Avago Technologies Ecbu IP (singapore) Pte. Ltd.

Len Li Kevin Lim

Boon Keat Tan

Joon Chok Lee

Rizal Bin Jaffar

Chi Mun Ho

Yoke Peng Boay

The color sensing circuit includes a light detector to receive light and to generate a signal that is dependent on the received light. The light detector includes a first electrode coupled to a first node and a second electrode coupled to a second predetermined signal. A storage device is provided that includes a first node and a second node coupled to the second predetermined signal. A first switch is provided that selectively couples the first node with the first electrode of the storage device based on a charge control signal. A signal processing circuit is provided that includes a first electrode and an output to generate an output signal that represents the light received by the light detector. A second switch is also provided that selectively couples the first electrode of the storage device with the first electrode of the signal processing circuit based on an evaluate control signal. The signal processing circuit selectively asserts the charge control signal and evaluate control signal.

Color sensing circuit employing charge storage device

In one embodiment, a user-selected color point is received. RGB tristimulus values are then derived for the color point. It is also determined whether the user-selected color point is outside a color selection range of the LED light source and, if so, an error flag is set. Pulse width modulated signals for a plurality of LED drivers for the LED light source are also generated. In another embodiment, tristimulus values representing a color of light produced by an LED light source are received. The received tristimulus values are then compared to tristimulus values corresponding to a user-identified color point. In response to the comparison, pulse width modulated signals are generated for a plurality of LED drivers for the LED light source. After a predetermined number of repetitions of these actions, an error flag is set if the user-selected color point has not been achieved by the LED light source.

Methods and apparatus for setting the color point of an LED light source

Optical feedback for controlling color of light from a light source is provided. Incident optical energy of the light is detected as a function of discrete steps of wavelength. For each discrete step of wavelength, an X, Y and Z tristimulus subvalue is produced. All the X, Y and Z tristimulus subvalues for all the discrete steps are summed together to produce an X, Y and Z tristimulus value for the light. The X, Y and Z tristimulus values are used as feedback in controlling color of the light generated by the light source.

Providing optical feedback on light color

Method and apparatus for compensating for variations in the output signal of a color sensor due to varying temperature of the color sensor. The color sensor receives light and generates an output signal that is based on the received light. The temperature compensation mechanism measures the temperature of the color sensor and uses the measured temperature to selectively adjust the output signal of the color sensor to generate a compensated output signal that is not dependent on temperature of the color sensor.

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Perak, Malaysia

Len Li Kevin Lim