Method for software driven generation of multiple simultaneous high speed pulse width modulated signals

• US 7,113,541 B1
• Filed: 06/25/1999
• Issued: 09/26/2006
• Est. Priority Date: 08/26/1997
• Status: Expired due to Fees

• Current Assignee: Philips Solid-State Lighting Solutions (Koninklijke Philips N.V.)
• Original Assignee: Color Kinetics Incorporated (Signify N.V.)
• Inventors: Lys, Ihor A., Morgan, Frederick M.
• Primary Examiner(s): Tran, Khai
• Assistant Examiner(s): Chang, Edith M.
• Application Number:
  US09/344,699
• Time in Patent Office: 2,650 Days
• Field of Search: 375/238, 375/366, 315/308, 315/291, 315/151, 315/316, 315/370, 315/156, 702/79, 702/188, 399/51, 250/205
• US Class Current: 375/238
• CPC Class Codes: H05B 45/20 Controlling the colour of the light
• CPC Class Codes: H05B 45/325 Pulse-width modulation [PWM]
• CPC Class Codes: H05B 47/155 Coordinated control of two or more light sources
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

Systems and methods can provide, in one aspect, a method for modulating the pulse width of control signals generated on a plurality of separate channels. In one practice, the methods described herein are suitable for execution on a microprocessor or micro controller platform that includes a timer interrupt mechanism which will generate an interrupt in response to a timer counting down a selected time interval or time period. In one practice, the timer is set to count down a period of time that is representative of a portion, or sub period, of the PWM cycle. Upon expiration of that time period, the timer executes an interrupt that causes the micro controller to enter an interrupt service routine (ISR) that can further modulate the PWM cycle of one or more signals.

Claims

1. A method of generating a plurality of pulse width modulated (PWM) signals provided on a corresponding plurality of I/O pins, comprising acts of:

A) determining said plurality of PWM signals from at least one set of pre-computed values corresponding to a plurality of sub periods of a PWM cycle,

B) updating at least one of the plurality of PWM signals by executing a first write to at least one of the corresponding plurality of I/O pins,

C) executing a series of instructions consuming a predetermined amount of time,

D) executing a second write to the at least one of the corresponding plurality of I/O pins, and

E) advancing a sub period bookkeeping value to point to a next sub period in the PWM cycle,

wherein the act B) includes acts of;

B1) conducting a single array read based on the at least one set of pre-computed values; and

B2) executing the first write as a single write to the corresponding plurality of I/O pins following the act B1).

2. The method of claim 1, further comprising an act of:

repeating at least the acts B) through E) for at least the next sub period in the PWM cycle.

3. The method according to claim 1, further including an act of:

providing a plurality of sets of pre-computed values, each set corresponding to a particular pattern of modulation.

4. The method according to claim 3, further including an act of:

allowing a user to select from said plurality of sets of pre-computed values, to provide user control over the plurality of pulse width modulated signals.

5. The method according to claim 1, further including an act of:

F) coupling said pulse width modulated signals to a plurality of lamps, each lamp corresponding to a different color, whereby an overall perceivable color of light generated by said plurality of lamps is controlled as a function of said pulse width modulated signals.

6. The method of claim 5, wherein the plurality of lamps includes at least one first LED adapted to output at least first radiation having a first spectrum and at least one second LED adapted to output second radiation having a second spectrum different than the first spectrum, and wherein the method further comprises an act of:

G) independently controlling at least a first intensity of the first radiation and a second intensity of the second radiation based on at least some of the PWM signals so as to controllably vary at least the overall perceivable color of the light generated by the plurality of lamps.

7. The method of claim 6, wherein the act G) includes an act of:

independently controlling at least the first intensity of the first radiation and the second intensity of the second radiation such that the light provides a single observable color at a given time.

8. The method of claim 6, wherein the act G) includes an act of:

independently controlling at least the first intensity of the first radiation and the second intensity of the second radiation so as to controllably vary an overall intensity of the light.

9. The method of claim 6, wherein the act G) includes an act of:

independently controlling at least the first intensity of the first radiation and the second intensity of the second radiation such that the light has a sufficient intensity to effectively illuminate a space.

10. The method of claim 6, wherein the act G) includes an act of:

independently controlling at least the first intensity of the first radiation and the second intensity of the second radiation so as to produce a dynamic lighting effect as perceived by an observer.

11. The method of claim 6, wherein the plurality of lamps includes at least one third LED adapted to output third radiation having a third spectrum different than the first spectrum and the second spectrum, wherein the act G) includes an act of:

independently controlling a third intensity of the third radiation using at least one of the PWM signals.

12. The method of claim 11, wherein the at least one first LED, the at least one second LED, and the at least one third LED respectively include at least one red LED, at least one green LED, and at least one blue LED.

13. The method of claim 6, wherein the plurality of lamps is associated with at least one sensor to monitor at least one detectable condition, and wherein the method further includes an act of:

performing the act A) in response to the at least one detectable condition.

14. The method of claim 6, further comprising an act of:

performing the act A) in response to a user operation of at least one user interface.

15. The method of claim 6, further comprising an act of:

performing the act A) in response to at least one control signal received from a network.

16. The method of claim 15, wherein the act A) includes acts of:

a1) receiving at least one addressed network signal including lighting information; and

a2) selecting at least one set of pre-computed values based at least in part on the lighting information.

17. The method of claim 16, wherein the act a1) includes an act of:

receiving the at least one addressed network signal based at least in part on a user operation of at least one user interface.

18. The method of claim 16, wherein the at least one addressed network signal includes address information and lighting information for a plurality of illumination apparatus, wherein the plurality of lamps are included in one illumination apparatus of the plurality of illumination apparatus, wherein the one illumination apparatus has a particular address associated therewith, and wherein the act a2) includes an act of:

processing the at least one addressed network signal based on the particular address associated with the one illumination apparatus and the address information in the at least one addressed network signal to recover the lighting information.

19. The method of claim 16, wherein the at least one addressed network signal is formatted using a DMX protocol, and wherein the act a2) includes an act of:

selecting the at least one set of pre-computed values based at least in part on the DMX protocol.

20. A system for modulating a pulse of at least one digital signal, comprising:

a memory having stored therein at least one set of pre-computed values, each pre-computed value being representative of a signal level for said at least one digital signal;

a programmable device having a program memory and a timer, said program memory storing a set of instructions capable of directing said programmable device to monitor said timer, and in response to a signal generated by said timer, to access said set of pre-computed values for selecting at least one signal level for said at least one digital signal;

an interrupt service routine capable of directing said programmable device to further modulate said at least one digital signal;

an amplifier for adjusting a characteristic of said at least one digital signal; and

a light source coupled to said at least one digital signal, wherein said at least one digital signal is configured to control at least one operating characteristic of said light source,

wherein;

the light source comprises at least one LED-based light source configured to output at least first radiation having a first spectrum and second radiation having a second spectrum different than the first spectrum; and

the at least one digital signal includes a plurality of digital signals configured to independently control at least a first intensity of the first radiation and a second intensity of the second radiation so as to controllably vary at least an overall color of a total visible radiation generated by the light source.

21. A system according to claim 20, wherein said programmable device comprises a microcontroller.

22. A system according to claim 20, wherein said programmable device comprises a microprocessor.

23. A system according to claim 20, wherein said interrupt service routine comprises a routine activated in response to a timer interrupt generated by said programmable device.

24. A system according to claim 20, wherein the memory has stored therein a plurality of sets of pre-computed values for said at least one digital signal.

25. A system according to claim 20, further comprising at least one user interface to allow a user to select from among said plurality of sets of pre-computed values and thereby control the at least one digital signal.

26. The system of claim 20, wherein the plurality of digital signals are configured to independently control at least the first intensity of the first radiation and the second intensity of the second radiation such that the total visible radiation generated by the light source represents a single observable color at a given time.

27. The system of claim 20, wherein the plurality of digital signals are configured to independently control at least the first intensity of the first radiation and the second intensity of the second radiation so as to controllably vary an overall intensity of the total visible radiation generated by the light source.

28. The system of claim 20, wherein the plurality of digital signals are configured to independently control at least the first intensity of the first radiation and the second intensity of the second radiation such that the total visible radiation has a sufficient intensity to effectively illuminate a space.

29. The system of claim 20, wherein the plurality of digital signals are configured to independently control at least the first intensity of the first radiation and the second intensity of the second radiation so as to produce a dynamic lighting effect as perceived by an observer.

30. The system of claim 20, wherein the at least one LED-based light source further is configured to output third radiation having a third spectrum different than the first spectrum and the second spectrum, and wherein the plurality of digital signals are configured to independently control a third intensity of the third radiation.

31. The system of claim 30, wherein the at least one LED-based light source includes at least one red LED, at least one green LED, and at least one blue LED.

32. The system of claim 20, further including at least one sensor to monitor at least one detectable condition, wherein the at least one set of pre-computed values is determined in response to the at least one detectable condition.

33. The system of claim 20, further comprising at least one user interface to control the programmable device so as to modulate the plurality of digital signals in response to user operation of the at least one user interface.

34. The system of claim 33, wherein the at least one user interface comprises at least one of at least one potentiometer, a thumb plate, a trackball, a joystick, a switch, and a network interface.

35. The system of claim 20, wherein the programmable device is configured as an addressable programmable device capable of receiving at least one network signal including address information and lighting information.

36. The system of claim 35, wherein the addressable programmable device is configured to generate the plurality of digital signals based at least in part on the lighting information.

37. The system of claim 36, wherein the at least one network signal is provided to the addressable programmable device based at least in part on user operation of at least one user interface in communication with the addressable programmable device.

38. The system of claim 36, wherein the addressable programmable device is configured to process the at least one network signal based on an address of the addressable programmable device and the address information in the network signal to recover the lighting information from the at least one network signal.

39. The system of claim 36, wherein the addressable programmable device has an alterable address.

40. The system of claim 36, wherein the at least one network signal is formatted using a digital multiplex (DMX) protocol, and wherein the addressable programmable device is configured to generate the plurality of digital signals based at least in part on the DMX protocol.