Koninklijke Philips Corporation N.v.

Johannes Aldegonda Theodora Maria Van Den Homberg

Albert Hendrik Jan Immink

Bart Michiel De Boer

Aalbert Stek

An optical disc drive apparatus includes a laser device for generating a light beam for optically reading data from a disc. The laser device is electrically incorporated in a resonant circuit which includes an inductance coupled to the laser device.

Disc drive apparatus

A driver for driving a light generator for generating light, comprising a digitalto-analog converter (DAC) having a data input, a data output for generating an analog signal, a first multiplexer (MUX) for cyclic selection of a number of data levels corresponding to desired intensity levels of the light and for coupling the data levels to the data input; a de multiplexer (DE-MUX) synchronized with the first multiplexer (MUX) for de-multiplexing the analog signal into a set of analog signals; memory means for temporarily storing the set of analog signals; and a second multiplexer (MUX) for selection of the stored set of analog signals and for generating a drive signal (IL) for the light generator. The memory means is preferably implemented by a set of capacitors (C-C). Usually, for instance in an optical disc drive, the light generator is implemented by a laser (L). In this situation the data input of the digital-to-analog converter comprises a threshold data input part; a delta data input part; a threshold gain reference input associated with the threshold data input part; and a delta gain reference input associated with the delta data input part. So in fact the DAC is split into two parts (DACand DAC) for separate threshold power and delta power control of the laser (LS).

Laser driver/method for generating a laser drive signal

A servo system comprising an analog sigma delta modulator for generating a normalized digital error correction signal from first and second analog control signals. The sigma delta modulator comprises an analog low-pass filter, a quantizer delivering the digital error correction signal and a multiplying DA-converter in feedback arrangement between the output of the quantizer and the input of the low-pass filter for multiplying the feedback signals with the sum of the analog control signals.

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Eindhoven, Netherlands

Johannes Aldegonda Theodora Maria Van Den Homberg