Digitally controlled current regulator for high power solid state lighting

• US 8,427,066 B2
• Filed: 10/25/2011
• Issued: 04/23/2013
• Est. Priority Date: 05/22/2006
• Status: Active Grant

• Current Assignee: Chemtron Research LLC (Intellectual Ventures LLC)
• Original Assignee: Point Somee LLC (Intellectual Ventures LLC)
• Inventors: Shteynberg, Anatoly, Rodriguez, Harry
• Primary Examiner(s): Vo, Tuyet Thi
• Application Number:
  US13/280,555
• Publication Number:
  US 20120081018A1
• Time in Patent Office: 546 Days
• Field of Search: 315/247, 315/246, 315/224, 315/291, 315307-326, 315/180.S
• US Class Current: 315/247
• CPC Class Codes: H05B 45/14 using electrical feedback from LEDs or from LED modules
• CPC Class Codes: H05B 45/3725 Switched mode power supply [SMPS]
• CPC Class Codes: H05B 45/375 using buck topology
• CPC Class Codes: H05B 45/38 using boost topology
• CPC Class Codes: H05B 47/165 following a pre-assigned programmed sequence; Logic control [LC]
• CPC Class Codes: H05B 47/17 Operational modes, e.g. switching from manual to automatic mode or prohibiting specific operations
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

A representative apparatus embodiment provides for controlling current supplied to solid state lighting, such as light emitting diodes. A representative apparatus comprises a memory adapted to store a plurality of current parameters, and a control circuit adapted to modulate an energizing cycle time period for providing a substantially constant DC average current to the solid state lighting in response to a selected current parameter from the plurality of current parameters. In a representative embodiment, the control circuit modulates a current provided to the solid state lighting in response to a predetermined minimum current level (I_MIN) parameter and a predetermined peak current level (I_P) parameter, such that the DC average current level (I_O) is substantially proportional to one-half of a sum of a predetermined peak current level (I_P) and a predetermined minimum current level

$I_M\left(I_O\propto \frac{I_P+I_{\mathrm{MIN}}}{2}\right).$

Claims

1. A current regulator configured to control current to solid state lighting, the current regulator couplable to a power source, the current regulator comprising:

a memory configured to store a plurality of current parameters;

a control circuit coupled to the memory, wherein the control circuit is configured to modulate an energizing cycle time period, and wherein the control circuit is further configured to provide a substantially constant DC average current to the solid state lighting in response to a selected current parameter from the plurality of current parameters;

an inductor coupled to the solid state lighting;

a switch coupled to the control circuit and to either the inductor or the solid state lighting;

a current sensor coupled to the switch; and

a first comparator coupled to the current sensor and the control circuit, wherein the control circuit is further configured to turn the switch on to commence an energizing cycle and to turn the switch off when the first comparator indicates that an inductor current has increased to a predetermined peak level.

2. The current regulator of claim 1, further comprising:

a voltage sensor; and

a second comparator coupled to the voltage sensor and the control circuit, wherein the control circuit is further configured to turn the switch on to commence an energizing cycle when the second comparator indicates that an inductor current has decreased to a predetermined minimum level.

3. The current regulator of claim 1, further comprising:

a second current sensor; and

a second comparator coupled to the second current sensor and the control circuit, wherein the control circuit is further configured to turn the switch on to commence an energizing cycle when the second comparator indicates that an inductor current has decreased to a predetermined minimum level.

4. The current regulator of claim 1, wherein the power source is a battery, a DC power source, or an AC power source coupled to a rectifier.

5. The current regulator of claim 1, wherein the plurality of current parameters comprise a predetermined minimum current level (I_MIN) and a predetermined peak current level (I_P).

6. The current regulator of claim 5, wherein the predetermined minimum current level (I_MIN) is substantially close to zero.

7. The current regulator of claim 5, wherein the control circuit is further configured to provide the substantially constant DC average current by maintaining substantially constant a predetermined peak current level (I_P) and a predetermined minimum current level (I_MIN).

8. The current regulator of claim 5, wherein the control circuit is further configured to modulate the energizing cycle time period by providing an increasing current level to an inductor until the predetermined peak current level (I_P) is substantially reached and subsequently by providing a decreasing current level to the inductor until the predetermined minimum current level (I_MIN) is substantially reached.

