Light receiving amplifier circuit and optical pickup device having the same
First Claim
Patent Images
1. A light receiving amplifier circuit comprising:
- a light receiving element which converts received light into a current and outputs the current thus converted;
a current-to-voltage conversion circuit which converts the output current of the light receiving element into a voltage;
a reference voltage supplying amplifier having an identical structure with the current-to-voltage conversion circuit except that the light receiving element is not connected and a band limiting capacitor is provided; and
a differential amplifier circuit which amplifies a difference between the output voltage of the current-to-voltage conversion circuit and a reference voltage that is an output voltage of the reference voltage supplying amplifier, the current-to-voltage conversion circuit and the reference voltage supplying amplifier each including;
a grounded-emitter amplifier circuit employing a grounded-emitter transistor, the grounded-emitter transistor having a base serving as an input terminal, and a terminal serving as an output terminal for obtaining an output voltage which varies depending on an output from an output node of the grounded-emitter amplifier circuit; and
a plurality of feedback resistors being provided in parallel on feedback paths from the output terminal to the base so as to be selectively used, the band limiting capacitor being connected between the output node of the grounded-emitter amplifier circuit and a grounded point where the emitter is grounded.
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Abstract
In a light receiving amplifier circuit, a dummy amplifier has an identical structure with an IV amplifier except that the dummy amplifier is not connected to a light receiving element and includes a capacitor, i.e., a band limiting capacitor. Further, the capacitor is connected between the collector of the grounded-emitter transistor Tr and GND.
20 Citations
18 Claims
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1. A light receiving amplifier circuit comprising:
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a light receiving element which converts received light into a current and outputs the current thus converted;
a current-to-voltage conversion circuit which converts the output current of the light receiving element into a voltage;
a reference voltage supplying amplifier having an identical structure with the current-to-voltage conversion circuit except that the light receiving element is not connected and a band limiting capacitor is provided; and
a differential amplifier circuit which amplifies a difference between the output voltage of the current-to-voltage conversion circuit and a reference voltage that is an output voltage of the reference voltage supplying amplifier, the current-to-voltage conversion circuit and the reference voltage supplying amplifier each including;
a grounded-emitter amplifier circuit employing a grounded-emitter transistor, the grounded-emitter transistor having a base serving as an input terminal, and a terminal serving as an output terminal for obtaining an output voltage which varies depending on an output from an output node of the grounded-emitter amplifier circuit; and
a plurality of feedback resistors being provided in parallel on feedback paths from the output terminal to the base so as to be selectively used, the band limiting capacitor being connected between the output node of the grounded-emitter amplifier circuit and a grounded point where the emitter is grounded. - View Dependent Claims (6, 8, 9, 10, 11, 12)
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2. A light receiving amplifier circuit comprising:
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a light receiving element which converts received light into a current and outputs the current thus converted;
a current-to-voltage conversion circuit which converts the output current of the light receiving element into a voltage;
a reference voltage supplying amplifier having an identical structure with the current-to-voltage conversion circuit except that the light receiving element is not connected and a band limiting capacitor is provided; and
a differential amplifier circuit which amplifies a difference between the output voltage of the current-to-voltage conversion circuit and a reference voltage that is an output voltage of the reference voltage supplying amplifier, the current-to-voltage conversion circuit and the reference voltage supplying amplifier each including;
a grounded-emitter amplifier circuit employing a grounded-emitter transistor, the grounded-emitter transistor having a base serving as an input terminal, and a terminal serving as an output terminal for obtaining an output voltage which varies depending on an output from an output node of the grounded-emitter amplifier circuit; and
a plurality of feedback resistors being provided in parallel on feedback paths from the output terminal to the base so as to be selectively used, the current-to-voltage conversion circuit and the reference voltage supplying amplifier each further including a bias-use constant current source for supplying a bias current to the base, and the band limiting capacitor being connected between the base and the output node of the grounded-emitter amplifier circuit. - View Dependent Claims (5, 7, 13)
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3. A light receiving amplifier circuit comprising:
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a light receiving element which converts received light into a current and outputs the current thus converted;
a current-to-voltage conversion circuit which converts the output current of the light receiving element into a voltage;
a reference voltage supplying amplifier having an identical structure with the current-to-voltage conversion circuit except that the light receiving element is not connected and a band limiting capacitor is provided; and
a differential amplifier circuit which amplifies a difference between the output voltage of the current-to-voltage conversion circuit and a reference voltage that is an output voltage of the reference voltage supplying amplifier, the current-to-voltage conversion circuit and the reference voltage supplying amplifier each including;
a grounded-emitter amplifier circuit employing a grounded-emitter transistor, the grounded-emitter transistor having a base serving as an input terminal, and a terminal serving as an output terminal for obtaining an output voltage which varies depending on an output from an output node of the grounded-emitter amplifier circuit; and
a plurality of feedback resistors being provided in parallel on feedback paths from the output terminal to the base so as to be selectively used, the current-to-voltage conversion circuit and the reference voltage supplying amplifier each further including a bias-use constant current source for supplying a bias current to the base, and the band limiting capacitor being connected between the base and a grounded point where the emitter is grounded. - View Dependent Claims (14)
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4. A light receiving amplifier circuit comprising:
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a light receiving element which converts received light into a current and outputs the current thus converted;
a current-to-voltage conversion circuit which converts the output current of the light receiving element into a voltage;
a reference voltage supplying amplifier having an identical structure with the current-to-voltage conversion circuit except that the light receiving element is not connected and a band limiting capacitor is provided; and
a differential amplifier circuit which amplifies a difference between the output voltage of the current-to-voltage conversion circuit and a reference voltage that is an output voltage of the reference voltage supplying amplifier, the current-to-voltage conversion circuit and the reference voltage supplying amplifier each including;
a grounded-emitter amplifier circuit employing a grounded-emitter transistor, the grounded-emitter transistor having a base serving as an input terminal, and a terminal serving as an output terminal for obtaining an output voltage which varies depending on an output from an output node of the grounded-emitter amplifier circuit; and
a plurality of feedback resistors being provided in parallel on feedback paths from the output terminal to the base so as to be selectively used, the current-to-voltage conversion circuit and the reference voltage supplying amplifier each further including a bias-use constant current source for supplying a bias current to the base, and the band limiting capacitor being connected in parallel to the feedback resistors.
