NUM> is to use based on the voltage peak output from the detector <NUM> such that the tunable white circuit remains class <NUM> compliant. According to a particular implementation, the voltage controller <NUM> may utilize a voltage peak threshold where any voltage peak that is below the voltage peak threshold does not trigger the voltage controller <NUM> to adjust the current. When the voltage peak is at least the voltage peak threshold, the voltage controller <NUM> may adjust the current output by the power source <NUM> in a dynamic manner (e.g., set the current on the power source <NUM> lower so that a subsequent voltage peak reading by the detector <NUM> reaches, at most, the voltage peak threshold). Thus, while the voltage peak remains above the voltage peak threshold as detected by the detector <NUM>, the voltage controller <NUM> may continuously adjust the setting of the power source <NUM> to control the current being output (e.g., set the current lower if the detected voltage peak that is above the voltage peak threshold has increased, set the current higher if the detected voltage peak that is above the voltage peak threshold has decreased, etc.).

The detector <NUM> and the voltage controller <NUM> may also be used after the condition that presented the high voltage issue has been addressed. For example, after the condition has been addressed, the voltage peak that is detected may no longer be above the voltage peak threshold. The voltage controller <NUM> may adjust the setting for the current of the power source <NUM> so that the subsequent voltage peak that is detected reaches, at most, the voltage peak threshold. In this scenario, the voltage controller <NUM> may raise the setting for the current to a value corresponding to a normal operating state of the tunable white circuit.

The protection mechanism <NUM> may further include a detector <NUM> associated with a semiconductor controller <NUM>. The detector <NUM> and the semiconductor controller <NUM> may be the second protector of the protection mechanism <NUM>. The detector <NUM> may detect or monitor a voltage peak in the tunable white circuit in a manner substantially similar to the detector <NUM>. The detected voltage peak output by the detector <NUM> may be compared to a comparator threshold. When the detected voltage peak is at least the comparator threshold, the semiconductor controller <NUM> may receive a signal indicating an operation to be performed. For example, the semiconductor controller <NUM> may be configured to deactivate the semiconductors <NUM>, <NUM>. The comparator threshold may be set to a value that is indicative of the tunable white circuit exceeding values corresponding to the class <NUM> compliance standard. For example, the comparator threshold may be substantially similar in value to the voltage peak threshold. Accordingly, the second protector may be configured to provide an automatic shutdown mechanism for the tunable white circuit by preventing any further current from flowing through a remaining, functioning LED when the other LED has failed.

To re-activate the semiconductors <NUM>, <NUM>, the tunable white circuit may be reset. For example, the semiconductor control <NUM> may have a default position to keep the semiconductors <NUM>, <NUM> in an activated state. In another manner, the semiconductor control <NUM> may detect when a signal is not being received based on the output from the detector <NUM>. When no signal is being received, the semiconductor control <NUM> may revert to setting the semiconductors <NUM>, <NUM> in an activated state. Thus, during times when a signal is received, the semiconductor control <NUM> may deactivate the semiconductors <NUM>, <NUM> and during times when no signal is received, the semiconductor control <NUM> may activate the semiconductors <NUM>, <NUM>. When transitioning from a deactivated state to an activated state, the semiconductor control <NUM> may determine when no signal is received for a predetermined duration of time to eliminate random instances when this condition occurs and to ensure this transition is when this condition persists.

The lighting device <NUM> including the first protector and the second protector is only illustrative. Those skilled in the art will appreciate that the first protector or the second protector acting alone may sufficiently provide the protection during the high voltage issue scenario where a functioning load experiences the high voltage peak when another load has failed. Accordingly, in other implementations, the lighting device <NUM> may include one or the other protector in the protection mechanism. The lighting device <NUM> may also be configured as illustrated to ensure that the protection is provided through a secondary manner of protecting the circuit pathways and the loads. The lighting device <NUM> may further include the first and second protector in the protection mechanism <NUM> to comply with various standards. For example, the class <NUM> compliance standard requires that a redundant safety mechanism be provided in the lighting device <NUM>. Accordingly, to also satisfy the class <NUM> compliance standard, the lighting device <NUM> may include both the first protector and the second protector. The inclusion of both protectors may be arranged such that one protector may act as a primary while the other protector may act as a secondary or both protectors may act in a similar capacity to afford protection to the tunable white circuit.

