Patent Application
20150061497
A three-way lamp, e.g., three way incandescent lamp, produces three levels of light intensity (i.e., low, medium, and high), typically using two lamp filaments within the same optical housing. The two filaments are typically of different wattages. For example, one lamp filament can be a low wattage filament, and the other filament can be a high wattage filament.
Conventionally, these two filaments are connected in parallel to the lamp base. The lamp base itself has two contacts and a neutral contact. Each of the filaments operates at full voltage when activated.
Proper installation of the three-way lamp is achieved by using a three-way lamp socket, which has three contacts instead of the usual two for a single filament lamp. This third contact is typically off center in the bottom of the socket, and makes contact with the second filament circuit.
The three-way lamp is controlled using a three-way switch, which itself has four positions. Starting from the ‘off’ position, the switch can sequentially connect power to one filament (typically the lower wattage filament,), then the other filament, and then both filaments.
In accordance with embodiments, a three-way lamp includes light emitting diodes (LED) as light sources, two AC input terminals, and two or more bias switches accessible on an outer surface of the lamp. In one implementation, there can be three bias switches. These bias switches can be used to set the light intensity level produced by the LED light sources depending on the AC input presence (at one terminal, the other terminal, or both AC input terminals). The bias switches themselves can be located on the lamp's capper to be readily accessible by a user, so that the three light illumination intensity output levels of the three-way lamp can be programmed by the user.
AC line detector 220 detects the presence of AC voltage on the terminal(s) of input 210. Rectifier 230 rectifies the AC voltage. In one implementation, the rectifier can be a full wave rectifier, and can include an EMI filter stage.
The rectified voltage is provided to power supply 240, where an auxiliary regulator circuit develops the DC supply voltage used by electronic circuitry. Also connected to the rectifier is switch mode converter 250, which generates a controlled DC voltage that drives LED light sources 260. This controlled DC voltage is tightly regulated to provide the desired current to the LED light sources. Thus, effectively acting as a constant current source to the LED strings.
The level of the LED drive current from the switch mode converter is adjusted by an input from control circuit 270. The control circuit receives signals from the AC line detector, and includes circuitry that sets the current level(s) for the LED light sources. The user adjustable bias switches help to bias this circuitry to set the LED light source current level(s). Control circuit 270 controls the power levels depending on the AC line input selection and the bias switch settings.
LED light sources can be a LED Chip on Board, a set of LED die, or LED packages in strings. In accordance with one embodiment, four of these LED light sources can be serially connected to form LED strings. This series string of LEDs can then be repeated (e.g., four times) for a total of 16 LED packages as light source LED string 260. In accordance with some embodiments, all of the LED light sources receive the drive power from the switch mode converter. The light intensity of the LED light sources varies with the AC line input selection, as impacted by the bias switch selections made by the user.
In accordance with some embodiments, the user can program three-way lamp 100 to particular illumination levels by varying the setting of the three bias switches located on the shell of capper 120. In one implementation, the bias switches can be DIP switches. Other implementations of the bias switches could include rotary dial switches, etc.
Bias switches 124 can control the three illumination intensity levels of the three-way lamp to an individual level. The three illumination output levels can be controlled independently unlike the dependency between illumination levels of the conventional three-way lamp. Conventional three-way lamps have illumination levels determined by the wattage of the two filaments that produce the three illumination levels. For example, in a conventional three-way lamp the filaments can be 50 and 100 watts, so the lamp can only produce illumination levels of 50, 100 and 150 watts.
In accordance with embodiments, three-way lamp 100 can control each basic level in the driver electronics. By use of the bias switches the output level can be controlled to a finer level. For example, depending on the internal bias circuitry values selected by the bias switches, bias switch SW1 (
If the lamp fixture three-way switch is selected so that an AC input is present on both AC line 1 and AC line 2 (points A and B), then transistors Q1, Q2, Q3, Q4 are operative which effectively removes parallel resistor networks RN1, RN2 and selector switches S1, S2 from the circuit. In this situation, the LED driver power is solely determined by the resistance of resistor network RN3 as selected by the setting of bias switch S3.
If either of the two input AC lines is singularly active, then the absence of power on the other AC line disables that bias circuit's transistors. For example, if AC line 1 has no AC input connected, then Q1 is turned off, which raises the gate voltage of Q2 and turns Q2 on. The resistance of resistor network RN1 is selected by switch S1, and is in parallel (to ground through transistor Q2) with the resistance of resistor network RN3 as selected by switch S3. Thus, lowering the resistance path of control point C to ground, and lowering the output current set point (Point C). This change in resistance (increase or decrease) can be predetermined by setting the bias switches S1, S2, S3 to various positions. Although transistors Q1, Q2, Q3, Q4 are depicted as re-channel FETS, other implementations can include other switching elements such as p-channel FETS, bipolar junction transistors, etc.
Although specific hardware and methods have been described herein, note that any number of other configurations may be provided in accordance with embodiments of the invention. Thus, while there have been shown, described, and pointed out fundamental novel features of the invention, it will be understood that various omissions, substitutions, and changes in the form and details of the illustrated embodiments, and in their operation, may be made by those skilled in the art without departing from the spirit and scope of the invention. Substitutions of elements from one embodiment to another are also fully intended and contemplated. The invention is defined solely with regard to the claims appended hereto, and equivalents of the recitations therein.
