Patent Description:
In a conventional lighting device, certain LED drivers with a DALI interface include an on-board current source (e.g., a DALI power supply). A conventional current setting for the current source in these LED drivers is approximately 55mA. However, implementations of the lighting device with the LED drivers and the DALI interface may use a higher current. For example, a current setting of approximately 110mA or more may be used in these implementations. One approach to accommodate different current settings is to make the same product with a different version of the power supply. However, this approach may be more costly and more limiting as the current setting that is preselected is the only option. For example, the lower current may be used for standard implementations but may not be used for implementations requiring the higher current. In another example, the higher current may create issues with backward compatibility. Selecting the higher current may also raise issues related to complying with the DALI Standard that specifies a maximum current of 250mA. If multiple LED drivers are connected to the same DALI bus wires, the power supplies become additive and may lead to exceeding the 250mA DALI limit (e.g., any more than two LED drivers operating at 110mA would exceed the 250mA DALI limit).

In addition, a conventional approach to turning the current supply on or off is to utilize a microprocessor or controller that generates a signal to indicate when the current is to be supplied. In one manner, the conventional approach may require an isolated interface where the microprocessor is disposed on a side of the isolated interface where the signal must go across an isolation barrier of the isolated interface. For example, the isolated interface may be an opto isolator. The opto isolator may be turned on and off so that an opto diode of the opto isolator is conducting or not conducting resulting in the current supply being on or off, respectively. However, this only allows the use of a single current setting which faces the above described drawbacks. If the current setting is to be variable and selectable, an approach to achieve this operation is to introduce a second opto isolator. Thus, the first opto isolator may be used to turn the current supply on or off while the second opto isolator may be used to select a value of the current provided by the current supply that is turned on.

When considered from an individual scale, the introduction of the second opto isolator may appear cost effective as a solution to the issue of selecting a variable current setting for the DALI current source. However, when considered on a manufacturing scale in which the product is manufactured and sold in high volume (e.g., millions of units), the introduction of the additional opto isolator becomes a major cost. Accordingly, any part of the circuit that may be simplified or lowered in cost is of great importance.

The exemplary embodiments are directed to a powered device configuring a power supply. The powered device comprises a digital addressable lighting interface (DALI) connected to a load to be powered by a power source. The powered device comprises an isolator. The powered device comprises a controller positioned on a primary side of the isolator. The controller is configured to generate a first signal to select whether to provide power to the DALI at a zero current value or a maximum current value. The controller is further configured to generate a second signal to provide power to the DALI at a selected current value between the zero current value and the maximum current value.

The exemplary embodiments are directed to a method for configuring a power supply. The method comprises generating a first signal to select whether to provide power to a digital addressable lighting interface (DALI) connected to a load to be powered by a power source at a zero current value or the maximum current value. The method comprises generating a second signal to select to provide power to the DALI at a selected current value that is between the zero current value and the maximum current value.

The exemplary embodiments are directed to a powered device configuring a power supply. The powered device comprises a power supply, a digital addressable lighting interface (DALI) connected to a load to be powered by the aux power supply, and an opto isolator. The powered device comprises a microprocessor positioned on a primary side of the opto isolator. The microprocessor is configured to generate an activation drive signal to select whether to provide power to the DALI at a zero current value or a maximum current value. The microprocessor is further configured to generate a pulse width modulated (PWM) signal to select to provide power to the DALI at a selected current value between the zero current value and the maximum current value. The powered device comprises a buck converter receiving a reference current based on the PWM signal to generate a fixed voltage corresponding to the selected current value that is provided to the DALI.

<CIT> discloses an apparatus for controlling lighting in a DALI system.

<CIT> discloses a lighting driver with integrated DALI driver.

<CIT> discloses a PWM controlled power adjustment for LED lighting devices.

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 dynamically selecting a current setting for a Digital Addressable Lighting Interface (DALI) current source in an electronic device that utilizes the DALI. The exemplary embodiments provide a compact approach to selecting when a current is to be supplied to the DALI and a current setting. The exemplary embodiments directed to a current source that is configurable to different current settings from a primary side microprocessor while only including a minimal number of components. As will be described in detail below, the exemplary embodiments provide a mechanism that utilizes a pulse width modulation (PWM) signal across an isolation barrier that sets multiple configuration parameters with a single opto isolator.