The lighting device <NUM> is illustrated where the components are incorporated into one overall electronic device. However, in another implementation, the components of the lighting device <NUM> may be at least partially separated from one another while having a communication functionality, may be modular components (e.g., separate components connected to one another), may be incorporated into one or more devices, or a combination thereof. For example, the lighting device <NUM> may include the detectors <NUM>, <NUM> that provide outputs to a modular determination component that sends a signal to a corresponding component (e.g., the voltage controller <NUM>, the semiconductor controller <NUM>, etc.). The lighting device <NUM> may also utilize a wired connection between the components. However, those skilled in the art will understand that any manner of communication of signals, power, or other indications/commands may be used between the components of the lighting device <NUM>. For example, a wired connection, a wireless connection, a network connection, or a combination thereof may be used.

<FIG> shows an exemplary implementation of a lighting device <NUM> according to the exemplary embodiments. The lighting device <NUM> may be a particular arrangement of the lighting device <NUM> of <FIG> according to the exemplary embodiments. The implementation of the lighting device <NUM> illustrated in <FIG> relates to the protection mechanism <NUM> utilizing the first protector including the detector <NUM> and the voltage controller <NUM> and the second protector including the detector <NUM> and the voltage controller <NUM>. The lighting device <NUM> may include a current source <NUM>, an inductor <NUM>, LEDs <NUM>, <NUM>, MOSFETs <NUM>, <NUM>, a voltage peak detector <NUM> with a voltage controller <NUM>, and a voltage peak detector <NUM> with a comparator <NUM>, and a semiconductor controller <NUM>.

The implementation of the lighting device <NUM> in <FIG> may be any circuitry implementation in which the components are interconnected with one another for signals to be exchanged and current to be supplied, detected, and modified along various circuit pathways. These components may be included on one or more integrated circuits, on one or more printed circuit boards, or implemented individually as needed. The exemplary implementation of the lighting device <NUM> described herein relates to the lighting device <NUM> being a set of circuitry components. However, the lighting device <NUM> may also be implemented in a variety of other ways. For example, the lighting device <NUM> may include more complex components, particularly if dynamic settings (e.g., greater than two settings) are to be used.

In this example, the lighting device <NUM> may include the LED <NUM> operating as a cool LED at <NUM> and the LED <NUM> operating as a warm LED at <NUM>. As illustrated, in the implementation of <FIG>, the tunable white circuit includes the inductor <NUM> to provide a performance control while introducing a high voltage issue that places the tunable white circuit beyond class <NUM> compliance standards on one of the LEDs <NUM>, <NUM> when the other one of the LEDs <NUM>, <NUM> fails. The lighting device <NUM> also includes both the first protector and the second protector.

The current source <NUM> may be a UL class <NUM> compliant power source outputting a voltage V0 at a selected current (e.g., as set by the voltage controller <NUM>). The current may flow to the inductor <NUM> that stores the energy in a magnetic field to be distributed to the LEDs <NUM>, <NUM>. Depending on the overall cycle and the on duty cycle for each LED <NUM>, <NUM>, the LEDs <NUM>, <NUM> may be illuminated at scheduled times. The MOSFETs <NUM>, <NUM> may be in a default, activated state that enables the circuit to be closed for the LED <NUM>, <NUM>, respectively, which effectively controls when the LEDs <NUM>, <NUM> are "activated" or available for use.

In using the protection mechanism <NUM>, one of the LEDs <NUM>, <NUM> may fail leading to a high voltage scenario. For example, the LED <NUM> may fail (e.g., leading to an open circuit). Accordingly, the LED <NUM> which is still functional (e.g., maintains a closed circuit) may have a peak voltage that measures in excess of a class <NUM> compliant standard (e.g., during times when the duty cycle of the LED <NUM> is off). The protection mechanism <NUM> may be configured to monitor when such a peak voltage occurs to perform subsequent operations to remedy this condition.

