Devices and systems having ac led circuits and methods of driving the same

Abstract

A lighting device and system having at least one circuit, the circuit having at least two LEDs connected in series, parallel or anti-parallel configuration and at least one current limiting diode. The device or system may be driven with AC or DC power and may further include a sensor and polarity switching circuit to utilize all LEDs within the circuit when drive by DC power.

What is claimed is: 
     
         1 . A lighting device comprising:
 at least one circuit capable of emitting light when powered by an AC power source, the at least one circuit having
 at least two LEDs connected in a series, a parallel, or an anti-parallel configuration, and 
 at least one current limiting diode connected in series or parallel with at least one of the at least two LEDs. 
   
     
     
         2 . The lighting device of  claim 1  wherein the at least one circuit includes
 at least first and second branches connecting at first and second common points, the common points providing an input and an output for a driving voltage for the circuit,
 the first branch having at least a first and a second LED, the first LED being connected to the second LED in opposing series relationship, with the inputs of the first and second LEDs defining a first branch junction, 
 the second branch having at least a third and a fourth LED, the third LED being connected to the fourth LED in opposing series relationship, with the outputs of the third and fourth LEDs defining a second branch junction, 
 the first and second branches being connected to one another such that the output of the first LED is connected to the input of the third LED at the first common point and the output of the second LED is connected to the input of the fourth LED at the second common point; and, 
 
 the at least one current limiting diode forming a first cross-connecting circuit branch, the first cross-connecting circuit branch being configured such that the input of the at least one current limiting diode is connected to the second branch junction and the output of the constant current diode is connected to the first branch junction. 
 
     
     
         3 . The lighting device of  claim 2  wherein the at least one circuit further includes at least one additional LED connected in series with:
 each of the second and fourth LEDs than is connected in series with each of the first and third LEDs between each LEDs respective common point and branch junction, or 
 each of the first and third LEDs than is connected in series with each of the second and fourth LEDs between each LEDs respective common point and branch junction. 
 
     
     
         4 . The lighting device of  claim 2  wherein the at least one LED circuit includes n additional LEDs, in pairs, wherein the pairs are configured among the first and second branches of the at least one circuit such that that the current draw through the at least one circuit during both AC phases is substantially the same. 
     
     
         5 . The lighting device of  claim 2  wherein the at least one circuit includes x cross-connecting circuit branches, each cross-connecting circuit branch
 having one or more constant current diodes, and 
 being connected in parallel to the first cross-connecting circuit branch. 
 
     
     
         6 . The lighting device of  claim 1  wherein the at least two LEDs are connected in an anti-parallel configuration. 
     
     
         7 . The lighting device of  claim 6  wherein at least one current limiting diode is connected in series with each of the at least two LEDs. 
     
     
         8 . The lighting device of  claim 6  wherein at least one additional LED is connected in series with each anti-parallel LED forming series strings of LEDs connected in anti-parallel configuration. 
     
     
         9 . The lighting device of  claim 8  wherein at least one current limiting diode is connected in series with each series string of LEDs. 
     
     
         10 . The lighting device of  claim 6  further comprising a bridge rectifier connected in series with the anti-parallel LEDs so that at least one LED is forward biased by power provided by the bridge rectifier and at least one LED is reverse biased by power provided by the bridge rectifier. 
     
     
         11 . The lighting device of  claim 10  further comprising a load sensor for sensing operation of the at least one forward biased LED. 
     
     
         12 . The lighting device of  claim 11  further comprising a polarity switching circuit capable of reversing the polarity of the power provided by the bridge rectifier to forward bias the at least one LED that was reversed biased if the sensor fails to detect that the at least one forward biased LED is operating. 
     
     
         13 . The lighting device of  claim 1  wherein the at least one circuit is integrated in a single chip. 
     
     
         14 . The lighting device of  claim 13  wherein the chip includes at least two power connection leads, the power connection leads being connected to opposite sides of the at least one circuit. 
     
     
         15 . The lighting device of  claim 1  wherein the at least one circuit is formed by integrating individual LED die on a substrate forming an LED package. 
     
     
         16 . The lighting device of  claim 15  wherein the substrate and LEDs formed thereon are coated in phosphor. 
     
