Multimode controller for LED light sources
View Patent ↗A multimode controller for LED light sources, especially sources in warning lights, such as light bars, provides for a temporary increase in brightness from the LEDs by providing a burst mode, in addition to a flashing mode and a continuous mode. The modes are carried out by programming a microprocessor which receives signals from control switches, which may be pressed and released. The programming precludes the burst mode to continue for longer than a predetermined time thereby ensuring that the power does not exceed the LEDs damage threshold characteristic. The controller thereby provides for temporary bursting to make visible the region in front of or around an emergency vehicle for a short period of time without the need for light sources dedicated solely to the high intensity brightness mode of operation of a warning light system.
1. A multimode controller for one or more LED light sources which comprises:
a source of power,
means for selectively operating said one or more LED light sources by electrically pulsing continuously or intermittently to provide at least a first mode of operation at less than full power from said source, and
means for operating said one or more LED light sources temporarily in a second burst mode to continuously draw greater power than said first mode from said power source during said second burst mode which enables said one or more LED light sources to provide a burst of illumination greater in brightness than provided in said first mode, said greater power draw being for a period of time which does not exceed a power damage threshold level characteristic of said one or more LED light sources, whereby to facilitate control of a warning light system of an emergency vehicle which contains said LED light sources.
2. The controller according to claim 1 further comprising means for enabling selecting said second mode only when said first mode has been selected thereby switching from said first mode to said second mode.
3. The controller according to claim 1 wherein said first mode providing means further comprises means for providing a flashing mode in which said one or more LED light sources provides a train of pulses of illumination, the duty cycle of the electrical operating pulses being in a train drawing power from said source which is less than said damage threshold power level.
4. The controller according to claim 3 wherein said first mode providing means further comprises means for providing a continuous mode in which said one or more LED sources operate by being pulsed at a rate above the persistence of vision rate of the emergency vehicle operation to appear to provide continuous illumination and which provides said one or more LED sources with said electrical pulses from said power source at a level less than said threshold power level.
5. The controller according to claim 4 further comprising means for enabling selecting of said second mode only when said continuous mode is selected.
6. The controller according to claim 4 wherein said power source provides a voltage output subject to variations in level, and further comprises means for sensing the voltage output of said power source and modulating the rate of the electrical pulses and rate at which the pulsed illumination from said one or more sources appears to be continuous due to the persistence of vision of an observer, inversely with the level of said voltage output so that the brightness of illumination during said first mode appears substantially constant.
7. The controller according to claim 6 wherein said pulse rate is modulated at a rate 35-50% of a maximum rate during said continuous mode and 65-85% of said maximum rate during said flashing mode whereby said illumination brightness is lower during said first mode than during the burst of illumination in said second mode.
8. The controller according to claim 5 further comprising common operation selecting means for selecting said second mode when said continuous mode is selected and for changing the pattern of flashing of said one or more LED sources when said flashing mode is selected.
9. A multimode controller for one or more LED light sources which comprises:
a source of power,
a first switch and a computer programmed for selectively operating by electrically pulsing said one or more LED light sources continuously or intermittently to provide at least a first mode of operation at less than full power from said source, and
a second switch and said computer for operating said one or more LED light sources temporarily in a second, burst mode to continuously draw greater power from said power source than during said first, mode which enables said one or more LED light sources to provide a burst of illumination greater in brightness than provided in said first mode, said greater power draw being for a period of time which does not exceed a power damage threshold level characteristic of said one or more LED light sources, whereby to facilitate control of a warning light system of an emergency vehicle which contains said LED light sources.