Control apparatus and method for use with digitally controlled light sources
First Claim
1. An apparatus for control of a luminaire including one or more light-emitting elements in one or more colours, each of the one or more light-emitting elements supplied with electrical current to produce light, said apparatus comprising a) means to adjust the electrical current to the one or more light-emitting elements using pulse width modulation or pulse code modulation, each of said pulse width modulation and pulse code modulation having a pulse cycle;
- and b) means to modulate a pulse width for each pulse cycle, thereby increasing control resolution of the one or more light-emitting elements.
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Abstract
The present invention provides an extension to a standard N-bit digital pulse width control method which can discriminate 2N discrete pulse widths per pulse cycle. The present invention provides a method and apparatus that can modulate the pulse widths over a period of 2M pulse cycles in which each pulse cycle can have its own pulse width or respective duty cycle. The resulting time averaged or effective pulse width therefore can be controlled with a resolution of 2N+M states rather than a resolution of 2N states as is common with standard methods.
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Citations
9 Claims
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1. An apparatus for control of a luminaire including one or more light-emitting elements in one or more colours, each of the one or more light-emitting elements supplied with electrical current to produce light, said apparatus comprising
a) means to adjust the electrical current to the one or more light-emitting elements using pulse width modulation or pulse code modulation, each of said pulse width modulation and pulse code modulation having a pulse cycle; - and
b) means to modulate a pulse width for each pulse cycle, thereby increasing control resolution of the one or more light-emitting elements. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An extended pulse width modulation method for transforming a (N+M)-bit signal into a stream of 2M words of N-bit width for a total of 2M pulse cycles, the method comprising the steps of:
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a) receiving the (N+M)-bit signal;
b) splitting the (N+M)-bit signal into an N-bit portion and an M-bit portion;
c) interpreting the N-bit portion as a binary coded number n;
d) interpreting the M-bit portion as a binary coded number m;
e) encoding (n+1) in a form of a binary N-bit word and feeding the word for m pulse cycles into the stream; and
f) encoding n in a form of a binary N-bit word for (2M−
m) pulse cycles and feed the word into the stream;
thereby forming the stream of 2M words of N-bit width for a total of 2M pulse cycles.
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9. An extended pulse width modulation apparatus for transforming a (N+M)-bit signal into a stream of 2M words of N-bit width for a total of 2M pulse cycles, the apparatus comprising:
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a) means for receiving the (N+M)-bit signal;
b) means for splitting the (N+M)-bit signal into an N-bit portion and an M-bit portion;
c) means for interpreting the N-bit portion as a binary coded number n;
d) means for interpreting the M-bit portion as a binary coded number m;
e) means for encoding (n+1) in a form of a binary N-bit word and feeding the word for m pulse cycles into the stream; and
f) means for encoding n in a form of a binary N-bit word for (2M−
m) pulse cycles and feed the word into the stream;
thereby forming the stream of 2M words of N-bit width for a total of 2M pulse cycles.
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Specification