JP3442915B2 - Semiconductor integrated circuit device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical receiver, and more particularly to an apparatus for receiving an optical pulse signal and converting it into a pulse voltage signal.

[0002]

2. Description of the Related Art Optical transmission has been widely used as a signal transmission method, and there is a demand for an inexpensive optical transmission device that enables large-capacity transmission. The optical transmitter on the transmission side of the optical transmission converts the pulse voltage signal into a pulsed optical signal and transmits it. The optical receiving device on the receiving side of the optical transmission receives the optical pulse signal and converts the received optical signal into a pulse voltage signal.

FIG. 12 shows an example of a conventional transmission device.
The transmitter of FIG. 12 includes a transmitter and a receiver, and the transmitter includes a transmitter 11 and an LED (light emitting diode) 12. The receiving device also includes a PD (photodiode) 13, a preamplifier 14, an amplifier 15, and a comparator 16.

FIG. 13 shows an example of each signal waveform shown in FIG.
When the input voltage as shown in FIG. 13A is input to the transmitter 11, the transmitter 11 applies the current having the waveform as shown in FIG. 13B to the LED 12. The LED 12 emits light to transmit an optical signal, which is received by the PD 13. At this time, the current having the waveform shown in FIG. 13C flows through the PD 13. The preamplifier 14 is an IV converter that converts a current into a voltage and amplifies it, and an output waveform of the preamplifier 14 has a voltage waveform shown in FIG. Further, the voltage waveform of FIG. 13 (d) is amplified by the amplifier 15,
The pulse voltage waveform of FIG. 13E is obtained by the comparator 16 comparing the appropriate threshold value Vth with the amplified voltage waveform.

[0005]

Here, FIG. 13 (d)
The output waveform of the preamplifier 14 shown in (1) does not become an accurate rectangular waveform due to the resistance and capacitance included in the diode. In order to explain this, FIG. 14A shows a simple model circuit of the preamplifier 14 and a PD connected thereto.
The capacities of 13 and PD 13 are shown separately. The model circuit of the preamplifier 14 in this figure is a simplified circuit for showing the basic principle of the preamplifier.

In FIG. 14 (a), the preamplifier 14 includes a resistor 21 and a Schottky diode 22, and PD1
3 includes a PD 23 and a capacitor 24. Note that Vcc is a power supply voltage. The optical signal as shown in FIG.
If it is supplied to D23, a current corresponding to this optical signal tends to flow through PD23. However, due to the capacitance 24, the rising and falling portions of the voltage applied to the output terminal of the preamplifier 14 are delayed, and as a result, FIG.
The voltage waveform as shown by the solid line is obtained as the output of the preamplifier 14.

The waveform indicated by the dotted line in FIG. 14C is the voltage waveform that appears at the output terminal when the Schottky diode 22 of FIG. 14A is not present. Actually, the output voltage is clamped by the Schottky diode 22 of the preamplifier 14,
The voltage waveform shown by the solid line in (c) is obtained.

For the above reason, the output waveform of the preamplifier 14 in FIG. 13 (d) does not faithfully reflect the transmitted signal. Therefore, the output waveform of the comparator 16 obtained by thresholding this signal (see FIG.
In (e), the pulse width is longer than that of the transmitted signal. Even if the waveform is deformed as shown in FIG. 13D, there is no problem if the pulse width of the transmitted signal is relatively long, that is, if T >> Te. However, when the pulse width becomes shorter and T / 2 <Te, the pulse width on the transmitting side and the pulse width on the receiving side greatly differ. In such a case, a problem arises in the modulation / demodulation system in which 0 and 1 are represented depending on the pulse width.

FIG. 15 shows the preamplifier 14 of FIG.
The output waveform of is expanded. In the voltage waveform in the figure, if the threshold voltage can be set to a voltage Vr slightly lower than the maximum voltage Vh, the influence of the Te portion can be suppressed to the minimum. That is, even if the pulse width on the transmitting side becomes shorter, the pulse voltage waveform having the same pulse width on the receiving side can be obtained.