In using the first protector including the voltage peak detector <NUM> and the voltage controller <NUM>, in a manner substantially similar to the manner described above with regard to the lighting device <NUM> of <FIG>, the voltage peak detector <NUM> may monitor the voltage peak occurring in the tunable white circuit while current is flowing from the current source <NUM>. The voltage peak detector <NUM> may output the voltage peak to the voltage controller <NUM> which then determines whether to alter the setting of an output current generated by the current source <NUM>. The voltage controller <NUM> may utilize a voltage peak threshold based on a class <NUM> compliance standard that results in the tunable white circuit remaining class <NUM> compliant. Thus, when the voltage controller <NUM> receives a voltage peak from the voltage peak detector <NUM> that registers in excess of the voltage peak threshold, the voltage controller <NUM> may adjust the setting for the current output by the current source <NUM>. When the overall cycle of the voltage waveform is a square wave and only the LED <NUM> has failed, the voltage peak that is at least the voltage peak threshold may repeat during the on duty cycle of the LED <NUM>. In this manner, the voltage controller <NUM> may identify when the LED <NUM> has likely failed. When the voltage controller <NUM> has adjusted the setting of the current output by the current source <NUM> based on the detected voltage peak output by the voltage peak detector <NUM>, the tunable white circuit may again be class <NUM> compliant.

As described above, the voltage peak threshold may enable the voltage controller <NUM> to determine how to set the current output by the current source <NUM>. For example, while the voltage peak is at least the voltage peak threshold, the voltage controller <NUM> may dynamically select the proper current setting so that the tunable white circuit is class <NUM> compliant. In another example, while the voltage peak is less than the voltage peak threshold, the voltage controller <NUM> may select a maximum current setting in which the tunable white circuit is class <NUM> compliant.

In using the second protector including the voltage peak detector <NUM>, the comparator <NUM>, and the semiconductor controller <NUM>, in a manner substantially similar to the manner described above with regard to the lighting device <NUM> of <FIG>, the voltage peak detector <NUM> may monitor the voltage peak occurring in the tunable white circuit while current is flowing from the current source <NUM>. When both the first protector and the second protector are part of the lighting device <NUM>, the voltage peak detector <NUM> and the voltage peak detector <NUM> should measure substantially identical voltage peaks. The voltage peak detector <NUM> may output the voltage peak to the comparator <NUM> which then determines whether to generate a signal to be transmitted to the semiconductor controller <NUM>. The comparator <NUM> may be configured with hysteresis to compensate for any lag issues in view of the incorporation of the inductor <NUM> and the square voltage waveform. The comparator <NUM> may be set with a comparator threshold that determines when to select a circuit pathway that sends a signal to the semiconductor controller <NUM>. In the scenario where the LED <NUM> has failed and the voltage peak measured during the on duty cycle of the LED <NUM> results in the high voltage for the LED <NUM>, the comparator <NUM> may generate and transmit the signal to the semiconductor controller <NUM>. Upon receipt of the signal, the semiconductor controller <NUM> may deactivate both the MOSFETs <NUM>, <NUM>. By deactivating the MOSFETs <NUM>, <NUM>, the LEDs <NUM>, <NUM> may no longer receive current, thereby placing the tunable white circuit in a condition that is class <NUM> compliant.

As described above, the comparator threshold may define an on/off setting of the MOSFETs <NUM>, <NUM> by either transmitting a signal or remaining passive. The comparator threshold may be substantially similar in value to the voltage peak threshold.

<FIG> shows an exemplary implementation of a voltage control protector <NUM> used in the implementation of <FIG> according to the exemplary embodiments. The voltage control protector <NUM> illustrates an exemplary circuitry arrangement that may be used to achieve the operations described above for the first protector of the protection mechanism <NUM>. However, the voltage control protector <NUM> may utilize a different circuitry arrangement within the scope of the exemplary embodiments and still perform the above described operations in protecting the tunable white circuit. In the voltage control protector <NUM>, peak voltage detection <NUM> comprises of D980 and C981 where the voltage peak on C981 is fed to the voltage feedback control circuit. The voltage feedback control circuit may regulate the voltage on C981 to be the same or lower than a predetermined voltage setting (e.g., 56V), which will be always lower than the UL class <NUM> compliance standard limit (e.g., 60V). Peak voltage detection <NUM> comprises of D980A and C980 where the voltage peak on C980 is divided by resistors R988 and R989. The Voltage on R988 compares with reference voltage 3V3 (e.g., <NUM>. The components U980, R985, and R986 create an accurate comparator when the voltage on R988 is higher than the reference voltage (e.g., <NUM>. When a collector of U980 (e.g., pin <NUM>) becomes high, through D983 and R987, to create a hysteresis, through Zener D982, the transistor U981 is turned on. Through dual diode D981, <NUM> MOSFET driving signals in the voltage control protector <NUM> is pulled low and the MOSFETs U951 and U952 are turned such that the output voltage at LEDTW+ is the same as VLED+, which is compliant with the UL class <NUM> standard. The voltage control protector <NUM> keeps output voltages at LEDTW+ to always be below the UL class <NUM> standard limit (e.g., 60V) even with single fault in one of the LEDs <NUM>, <NUM>.

