Compact converter plug for LED light strings
View Patent ↗Disclosed is a compact converter plug that can be used with LED lighting strings. The converter plug has a size and shape that is comparable to a standard wall plug and is capable of plugging into a standard wall socket. The converter plug is waterproof and can be easily assembled. A unique converter circuit is utilized that is compact and highly efficient. Monitoring is performed by a transformer coil that generates a monitoring signal. The converter is controlled by controlling the modulation frequency of a direct current signal using a controller.
1. A converter plug for an LED light string that plugs into a household alternating current socket that converts alternating current household power to a low voltage direct current output comprising:
an enclosure that is watertight and has a shape and size similar to a wall plug;
plug blades that have a watertight seal with said enclosure;
a printed circuit board having converter circuitry mounted on at least one surface of said printed circuit board, said printed circuit board mounted in said enclosure, said converter circuitry comprising;
a rectifier that rectifies a source of alternating current from a household socket to produce a rectified alternating current signal at an output of said rectifier;
a low pass filter, connected to said output of said rectifier, that filters said rectified alternating current signal to provide a filtered, rectified, alternating current signal;
a high speed switching transistor that modulates said filtered, rectified, alternating signal to produce a modulated, rectified signal having a selected modulation frequency;
a first coil, in a transformer, coupled to said modulated, rectified signal that induces voltage changes in a second transformer coil to produce a second induced voltage and induces voltage changes in a third transformer coil to produce a third induced voltage;
a voltage detection circuit connected to said third transformer coil that produces a monitoring signal, without an optical coupler, from said third induced voltage on said third transformer coil that is proportional to said second induced voltage on said second transformer coil;
a controller that controls said selected modulation frequency of said modulated, rectified signal in response to said monitoring signal.
2. The converter plug of claim 1 further comprising:
a connector disposed on said enclosure having sockets that are adapted to connect to plugs on said LED light string, said connector being watertight and having a watertight coupler that mates with said LED light string to provide a watertight connection between said connector and said light string, said connector being mounted on, and sealed to, said enclosure so that said enclosure and said watertight connector are watertight, said watertight coupler allowing said converter plug to be disconnected from and directly connected to said LED light string.
3. The converter plug of claim 2 wherein said watertight coupler comprises a cylindrical threaded extension connected to said enclosure that is adapted to mate with a threaded cap disposed on an extendable power plug that forms a portion of said LED light string.
4. The converter plug of claim 3 wherein said watertight coupler comprises an extension that is connected to said enclosure having a surface that creates a watertight friction fit with an extendable power plug of said LED light string.
5. The converter plug of claim 1 wherein said rectifier is a full wave rectifier.
6. The converter plug of claim 1 further comprising:
a power circuit coupled to said third transformer coil that produces a power signal that powers said controller.
7. A converter plug for use with an LED light string comprising:
plug blades that fit in an alternating current wall socket;
a housing having an end portion that is molded around said plug blades that provides a watertight seal between said housing and said plug blades;
a printed circuit board having converter circuitry mounted thereon, said printed circuit board having pins that provide direct current power from said printed circuit board;
an end cap that attaches to said housing so that a watertight seal is created between said end cap and said housing;
a connector molded to said end cap having sockets that are electrically connected to said pins on said printed circuit board, said connector having a watertight coupling for coupling said converter plug to said LED light string;
a rectifier that rectifies a source of alternating current from a household socket to produce a rectified alternating current signal at an output of said rectifier;
a low pass filter, connected to said output of said rectifier, that filters said rectified alternating current signal to provide a filtered, rectified signal;
a high speed switching transistor that modulates said filtered, rectified signal to produce a modulated, rectified signal having a selected modulation frequency;
a first coil, in a transformer, coupled to said modulated, rectified signal that induces voltage changes in a second transformer coil to produce a second induced voltage and induces voltage changes in a third transformer coil to produce a third induced voltage;
a voltage detection circuit connected to said third transformer coil that produces a monitoring signal, without an optical coupler, from said third induced voltage on said third transformer coil that is proportional to said second induced voltage on said second transformer coil;
a controller that controls said selected modulation frequency of said modulated direct current signal in response to said monitoring signal.
8. The converter plug of claim 7 further comprising:
a power circuit coupled to said third transformer coil that produces a power signal that powers said controller.
9. The converter plug of claim 7 wherein said rectifier is a full wave rectifier.
10. A converter circuit for use in a converter plug for producing a direct current output for an LED light string comprising:
a rectifier that rectifies a source of alternating current from a household socket to produce a rectified alternating current signal at an output of said rectifier;
a low pass filter, connected to said output of said rectifier, that filters said rectified alternating current signal to provide a filtered, rectified, alternating signal;
a filter absorber that protects said converter circuit from voltage spikes;
a high speed switching transistor that modulates said filtered, rectified, alternating signal to produce a modulated, rectified signal having a selected modulation frequency;
a first coil, in a transformer, coupled to said modulated, rectified signal that induces voltage changes in a second transformer coil to produce a second induced voltage and induces voltage changes in a third transformer coil to produce a third induced voltage;
a voltage detection circuit connected to said third transformer coil that produces a monitoring signal, without an optical coupler, from said third induced voltage on said third transformer coil that is proportional to said second induced voltage on said second transformer coil;
a controller that controls said modulation frequency of said modulated direct current signal in response to said monitoring signal.
11. The converter circuit of claim 10 further comprising:
a power circuit coupled to said third transformer coil that produces a power signal that powers said controller.
12. The converter circuit of claim 10 wherein said rectifier is a full wave rectifier.