IP Library Granted Patent US 11,109,468
Granted Patent B1
US 11,109,468 · App. 17/077,614 · Granted Aug 31, 2021

Lighting apparatus with reduced abrupt brightness changes

Inventors: Yifeng Qiu (San Jose, CA); Alan Andrew McReynolds (Los Altos, CA)
Assignee: Lumileds LLC
H05B47/17H05B45/20H05B45/325
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Quick Facts
Patent No.
US 11,109,468
App. No.
17/077,614
Granted
Aug 31, 2021
Kind
B1
Abstract

A light-emitting apparatus can reduce flicker and retain power efficiency. A method can include driving, by a light emitting element (LEE) driver circuit, first, second, and third LEEs using a pulse width modulation (PWM) driving scheme to generate light of a first color, the first, second, and third LEEs configured to emit different colors, alternating, by the LEE driver circuit, between driving the first, second, and third LEEs using a hybrid driving scheme and the PWM driving scheme, and after alternating between driving the first, second, and third LEEs in the hybrid and PWM driving schemes, driving, by the LEE driver circuit, the first, second, and third LEEs using the hybrid driving scheme.

Claims (34)

1. A method comprising:

driving, by a light emitting element (LEE) driver circuit, first, second, and third LEEs using a pulse width modulation (PWM) driving scheme to generate light of a first color, wherein the first, second, and third LEEs are configured to emit respective different colors;

alternating, by control circuitry, a driving scheme implemented by the LEE driver circuit, between driving the first, second, and third LEEs using a hybrid driving scheme and the PWM driving scheme; and

after alternating between driving the first, second, and third LEEs in the hybrid or PWM driving schemes, driving, by the LEE driver circuit, the first, second, and third LEEs using the hybrid driving scheme.

2. The method of claim 1 , wherein:

the PWM driving scheme includes driving, in sequence, the first LEE, the second LEE, and the third LEE; and

the hybrid driving scheme includes driving, in sequence, a first pair of the first, second, and third LEEs simultaneously and a second, different pair of the first, second, and third LEEs simultaneously.

3. The method of claim 1 , wherein alternating between driving the first, second, and third LEEs using the hybrid driving scheme and the PWM driving scheme occurs responsive to determining a color provided by a device including the driver circuit and the first, second, and third LEEs has changed to a second color.

4. The method of claim 3 , further comprising, before alternating between driving the first, second, and third LEEs using the hybrid driving scheme and the PWM driving scheme, altering a duty cycle of the first, second, and third LEEs to produce the second color using the PWM driving scheme.

5. The method of claim 4 , wherein the second color is in a range of colors provided by the hybrid driving scheme and the first color is outside the range of colors provided by the hybrid driving scheme.

6. The method of claim 5 , wherein the first, second, and third LEEs provide light of one of red, green, and blue color.

7. The method of claim 6 , wherein the first, second, and third LEEs include light emitting diodes (LEDs).

8. A device comprising:

driver circuitry operable to drive light emitting elements (LEEs) in a pulse width modulation (PWM) driving scheme and a hybrid driving scheme, wherein the LEEs include three or more LEEs that emit respective different colors of light; and

controller circuitry configured to send electrical signals to the driver circuitry that cause the driver circuitry to operate the LEEs in the PWM driving scheme to generate light of a first color, then alternate a driving scheme implemented by the driver circuitry to driving the LEEs in the hybrid driving scheme or the PWM driving scheme, and then drive the LEEs in the hybrid driving scheme.

9. The device of claim 8 , wherein:

the PWM driving scheme includes driving, in sequence, first, second, and third LEEs of the LEEs; and

the hybrid driving scheme includes driving, in sequence, a first pair of the first, second, and third LEEs simultaneously and a second, different pair of the first, second, and third LEEs simultaneously.

10. The device of claim 8 , wherein controller circuitry is further configured to receive data indicating a color provided by the device has changed to a second color, and wherein causing the driver circuitry to alternate between driving the LEEs using the hybrid driving scheme and the PWM driving scheme, and wherein occurs responsive to the controller circuitry receiving the data.

11. The device of claim 10 , further comprising, before causing the driver circuitry to alternate between driving the first, second, and third LEEs using the hybrid driving scheme and the PWM driving scheme, the controller circuitry is further configured to cause the driver circuitry to alter a duty cycle of the first, second, and third LEEs to produce the second color using the PWM driving scheme.

12. The device of claim 11 , wherein the second color is in a range of colors provided by the hybrid driving scheme and the first color is outside the range of colors provided by the hybrid driving scheme.

13. The device of claim 12 , wherein the first, second, and third LEEs provide light of one of red, green, and blue color.

14. The device of claim 13 , wherein the first, second, and third LEEs include light emitting diodes (LEDs).

15. A system comprising:

a plurality of light emitting elements (LEEs) configured to emit respective different colors of light;

driver circuitry operable to drive the LEEs using a pulse width modulation (PWM) driving scheme or a hybrid driving scheme, the LEEs including three or more LEEs that emit respective different colors of light; and

controller circuitry configured to provide electrical signals that cause the driver circuitry to operate the LEEs using the PWM driving scheme to generate light of a first color, then alternate driving the LEEs in the hybrid driving scheme or the PWM driving scheme, and then drive the LEEs in the hybrid driving scheme.

16. The system of claim 15 , wherein:

the PWM driving scheme includes driving, in sequence, first, second, and third LEEs of the LEEs; and

the hybrid driving scheme includes driving, in sequence, a first pair of the first, second, and third LEEs simultaneously and a second, different pair of the first, second, and third LEEs simultaneously.

17. The system of claim 15 , wherein controller circuitry is further configured to receive data indicating a color provided by the device has changed to a second color, and wherein causing the driver circuitry to alternate between driving the LEEs using the hybrid driving scheme and the PWM driving scheme, and wherein occurs responsive to the controller circuitry receiving the data.

18. The system of claim 17 , further comprising, before causing the driver circuitry to alternate between driving the first, second, and third LEEs using the hybrid driving scheme and the PWM driving scheme, the controller circuitry is further configured to cause the driver circuitry to alter a duty cycle of the first, second, and third LEEs to produce the second color using the PWM driving scheme.

19. The system of claim 18 , wherein the second color is in a range of colors provided by the hybrid driving scheme and the first color is outside the range of colors provided by the hybrid driving scheme.

20. The system of claim 19 , wherein the first, second, and third LEEs provide light of one of red, green, and blue color.

Assignments (5)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jul 10, 2025
From: LUMILEDS LLC
To: LUMILEDS SINGAPORE PTE. LTD.
Reel/Frame 071888/0086 →
RELEASE OF SECURITY INTEREST Recorded Jan 29, 2025
From: SOUND POINT AGENCY LLC
To: LUMILEDS LLC; LUMILEDS HOLDING B.V.
Reel/Frame 070046/0001 →
SECURITY INTEREST Recorded Jan 5, 2023
From: LUMILEDS LLC; LUMILEDS HOLDING B.V.
To: SOUND POINT AGENCY LLC
Reel/Frame 062299/0338 →
PATENT SECURITY AGREEMENT Recorded Dec 9, 2022
From: LUMILEDS, LLC
To: DEUTSCHE BANK AG NEW YORK BRANCH
Reel/Frame 062114/0001 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Oct 22, 2020
From: QUI, YIFENG; MCREYNOLDS, ALAN A.
To: LUMILEDS LLC
Reel/Frame 054141/0414 →