<FIG> shows an exemplary implementation of a semiconductor control protector <NUM> used in the implementation of <FIG> according to the exemplary embodiments. The semiconductor control protector <NUM> includes X2 which are the connection terminals. The warm LED strings including the warm LED <NUM> is connected between LEDTW+ and LEDWW- and the cool LED strings including the cool LED <NUM> is connected between LEDTW+ and LEDCW-. The inductor L950 keeps a current balance between the two LED strings. The MOSFETs U951 and U952 are turned on alternatively with a fixed frequency. U950 is a <NUM> channel MOSFET driving integrated circuit. Signals UC_ WW_PWM and UC_CW_PWM are from a microcontroller that controls the duty cycle of the LEDs <NUM>, <NUM>.

<FIG> shows a method <NUM> for protecting a lighting device using a voltage control protector <NUM> according to the exemplary embodiments. The method <NUM> may relate to the mechanism of the exemplary embodiments in which the voltage controller <NUM> is used to protect the lighting device <NUM> and stay within standards set forth for the type of device that the lighting device <NUM> is (e.g., class <NUM>). The method <NUM> will be described from the perspective of the voltage controller <NUM> (e.g., as implemented in the voltage control protector <NUM>) as well as the implementation of the lighting device <NUM> as circuitry units as illustrated in <FIG>. Substantially similar components of the lighting device <NUM> and exemplary implementation of the lighting device <NUM> will be used interchangeably.

In <NUM>, the voltage peak detector <NUM> monitors the voltage peak of the tunable white circuit. Under normal operating conditions, the voltage peak should not exceed a voltage peak threshold. However, particularly through the introduction of the inductor <NUM>, there may be scenarios when one of the LEDs <NUM>, <NUM> fails leading to a high voltage issue arising in which the functional one of the LEDs <NUM>, <NUM> exhibits a voltage peak which is at least the voltage peak threshold. In <NUM>, the voltage peak detector <NUM> transmits the reading of the voltage peak to the voltage controller <NUM>.

In <NUM>, the voltage controller <NUM> determines whether to adjust the setting of the current that is output by the current source <NUM>. For example, the voltage peak that is received from the voltage peak detector <NUM> may be less than the voltage peak threshold. Accordingly, in <NUM>, the voltage controller <NUM> maintains a setting of the current to be output by the current source <NUM>. Assuming no previous modifications, the setting may be a maximum current that allows the tunable white circuit to be class <NUM> compliant (e.g., with any tolerances that may be factored). The first protector then proceeds to <NUM> where it determines whether the tunable white circuit is still in use. If still in use, the first protector returns to <NUM> to continue monitoring the voltage peak in the tunable white circuit.

Returning to <NUM>, in another example, the voltage peak that is received from the voltage peak detector <NUM> may be greater than the voltage peak threshold. Accordingly, in <NUM>, the voltage controller determines a setting to be used for the current to be output by the current source <NUM> in view of the high voltage scenario. In <NUM>, the voltage controller <NUM> sets the updated current of the current source <NUM>. The first protector then proceeds to <NUM>.

<FIG> shows a method <NUM> for protecting a lighting device using a semiconductor control protector <NUM> according to the exemplary embodiments. The method <NUM> may relate to the mechanism of the exemplary embodiments in which the semiconductor controller <NUM> is used to protect the lighting device <NUM> and stay within standards set forth for the type of device that the lighting device <NUM> is (e.g., class <NUM>). The method <NUM> will be described from the perspective of the semiconductor controller <NUM> (e.g., as implemented in the semiconductor control protector <NUM>) as well as the implementation of the lighting device <NUM> as circuitry units as illustrated in <FIG>. Substantially similar components of the lighting device <NUM> and exemplary implementation of the lighting device <NUM> will be used interchangeably.