However, although it is necessary to set the threshold voltage to a voltage slightly lower than the maximum voltage Vh, it is difficult to set such a threshold voltage in view of voltage fluctuation and the like. It should be noted that, in reality, after being amplified by the amplifier 15, the comparison with the threshold value is performed by the comparator 16, but here, for simplification of description, the threshold value in the output waveform of the preamplifier 14 is considered.

Photodiodes used as the PD 13 include expensive ones having a capacity of several picofarads to inexpensive photodiodes having a capacity of several tens of picofarads. The pulse frequency of the transmitted optical signal is several tens of M
When the frequency becomes higher than Hz, it becomes necessary to use an expensive photodiode having a capacity of several picofarads, which leads to an increase in price of the optical transmission device.
This is not desirable for an optical transmission device that is mass-produced and used for general computer-to-computer communication.

Therefore, an object of the present invention is to provide an optical receiving apparatus capable of reproducing a voltage waveform having a pulse width close to that of the transmitting side on the receiving side in order to realize high-speed optical transmission. .

[0013]

According to a first aspect of the present invention, an apparatus for converting a pulse current signal into a pulse voltage signal by current-voltage converting the pulse current signal into a first voltage signal. A current-voltage converter, a voltage divider that divides the first voltage signal by voltage to generate a second voltage signal having a reduced amplitude, and a third voltage delayer that delays the second voltage signal in time.
And a comparator that compares the voltage of the first voltage signal with the voltage of the third voltage signal to generate the pulse voltage signal.

In the above invention, the amplitude of the first voltage signal output from the current-voltage converter is reduced by the voltage divider and delayed by the delay unit to generate a third voltage signal. . Therefore, the third voltage signal has a voltage waveform in which the first voltage signal has a small amplitude and is delayed in time.
It can function as an appropriate threshold voltage at the falling edge of the voltage signal. Further, the comparison unit is the first
A pulsed voltage signal is generated by comparing the voltage signal of 1 and the third voltage signal. Therefore, the pulse voltage signal that is the device output has a pulse width that is substantially the same as the pulse width of the input pulse current signal.

According to a second aspect of the present invention, in the apparatus according to the first aspect, the comparison section is high when the voltage of the first voltage signal exceeds the voltage of the third voltage signal. It outputs the level voltage, and otherwise outputs the low level. In the above invention, using the third voltage signal as the threshold voltage, a pulse voltage signal having a pulse width substantially the same as the pulse width of the input pulse current signal is generated from the first voltage signal. can do.

According to the invention of claim 3, claim 1 or 2
In the device described above, the comparison section includes a differential amplifier circuit that amplifies a difference between the first voltage signal and the third voltage signal to generate a differential amplified voltage signal, and the differential amplified voltage signal. Is compared with a predetermined threshold voltage to generate the pulse voltage signal.

In the above invention, the first voltage signal and the third voltage signal
The difference voltage signal is amplified and the amplified difference amplified voltage signal is compared with a predetermined threshold voltage to generate a pulse voltage signal. Therefore, it is possible to generate a pulse voltage signal having a pulse width substantially the same as the pulse width of the input pulse current signal.

In the invention of claim 4, claims 1 to 3
In the device according to any one of the preceding claims, the voltage divider is a resistor string in which at least two resistors are connected in series,
The first voltage signal is applied to the resistor string, and the voltage across the resistor is output as the second voltage signal.

In the above invention, it is possible to generate a pulse voltage signal having a pulse width substantially the same as the pulse width of the input pulse current signal by using the voltage dividing unit constituted by the resistor. According to a fifth aspect of the present invention, in the device according to any one of the first to fourth aspects, the delay unit is a capacitor.

In the above invention, it is possible to generate the pulse voltage signal having a pulse width substantially the same as the pulse width of the input pulse current signal by using the delay unit constituted by the capacitance. In the invention of claim 6, claim 4
In the device described above, the delay unit is a capacitor connected in parallel to one of the resistors to which the voltage of the second voltage signal is applied.

