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Photodetector apparatus

a technology of photodetector and apparatus, which is applied in the field of photodetector apparatus, can solve the problems that the conventional photodetector apparatus has failed to output signals with a sufficient s/n ratio

Inactive Publication Date: 2001-11-15
HAMAMATSU PHOTONICS KK
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the conventional photodetector apparatus have failed to output signals with a sufficient S / N ratio.
In this case, even though the respective potentials of two output terminals in the first full differential amplifier may be unstable, each of the integral signals outputted from the first full differential amplifier becomes stable.
In this case, even though the respective potentials of two output terminals of the second full differential amplifiers may be unstable, each of the fluctuations of integral signals outputted from the second full differential amplifier becomes stable.

Method used

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Examples

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first embodiment

[0027] First Embodiment

[0028] A first embodiment of the photodetector apparatus in accordance with the present invention will now be explained.

[0029] FIG. 1 is a circuit diagram of the photodetector apparatus in accordance with the first embodiment. The photodetector apparatus in accordance with this embodiment comprises a photodiode PD, an integrating circuit 10, a holding circuit 30, a differential amplifier circuit 40, and a timing control circuit 50. In this drawing, routes of control signals outputted from the timing control circuit 50 so as to be fed into the integrating circuit 10 and holding circuit 30, respectively, are partly omitted.

[0030] The photodiode PD has a cathode terminal connected to a power voltage V.sub.cc. The integrating circuit 1O for inputting current signals outputted from the anode terminal of the photodiode PD comprises a 2-input / 2-output full differential amplifier A.sub.0, capacitors C.sub.01 and C.sub.02, switches S.sub.01, S.sub.02, S.sub.11, and S.s...

second embodiment

[0044] Second Embodiment the photodetector apparatus in accordance with the present invention will now be explained. FIG. 3 is a circuit diagram of the photodetector apparatus in accordance with the second embodiment. The photodetector apparatus in accordance with this embodiment comprises a photodiode PD, an integrating circuit 10, a CDS (correlated double sampling) circuit 20, a holding circuit 30, a differential amplifier circuit 40, and a timing control circuit 51. Routes of control signals outputted from the timing control circuit 51 so as to be fed into the integrating circuit 10, CDS circuit 20, and holding circuit 30, respectively, are partly omitted in this drawing as well.

[0045] The photodetector apparatus in accordance with this embodiment differs from that in accordance with the first embodiment in that the CDS circuit 20 is disposed between the integrating circuit 10 and holding circuit 30, and that the timing control circuit 51 is disposed in place of the timing contro...

third embodiment

[0063] Third Embodiment

[0064] A third embodiment of the photodetector apparatus in accordance with the present invention will now be explained. FIG. 5 is a circuit diagram of the photodetector apparatus in accordance with the third embodiment. The photodetector in accordance with this embodiment has a photosensitive section in which M photodiodes PD are arranged in a one-dimensional array. Individual units 100.sub.1 to 100.sub.M shown in this drawing have configurations identical to each other, each comprising the photodiode PD, integrating circuit 10, CDS circuit 20, holding circuit 30, and switches S.sub.91 and S.sub.92 similar to those explained in the second embodiment. The two outputs of each of the units 100.sub.1 to 100.sub.M are connected to the differential amplifier circuit 40 in common. Routes of control signals outputted from a timing control circuit 52 so as to be fed into the units 100.sub.1 to 100.sub.M, respectively, are omitted in this drawing as well.

[0065] The tim...

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Abstract

An integrating circuit for inputting current signals outputted from the anode terminal of a photodiode comprises a 2-input / 2-output full differential amplifier A0; capacitors; switches; and an additional capacitor. The capacitor and switch are connected in parallel between the "-" input terminal and "+" output terminal of full differential amplifier. The "-" input terminal of differential amplifier is connected to the anode terminal of photodiode PD. The capacitor and switch are connected in parallel between the "+" input terminal and "-" output terminal of full differential amplifier. The "+" input terminal of full differential amplifier is connected to the additional capacitor having a capacitance substantially equal to the junction capacitance of photodiode.

Description

[0001] This is a continuation-in-part application of application Ser. No. PCT / JP99 / 06757 filed on Dec. 2, 1999, now pending.[0002] 1. Field of the Invention[0003] The present invention relates to a photodetector apparatus which receives an optical signal having arrived there with a photodiode, so as to detect the intensity of optical signal.[0004] 2. Related Background Art[0005] A photodetector apparatus comprises a photodiode and an integrating circuit, in which the photodiode converts inputted optical signals into current signals and outputs thus obtained current signals, and the integrating circuit inputs and integrates the current signals outputted from the photodiode, thereby outputting a voltage signal. According to the integral signal outputted from the integrating circuit, the intensity of optical signal is detected.[0006] The integrating circuit in a conventional photodetector apparatus usually comprises a 2-input / 1-output differential amplifier. Namely, the photodiode is c...

Claims

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Application Information

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IPC IPC(8): G01J1/44G06G7/186H04N5/32H01L31/10H03F3/30H03F3/45
CPCG01J1/44G06G7/1865H03F3/3001H03F3/45076
Inventor MIZUNO, SEIICHIRO
Owner HAMAMATSU PHOTONICS KK