| US 7,603,043 B2 | ||
| Light receiving element circuit and optical disk drive | ||
| Masahiro Aoki, Yamato (Japan); Yasushi Higashiyama, Yokohama (Japan); and Masashi Ueno, Tokyo (Japan) | ||
| Assigned to Kabushiki Kaisha Toshiba, Tokyo (Japan) | ||
| Filed on Jul. 12, 2006, as Appl. No. 11/485,221. | ||
| Claims priority of application No. 2005-203291 (JP), filed on Jul. 12, 2005; and application No. 2005-344228 (JP), filed on Nov. 29, 2005. | ||
| Prior Publication US 2007/0014212 A1, Jan. 18, 2007 | ||
| Int. Cl. H04B 10/06 (2006.01) | ||
| U.S. Cl. 398—202 [398/207; 398/212] | 11 Claims |
| 1. A light receiving element circuit comprising:
a plurality of light receiving elements which photoelectrically convert light signals carrying information, respectively;
a plurality of first amplification circuits which amplify electric signals from the light receiving elements, respectively,
wherein each of the plurality of first amplification circuits includes a current-voltage conversion circuit which converts
a current obtained from the light receiving element into a voltage;
a selecting section which selectively outputs one of the signals amplified by the plurality of first amplification circuits;
and
a second amplification circuit which amplifies the signal output from the selecting section and which supplies the signal
to an output, wherein the second amplification circuit includes a differential output circuit which amplifies an output signal
of the current-voltage conversion circuit and which outputs the signal as a differential signal,
wherein the light receiving element circuit further comprises:
a negative-phase-side reference voltage generation circuit which generates a negative-phase-side reference voltage of the
differential output circuit from a power supply voltage and a reference voltage of the light receiving element circuit,
wherein the differential output circuit comprises:
a positive-phase output-side amplification circuit having a non-inverting input terminal to which an output signal of a photoelectric
conversion circuit is supplied, and an inverting terminal to which the reference voltage is supplied as the positive-phase-side
reference voltage, which outputs a positive-phase-side reference voltage when the light receiving element is not irradiated
with light; and
a negative-phase output-side amplification circuit having a non-inverting input terminal to which the output signal of the
photoelectric conversion circuit is supplied, and an inverting terminal to which the negative-phase-side reference voltage
is supplied, which outputs a predetermined voltage higher than the positive-phase-side reference voltage when the light receiving
element is not irradiated with the light.
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