The exemplary embodiments are described with regard to particular circuitry components that are interconnected within the power control mechanism 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 manner of dynamically selecting a current setting across an isolator. 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 include 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 electronic device is described as including an isolator such as an opto isolator. However, the opto isolator may be any isolator circuit component between a controller (e.g., a microprocessor) and a DALI.

The exemplary embodiments are further described with regard to certain values associated with the powered device as a whole or for individual components of the powered device. For example, the values may be selectable current settings. In another example, the values may be parameters of a PWM signal. However, these exemplary values pertain to a particular implementation of the exemplary embodiments. Thus, any value used to describe the current setting selection mechanism 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 current setting selection mechanism that allows a current to be selectively supplied to a DALI as well as a plurality of different current settings for that current. Through a single opto isolator between the controller and the DALI, the controller may generate a corresponding signal that enables the current to be supplied at a particular current setting. In this manner, a single opto-isolator may be used to both turn the current supply on or off and select the amount of current to be supplied.

<FIG> shows an exemplary powered device <NUM> according to the exemplary embodiments. The powered device <NUM> includes a power source <NUM> that provides power to a load <NUM> through a DALI <NUM>. The load <NUM> may be any type of component that draws power (e.g., a LED, a light bulb, an audio output component, etc.). The powered device <NUM> may include a controller <NUM> that generates a signal to control whether the load <NUM> is to be supplied current through the DALI <NUM> and an isolator <NUM> through which the signal from the controller <NUM> crosses.

The current setting selection mechanism according to the exemplary embodiments may utilize the controller <NUM> to receive an input or determine a current setting to be provided to the DALI <NUM>. Based on the current setting, the controller <NUM> may generate an activation drive signal or a modulated drive signal that crosses an isolation barrier of the isolator <NUM> and results in a corresponding current having a selected value from the power source <NUM> to flow to the DALI <NUM> and the load <NUM>.

In a first operation, the controller <NUM> may be configured to turn the current to the DALI <NUM> on or off. The controller <NUM> may generate an activation drive signal. When the activation drive signal is off, the current supply to the DALI <NUM> is off (e.g., 0mA). When the activation drive signal is on, the current supply to the DALI <NUM> is on (e.g., a maximum current value such as 110mA).

In a second operation, according to the exemplary embodiments, the controller <NUM> may be configured to enable current to flow to the DALI <NUM> at a selected value. The controller <NUM> may generate a modulated drive signal. When the current setting to be used is not <NUM> or the maximum current, the controller <NUM> may identify the current value of the current setting. The controller <NUM> may then determine a corresponding pulse width modulation (PWM) signal that results in the current setting to be provided to the DALI <NUM>. Accordingly, when the current to be provided to the DALI <NUM> is a value between the off and on values (e.g., 0mA to a maximum current), the controller <NUM> may utilize the modulated drive signal.

The modulated drive signal may be generated as a PWM signal such that a diode of the isolator <NUM> may be driven to conduct with a duty cycle and frequency corresponding to the selected PWM. The modulated drive signal may enable the current to be supplied to the DALI <NUM> with a current proportional to the PWM duty cycle of the isolator <NUM>. According to the exemplary embodiments, the single isolator <NUM> may be used to set any current level for the DALI <NUM> between 0mA and a predefined maximum current by changing the duty cycle of the modulated drive signal from <NUM> to <NUM>%, where the duty cycle is directly proportional to the current set point. Those skilled in the art will understand that the logic for the proportionality may be inverted.

The powered device <NUM> is illustrated where the components are incorporated into one overall electronic device. However, in another implementation, the components of the powered 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. The powered 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 powered device <NUM>. For example, a wired connection, a wireless connection, a network connection, or a combination thereof may be used.

<FIG> shows a powered device <NUM> according to the invention. The powered device <NUM> may be a particular arrangement of the powered device <NUM> of <FIG> according to the exemplary embodiments. The implementation of the powered device <NUM> illustrated in <FIG> relates to the current setting selection mechanism being arranged in a particular manner in which an activation drive signal may turn a current on or off from a zero current to a maximum current or a modulated drive signal may turn a current on to a selected current between zero and the maximum current. The powered device <NUM> includes a microprocessor <NUM>,an opto isolator <NUM>, a buck converter <NUM>, a voltage reference <NUM> and a DALI. The powered device <NUM> may include a resistor <NUM>, a resistor <NUM>, a resistor <NUM>, a capacitor <NUM> and a aux power supply <NUM>, a negative DALI port <NUM> and a positive DALI port <NUM> which may be ports of the DALI.

The implementation of the powered device <NUM> in <FIG> may be any circuitry implementation in which the components are interconnected with one another for signals to be exchanged and power to be supplied 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 powered device <NUM> described herein relates to the powered device <NUM> being a set of circuitry components. However, the powered device <NUM> may also be implemented in a variety of other ways.

In the implementation of the powered device <NUM>, select components may correspond to the powered device <NUM>. For example, the microprocessor <NUM> may correspond to the controller <NUM>; the opto isolator <NUM> may correspond to the isolator <NUM>; the aux power supply <NUM> may correspond to the power source <NUM>; and the negative DALI port <NUM> and the positive DALI port <NUM> may be ports of the DALI <NUM>. Since the powered device <NUM> illustrates a particular implementation of the powered device <NUM>, the components included in the powered device <NUM> are only illustrative. In an example for a better understanding, but not belonging to the present invention the isolator <NUM> being an opto isolator <NUM> is only illustrative and any isolator circuit may be used. In another example, the controller <NUM> being a microprocessor <NUM> is only illustrative and any control circuit may be used.

According to the exemplary implementation of the powered device <NUM>, the microprocessor <NUM> is positioned on a primary side of the opto isolator <NUM>. In the first operation utilizing the activation drive signal, the microprocessor <NUM> generates an on activation drive signal or an off activation drive signal when the current to be provided to the DALI <NUM> via the negative DALI port <NUM> and the positive DALI port <NUM> is either <NUM> or a maximum current. The microprocessor <NUM> may utilize any activation drive signal to cause the opto isolator <NUM> to be on or off resulting in the zero current or the maximum current.

In the second operation utilizing the modulated drive signal, the microprocessor <NUM> on the primary side isolation may generate a PWM signal that drives a diode of the opto isolator <NUM> via the resistor <NUM>. The output of the opto isolator <NUM> is connected to the reference voltage <NUM> (Vref) through a current limiting resistor <NUM>. This circuit pathway generates a square wave signal at the junction of the resistor <NUM> and the resistor <NUM> (e.g., assuming that the resistor <NUM> is very large compared to the resistor <NUM> such as beyond a predetermined difference that generates the square wave signal). The resistor <NUM> in conjunction with the capacitor <NUM> may be used as a filter that converts an input to the resistor <NUM> (e.g., the output of the resistor <NUM>) which is based on the PWM. The input of the resistor <NUM> may be approximately <NUM> or Vref based on the duty cycle. The resistor <NUM> and the capacitor <NUM> may be used to average the PWM signal to generate a DC voltage reference that is used to set the current reference (Iref) for the buck converter <NUM>.

If the PWM is defined as the voltage between the resistors <NUM>, <NUM> (e.g., the inverted signal of the PWM of the microprocessor <NUM>), then the duty cycle of the PWM may be proportional to the current set point for the current source of the DALI <NUM>. As illustrated, the current source for the DALI <NUM> may be the buck converter <NUM>. Since the buck converter <NUM> input pins are usually of a high impedance, there is no need for further buffering after the capacitor <NUM>. The output of the buck converter <NUM> may be a fixed voltage to the negative DALI port <NUM>.

Furthermore, since the current setting selection mechanism is a configuration set point for the supply current of the DALI <NUM>, a very fast reaction speed is not necessary as the current supply may be fixed for a given installation and no dynamic reference current changes are needed. Accordingly, the exemplary embodiments enable the current setting selection mechanism to freely choose the PWM frequency to be slow enough for the opto isolator <NUM> (which may be a standard opto isolator without any modification) to allow the powered device <NUM> to be very low cost. For example, a <NUM> PWM frequency may be chosen which makes the rise and fall time delays of the opto isolator <NUM> negligible and allows for significantly accurate current setting for the Isource of the buck converter <NUM>. The microcontroller <NUM> may allow the PWM duty cycle to be accurate, even if the frequency may not be as accurate.

<FIG> shows a method <NUM> according to the invention for dynamically selecting a current according to the exemplary embodiments. The method <NUM> may relate to the mechanism of the exemplary embodiments in which the microprocessor <NUM> is configured to determine when current is to be supplied to the DALI interface <NUM> (e.g., including the DALI ports <NUM>, <NUM>) and an amount of current to be supplied (e.g., from <NUM> to <NUM>% of an available current). The method <NUM> will be described with respect to the powered device <NUM> of <FIG> as well as the implementation of the powered device <NUM> as illustrated in <FIG>. Substantially similar components of the powered device <NUM> and exemplary implementation of the powered device <NUM> will be used interchangeably.

In <NUM>, the powered device <NUM> determines a current to be supplied to the DALI <NUM>. As described above, the microcontroller <NUM> may receive an input corresponding to a current setting or determine a current setting to be used in the powered device <NUM>. In <NUM>, the powered device <NUM> determines whether current is to be supplied to the DALI <NUM>. If no current is to be supplied to the DALI <NUM>, the powered device <NUM> continues to <NUM> where the activation drive signal causes the diode of the opto isolator <NUM> to not conduct resulting in no current being supplied to the DALI <NUM>. For example, the microprocessor <NUM> may generate an off activation drive signal. If current is to be supplied to the DALI <NUM>, the powered device <NUM> continues to <NUM>.

Whether the current is to be supplied to the DALI <NUM> may also be based on a duty cycle of the powered device <NUM>. For example, the duty cycle may indicate when a particular load <NUM> is to receive power. The duty cycle may also have a waveform such as a square wave. Accordingly, based on the square wave, the current to be supplied may be <NUM> or a selected current value. The selected current value may correspond to the input or determination performed in <NUM>.

In <NUM>, the powered device <NUM> determines whether the current to be supplied is a maximum current (e.g., during an on duty cycle). If the current to be supplied is the maximum current, the powered device continues to <NUM> where the activation drive signal causes the diode of the opto isolator <NUM> to conduct resulting in the maximum current being supplied to the DALI <NUM>. For example, the microprocessor <NUM> may generate an on activation drive signal. If the current is to be set at a value between <NUM> and the maximum value, the powered device <NUM> continues to <NUM>.

In <NUM>, the powered device <NUM> determines the modulated drive signal having a duty cycle and a frequency that corresponds to the selected current setting for current to be supplied to the DALI <NUM>. For example, the microprocessor <NUM> may generate the modulated drive signal as a PWM signal. In <NUM>, the PWM signal drives the diode of the opto isolator <NUM> to conduct with the corresponding duty cycle and frequency. Through the voltage reference <NUM>, the resistors <NUM>, <NUM>, the capacitor <NUM>, and the buck converter <NUM>, the current may be provided to the DALI <NUM> (e.g., via the negative DALI port <NUM>) at the selected current value which is greater than <NUM> but less than the maximum current value.

The exemplary embodiments provide a device, system, and method of dynamically selecting a current setting for power to be provided to load via a DALI. The current setting selection mechanism according to the exemplary embodiments perform either a first operation to turn a current to the DALI on or off using an activation drive signal or a second operation to provide a current to the DALI at a selected current value using a modulated drive signal. The modulated drive signal may be configured as a PWM having a duty cycle and a frequency that corresponds to the selected current value.

Claim 1:
A powered device (<NUM>), comprising:
a digital addressable lighting interface, DALI (DALI, <NUM>,<NUM>), connected to a load, the load to be powered by a power source;
an opto <NUM>. isolator (<NUM>);
a controller (<NUM>) positioned on a primary side of the isolator, characterised in that the controller is configured to generate a first signal to select whether to provide power to the opto isolator so that the opto isolator is conducting or not conducting, wherein when the opto isolator is conducting the DALI has a maximum current value and when the opto isolator is not conducting the DALI has a zero current value, the controller further configured to generate a modulated second signal to provide power to the opto isolator, so that the opto isolator is conducting with a duty cycle and frequency, and wherein the DALI has a selected current value between the zero current value and the maximum current value, based on the modulated second signal; and
a buck converter (<NUM>) which is configured for receiving a current reference based on a voltage reference based on the second signal, the buck converter being configured for generating a fixed voltage to the DALI.