9. The current regulator of claim 8, wherein the DC average current level (I_O) is substantially equal to one-half of a sum of a predetermined peak current level (I_P) and a predetermined minimum current level

10. The current regulator of claim 8, wherein the DC average current level (I_O) is substantially proportional to one-half of a sum of a predetermined peak current level (I_P) and a predetermined minimum current level

11. An apparatus for controlling current to solid state lighting, the apparatus couplable to a power source, the apparatus comprising:

a memory configured to store a predetermined minimum current level (I_MIN) parameter and a predetermined peak current level (I_P) parameter;

an inductor coupled to the solid state lighting;

a controller coupled to the memory, wherein the controller is configured to provide a substantially constant DC average current to the solid state lighting, wherein the controller is further configured to modulate a current provided to the solid state lighting in response to the predetermined minimum current level (I_MIN) parameter and the predetermined peak current level (I_P) parameter, and wherein the controller includes;

a control circuit;

a switch coupled to the control circuit and to either the inductor or the solid state lighting; and

a current sensor coupled to the switch; and

a first comparator coupled to the current sensor and the control circuit, wherein the control circuit is configured to turn the switch on to commence an energizing cycle and to turn the switch off when the first comparator indicates that an inductor current has reached the predetermined peak current level.

12. The apparatus of claim 11, wherein the predetermined minimum current level (I_MIN) is substantially close to zero.

13. The apparatus of claim 11, wherein the controller is further configured to provide the substantially constant DC average current by maintaining substantially constant a predetermined peak current level (I_P) and a predetermined minimum current level (I_MIN).

14. The apparatus of claim 11, wherein the controller is further configured to provide an increasing current level to an inductor until a predetermined peak current level (I_P) is substantially reached and to provide a decreasing current level to the inductor until a predetermined minimum current level (I_MIN) is substantially reached.

15. The apparatus of claim 11, wherein the DC average current level (I_O) is substantially equal to one-half of a sum of a predetermined peak current level (I_P) and a predetermined minimum current level

16. The apparatus of claim 11, wherein the DC average current level (I_O) is substantially proportional to one-half of a sum of the predetermined peak current level (I_P) and the predetermined minimum current level

17. The apparatus of claim 11, wherein the controller further comprises:

a voltage sensor; and

a second comparator coupled to the voltage sensor and the control circuit, wherein the control circuit is further configured to turn the switch on to commence an energizing cycle when the second comparator indicates that an inductor current has reached the predetermined minimum current level.

18. The apparatus of claim 11, wherein the controller further comprises:

a second current sensor; and

a second comparator coupled to the second current sensor and the control circuit, wherein the control circuit is further configured to turn the switch on to commence an energizing cycle when the second comparator indicates that an inductor current has reached the predetermined minimum current level.

19. A current regulator configured to provide substantially constant DC average current to solid state lighting, the current regulator couplable to a power source, the current regulator comprising:

an inductor coupled to the power source and the solid state lighting;

a switch coupled to either the inductor or the solid state lighting;

a first current sensor coupled to the switch;

a first comparator coupled to the first current sensor;

a voltage sensor coupled to the switch;

a second comparator coupled to the voltage sensor;

a memory configured to store a plurality of current parameters; and

a control circuit coupled to the memory and to the first and second comparators, wherein the control circuit is configured to turn the switch on to commence an energizing cycle when the second comparator indicates that an inductor current has reached a predetermined minimum level and to turn the switch off when the first comparator indicates that the inductor current has reached a predetermined peak level.

20. An apparatus couplable to solid state lighting, the apparatus comprising:

means for storing a plurality of current parameters;

means for modulating an energizing cycle time period;

means for providing a substantially constant DC average current to the solid state lighting in response to a selected current parameter from the plurality of current parameters;

means for indicating that an inductor current has increased to a predetermined peak level; and

means for activating a switch to commence an energizing cycle and deactivating the switch when the inductor current has increased to a predetermined peak level.

21. The apparatus of claim 20, further comprising:

means to indicate that an inductor current has decreased to a predetermined minimum level; and

means for turning the switch on to commence an energizing cycle when the inductor current has decreased to the predetermined minimum level.

22. An apparatus configured to control current to solid state lighting, the system couplable to a power source, the system comprising:

means for storing a predetermined minimum current level (I_MIN) parameter and a predetermined peak current level (I_P) parameter;

means for providing a substantially constant DC average current to the solid state lighting;

means for modulating a current provided to the solid state lighting in response to the predetermined minimum current level (I_MIN) parameter and the predetermined peak current level (I_P) parameter;

means for indicating that an inductor current level has reached a predetermined peak level; and

means for turning a switch on to commence an energizing cycle and turning the switch off when the inductor current has reached the predetermined peak level.

23. The apparatus of claim 22, further comprising:

means to indicate that an inductor current has reached a predetermined minimum level; and

means for turning the switch on to commence an energizing cycle when the inductor current has reached the predetermined minimum level.