Control of Delivery of Current Through One or More Discharge Lamps
AssigneeMarvell International Ltd.
InventorsHubertus Notohamiprodjo, Radu Pitigoi-Aron
Life of this patent
Estimating the term…
Abstract
Control of delivery of current through one or more discharge lamps. Methods include alternately switching on and off switching elements that control a fluorescent lamp, in response to receiving input, until the brightness of the lamp decreases to a threshold. Further, methods include providing control signals at complementary duty cycles to further decrease the brightness and alternating the duty cycles of the signals applied to the filaments of the fluorescent lamp. Methods include digitally comparing voltage signals supplied to a fluorescent lamp and the current drawn by the fluorescent lamp.
Claims16
1-21. (canceled)
A method to identify a current drawn by a fluorescent lamp in a circuit, the method comprising:
- receiving a voltage supplied to a fluorescent lamp drawing a current in response to the voltage;
- digitally sampling the voltage at a sampling frequency and associating a first time stamp with a voltage value representing an inflection in observed voltage;
- receiving the current after receiving the voltage;
- digitally sampling the current at the sampling frequency and associating multiple second time stamps with a corresponding multiple current values;
- identifying a second time stamp, a difference between the first time stamp and the second time stamp being within a threshold;
- and
- identifying a current value associated with the second time stamp as the current drawn by the fluorescent lamp.
A processor configured to identify a current drawn by a fluorescent lamp in a circuit, the processor configured to perform operations comprising:
- receiving a voltage supplied to a fluorescent lamp drawing a current in response to the voltage;
- digitally sampling the voltage at a sampling frequency and associating a first time stamp with a voltage value representing an inflection in observed voltage;
- receiving the current after receiving the voltage;
- digitally sampling the current at the sampling frequency and associating multiple second time stamps with a corresponding multiple current values;
- identifying a second time stamp, a difference between the first time stamp and the second time stamp being within a threshold;
- and
- identifying a current value associated with the second time stamp as the current drawn by the fluorescent lamp.
A system to digitally compare analog signals in a circuit, the system comprising:
- a fluorescent lamp;
- a source to pass a voltage to the fluorescent lamp through a circuit, the fluorescent lamp drawing a current in response to the voltage;
- an analog-to-digital converter operatively coupled to the circuit to receive the voltage and to receive the current;
- and
- a processor to identify a current drawn by a fluorescent lamp, the processor configured to perform operations comprising:
- receiving the voltage supplied to the fluorescent lamp;
- digitally sampling the voltage at a sampling frequency and associating a first time stamp with a voltage value representing an inflection in observed voltage;
- receiving the current after receiving the voltage;
- digitally sampling the current at the sampling frequency and associating multiple second time stamps with a corresponding multiple current values;
- identifying a second time stamp, a difference between the first time stamp and the second time stamp being within a threshold;
- and
- identifying a current value associated with the second time stamp as the current drawn by the fluorescent lamp.
Dependencies are inferred from the claim text.