Led lighting system

• US 20090021185A1
• Filed: 07/13/2005
• Published: 01/22/2009
• Est. Priority Date: 08/04/2004
• Status: Active Grant

• Current Assignee: Winnie Lai-Ling Ng
• Original Assignee: Dr. Led (Holdings), Inc.
• Inventors: Ng, James K.
• Granted Patent: US 7,847,486 B2
• Time in Patent Office: Days
• US Class Current: 315/294
• CPC Class Codes: H05B 45/395 Linear regulators
• CPC Class Codes: H05B 45/397 Current mirror circuits
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

A lighting system has an array (100) of at least one light-emitting solid-state element such as a light-emitting diode (LED) or a laser diode. A voltage source (10), which may supply either alternating or direct current, energizes the array. Array state circuitry (125; Q2, R2), electrically connected in series with the array (100), senses at least one state of the array, such as the amount of current passing through the array, or temperature. Secondary circuitry (127; R1, Q1; 200, 201, 202; 200, R4, Q1; 126, 127) is connected in parallel with the array (100). A switching component (Q1; Q1, Q3; 202) adjusts the current passing through the secondary circuitry in accordance with the sensed state of the array such that current through the array is maintained substantially constant. A third, parallel, excess current shunt path may also be provided, in which case so is excess current shunt circuitry, which senses current flowing in the secondary circuitry and shunts current in the secondary circuitry in excess of an excess current threshold to the excess current shunt path, whereby overflow current above a first threshold for the array (100) is shunted away from the array and excess current above a second threshold is shunted from the secondary circuits to the excess current shunt circuitry. A wide-angle mounting arrangement is also provided for the array.

Claims

1. A lighting system comprising:

an array (100) of at least one light-emitting solid-state element, and a voltage source (10) that energizes the array,

array state circuitry (125;

Q2, R2), electrically connected in series with the array (100) and the sensing at least one state of the array;

secondary circuitry (127;

R1, Q1;

200, 201, 202;

200, R4, Q1;

126, 127) connected in parallel with the array (100); and

a switching component (Q1;

Q1, Q3;

202) adjusting the current passing through the secondary circuitry in accordance with the sensed state of the array such that current through the array is maintained substantially constant.

2. A lighting system as in claim 1, in which the voltage source (10) supplies alternating current (AC), further comprising rectification circuitry that rectifies the AC current before it is applied to the array (100).

3. A lighting system as in claim 1, further comprising a capacitor (C1) connected in parallel with the array (100) so as to smooth and average the current applied to the array.

4. A lighting system as in claim 2, further including a current-limiting element (C2) in series with the AC voltage source (10) and between the voltage source and the array (100), the AC voltage source and the current-limiting element together forming an AC current source for the array (100).

5. A lighting system as in claim 1, in which the voltage source (10) supplies direct current (DC) to the array.

6. A lighting system as in claim 5, in which the voltage source (10) is a battery (BAT).

7. A lighting system as in claim 5, in which the voltage source (10) is an array of photoelectric elements (100).

8. A lighting system as in claim 1, in which the voltage source (10) is a radio frequency (RF) receiving circuit (ANT, RFL, RFC) that supplies the array (100) with current extracted from ambient RF energy.

9. A lighting system as in any preceding claim 1, in which the array state is the amount of electric current passing through the array (100).

10. A lighting system as in claim 1, in which:

the array state is temperature;

the array state circuitry includes a temperature-sensitive element that, upon sensing a temperature greater than a threshold temperature, chokes off biasing current to the secondary circuitry and thereby reduces the array'"'"'s (100) nominal current.

11. A lighting system as in any preceding claim 1, in which the secondary circuitry includes a load (R1;

200) through which passes overflow current shunted from the array by the array state circuitry and the switching component.

12. A lighting system as in claim 11, in which the load is at least one resistive element.

13. A lighting system as in claim 11, in which the load is a secondary array (200) of light-emitting, solid state elements.

14. A lighting system as in claim 1, further comprising:

an excess current shunt path connected in parallel with the array and the secondary circuitry;

excess current shunt circuitry that senses current flowing in the secondary circuitry and that shunts current in the secondary circuitry in excess of an excess current threshold to the excess current shunt path, whereby overflow current above a first threshold for the array (100) is shunted away from the array and excess current above a second threshold is shunted from the secondary circuitry to the excess current shunt circuitry.

15. A lighting system as in any preceding claim 1, further comprising a curved base (170) on which the light-emitting, solid state elements of the array (100) are mounted such that the light beams of adjacent light-emitting, solid state elements overlap and the array as a whole provides wide-angle illumination.

16. A lighting system as in claim 15, in which the base is substantially cylindrical.

17. A lighting system as in any preceding claim 1, in which the light-emitting, solid state elements are light-emitting diodes (LEDs).

18. A lighting system as in any preceding claim 1, in which the light-emitting, solid state elements are laser diodes.

19. A lighting system as in any preceding claim 1, in which the array (100) comprises a plurality n of current paths, each of which includes a plurality m of series-connected, light-emitting solid-state elements.

20. A lighting system that has:

an array having a plurality n of current paths, each of which includes a plurality m of series-connected, light-emitting solid-state elements;

voltage supply circuitry that applies direct current (DC) to the array;

a capacitor connected in parallel with the array so as to smooth and average the current applied to the array;

array state circuitry, electrically connected in series with the array and the sensing at least one state of the array;

secondary circuitry connected in parallel with the array;

an excess current shunt path connected in parallel with the array and the secondary circuitry;

excess current shunt circuitry that senses current flowing in the secondary circuitry and that shunts current in the secondary circuitry in excess of an excess current threshold to the excess current shunt path, whereby overflow current above a first threshold for the array is shunted away from the array and excess current above a second threshold is shunted from the secondary circuitry to the excess current shunt circuitry;

a switching component adjusting the current passing through the secondary circuitry in accordance with the sensed state of the array such that current through the array is maintained substantially constant; and

a load, included in the secondary circuitry, through which passes overflow current shunted from the array by the array state circuitry and the switching component.