Systems and methods for reducing energy requirements of an electric light
Systems and methods of driving a light source, such as a light emitting diode (LED), while minimizing power consumption. Different techniques can be implemented in circuits that eliminate the traditional need for a sense resistor. By eliminating the sense resistor, a LED driving circuit's efficiency can be improved by up to and exceeding 30%. A pulse-width modulator can be used to control current flow in a buck, boost, or buck-boost circuits. Many of the configurations discussed eliminate the need for a sense resistor, which needlessly dissipates power. Others use a sense resistor minimally compared to traditional LED driving circuits.
1. An electric candle powered by a stored power source, comprising:
an inductor;
a light source;
a circuit coupled to a battery that is configured to power the light source, wherein the circuit comprises:
a switch coupled with the light source and configured to permit current to pass through the inductor and the light source when the switch is closed;
a resistor coupled with the light source; and
a comparator coupled with the resistor and a processor, wherein the comparator controls a current flow to the light source by comparing an average voltage of the resistor to a digital-to-analog convertor output received from the processor to produce a comparison signal;
wherein the processor is configured to receive the comparison signal and control the switch to modify the current flow as a function of the comparison signal, to maintain a predefined brightness of the light source as a voltage of the stored power source decreases.
2. The circuit of claim 1 , wherein the light source comprises a LED.
3. The circuit of claim 1 , wherein the light source is driven in a constant current mode.
4. The circuit of claim 1 , wherein the light source comprises a plurality of LEDs arranged in parallel.
5. The circuit of claim 1 , further comprising the processor coupled with the comparator.
6. The circuit of claim 5 , wherein the switch is modulated by the processor.
7. The circuit of claim 1 , further comprising a fixed resistor divider coupled with the comparator.
8. The circuit of claim 1 , further comprising a coil coupled with the light source.
9. The circuit of claim 1 , further comprising a second switch coupled with the light source.
10. The circuit of claim 9 , wherein the processor is coupled with the second switch, and modulates opening and closing of the second switch to change a voltage received by the light source.
11. The circuit of claim 9 , wherein the processor modulates the second switch.
12. The candle of claim 1 , wherein the inductor configured to cause a flame element of the candle to move, and the light source shines light on to the flame element.