Various embodiments relate generally to lighting systems.
High-intensity discharge lamps (HID lamps) are a type of electrical gas-discharge lamp which produces light by means of an electric arc between tungsten electrodes housed inside a translucent or transparent fused quartz or fused alumina arc tube. This tube is filled with noble gas and often also contains suitable metal or metal salts. The noble gas enables the arc's initial strike. Once the arc is started, it heats and evaporates the metallic admixture. Its presence in the arc plasma greatly increases the intensity of visible light produced by the arc for a given power input, as the metals have many emission spectral lines in the visible part of the spectrum. High-intensity discharge lamps are a type of arc lamp.
Apparatus and associated methods relate to powering a constant voltage DC load using a rectified output of a lighting ballast. In an illustrative example, the ballast may be configured to operate as a constant-current source. The DC load may, for example, comprise an array of LED strings connected in parallel. The number of LED strings may, for example, be selected to match a power output of the ballast. The number of LEDs in each string may, for example, be selected to match a rectified voltage output range of the ballast. A normally-open thermostat may, for example, be connected in parallel between the ballast and a rectifier and be configured to short-circuit the ballast if the circuit overheats. Various embodiments may advantageously utilize existing power processing functions of an electronic ballast to reduce complexity of a driver circuit for a constant voltage DC source.
The details of various embodiments are set forth in the accompanying drawings and the description below. Other features and advantages will be apparent from the description and drawings, and from the claims.
Like reference symbols in the various drawings indicate like elements.
In various embodiments the ballast 101 may, for example, be a circuit which behaves as a constant power source. For example, the ballast 101 may behave as a constant current source over an operating voltage range. The ballast 101 may, for example, be an electronic ballast. In some embodiments the electronic ballast may, for example, be a non-magnetic ballast. For example, the ballast 101 may change a frequency of alternating current (AC) power supplied by the ballast input power source 108 without any (substantial) change in a voltage of the AC power. The ballast 101 may, for example, increase a frequency of the AC power significantly above an input frequency (e.g., about 60 Hz). The frequency may, by way of example and not limitation, be increased by one or more orders of magnitude (e.g., to about 20 kHz). In various embodiments the ballast 101 may, by way of example and not limitation, include multiple inductance coils. In various embodiments the ballast 101 may, for example, be designed to power a high-intensity discharge (HID) lamp. For example, the ballast 101 may be configured to provide a constant power supply (e.g., constant current).
Although various embodiments have been described with reference to the Figures, other embodiments are possible. For example, an apparatus for powering constant voltage DC loads from a lighting ballast may include a ballast, a rectifier element, and one or more substantially constant voltage DC loads. In various embodiments, the input terminals of the ballast may be coupled to a power source. The output terminals of the ballast may, for example, be coupled to the AC terminals of a rectifier element. The DC terminals of the rectifier element may, for example, be coupled to the terminals of the substantially constant voltage DC load.
An apparatus for powering constant voltage DC loads from a lighting ballast may include a ballast, a rectifier element, one or more substantially constant voltage DC loads, and a thermostat. In some illustrative embodiments, the input terminals of the ballast may be coupled to a power source, the output terminals of the ballast may be coupled to the AC terminals of a rectifier element, the DC terminals of the rectifier element may be coupled to the terminals of the substantially constant voltage DC load, and/or the terminals of the thermostat may be coupled to the output terminals of the ballast. The ballast may be an electronic ballast. The rectifier element may be a diode bridge. The one or more substantially constant voltage DC loads may include multiple LEDs. The thermostat may be a normally open bi-metal thermostat.
An LED lighting method may include, in an exemplary aspect, rectifying the output power of a lighting ballast to produce a substantially DC output. The method may include determining the operational power and rectified voltage range of the ballast. The method may include choosing an array of LEDs to match the power of the ballast. The method may include arranging the series and parallel connections of the LEDs such that the applied voltage when operating at the ballast power is near the midpoint of the ballast rectified voltage range. The method may include supplying power from the ballast via a rectifying element to the series and parallel arrangement of LEDs.
Creating LED lamps that are installed in the same way as a bulb replacement may be highly advantageous to reduce the cost of retrofit installation in existing light fixtures. In the case of discharge lamps, the ballast that is used to control the power in the discharge bulb may be incorporated into the fixture. LED lamps designed for installation in these fixtures may accept the power and waveforms that are generated by the ballast in order to function in these applications. An optimal solution disclosed herein is to utilize the existing power processing functions of the ballast to reduce the complexity of the driver electronics in the LED lamp.
Temporary auxiliary energy inputs may be received, for example, from chargeable or single use batteries, which may enable use in portable or remote applications. Some embodiments may operate with other DC voltage sources, such as batteries, for example. Alternating current (AC) inputs, which may be provided, for example from a 50/60 Hz power port, or from a portable electric generator, may be received via a rectifier and appropriate scaling. Provision for AC (e.g., sine wave, square wave, triangular wave) inputs may include a line frequency transformer to provide voltage step-up, voltage step-down, and/or isolation.
Various examples of modules may be implemented using circuitry, including various electronic hardware. By way of example and not limitation, the hardware may include transistors, resistors, capacitors, switches, integrated circuits, other modules, or some combination thereof. In various examples, the modules may include analog logic, digital logic, discrete components, traces and/or memory circuits fabricated on a silicon substrate including various integrated circuits (e.g., FPGAs, ASICs), or some combination thereof. In some embodiments, the module(s) may involve execution of preprogrammed instructions, software executed by a processor, or some combination thereof. For example, various modules may involve both hardware and software.
A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made. For example, advantageous results may be achieved if the steps of the disclosed techniques were performed in a different sequence, or if components of the disclosed systems were combined in a different manner, or if the components were supplemented with other components. Accordingly, other implementations are contemplated within the scope of the following claims.
This application claims the benefit of U.S. Provisional Application Ser. No. 62/979,254, titled “DRIVER INCORPORATING A LIGHTING BALLAST FOR SUPPLYING CONSTANT VOLTAGE LOADS,” filed by Frank Shum and Ray Orr, on Feb. 20, 2020. This application incorporates the entire contents of the foregoing application(s) herein by reference.
Number | Name | Date | Kind |
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20110121756 | Thomas | May 2011 | A1 |
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20180116030 | Sam | Apr 2018 | A1 |
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Number | Date | Country | |
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20210267033 A1 | Aug 2021 | US |
Number | Date | Country | |
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62979254 | Feb 2020 | US |