Low power lighting system with LED illumination
OwnerCharles Henry Hamp, David James Mitchellinventors
Life of this patent
Estimating the term…
Abstract
A DC-DC converter is configured as a constant current source to drive an LED load. This circuit configuration draws constant power from the input supply and delivers a constant current to the light source. A wide range of output voltages can be supported due to the implementation of current feedback for closed loop control. This allows for a selectable number of LED's to be powered simultaneously in a series configuration. Exceptional battery life is achieved due to the constant power discharge mode achieved with constant current feedback control. LED's powered at a constant current maintain a constant brightness level throughout the life of the battery.
Claims11
A power conserving device, comprising:
- a constant current circuit configured to generate a constant load current based on an input voltage from a power source and a feedback voltage;
- a load device coupled to the constant current circuit and configured to drop a load voltage based on the constant load current;
- and
- a feedback circuit coupled to the load device and the constant current circuit and configured to determine the feedback voltage based on constant load current
A flashlight, comprising:
- a constant current circuit configured to generate a constant load current based on an input voltage from a power source and a feedback voltage;
- a light source coupled to the constant current circuit and configured to emit light generated from the constant load current;
- and
- a feedback circuit coupled to the constant current circuit and the light source and configured to determine the feedback voltage based on the constant load current.
A method of generating a light beam in a flashlight, the method comprising:
- applying an input voltage to a constant current circuit;
- applying feedback voltage to the constant current circuit;
- generating a constant load current in the constant current circuit based on the input voltage and the feedback voltage;
- supplying the constant load current to a light source wherein the light source emits light generated from the constant load current;
- and
- determining the feedback voltage in a feedback circuit based on the constant load current.
Dependencies are inferred from the claim text.