In the above invention, the capacitor connected in parallel with the resistor is used as the delay unit, so that the third voltage waveform delayed according to the charging and discharging of the capacitor can be obtained. According to a seventh aspect of the invention, the device according to the sixth aspect further includes another resistor connected in series with the capacitor.

In the above invention, the time constant governing the shape of the third voltage waveform can be easily adjusted by providing the resistor connected in series with the capacitor. According to an eighth aspect of the present invention, in the apparatus according to any one of the first to fourth aspects, the delay section is a delay circuit that delays and outputs an input signal.

In the above invention, it is possible to generate a pulse voltage signal having a pulse width substantially the same as the pulse width of the input pulse current signal by using the delay section constituted by the delay circuit. In the invention of claim 9,
2. The device according to claim 1, wherein the delay section delays the first voltage signal and supplies the delayed first voltage signal to the voltage dividing section, whereby the second voltage The signal is delayed in time to become the third voltage signal.

In the above invention, the delay unit may be provided between the current-voltage converter and the voltage divider. According to a tenth aspect of the invention, in the apparatus according to the sixth or seventh aspect, a delay circuit provided between the current-voltage conversion section and the voltage division section is further included.

In the above invention, the inclusion of the delay circuit makes it possible to obtain the third voltage signal having a steeper fall. Therefore, it is possible to generate a pulse voltage signal having a pulse width closer to the pulse width of the input pulse current signal.

According to an eleventh aspect of the present invention, in the apparatus according to the third aspect, the differential amplification voltage signal is fed back to the input of the differential amplification circuit to feed the differential amplification circuit. It further includes a DC feedback circuit that cancels the DC component at the input.

In the above invention, the DC offset of the differential amplifier circuit can be canceled by applying the DC feedback. Therefore, the signal component is not buried in the DC component in the output of the differential amplifier circuit. In the invention of claim 12, claims 1 to 11
The described apparatus inputs the pulse current signal from an element that receives an optical pulse signal and converts it into the pulse current signal.

In the above invention, it is possible to generate a pulse voltage signal having a pulse width substantially the same as the pulse width of the transmitted optical pulse signal.

[0029]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a circuit diagram of an optical receiver according to a first embodiment of the present invention. In FIG. 1, the same elements as those of FIG. 12 are referred to by the same numerals, and a description thereof will be omitted. 1 includes a PD 13, a preamplifier 14, an amplifier (differential amplifier) 15, a comparator 16,
It includes resistors R1 and R2 and a capacitor C. In the circuit of FIG. 1, the output voltage Va of the preamplifier 14 is steadily divided into a voltage of Vb = VaR2 / (R1 + R2) (1) by the voltage dividing circuit including the resistors R1 and R2. Since the capacitor C is connected in parallel to the resistor R2, the voltage Vb includes a time delay with respect to the signal waveform of the voltage Va when a transient response is considered. That is, in the circuit of FIG. 1, the waveform of the voltage Vb is the waveform of the voltage Va multiplied by R2 / (R1 + R2) and added with a time delay.

The present invention, in principle, reduces the amplitude (R2 /
A pulse delay waveform is obtained by adding a time delay to the (R1 + R2) times voltage and using the obtained waveform as a threshold value. The situation is shown in FIG. The waveform of the output voltage Va of the preamplifier 14 is shown by the solid line in FIG. A dotted line shows the waveform of the voltage Vb, which has a reduced amplitude and is delayed. If the voltage waveform shown by the dotted line is used as the threshold voltage with respect to the voltage waveform shown by the solid line, at the timing of A, Vth
A threshold value of 1 is used, and at the timing of B, Vth2
Will be used. Therefore, A and B
Only between the timings, the voltage waveform of the solid line exceeds the threshold voltage (dotted line). As a result, a pulse voltage waveform having a high level between A and B (FIG. 2B) is obtained.

