Preamplifier and optical receiving device including the same

1. A preamplifier, comprising:

a single-ended amplifier which converts an input current signal into a voltage signal, and outputs an amplified voltage signal according to a preset amplification gain;

a differential amplifier which includes first and second differential inputs, and which outputs a negative-phase signal and a positive-phase signal, wherein the amplified voltage signal is applied to the first differential input of the differential amplifier;

an operational amplifier which includes first and second inputs which respectively receive the negative-phase signal and the positive-phase signal, wherein an output of the operational amplifier is applied to the second differential input of the differential amplifier; and

a clipping circuit that clips an amplitude of the negative-phase signal output by the differential amplifier,

wherein the clipping circuit includes a diode connected between positive power terminal and a signal line transmitting the negative-phase signal, wherein an anode of the diode is connected to the positive power terminal.

2. The preamplifier according to claim 1 , wherein the signal line is a negative-phase signal output terminal of the differential amplifier.

3. A preamplifier, comprising:

a single-ended amplifier which converts an input current signal into a voltage signal, and outputs an amplified voltage signal according to a preset amplification gain;

a differential amplifier which includes first and second differential inputs, and which outputs a negative-phase signal and a positive-phase signal, wherein the amplified voltage signal is applied to the first differential input of the differential amplifier;

an operational amplifier which includes first and second inputs which respectively receive the negative-phase signal and the positive-phase signal, wherein an output of the operational amplifier is applied to the second differential input of the differential amplifier; and

a clipping circuit that clips an amplitude of the negative-phase signal output by the differential amplifier,

wherein the clipping circuit is a diode connected between a signal line transmitting the positive-phase signal and a negative power terminal, wherein a cathode of the diode is connected to the negative power terminal.

4. The preamplifier according to claim 3 , wherein the signal line is a positive-phase signal output terminal of the differential amplifier.

5. A preamplifier, comprising:

a single-ended amplifier which converts an input current signal into a voltage signal, and outputs an amplified voltage signal according to a preset amplification gain;

a differential amplifier which includes first and second differential inputs, and which outputs a negative-phase signal and a positive-phase signal, wherein the amplified voltage signal is applied to the first differential input of the differential amplifier;

an operational amplifier which includes first and second inputs which respectively receive the negative-phase signal and the positive-phase signal, wherein an output of the operational amplifier is applied to the second differential input of the differential amplifier; and

a clipping circuit that clips an amplitude of the negative-phase signal output by the differential amplifier,

wherein the clipping circuit is an output offset generating circuit interposed between an input of the operational amplifier and a positive-phase signal output terminal and a negative-phase signal output terminal of the differential amplifier, and wherein the output offset generating circuit offsets the positive-phase signal such that a DC voltage of the positive-phase signal is higher than that of the negative-phase signal prior to being input to the operational amplifier.

6. The preamplifier according to claim 5 , wherein the output offset generating circuit includes a number of positive-phase side diode stages and a different number of negative-phase side diode stages.

7. The preamplifier according to claim 5 , wherein the output offset generating circuit includes a positive-phase side voltage dividing resistance that is different than a negative-phase voltage dividing resistance.

8. The preamplifier according to claim 5 , wherein the output offset generating circuit is configured to apply an external voltage to the negative-phase signal.

9. An optical receiving device including a light receiving element that converts a received optical signal into a current signal, and a preamplifier that converts the current signal outputted from the light receiving element into an amplified output voltage signal, wherein the preamplifier comprises:

a single-ended amplifier which converts the current signal into a voltage signal, and outputs an amplified voltage signal according to a preset amplification gain;

a differential amplifier which includes first and second differential inputs, and which outputs a negative-phase signal and a positive-phase signal, wherein the amplified voltage signal is applied to the first differential input of the differential amplifier;

an operational amplifier which includes first and second inputs which respectively receive the negative-phase signal and the positive-phase signal, wherein an output of the operational amplifier is applied to the second differential input of the differential amplifier;

a clipping circuit that clips an amplitude of the negative-phase signal output by the differential amplifier;

a threshold setting limiter amplification circuit that determines a level of the amplified output voltage signal outputted from the preamplifier based on a preset threshold and outputs a determined level of the voltage signal; and

a clock/data identification recovery circuit that recovers and outputs a clock signal and a data signal in synchronization with the clock signal from a signal outputted from the threshold setting limiter amplification circuit,

wherein the clipping circuit includes a diode connected between positive power terminal and a signal line transmitting the negative-phase signal, wherein an anode of the diode is connected to the positive power terminal.

