Abstract: A high frequency modulator is described. It comprises: a first converter for receiving a constant current signal and transmitting a first converted signal; an adder coupled the first converter and operative for transmitting a summed signal in response to receiving the first converted signal and selectively receiving a triangular signal; a first oscillator coupled to the adder for receiving the summed signal, the first oscillator operative for transmitting a time varying current signal; a second converter coupled to the first oscillator for receiving the time varying current signal and operative for transmitting a second converted signal; and an output device selectively coupled to the second converter and operative for transmitting an output signal in response to receiving either the second converted signal or an offset signal.

Abstract: A current gain control system is described and comprises first and second gain blocks respectively associated with the first and second input channels, wherein first and second gain blocks transmit first and second gain signals in response to receiving first and second input signals; first and second converters adapted to be respectively coupled to the first and second gain blocks, the first and second converters operative for setting gains associated with the first and second input channel and for transmitting first and second converted signals in response to receiving the first and second gain signals; and first and second switches for selectively coupling the first and second converters to first and second channel drivers, respectively, wherein the first and second channel drivers transmit channel gain signals in response to receiving the first converted signal, and the channel gain signal allows control of the gain associated with the input channel.

Abstract: An optical disc apparatus includes an emitter which emits a laser beam to a optical disc, a divided photodetector including a first dived portion and a second dived portion disposed in a light path of the reflected beam from the optical disc, and producing a first photodetector signal and a second photodetector signal, a phase difference detector which produces a phase difference signal from a phase difference between the first and the second photodetector signals, an integrator which produces a integral signal from a integration of the phase difference signal, a tracking controller configure to perform tracking control based on the integral signal, and a limiter which limits a signal to be supplied from the divided photodetector to the phase difference detector or a signal to be supplied from the phase difference detector to the integrator based on a detection status of a signal detected by the dived photodetector.

Abstract: An over current protection device is described. It includes a plurality of input channels for receiving an input signal; a plurality of low pass filters coupled to a first group of the plurality of input channels, wherein each low pass filter is associated with one input channel within the first group of input channels, the plurality of low pass filters operative for removing spikes in associated with the input signal; and a plurality of digital to analog converters coupled to a second group of the plurality of input channels, wherein each digital to analog converter is associated with one low pass filter in the second group of input channels, the digital to analog converters operative for triggering over current protection when a signal received from the associated low pass filter is beyond a preset level, wherein the over current protection device is on chip with the laser diode driver.

Abstract: A modulation control system for use with a high frequency modulator is described. This system comprises a latch for selectively receiving enable signals, wherein the latch transmits a latched signal in response to receiving at least two of the enable signals; a selection device coupled to the latch for receiving the latched signal, a voltage source, and a terminal for receiving at least one of the enable signals, wherein the selection device transmits a selected signal; and a logic device coupled to the selection device and a terminal for receiving a modulated enable signal, wherein the logic device transmits a synchronized signal for either enabling or disabling the high frequency modulator in response to receiving the selected signal associated with at least one of the enable signals.

Abstract: According to one embodiment, an optical disk device includes a laser light source that emits laser light to be applied to an optical disk, an automatic power control circuit that controls a laser output of the laser light source, and a control processor that performs a setting data transmission process for the automatic power control circuit. The automatic power control circuit includes an operation setting module that makes an operation setting according to setting data obtained in the setting data transmission process of the control processor and a condition determining module that determines whether an operation setting permission condition containing the number of clocks during a transmission period of the setting data is adequate, and inhibits the operation setting of the operation setting module when the operation setting permission condition is not adequate.

Abstract: A high frequency modulator is described. It comprises: a first converter for receiving a constant current signal and transmitting a first converted signal; an adder coupled the first converter and operative for transmitting a summed signal in response to receiving the first converted signal and selectively receiving a triangular signal; a first oscillator coupled to the adder for receiving the summed signal, the first oscillator operative for transmitting a time varying current signal; a second converter coupled to the first oscillator for receiving the time varying current signal and operative for transmitting a second converted signal; and an output device selectively coupled to the second converter and operative for transmitting an output signal in response to receiving either the second converted signal or an offset signal.

Abstract: A current gain control system is described and comprises first and second gain blocks respectively associated with the first and second input channels, wherein first and second gain blocks transmit first and second gain signals in response to receiving first and second input signals; first and second converters adapted to be respectively coupled to the first and second gain blocks, the first and second converters operative for setting gains associated with the first and second input channel and for transmitting first and second converted signals in response to receiving the first and second gain signals; and first and second switches for selectively coupling the first and second converters to first and second channel drivers, respectively, wherein the first and second channel drivers transmit channel gain signals in response to receiving the first converted signal, and the channel gain signal allows control of the gain associated with the input channel.

Abstract: An over current protection device is described. It includes a plurality of input channels for receiving an input signal; a plurality of low pass filters coupled to a first group of the plurality of input channels, wherein each low pass filter is associated with one input channel within the first group of input channels, the plurality of low pass filters operative for removing spikes in associated with the input signal; and a plurality of digital to analog converters coupled to a second group of the plurality of input channels, wherein each digital to analog converter is associated with one low pass filter in the second group of input channels, the digital to analog converters operative for triggering over current protection when a signal received from the associated low pass filter is beyond a preset level, wherein the over current protection device is on chip with the laser diode driver.