In the circuit according to the first embodiment of FIG. 1, the waveform of the voltage Vb is Vb (t) = R2 / (R1 + R2) .Va (t). (1-e- ^{t / cR} ) ( 2) Here, R = R1R2 / (R1 + R2).
That is, the waveform of the voltage Vb has a charge / discharge curve with a time constant τ = CR. In the circuit of FIG. 1, the voltage Va
(T) and the voltage Vb (t) are input to the terminals of the amplifier 15. With this, the difference between the waveform of the voltage Va and the waveform of the voltage Vb is obtained. This state is shown in FIG.

In FIG. 3A, the voltage Va (t) is shown by a solid line and the voltage Vb (t) is shown by a dotted line. The output voltage waveform Vo (t) of the amplifier 15 is shown in FIG. As shown in FIG. 3B, since the output waveform of the amplifier 15 is the difference between Va (t) and Vb (t), the trailing edge of the pulse is not tailed. It should be noted that although the amplitude immediately after the rising is not so large as to correspond to the difference between Va (t) and Vb (t), this indicates the saturation of the output of the amplifier 15.

By comparing the voltage waveform Vo (t) of FIG. 3 (b) with an appropriate threshold value Vth by the comparator 16, the output voltage waveform of FIG. 3 (c) is obtained.
The output voltage waveform of FIG. 3C has a pulse width almost the same as the pulse width of the transmitted optical pulse signal.
Since the voltage waveform Vo (t) in FIG. 3B has a steep falling edge, the voltage value of the threshold value Vth is not critical with respect to the pulse width, and its setting is easy.

As described above, by using the circuit of the optical receiving apparatus of FIG. 1, it is possible to generate a voltage pulse signal having a pulse width substantially the same as that of the transmitted optical pulse signal. In the present invention, the voltage Vb (t) is used as a threshold value with respect to the voltage Va (t), but the amplifier 15 that amplifies the difference between the input signals functions in principle similar to the comparator. It is a thing. Therefore, in the process of amplifying the difference between the voltage Va (t) and the voltage Vb (t) in the amplifier 15, the pulse width is corrected simultaneously with the signal amplification by using Vb (t) as a threshold value. It can be interpreted as

FIG. 4 is a circuit diagram of an optical receiver according to the second embodiment of the present invention. In the circuit diagram of FIG. 4, the same elements as those of the circuit diagram of FIG. 1 are referred to by the same numerals, and a description thereof will be omitted. The optical receiving device of FIG. 4 is obtained by connecting a resistor R3 in series to the capacitor C of the optical receiving device of FIG. This resistor R3 has a time constant τ in the equation (2).
It is added to adjust (= CR).

In the optical receiver of FIG. 1, when adjusting the time constant τ in order to obtain an appropriate amplifier output waveform Vo (t) (FIG. 3 (b)), it is conceivable to change R1 or R2. However, changing R1 or R2 changes the voltage division ratio R2 / (R1 + R2), which is not desirable. For example, if R1 is made too large, the amplitude of the voltage waveform Vb (t) drops as shown in FIG. 5, resulting in a large pulse width.

Even if the adjustment resistor R3 shown in FIG. 4 is changed, the amplitude of the voltage waveform Vb (t) is R2 / (R1 + R).
It remains 2). In this case, the time constant τ is C (R + R
3), and only the time constant τ can be linearly changed without changing the amplitude of the voltage Vb.

Therefore, in the optical receiving apparatus according to the second embodiment of the present invention, the time constant τ for obtaining an appropriate pulse width is easily set by changing the adjusting resistor R3. be able to. FIG. 6 shows a circuit diagram of an optical receiver according to a third embodiment of the present invention. In the circuit diagram of FIG. 4, the same elements as those of the circuit diagram of FIG. 1 are referred to by the same numerals, and a description thereof will be omitted.

