Digitally controlled current regulator for high power solid state lighting

• US 8,067,896 B2
• Filed: 05/18/2007
• Issued: 11/29/2011
• Est. Priority Date: 05/22/2006
• Status: Expired due to Fees

• Current Assignee: Chemtron Research LLC (Intellectual Ventures LLC)
• Original Assignee: Exclara, Inc. (Million Star Technology Ltd.)
• Inventors: Rodriguez, Harry, Shteynberg, Anatoly
• Primary Examiner(s): Vo; Tuyet Thi
• Application Number:
  US11/804,549
• Publication Number:
  US 20070267978A1
• Time in Patent Office: 1,656 Days
• Field of Search: 315/247, 315/246, 315/224, 315/225, 315/185.S, 315/291, 315/297, 315307-326, 345/102, 345/101, 345/82, 345/76, 345/204, 345211-214
• 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

An exemplary apparatus embodiment provides for controlling current supplied to solid state lighting, such as light emitting diodes. An exemplary 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 of the plurality of current parameters. In an exemplary 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 for controlling current to solid state lighting, the current regulator couplable to a power source, the current regulator comprising:

a memory to store a plurality of current parameters; and

a control circuit coupled to the memory, the control circuit 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 of the plurality of current parameters, wherein the plurality of current parameters comprise a predetermined minimum current level (I_MIN) and a predetermined peak current level (I_P), and 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

2. The current regulator of claim 1, wherein the predetermined minimum current level (I_MIN) is substantially close to zero.

3. The current regulator of claim 1, wherein the control circuit further is to provide the substantially constant DC average current by maintaining substantially constant the predetermined peak current level (I_P) and the predetermined minimum current level I_MIN.

4. The current regulator of claim 1, wherein the control circuit further is 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.

5. The current regulator of claim 4, wherein the substantial proportionality of the DC average current level (I_O) further is a substantial equality

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

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

a controller coupled to the memory, the control circuit to provide a substantially constant DC average current to the solid state lighting by 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, 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

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

8. The apparatus of claim 6, wherein the controller further is to provide the substantially constant DC average current by maintaining substantially constant the predetermined peak current level (I_P) and the predetermined minimum current level I_MIN.

9. The apparatus of claim 6 wherein the controller further is to provide an increasing current level to an inductor until the predetermined peak current level (I_P) is substantially reached and to provide a decreasing current level to the inductor until the predetermined minimum current level (I_MIN) is substantially reached.

10. The apparatus of claim 6, wherein the substantial proportionality of the DC average current level (I_O) further is a substantial equality

11. A current regulator for providing 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 coupled to the solid state lighting;

a switch coupled to the inductor or to 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 second current sensor in series with the inductor;

a third comparator coupled to the second current sensor;

a memory to store a plurality of current parameters; and

a control circuit coupled to the memory and to the first, second and third comparators, the control circuit to turn the switch on to commence an energizing cycle when the second comparator or the third comparator indicate 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.