In <NUM>, the voltage peak detector <NUM> monitors the voltage peak of the tunable white circuit. The voltage peak detector <NUM> may monitor the voltage peak in a manner substantially similar to the voltage peak detector <NUM> as described above in the method <NUM> except with a comparator threshold. However, the particular manner with which the voltage peak is measured may differ based on implementation (e.g., the differing approaches of the circuit implementations of the voltage control protector <NUM> and the semiconductor control protector <NUM>). In <NUM>, the voltage peak detector <NUM> transmits the reading of the voltage peak to the comparator <NUM>.

In <NUM>, the comparator <NUM> determines whether the voltage peak reading is within the comparator threshold. If less than the comparator threshold, the comparator <NUM> selects a default circuit pathway that places the comparator <NUM> in a passive state such that the operations conditions are maintained. The second protector then continues to <NUM> to determine whether the tunable white circuit is still in use. If still in use, the second protector returns to <NUM> to continue monitoring the voltage peak in the tunable white circuit.

Returning to <NUM>, if the voltage peak reading is at least the comparator threshold, in <NUM>, the comparator <NUM> selects another circuit pathway resulting in a signal being generated and transmitted to the semiconductor controller <NUM>. In <NUM>, the semiconductor controller <NUM> deactivates the MOSFETs <NUM>, <NUM>. The second protector then proceeds to <NUM>.

As described above and as illustrated in the lighting devices <NUM>, <NUM>, the protection mechanism <NUM> may include both the first protector including the detector <NUM> and the voltage controller <NUM> and the second protector including the detector <NUM> and the semiconductor controller <NUM>. Thus, the methods <NUM> and <NUM> being described as separate protection approaches is only illustrative of when the tunable white circuit utilizes a single protector. However, the methods <NUM> and <NUM> may be combined and the results from using either the method <NUM> or the method <NUM> may be incorporated into an overall combined method that may affect how the other one of the method <NUM> or <NUM> is performed.

The exemplary embodiments provide a device, system, and method of protecting a tunable white circuit of an electronic device including at least two loads that may be managed by respective semiconductors. The protection mechanism according to the exemplary embodiments address a high voltage issue scenario when a first load fails and a second functional load experiences a voltage peak that may exceed an intended maximum (e.g., as set by a compliance standard). The protection mechanism provides a first protector that monitors a voltage peak and adjusts a current setting of a current source based on the voltage peak. The protection mechanism also provides a second protector that may operate in tandem or individually from the first protector that also monitors a voltage peak and deactivates the semiconductors so that power is not supplied to the LEDs. The protection mechanism may further incorporate both the first protector and the second protector when an increased protection mechanism is to be used, a redundant approach is to be applied, and/or a compliance standard is to be met.

Those skilled in the art will understand that the above-described exemplary embodiments may be implemented in any suitable software or hardware configuration or combination thereof. In a further example, the exemplary embodiments of the above described method may be embodied as a computer program product containing lines of code stored on a computer readable storage medium that may be executed on a processor or microprocessor. The storage medium may be, for example, a local or remote data repository compatible or formatted for use with the above noted operating systems using any storage operation.

Claim 1:
A lighting device (<NUM>), comprising:
a current source (<NUM>) adapted to generate a current;
a first load (<NUM>) and a second load (<NUM>) adapted to receive the current;
a first semiconductor (<NUM>) and a second semiconductor (<NUM>) adapted to manage the current flowing to the first load and the second load, respectively;
an inductor (<NUM>) positioned between the current source and the first and second loads;
a detector (<NUM>) adapted to monitor a voltage peak of the first and second loads (<NUM>, <NUM>); and
a voltage controller (<NUM>) adapted to receive a reading of the voltage peak from the detector and adapted to determine when the voltage peak is at least a voltage peak threshold, the voltage controller configured to adjust a setting for the current generated by the current source based on the reading of the voltage peak;
characterized in that the lighting device comprises a comparator (<NUM>) adapted to receive a further reading of the voltage peak from a further detector (<NUM>) and adapted to determine when the voltage peak is at least a comparator threshold when one of the first load (<NUM>) and the second load (<NUM>) has failed resulting in an open circuit and the other one of the first load (<NUM>) and the second load (<NUM>) remains functional, the functional load experiencing the voltage peak that is at least the voltage peak threshold, the comparator (<NUM>) configured to generate a signal when the voltage peak is at least the comparator threshold; and
a semiconductor controller (<NUM>) configured to receive the signal and deactivate the first and second semiconductors (<NUM>, <NUM>).