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15. An optical pickup device comprising a light receiving amplifier circuit as a light receiving amplifier used for optical pickup of an optical disk, the light receiving amplifier circuit including:
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a light receiving element which converts received light into a current and outputs the current thus converted;
a current-to-voltage conversion circuit which converts the output current of the light receiving element into a voltage;
a reference voltage supplying amplifier having an identical structure with the current-to-voltage conversion circuit except that the light receiving element is not connected and a band limiting capacitor is provided; and
a differential amplifier circuit which amplifies a difference between the output voltage of the current-to-voltage conversion circuit and a reference voltage that is an output voltage of the reference voltage supplying amplifier, the current-to-voltage conversion circuit and the reference voltage supplying amplifier each including;
a grounded-emitter amplifier circuit employing a grounded-emitter transistor, the grounded-emitter transistor having a base serving as an input terminal, and a terminal serving as an output terminal for obtaining an output voltage which varies depending on an output from an output node of the grounded-emitter amplifier circuit; and
a plurality of feedback resistors being provided in parallel on feedback paths from the output terminal to the base so as to be selectively used, the band limiting capacitor being connected between the output node of the grounded-emitter amplifier circuit and a grounded point where the emitter is grounded.
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16. An optical pickup device comprising a light receiving amplifier circuit as a light receiving amplifier used for optical pickup of an optical disk, the light receiving amplifier circuit including:
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a light receiving element which converts received light into a current and outputs the current thus converted;
a current-to-voltage conversion circuit which converts the output current of the light receiving element into a voltage;
a reference voltage supplying amplifier having an identical structure with the current-to-voltage conversion circuit except that the light receiving element is not connected and a band limiting capacitor is provided; and
a differential amplifier circuit which amplifies a difference between the output voltage of the current-to-voltage conversion circuit and a reference voltage that is an output voltage of the reference voltage supplying amplifier, the current-to-voltage conversion circuit and the reference voltage supplying amplifier each including;
a grounded-emitter amplifier circuit employing a grounded-emitter transistor, the grounded-emitter transistor having a base serving as an input terminal, and a terminal serving as an output terminal for obtaining an output voltage which varies depending on an output from an output node of the grounded-emitter amplifier circuit; and
a plurality of feedback resistors being provided in parallel on feedback paths from the output terminal to the base so as to be selectively used, the current-to-voltage conversion circuit and the reference voltage supplying amplifier each further including a bias-use constant current source for supplying a bias current to the base, and the band limiting capacitor being connected between the base and the output node of the grounded-emitter amplifier circuit.
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17. An optical pickup device comprising a light receiving amplifier circuit as a light receiving amplifier used for optical pickup of an optical disk, the light receiving amplifier circuit including:
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a light receiving element which converts received light into a current and outputs the current thus converted;
a current-to-voltage conversion circuit which converts the output current of the light receiving element into a voltage;
a reference voltage supplying amplifier having an identical structure with the current-to-voltage conversion circuit except that the light receiving element is not connected and a band limiting capacitor is provided; and
a differential amplifier circuit which amplifies a difference between the output voltage of the current-to-voltage conversion circuit and a reference voltage that is an output voltage of the reference voltage supplying amplifier, the current-to-voltage conversion circuit and the reference voltage supplying amplifier each including;
a grounded-emitter amplifier circuit employing a grounded-emitter transistor, the grounded-emitter transistor having a base serving as an input terminal, and a terminal serving as an output terminal for obtaining an output voltage which varies depending on an output from an output node of the grounded-emitter amplifier circuit; and
a plurality of feedback resistors being provided in parallel on feedback paths from the output terminal to the base so as to be selectively used, the current-to-voltage conversion circuit and the reference voltage supplying amplifier each further including a bias-use constant current source for supplying a bias current to the base, and the band limiting capacitor being connected between the base and a grounded point where the emitter is grounded.
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18. An optical pickup device comprising a light receiving amplifier circuit as a light receiving amplifier used for optical pickup of an optical disk, the light receiving amplifier circuit including:
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a light receiving element which converts received light into a current and outputs the current thus converted;
a current-to-voltage conversion circuit which converts the output current of the light receiving element into a voltage;
a reference voltage supplying amplifier having an identical structure with the current-to-voltage conversion circuit except that the light receiving element is not connected and a band limiting capacitor is provided; and
a differential amplifier circuit which amplifies a difference between the output voltage of the current-to-voltage conversion circuit and a reference voltage that is an output voltage of the reference voltage supplying amplifier, the current-to-voltage conversion circuit and the reference voltage supplying amplifier each including;
a grounded-emitter amplifier circuit employing a grounded-emitter transistor, the grounded-emitter transistor having a base serving as an input terminal, and a terminal serving as an output terminal for obtaining an output voltage which varies depending on an output from an output node of the grounded-emitter amplifier circuit; and
a plurality of feedback resistors being provided in parallel on feedback paths from the output terminal to the base so as to be selectively used, the current-to-voltage conversion circuit and the reference voltage supplying amplifier each further including a bias-use constant current source for supplying a bias current to the base, and the band limiting capacitor being connected in parallel to the feedback resistors.
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Specification