The optical receiver of FIG. 6 is obtained by adding a delay circuit 30 to the optical receiver of FIG. Delay circuit 3
0 consists of, for example, a single-stage buffer amplifier. By adding this delay circuit, the voltage waveform Vb (t) is delayed by the time Td as shown by the dotted line in FIG. In the voltage waveform Vb (t) of FIG. 7A, the falling start point Ds is delayed by Td. Therefore, in the vicinity of the intersection of the voltage waveform Va (t) shown by the solid line and the voltage waveform Vb (t) shown by the dotted line, the difference between the voltage waveforms is the case of the optical receiver of FIG. 1 (FIG. 3A). In the case of the voltage waveform of 1), it will change more rapidly.

FIG. 7B shows the voltage waveform Va of FIG. 7A.
A voltage waveform obtained by amplifying the difference between (t) and the voltage waveform Vb (t) by the amplifier 15 is shown. Amplifier 15 shown in FIG.
For the above-mentioned reason, the output voltage waveform Vo (t) of No. 1 has a more steep fall than the voltage waveform Vo (t) shown in FIG. Therefore, the output waveform obtained by comparing with the threshold voltage Vth by the comparator 16 (FIG. 7C) has a pulse width closer to the pulse width of the transmitted optical pulse signal.

Therefore, in the optical receiver according to the third embodiment of the present invention, by using the delay circuit 30, a voltage waveform having a pulse width closer to the pulse width of the transmitted optical pulse signal is generated. be able to. Figure 8
Shows a modification of the third embodiment of the present invention. In the circuit of FIG. 8, the capacitor C of the circuit of FIG. 6 is removed.

As described above, the principle of the present invention is to divide a voltage to generate a voltage waveform having a small amplitude, delay the voltage waveform in time, and use it as a threshold voltage. Therefore, even if both the capacitor C and the delay circuit 30 are not used as shown in FIG. 6, the present invention can be configured by using one of them as a delay element. That is, in FIG. 8, if the delay circuit 30 is considered as a delay element instead of the capacitor C of FIG. 1, the same effect as that of the optical receiving circuit of FIG. 1 can be achieved.

FIG. 9 shows voltage waveforms relating to the optical receiver of FIG. FIG. 9A shows the output voltage V of the preamplifier 14.
a (t) is shown by a solid line, and the voltage-divided and delayed voltage Vb (t) is shown by a dotted line. In this case, the delay circuit 30 needs to have a delay time Td such that Vb (t) intersects Va (t) at the falling portion. Figure 9
9B shows a voltage waveform obtained by amplifying the difference between the voltage waveform Va (t) and the voltage waveform Vb (t) of FIG. 9A by the amplifier 15. Further, FIG. 9C shows an output waveform obtained by comparison with the threshold voltage Vth by the comparator 16.

As shown in the modification of the third embodiment,
As the delay element, a delay circuit including a buffer amplifier or the like can be used instead of the capacitor. In this case, as in the case of using the capacitor, in principle, the optical receiver can generate a voltage waveform having a pulse width approximately the same as the pulse width of the transmitted optical pulse signal.

FIG. 10 is a circuit diagram of an optical receiver according to the fourth embodiment of the present invention. In the circuit diagram of FIG. 10, FIG.
The same elements as those in the circuit diagram are referred to by the same numerals, and the description thereof will be omitted. The optical receiver of FIG. 10 is obtained by adding a DC (direct current) feedback circuit 31 to the optical receiver of FIG. FIG. 11 is a diagram for explaining the effect of adding the DC feedback circuit 31. FIG. 11A shows a differential voltage waveform between both terminals of the amplifier 15, and it is assumed that a low frequency component due to a dark current of PD having an amplitude Dc or disturbance is added to the differential voltage waveform.
FIG. 11B shows a waveform obtained by amplifying the differential voltage waveform of FIG. 11A by the amplifier 15.

The output of the amplifier 15 is saturated at a certain voltage.
Therefore, when a large DC component or a low frequency component is added as compared with the signal component as shown in FIG.
As shown in FIG. 11B, in the voltage waveform after amplification, the signal component is buried in the DC component or the low frequency component. This is because the output voltage reaches near the saturation level due to the amplification of the DC component and the low frequency component, and as a result, the signal component appears only as a voltage fluctuation near the saturation level.

