Kabushiki Kaisha Toshiba

Masayuki Tazawa

Toyoki Taguchi

Tetsuya Nagahama

The semiconductor laser apparatus includes a semiconductor laser, a detection element for detecting the intensity of the output light from the semiconductor laser, an error detection circuit containing a gain controllable operation amplifying circuit and a gain-fixed type control amplifying circuit connected to a next stage to the gain controllable operation amplifying circuit, to which a semiconductor laser drive control signal is input and an output signal of the detection element is input as a negative feedback signal, for outputting an error signal corresponding to a difference between the two input signals, a high-frequency signal generating circuit for generating a high-frequency signal having a predetermined frequency, a high-frequency signal superimposing circuit for superimposing the high-frequency signal onto the output signal from the error detection circuit, and a laser drive circuit for supplying a drive current to the semiconductor laser on the basis of the output signal from the high-frequency signal superimposing circuit.

Semiconductor laser apparatus, information recording/reproduction apparatus and image recording apparatus

The semiconductor laser apparatus includes a semiconductor laser, a detection element for detecting the intensity of the output light from the semiconductor laser, an error detection circuit containing a gain controllable operation amplifying circuit and a gain-fixed type control amplifying circuit connected to a next stage to the gain controllable operation amplifying circuit, to which a semiconductor laser drive control signal is input and an output signal of the detection element is input as a negative feedback signal, for outputting an error signal corresponding to a difference between the two input signals, a high-frequency signal generating circuit for generating a high-frequency signal having a predetermined frequency, a high-frequency signal superimposing circuit for superimposing the high-frequency signal onto the output signal from the error detection circuit, and a laser drive circuit for supplying a drive current to the semiconductor laser on the basis of the output signal from the high-frequency signal superimposing circuit

Semiconductor laser control circuit, semiconductor laser apparatus, information recording/reproduction apparatus and image recording apparatus

There is provided a semiconductor laser driving circuit. The circuit has: an amplifier for receiving an emission level setting voltage, and outputting a first driving signal on the basis of the emission level setting voltage; a driving signal generation circuit for receiving a control signal for instructing a light-emission period of a semiconductor laser, and the first driving signal output from said amplifier, and outputting a second driving signal corresponding to a level of the first driving signal in accordance with a light-emission or extinction period; a driving circuit for receiving the second driving signal output from said driving signal generation circuit, and generating and outputting a driving current to be supplied to the semiconductor laser; and a control circuit for receiving the emission level setting voltage, and adjusting a level of the second driving signal during the extinction period in correspondence with the emission level setting voltage.

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Yokosuka, Japan

Masayuki Tazawa