Optical receiving circuit
AssigneeKabushiki Kaisha Toshiba
InventorToyoaki Uo
Life of this patent
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Abstract
An optical-receiving circuit includes a first photodiode converting an optical signal into a current signal, a first trans-impedance amplifier to which a first power supply voltage of Vreg is supplied and which has a negative feedback resistor and to which the current signal is input and which outputs a voltage signal, and an output circuit to which the voltage signal output from the first trans-impedance amplifier is input and which outputs a voltage signal to the outside. A temperature coefficient of a voltage of (Vreg−MVbe) is positive, in which Vbe is a base-emitter voltage of a transistor contained in the first trans-impedance amplifier and M is a coefficient that does not depend on the temperature.
Claims5
An optical-receiving circuit comprising:
- a first photodiode converting an optical signal into a current signal;
- a first trans-impedance amplifier to which a first power supply voltage of Vreg is supplied and which has a negative feedback resistor and to which the current signal is input and which outputs a voltage signal;
- and
- an output circuit to which the voltage signal output from the first trans-impedance amplifier is input and which outputs a voltage signal to the outside, the output circuit having an output transistor,
- a temperature coefficient of a voltage of (Vreg−MVbe) being positive, in which Vbe is a base-emitter voltage of a transistor contained in the first trans-impedance amplifier and M is a coefficient that does not depend on the temperature,
- a second power supply voltage being supplied to a collector of the output transistor through N (where, N≧1) diodes that are serially connected, and
- a temperature coefficient of the second power supply voltage being about N times of a temperature coefficient of the diodes.
Dependencies are inferred from the claim text.