Driver circuit and optical-transmission module
AssigneeHitachi, Ltd.
InventorsNorio Chujo, Yoshihiko Hayashi, Akio Osaki, Naohiko Baba
Life of this patent
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Abstract
A driver circuit comprises a first differential-amplifier circuit having a pair of first transistors with emitters thereof connected to each other and a first resistor provided between an emitter connection point of the first transistors and a first power supply. Different electric potentials are applied to the bases of the pair of the first transistors to set a ratio of a current flowing through one of the pair of the first transistors to a current flowing through the other first transistor at about {fraction (1/100)} or smaller. An amplitude of an output current is controlled by the higher of the electric potentials applied to the base of one of the first transistors.
Claims31
A driver circuit comprising a first differential-amplifier circuit having a pair of first transistors with emitters thereof connected to each other and a first resistor provided between an emitter connection point of the first transistors and a first power supply;
- wherein a higher base voltage is applied to the base of one of the first transistors than a base voltage applied to the base of the other first transistor, and
- wherein, with a difference in electric potential applied by the base voltages between bases of the pair of the first transistors to set a ratio of a current flowing through one of the pair of the first transistors to a current flowing through the other first transistor at about {fraction (1/100)} or smaller, an amplitude of an output current of the driver circuit is controlled by the higher electric voltage applied to the base of one of the first transistors than to the base of the other first transistor.
A driver circuit comprising a first differential-amplifier circuit having composed of a pair of first transistors employing bipolar transistors with emitters thereof connected to each other and a first resistor with resistance in the range of about 2 to 20 Ω provided between an emitter connection point of the pair of the first transistors and first power supply;
- wherein an amplitude of an output current of the driver circuit is controlled by electric potential applied to a base of at least one of the first transistors.
An optical-transmission module comprising:
- a first differential-amplifier circuit having a pair of first transistors with emitters thereof connected to each other and a first resistor provided between an emitter connection point of the first transistors and a first power supply;
- wherein a higher base voltage is applied to the base of one of the first transistors than a base voltage applied to the base of the other first transistor, and
- wherein, with a difference in electric potential applied by the base voltages between bases of the pair of the first transistors to set a ratio of a current flowing through one of the pair of the first transistors to a current flowing through the other first transistor at about {fraction (1/100)} or smaller, an amplitude of an output current of the driver circuit is controlled by the higher electric voltage applied to the base of one of the first transistors than to the base of the other first transistor;
- and
- a laser-diode module for outputting an optical-transmission wave by carrying out optical-intensity modulation on a laser diode on a basis of an output current signal or an output voltage signal output by the first differential-amplifier circuit.
An optical-transmission module comprising:
- a first differential-amplifier circuit having composed of a pair of first transistors employing bipolar transistors with emitters thereof connected to each other and a first resistor with resistance in the range of about 2 to 20 Ω provided between an emitter connection point of the pair of the first transistors and first power supply;
- wherein an amplitude of an output current of the driver circuit is controlled by electric potential applied to a base of at least one of the first transistors;
- a laser-diode module for outputting an optical-transmission wave by carrying out optical-intensity modulation on a laser diode on a basis of an output current signal or an output voltage signal output by the first differential-amplifier circuit.
An optical-transmission module comprising:
- a first differential-amplifier circuit having a pair of first transistors with emitters thereof connected to each other and a first resistor provided between an emitter connection point of the first transistors and a first power supply;
- wherein a higher base voltage is applied to the base of one of the first transistors than a base voltage applied to the base of the other first transistor, and
- wherein, with a difference in electric potential applied by the base voltages between bases of the pair of the first transistors to set a ratio of a current flowing through one of the pair of the first transistors to a current flowing through the other first transistor at about {fraction (1/100)} or smaller, an amplitude of an output current of the driver circuit is controlled by the higher electric voltage applied to the base of one of the first transistors than to the base of the other first transistor;
- and
- a optical-modulation module for outputting an optical-transmission wave by modulating a light emitted by a light source on the basis of an output current signal or an output voltage signal output by said first differential-amplifier circuit.
An optical-transmission module comprising:
- a first differential-amplifier circuit having composed of a pair of first transistors employing bipolar transistors with emitters thereof connected to each other and a first resistor with resistance in the range of about 2 to 20 Ω provided between an emitter connection point of the pair of the first transistors and first power supply;
- wherein an amplitude of an output current of the driver circuit is controlled by electric potential applied to a base of at least one of the first transistors;
- an optical-modulation module for outputting an optical-transmission wave by modulating a light emitted by a light source on the basis of an output current signal or an output voltage signal output by said first differential-amplifier circuit.
A driver circuit comprising:
- a differential-amplifier circuit having a pair of transistors;
- means for setting a ratio of a current flowing through one of the pair of transistors to a current flowing through the other transistor at about {fraction (1/100)} or smaller by applying a higher base voltage to the base of one of the pair of transistors than a base voltage applied to the other transistor;
- and
- means for controlling the amplitude of an output current of the driver circuit by the higher electric potential applied to said base of said one of said transistors.
An optical-transmission module comprising:
- a driver circuit having a differential-amplifier circuit with a pair of transistors and means for setting a ratio of a current flowing through one of a pair of transistors to a current flowing through the other transistor at about {fraction (1/100)} or smaller by applying a higher base voltage to the base of one of the pair of transistors than a base voltage applied to the other transistor and means for controlling the amplitude of an output current by the higher electric potential applied to said base of said one of said transistors;
- and
- a optical-modulation module for outputting an optical-transmission wave by modulating a light emitted by a light source on the basis of an output current signal or an output voltage signal output by said differential-amplifier circuit.
Dependencies are inferred from the claim text.