In the optical receiver of FIG. 10, in order to solve this problem, a DC feedback circuit 31 is inserted to cancel a DC component or a low frequency component applied between both terminals of the amplifier 15. ing. The DC feedback circuit 31 includes an amplifier 32 and a capacitor 3
Including 3. Note that a method of canceling the DC component and the low frequency component by such DC feedback is known, and detailed description thereof will be omitted.

In the optical receiver according to the fourth embodiment of the present invention, the DC feedback circuit 31 cancels the DC component and the low frequency component, so that the signal component is buried in the DC component and the low frequency component. Can be prevented. Therefore, in the optical receiving device, it is possible to satisfactorily generate a voltage waveform having a pulse width approximately the same as the pulse width of the transmitted optical pulse signal.

[0049]

According to the first aspect of the invention, the amplitude of the first voltage signal output from the current-voltage converter is reduced by the voltage divider, and the delay is delayed by the delay unit. Generate a voltage signal. Therefore, the third voltage signal is
Is a voltage waveform having a small amplitude and delayed in time, and can function as an appropriate threshold voltage at the falling portion of the first voltage signal. Further, the comparison unit generates the pulse voltage signal by comparing the first voltage signal and the third voltage signal. Therefore, the pulse voltage signal that is the device output has a pulse width that is substantially the same as the pulse width of the input pulse current signal.

According to the second aspect of the present invention, the third voltage signal is used as the threshold voltage, and a pulse width substantially the same as the pulse width of the input pulse current signal is generated from the first voltage signal. It is possible to generate a pulse voltage signal having. In the invention of claim 3, the difference between the first voltage signal and the third voltage signal is amplified, and the amplified difference amplified voltage signal is compared with a predetermined threshold voltage to obtain the pulse voltage signal. To generate. Therefore, it is possible to generate a pulse voltage signal having a pulse width substantially the same as the pulse width of the input pulse current signal.

According to the fourth aspect of the present invention, the voltage divider having the resistance can be used to generate a pulse voltage signal having a pulse width substantially the same as the pulse width of the input pulse current signal. it can. According to the fifth aspect of the invention, the pulse voltage signal having the pulse width substantially the same as the pulse width of the input pulse current signal can be generated by using the delay unit constituted by the capacitor.

According to the sixth aspect of the invention, by using the capacitor connected in parallel with the resistor as the delay unit, it is possible to obtain the third voltage waveform delayed in accordance with the charge and discharge of the capacitor. According to the invention of claim 7, by providing the resistor connected in series with the capacitor, the time constant that governs the shape of the third voltage waveform can be easily adjusted.

According to the eighth aspect of the present invention, the pulse voltage signal having a pulse width substantially the same as the pulse width of the input pulse current signal can be generated by using the delay section constituted by the delay circuit. it can. In the invention of claim 9, the delay unit may be provided between the current-voltage conversion unit and the voltage division unit.

According to the tenth aspect of the present invention, by including the delay circuit, it is possible to obtain the third voltage signal having a steeper fall. Therefore, it is possible to generate a pulse voltage signal having a pulse width closer to the pulse width of the input pulse current signal.

In the eleventh aspect of the invention, the DC offset of the differential amplifier circuit can be canceled by applying the DC feedback. Therefore, the signal component is not buried in the DC component in the output of the differential amplifier circuit. According to the twelfth aspect of the invention, it is possible to generate a pulse voltage signal having a pulse width substantially the same as the pulse width of the transmitted optical pulse signal.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an optical receiver according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing how a pulse voltage waveform is generated according to the principles of the present invention.

3 is a diagram showing voltage waveforms at respective points in the circuit of FIG.

FIG. 4 is a circuit diagram of an optical receiver according to a second embodiment of the present invention.

5 is a diagram illustrating a problem of time constant adjustment in the circuit of FIG.

FIG. 6 is a circuit diagram of an optical receiver according to a third embodiment of the present invention.

