Control circuit for optical transducers
First Claim
Patent Images
1. A method, comprising:
- referencing an optical transducer to a low-side voltage node; and
independently controlling a peak current and an average current of the optical transducer with stochastic control signals generated by a high-side stochastic modulator, wherein independently controlling the peak current and the average current comprises;
generating a first stochastic control signal with a first clock frequency;
generating a second stochastic control signal with a second clock frequency; and
combining the first stochastic control signal and the second stochastic control signal to generate a combined stochastic control signal.
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Abstract
A method and apparatus for high-side control of an optical transducer provides improved current control and temperature compensation and uses stochastic modulation for improved spectral characteristics.
50 Citations
19 Claims
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1. A method, comprising:
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referencing an optical transducer to a low-side voltage node; and independently controlling a peak current and an average current of the optical transducer with stochastic control signals generated by a high-side stochastic modulator, wherein independently controlling the peak current and the average current comprises; generating a first stochastic control signal with a first clock frequency; generating a second stochastic control signal with a second clock frequency; and combining the first stochastic control signal and the second stochastic control signal to generate a combined stochastic control signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An apparatus, comprising:
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a light-emitting diode (LED) referenced to a low-side voltage node; a controllable current supply coupled to a high-potential side of the LED; and a stochastic controller coupled to the controllable current supply, the stochastic controller configured to provide independent control of a peak current and an average current of the controllable current supply, wherein the stochastic controller comprises; a first stochastic signal density modulator (SSDM) configured to generate a first stochastic control signal with a first clock frequency, to control the peak current of the controllable current supply; a second SSDM configured to generate a second stochastic control signal with a second clock frequency, to control the average current of the controllable current supply; and a combiner configured to logically combine the first stochastic control signal and the second stochastic control signal into a combined stochastic control signal. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A system, comprising:
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a plurality of optical transducers referenced to a ground potential; a plurality of controllable current supplies, each coupled to a high-potential side of one of the plurality of optical transducers; and a plurality of stochastic controllers coupled to the plurality of controllable current supplies, wherein each stochastic controller is configured to provide independent control of a peak current and an average current in one of the plurality of optical transducers. - View Dependent Claims (16, 17)
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18. An apparatus, comprising:
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means for referencing an optical transducer to a low-side voltage node; and means for independently controlling a peak current and an average current of the optical transducer with stochastic control signals generated by a high-side stochastic modulator, wherein the means for independently controlling the peak current and the average current comprises; means for generating a first stochastic control signal with a first clock frequency; means for generating a second stochastic control signal with a second clock frequency; and means for combining the first stochastic control signal and the second stochastic control signal to generate a combined stochastic control signal. - View Dependent Claims (19)
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Specification