Control circuit and method for controlling light emitting diodes
First Claim
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1. A control circuit for controlling light emitting diodes, comprising:
- a first switch to turn a first string of light emitting diodes on or off, the first switch comprising a control input;
a first sigma delta modulator comprising;
a signal input to receive a first control signal;
a signal output electrically connected to the control input of the first switch; and
a clock input to receive a clock signal having a clock period; and
a first combiner circuit to generate the first control signal based on a data signal and a first noise signal;
wherein the first noise signal comprises a signal having a time-averaged mean value equal to about zero.
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Abstract
A control circuit for controlling light emitting diodes comprises a switch for turning on or off a string of light emitting diodes. A combiner generates a control signal from a data signal and a noise signal. A sigma delta modulator receives the control signal and a clock signal with a clock period and generates a switching signal for controlling the switch.
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Citations
18 Claims
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1. A control circuit for controlling light emitting diodes, comprising:
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a first switch to turn a first string of light emitting diodes on or off, the first switch comprising a control input; a first sigma delta modulator comprising; a signal input to receive a first control signal; a signal output electrically connected to the control input of the first switch; and a clock input to receive a clock signal having a clock period; and a first combiner circuit to generate the first control signal based on a data signal and a first noise signal; wherein the first noise signal comprises a signal having a time-averaged mean value equal to about zero. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of controlling light emitting diodes, comprising:
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generating a first control signal based on a data signal and a first noise signal; generating a first switching signal based on the first control signal using sigma delta modulation; and switching a first string of light emitting diodes on or off based on the first switching signal; wherein the first noise signal comprises a signal having a time-averaged mean value equal to about zero. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A control circuit for controlling light emitting diodes, comprising:
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means for generating a first control signal based on a data signal and a first noise signal; means for generating a first switching signal based on the first control signal using sigma delta modulation; and means for switching a first string of light emitting diodes on or off based on the first switching signal; wherein the first noise signal comprises a signal having a time-averaged mean value equal to about zero.
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Specification