7 is a diagram showing voltage waveforms at respective points in the circuit of FIG.

FIG. 8 is a circuit diagram of an optical receiving device according to a modification of the third embodiment of the present invention.

9 is a diagram showing voltage waveforms at respective points in the circuit of FIG.

FIG. 10 is a circuit diagram of an optical receiving device according to a fourth embodiment of the present invention.

11 is a diagram for explaining an advantage of the DC feedback circuit of FIG.

FIG. 12 is a configuration diagram of a conventional optical transmission device.

13 is a diagram showing signal waveforms at respective points in FIG.

14A is a principle circuit diagram of the preamplifier and PD of FIG. 12, and FIGS. 14B and 14C are signal waveform diagrams illustrating the operation of FIG.

FIG. 15 is a diagram for explaining a problem in generating a pulse voltage waveform in the device of FIG.

[Explanation of symbols]

11 Transmitter 12 LED 13 PD 14 preamplifier 15 amplifier 16 converter 21 Resistance 22 Schottky diode 23 LED 24 LED capacity 30 delay circuit 31 DC feedback circuit 32 amplifier 33 capacity

Continuation of front page (51) Int.Cl. ⁷ Identification code FI H04B 10/28 (56) Reference JP-A-63-73743 (JP, A) JP-A-1-129606 (JP, A) JP-A-6 -224711 (JP, A) JP-A-3-209219 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H03K 5/08

Claims (9)

(57) [Claims] 1. A pulse is obtained by converting a pulse current signal into a current voltage.
A device for converting into a voltage signal, A current voltage for converting the pulse current signal into a first voltage signal
A conversion part, Voltage-dividing the first voltage signalAnd delay it in time
And byReduced amplitudeDelayed byGenerates the second voltage signal
Voltage divider・ A delay part The voltage of the first voltage signal and the first voltage signalTwoAnd the voltage of the voltage signal of
Comparing unit for comparing and generating the pulse voltage signalAnd Previous
Amplify the difference between the first voltage signal and the second voltage signal
And a differential amplifier circuit that generates a differential amplified signal, The differential amplified signal is compared with a predetermined threshold voltage to
A comparison unit including a comparison circuit that generates a loose voltage signal; Feed the differential amplified signal to the input of the differential amplifier circuit.
By applying a feedback, the input of the differential amplifier circuit
DC feedback circuit for canceling DC component of force
A semiconductor integrated circuit device comprising: 2. The comparison unit outputs a voltage of a first level when the voltage of the first voltage signal exceeds the voltage of the second voltage signal, and outputs a voltage of the second level otherwise. The semiconductor integrated circuit device according to claim 1, wherein the semiconductor integrated circuit device outputs the voltage of 1. 3. The voltage divider comprises at least two resistors.
Is a resistance series connected in series, and the first series is connected to the resistance series.
Applied to the first node between the resistors
3. The semiconductor integrated circuit device according to claim 1, wherein the semiconductor integrated circuit device outputs a voltage corresponding to the second voltage signal . 4. The semiconductor integrated circuit device according to claim 1 , wherein the delay unit is a capacitor . 5. The delay unit includes at least one of the resistor strings.
Is the capacitance connected in parallel to the two resistors at the first node.
4. The semiconductor integrated circuit device according to claim 3 , wherein: 6. A further resistor connected in series with said capacitor.
6. The semiconductor integrated circuit device according to claim 5 , wherein: 7. The delay unit delays and outputs an input signal.
4. A delay circuit according to claim 1, wherein the delay circuit is a delay circuit.
2. The semiconductor integrated circuit device according to claim 1. 8. The current-voltage converter and the voltage divider
Characterized by further including a delay circuit provided between them
7. The semiconductor integrated circuit device according to claim 5 or 6 . 9. An optical pulse signal is received to receive the pulse current signal.
Inputting the pulse current signal from the element to be converted into signal
9. The semiconductor integrated circuit device according to claim 1 , wherein the semiconductor integrated circuit device comprises: