The invention described in this patent application was not the subject of federally sponsored research or development.
The present invention pertains to connecting multiple direct current electrical energy power supplies in proper form to LED modules which LED modules contain one or more individual LEDs or one or more sets of series-connected individual LEDs.
The development of LEDs as a light source for use in many applications has grown rapidly over the past several years. Accordingly, LEDs are now being used in applications where higher wattage incandescent lamps, fluorescent lamps or halogen lamps were previously used. As in any electrical application of electrical energy to lighting devices, there is a continuing demand to reduce costs by minimizing the number of energy consuming units in a multi-unit system and to reduce costs by increasing the efficiency of an electrical system by reducing the amount of electrical energy consumed.
The efficiency of an LED lighting system including LED modules having multiple LEDs contained therein is increased by use of the disclosed power system. The power system for an LED module including multiple individual LEDs of the present invention includes a plurality of direct current (DC) electrical energy power supplies. The number of direct current (DC) electrical energy output channels from the plurality of direct current (DC) electrical energy power supplies is equal to the number of individual LEDs in each LED module. Each one of the direct current (DC) electrical energy output channels is electrically connected to one of the individual LEDs in an LED module. For example, a first electrically positive polarity output of each of said direct current (DC) electrical output channels is connected to the positive polarity of an individual LED. The negative polarity of the direct current electrical energy power supply is connected to the negative polarity of each individual LED to close the electrical circuit. Alternatively, the first polarity may be electrically negative. In such case, closing the circuit will require connection to an electrically positive polarity.
The power system for a plurality of LED modules of the present invention wherein each LED module includes the same number of LEDs includes a plurality of direct current (DC) electrical energy power supplies wherein the number of direct current (DC) electrical energy output channels is equal to the number of individual LEDs or sets of series-connected individual LEDs in each LED module. Each of the individual LEDs or sets of series-connected individual LEDs in an LED module being electrically connected to an individual LED or a set of series-connected individual LEDs in the next LED module. Accordingly, a number of series connections across all LED modules that is equal to the number of individual LEDs or sets of series-connected individual LEDs in each LED module. Each of the direct current (DC) electrical energy channels is electrically connected to one of the series connections across all LED modules. The first electrical polarity output of the direct current (DC) electrical energy output channel is connected to the same polarity of the first individual LEDs. The output polarity of the last individual LED or set of series-connected individual LEDs in the series connection is connected to an electrically opposite polarity of the output of direct current (DC) electrical energy channel to close the electrical circuit to the direct current (DC) electrical energy power supply.
A still better understanding of the disclosed power system for an LED module including multiple LEDs may be had by reference to the drawings which provide a graphic description to supplement the following Description of the Embodiments, wherein:
A better understanding of the disclosed invention may be had from an understanding of a light emitting diode (LED) and how an LED receives electrical energy. Following this description of an LED and how the LED receives energy will be a description of the disclosed invention, its operation and its embodiments.
LEDs are current driven electrical devices. This means that the light output from an LED and the forward voltage across the LED are determined by the electrical current applied to the LED. Both alternating current (AC) electrical energy and direct current (DC) electrical energy can be used to cause LEDs to emit light. However, when an AC electrical energy source is used, which AC electrical energy source typically has a frequency of 50 Hz to 120 Hz, the light emitted from an LED will be perceived by the human eye as flickering. To eliminate such undesirable flickering, a direct current (DC) supply of electrical energy can be applied to the LED. Specifically, a constant amount of DC electrical current applied to an LED causes the LED to emit a stable, non-flickering output of visible light.
Because LEDs emit a stable, non-flickering output of visible light when a DC electrical current is applied to the LED, it becomes necessary to transform commonly available sources of AC electrical energy into DC supplies of electrical energy. Typically, such transformation of AC electrical energy into DC electrical energy is accomplished by the use of a DC electrical energy power supply. This DC electrical energy power supply takes the alternating current (AC) electrical energy from the AC electrical line as input, conventionally 110 volt AC/60 Hz, or 220 volt AC/50 Hz, converts the input of direct current (DC) electrical energy into direct current (DC) electrical energy as an output.
The foregoing operation of an LED and the flow of electrical energy to the LED is best illustrated in
Conventionally, there are two types of output electrical energy from a DC electrical energy power supply, a constant voltage DC output, such as 12 volts DC, 24 volts DC etc., or a constant current DC output, such as 0.5 amperes DC, 1 ampere DC, etc.
For a DC electrical energy power supply with a constant voltage DC output, its rated output wattage determines the maximum output of DC current at the rated output of constant voltage DC. For example, a constant-voltage DC electrical energy power supply rated at 96 watts and 24 volts DC, provides an output electrical energy as a constant DC voltage of 24 volts, and a DC electrical current of 0 to 4 amperes (96 watts/24 volts=4 amperes). The electrical load applied to the output (0-96 watts)of the constant voltage (DC) power supply determines the actual output of DC amperage from this constant voltage DC electrical energy power supply.
When the DC electrical energy power supply provides a constant voltage DC output, each LED module in the string receives the same DC voltage as input electrical energy to power the LEDs and thereby consumes a certain amount of DC amperage from the DC electrical energy power supply. The maximum number of LED modules that can be powered by this DC electrical energy power supply is determined by the rated DC amperage of each LED module, and the rated output DC wattage and constant DC voltage of the DC power supply. For example, if an LED module is rated at 24 volts and 0.2 amperes DC, a DC electrical energy power supply rated at 24 volts, 96 watts DC can power a maximum of 20 LED modules (96 watts/24 volts/0.2 amperes=20 LED modules).
For a DC electrical energy power supply with a constant amperage DC output, its rated output wattage determines the maximum output DC voltage at the rated constant amperage DC output. For example, a constant-amperage DC electrical energy power supply rated at 60 watts and 1 ampere DC, provides an output electrical energy as a constant DC amperage of 1 ampere, and a DC electrical voltage of 0 to 60 volts (60 watts/1 amp=60 volts). The electrical load applied to the output (0-60 watts) of the constant amperage direct current power supply determines the actual output of DC voltage from this constant amperage DC electrical energy power supply.
When the DC electrical energy power supply provides a constant amperage DC output, each LED module in the string of LED modules receives the same DC amperage as input electrical energy to illuminate the LEDs and thereby consumes a certain amount of DC voltage from the DC electrical energy power supply. The maximum number of LED modules that can be powered by this DC electrical energy power supply is determined by the rated DC voltage of each LED module, and the power supply's rated output DC wattage and constant DC amperage. For example, if an LED module is rated at 0.5 amperes and 3.0 volts DC, a DC electrical energy power supply rated at 0.5 amperes, 60 watts DC can power a maximum of 40 LED modules (60 watts/3.0 volts/0.5 amperes=40 LED modules).
For ease of use and incorporation into systems using LEDs to provide light energy, individual LEDs are typically incorporated into various types of LED modules. Such LED modules contain either a single LED as shown in
In large lighting installations, multiple LED modules are connected to one another by wires to form a string of LED modules. The string of LED modules is then connected to the DC output of a DC electrical energy power supply. The wires convey DC electrical energy to each LED module in the string of LED modules as shown in
The efficiency of electrical energy utilization in the prior art systems illustrated in
If a switch-mode driver circuit is used in each LED module, which switch mode driver circuit can increase the amount of input DC voltage and provides a DC constant amperage to the LEDs, the efficiency of the prior art LED system initializing a switch mode driver circuit may be greater than 75%. However, such switch-mode driver circuits are not frequently used because of their higher cost as multiple electrical components are needed to achieve a proper operation of the switch-mode driver circuit.
In addition, when prior art systems are used in long strings which include many LED modules, the available DC current (in amperes) from the DC electrical energy power supply to power an individual LED in an LED module is limited by its wattage rating according to electrical safety regulations. In turn this limitation on wattage reduces the light output per LED. Accordingly, to increase the total light output of the lighting system, there is a need to either use more LED modules, or to incorporate more individual LEDs into each LED module. As indicated above, the use of more individual LEDs or more LED modules raises both the cost of the lighting system and the amount of electrical energy consumed.
As discussed above, each DC electrical energy power supply can provide either a constant-voltage, or a constant-amperage DC electrical energy output. When the DC electrical energy power supply provides a constant amperage DC electrical energy output to a series connection of individual LEDs in the string of LED modules having multiple LEDs as shown in
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In the illustrated embodiments of the disclosed invention, each DC electrical energy power supply includes an electrically positive polarity and an electrically negative polarity. The electrically positive polarity is connected to the positive polarity of DC electrical energy input of one of the individual LEDs in the first module in the string of LED modules. The DC electrical energy output from this individual LED in the first module in the string of LED modules is then connected to the electrically positive polarity of DC electrical energy input of one of the individual LEDs in the second LED module in the string of LED modules. The same type of connection from the second LED module in the string of LED modules is repeatedly formed to reach one of the individual LEDs in the last module in the string of LED modules. The DC electrical energy output from this individual LED in this last LED module is then connected to the negative polarity of the same DC electrical energy power supply to form a closed electrical circuit.
A second DC electrical energy power supply forms the same type of series connections as described in the preceding paragraph with a second LED in each one of the LED modules in the same string of LED modules. The same type of series connection is formed between all individual LEDs in an LED module and all separate DC electrical energy power supplies.
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As described above, the electrical connection on the output side of the last LED modules in the string of LED modules is called an end plug 50 as shown in
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According to the preferred embodiment of the present invention, each LED within an LED module is provided with positive polarity DC electrical energy from one of the multiple DC electrical energy power supplies, or one of the individual DC output channels from a single DC electrical energy power supply. Once the positive polarity DC electrical energy flows into an individual LED, which causes a portion of the DC electrical energy to be used to emit light energy from the individual LED, the remaining DC electrical energy flows onto another individual LED in another LED module. At the end of the string of LED modules, the electrical circuit is closed by directing the positive polarity DC electrical energy to a common negative polarity of the DC electrical energy power supply(s).
Those of ordinary skill in the art will also understand that instead of using positive polarity DC electrical energy, the disclosed system will still operate if multiple channels of negative polarity DC electrical energy are used and a common positive polarity were used to complete the electrical circuit as shown in
Because the needed DC constant amperage supply of electrical energy comes from the DC power supply, there is no need to include an integrated circuit component on a printed circuit board within the LED module as shown in
As discussed above, when a string of LED modules is powered by a constant-voltage DC electrical energy power supply, as opposed to a constant amperage DC electrical energy power supply, the output DC amperage from the constant voltage DC electrical energy power supply is the sum of the DC amperages consumed by all the LED modules in the string of LED modules. Therefore, the DC amperage for each LED module is the maximum DC output amperage from the constant-voltage DC electrical energy power supply divided by the number of modules in the string. This limits the amount of DC electrical amperage available for each LED module, hence the light output that can be generated by each LED module is limited. When a constant-amperage DC electrical power supply is used in the present invention, the DC amperage for each LED in an LED module is equal to the rated DC output amperage from that constant-amperage DC electrical energy power supply, or from one of the output channels if it is a single power supply with multiple DC output channels is used. Therefore, the available DC amperage for each LED from a constant-amperage DC electrical power system, is multiple times higher than the available DC amperage for each LED from a constant-voltage DC electrical power system.
Since the light output of an individual LED is determined by the DC electrical amperage powering the LED, a constant-amperage DC electrical energy power supply in the present invention provides much higher available DC electrical amperage for each individual LED in any of the LED modules in the string, hence there is a much higher light output per individual LED. With this greater light output from each individual LED, the number of individual LEDs needed in each LED module can be reduced while the same level of light energy from the LED module is maintained.
The number of LED modules in the string of LED modules depends on the amount of energy provided by the positive polarity DC electrical energy supply and the amount of electrical energy needed for each individual LED to emit the desired level of light energy.
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Those of ordinary skill in the art will understand that a variety of different connectors may be used in addition to the ones illustrated in
As shown in
The cross-section of the end plug 50 shown in
Those of ordinary skill in the art will understand that when LEDs are connected into a DC series electrical circuit, one of the LEDs with an open-circuit failure will open the DC series electrical circuit so that no DC electrical energy will pass through the electrical circuit. In this case, an electrical bridge circuit 90 as shown in
Those of ordinary skill in the art will understand that the disclosed invention may include other changes and modifications known to those of ordinary skill in the art. Such changes and modifications shall be included within the scope and meaning of the appended claims.
This application claims the benefit of Provisional U.S. Patent Application Ser. No. 61/805,327, filed on Mar. 26, 2013, the entire disclosure of which is hereby incorporated by reference into the present disclosure.
Number | Date | Country | |
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61805327 | Mar 2013 | US |