10. The optical receiving device according to claim 9 , wherein the signal line is a negative-phase signal output terminal of the differential amplifier.

11. An optical receiving device including a light receiving element that converts a received optical signal into a current signal, and a preamplifier that converts the current signal outputted from the light receiving element into an amplified output voltage signal, wherein the preamplifier comprises:

a single-ended amplifier which converts the current signal into a voltage signal, and outputs an amplified voltage signal according to a preset amplification gain;

a differential amplifier which includes first and second differential inputs, and which outputs a negative-phase signal and a positive-phase signal, wherein the amplified voltage signal is applied to the first differential input of the differential amplifier;

an operational amplifier which includes first and second inputs which respectively receive the negative-phase signal and the positive-phase signal, wherein an output of the operational amplifier is applied to the second differential input of the differential amplifier;

a clipping circuit that clips an amplitude of the negative-phase signal output by the differential amplifier;

a threshold setting limiter amplification circuit that determines a level of the amplified output voltage signal outputted from the preamplifier based on a preset threshold and outputs a determined level of the voltage signal; and

a clock/data identification recovery circuit that recovers and outputs a clock signal and a data signal in synchronization with the clock signal from a signal outputted from the threshold setting limiter amplification circuit,

wherein the clipping circuit is a diode connected between a signal line transmitting the positive-phase signal and a negative power terminal, wherein a cathode of the diode is connected to the negative power terminal.

12. The preamplifier according to claim 11 , wherein the signal line is a positive-phase signal output terminal of the differential amplifier.

13. An optical receiving device including a light receiving element that converts a received optical signal into a current signal, and a preamplifier that converts the current signal outputted from the light receiving element into an amplified output voltage signal, wherein the preamplifier comprises:

a single-ended amplifier which converts the current signal into a voltage signal, and outputs an amplified voltage signal according to a preset amplification gain;

a differential amplifier which includes first and second differential inputs, and which outputs a negative-phase signal and a positive-phase signal, wherein the amplified voltage signal is applied to the first differential input of the differential amplifier;

an operational amplifier which includes first and second inputs which respectively receive the negative-phase signal and the positive-phase signal, wherein an output of the operational amplifier is applied to the second differential input of the differential amplifier;

a clipping circuit that clips an amplitude of the negative-phase signal output by the differential amplifier;

a threshold setting limiter amplification circuit that determines a level of the amplified output voltage signal outputted from the preamplifier based on a preset threshold and outputs a determined level of the voltage signal; and

a clock/data identification recovery circuit that recovers and outputs a clock signal and a data signal in synchronization with the clock signal from a signal outputted from the threshold setting limiter amplification circuit,

wherein the clipping circuit is an output offset generating circuit interposed between an input of the operational amplifier and a positive-phase signal output terminal and a negative-phase signal output terminal of the differential amplifier, and wherein the output offset generating circuit offsets the positive-phase signal such that a magnitude of the positive-phase signal is higher than the negative-phase signal prior to being input to the operational amplifier.

14. The preamplifier according to claim 13 , wherein the output offset generating circuit includes a number of positive-phase side diode stages and a different number of negative-phase side diode stages.

15. The preamplifier according to claim 13 , wherein the output offset generating circuit includes a positive-phase side voltage dividing resistance that is different than a negative-phase voltage dividing resistance.

16. The preamplifier according to claim 13 , wherein the output offset generating circuit is configured to apply an external voltage to the negative-phase signal.