     
         17 . The lighting device of  claim 13  comprising at least two circuits, the at least two circuits being connected in series or parallel, and formed on a single chip or substrate. 
     
     
         18 . The lighting device of  claim 13  further comprising at least two circuits electrically unconnected to each other, each of the at least two circuits having power connection leads connected to opposite ends of the circuit. 
     
     
         19 . The lighting device of  claim 1  wherein the lighting device is integrated within a lamp. 
     
     
         20 . The lighting device of  claim 19  wherein the lamp includes a base having at least two power connection leads, the power connection leads being connected to the at least one circuit so as to be able to provide power to the at least one circuit from a power supply. 
     
     
         21 . The lighting device of  claim 19  wherein the lamp is a brake light for an automobile. 
     
     
         22 . The lighting device of  claim 19  wherein the lamp is a headlight for an automobile. 
     
     
         23 - 42 . (canceled) 
     
     
         43 . An LED circuit comprising:
 at least two LEDs electrically connected and configured so that at least one LED is capable of emitting light during a positive phase if AC power is connected and at least one LED within the circuit is capable of emitting light during a negative phase if AC power is connected; and,   at least one current limiting diode connected in series or parallel with at least one of the at least two LEDs.   
     
     
         44 . The LED circuit of  claim 43  further comprising:
 at least first and second branches connecting at first and second common points, the common points providing an input and an output for a driving voltage for the circuit,
 the first branch having at least a first and a second LED, the first LED being connected to the second LED in opposing series relationship, with the inputs of the first and second LEDs defining a first branch junction, 
 the second branch having at least a third and a fourth LED, the third LED being connected to the fourth LED in opposing series relationship, with the outputs of the third and fourth LEDs defining a second branch junction, 
 the first and second branches being connected to one another such that the output of the first LED is connected to the input of the third LED at the first common point and the output of the second LED is connected to the input of the fourth LED at the second common point; and, 
 
 the at least one current limiting diode forming a first cross-connecting circuit branch, the first cross-connecting circuit branch being configured such that the input of the at least one current limiting diode is connected to the second branch junction and the output of the constant current diode is connected to the first branch junction. 
 
     
     
         45 . The LED circuit of  claim 44  wherein at least one additional LED connected in series with:
 each of the second and fourth LEDs than is connected in series with each of the first and third LEDs between each LEDs respective common point and branch junction, or 
 each of the first and third LEDs than is connected in series with each of the second and fourth LEDs between each LEDs respective common point and branch junction. 
 
     
     
         46 . The LED circuit of  claim 44  further comprising n additional LEDs, in pairs, wherein the pairs are configured among the first and second branches of the at least one circuit such that that the current draw through the at least one circuit during both AC phases is substantially the same. 
     
     
         47 . The LED circuit of  claim 44  further comprising x cross-connecting circuit branches, each cross-connecting circuit branch
 having one or more diodes, and 
 being connected in parallel to the first cross-connecting circuit branch. 
 
     
     
         48 . The LED circuit of  claim 43  wherein the at least two LEDs are connected in an anti-parallel configuration. 
     
     
         49 . The LED circuit of  claim 48  wherein at least one current limiting diode is connected in series with each of the at least two LEDs. 
     
     
         50 . The LED circuit of  claim 48  wherein at least one additional LED is connected in series with each anti-parallel LED forming series strings of LEDs connected in anti-parallel configuration. 
     
     
         51 . The LED circuit of  claim 50  wherein at least one current limiting diode is connected in series with each series string of LEDs. 
     
     
         52 . The LED circuit of  claim 43  wherein the at least one circuit is integrated in a single chip. 
     
     
         53 . The LED circuit of  claim 52  wherein the chip includes at least two power connection leads, the power connection leads being connected to opposite sides of the at least one circuit. 
     
     
         54 . The LED circuit of  claim 43  wherein the at least one circuit is formed by integrating individual LED die on a substrate forming an LED package. 
     
     
         55 . The LED circuit of  claim 54  wherein the substrate and LEDs formed thereon are coated in phosphor. 
     
     
         56 - 59 . (canceled)