Abstract: A modulation control system for use with a high frequency modulator is described. This system comprises a latch for selectively receiving enable signals, wherein the latch transmits a latched signal in response to receiving at least two of the enable signals; a selection device coupled to the latch for receiving the latched signal, a voltage source, and a terminal for receiving at least one of the enable signals, wherein the selection device transmits a selected signal; and a logic device coupled to the selection device and a terminal for receiving a modulated enable signal, wherein the logic device transmits a synchronized signal for either enabling or disabling the high frequency modulator in response to receiving the selected signal associated with at least one of the enable signals.

Abstract: An optical disc apparatus includes an emitter which emits a laser beam to a optical disc, a divided photodetector including a first divided portion and a second divided portion disposed in a light path of the reflected beam from the optical disc, and producing a first photodetector signal and a second photodetector signal, a phase difference detector which produces a phase difference signal from a phase difference between the first and the second photodetector signals, an integrator which produces a integral signal from a integration of the phase difference signal, a tracking controller configure to perform tracking control based on the integral signal, and a limiter which limits a signal to be supplied from the divided photodetector to the phase difference detector or a signal to be supplied from the phase difference detector to the integrator based on a detection status of a signal detected by the divided photodetector.

Abstract: An optical disc apparatus includes an emitter which emits a laser beam to a optical disc, a divided photodetector including a first dived portion and a second dived portion disposed in a light path of the reflected beam from the optical disc, and producing a first photodetector signal and a second photodetector signal, a phase difference detector which produces a phase difference signal from a phase difference between the first and the second photodetector signals, an integrator which produces a integral signal from a integration of the phase difference signal, a tracking controller configure to perform tracking control based on the integral signal, and a limiter which limits a signal to be supplied from the divided photodetector to the phase difference detector or a signal to be supplied from the phase difference detector to the integrator based on a detection status of a signal detected by the dived photodetector.

Abstract: According to one embodiment, an optical disk device includes a semiconductor laser, a circuit which generates a timing signal to determine a recording pulse timing, a circuit which sets a magnitude of a current for the laser, a circuit which switches the magnitude of the current according to the timing signal, a generation circuit which generates a correction signal from the timing signal to correct response characteristics of a recording pulse, a circuit which synthesizes the correction signal and signals obtained as the switch result to determine the magnitude of the current, and a circuit which feeds the current to the laser according to the synthesis result. The generation circuit extracts high-frequency components from the signals obtained as the switch result and the signal generated by the synthesis circuit, and switches a frequency and a signal gain of each of the components, in accordance with recording pulse conditions.

Abstract: According to one embodiment, an optical disk device includes a laser light source that emits laser light to be applied to an optical disk, an automatic power control circuit that controls a laser output of the laser light source, and a control processor that performs a setting data transmission process for the automatic power control circuit. The automatic power control circuit includes an operation setting module that makes an operation setting according to setting data obtained in the setting data transmission process of the control processor and a condition determining module that determines whether an operation setting permission condition containing the number of clocks during a transmission period of the setting data is adequate, and inhibits the operation setting of the operation setting module when the operation setting permission condition is not adequate.

Abstract: According to one embodiment, an optical disc apparatus, includes an offset addition section configured to add an offset amount to the electric signal output from each of a photo receiving elements in accordance with a first signal, a gain variable section configured to adjust a gain amount of each offset added electric signal obtained by adding an offset in accordance with a second signal, an A/D converter configured to convert each of the offset added electric signals to a digital signal from an analog signal, a servo signal arithmetic section configured to generate an error signal used for focus and tracking servo control from the digital signal, a reference signal generation section configured to generate the first signal and the second signal from the digital signal, and a gain/offset correction section configured to correct the error signal in accordance with the first signal and the second signal.

Abstract: In one embodiment of a heat sink fitted to an electronic component, a plurality of heat dissipating members having a flat main body portion and a fin portion formed by extending the main body portion are provided, and at least one of the heat dissipating members further has an extended portion formed by extending the fin portion or the main body portion, and an engaging portion formed in a tip of the extended portion.

Abstract: An optical disc apparatus includes an emitter which emits a laser beam to a optical disc, a divided photodetector including a first dived portion and a second dived portion disposed in a light path of the reflected beam from the optical disc, and producing a first photodetector signal and a second photodetector signal, a phase difference detector which produces a phase difference signal from a phase difference between the first and the second photodetector signals, an integrator which produces a integral signal from a integration of the phase difference signal, a tracking controller configure to perform tracking control based on the integral signal, and a limiter which limits a signal to be supplied from the divided photodetector to the phase difference detector or a signal to be supplied from the phase difference detector to the integrator based on a detection status of a signal detected by the dived photodetector.

Abstract: An optical disc drive according to an embodiment of this invention includes a light-receiving section for receiving light, a conversion section for converting the light received by the light-receiving section into an electrical signal, a generation section for generating a slewing rate control signal, and a signal processing section for processing the electrical signal using the slewing rate control signal.

Abstract: An optical disc drive according to an embodiment of this invention includes a light-receiving section for receiving light, a conversion section for converting the light received by the light-receiving section into an electrical signal, a generation section for generating a slewing rate control signal, and a signal processing section for processing the electrical signal using the slewing rate control signal.

Abstract: In an optical disk device with various types of optical disks, the amounts of light are set for the various types of optical disks by emitting laser light from a semiconductor laser oscillator while sequentially increasing the light amount thereof for the optical disks in an order from the optical disk of the smallest set light amount. That is, first, whether or not an optical disk of CD, CD-ROM or DVD-ROM can be suitably used is determined based on the amount of reflection light from the optical disk obtained by causing the semiconductor laser oscillator to emit laser light in the smallest light amount setting state, and if it is not determined that the optical disk can be suitably used, the light amount is raised to a level higher than the lowest light amount set level by one level.