Claims
- 1. A photoreceptive amplifier circuit for amplifying and outputting a signal from a photoreceptor on which optical signals of plural types of wavelength are supplied, comprising:
a former-stage amplifier for receiving the signal from the photoreceptor, a latter-stage amplifier for amplifying output of the first-stage amplifier, the former-stage amplifier including a feedback resistor and the latter-stage amplifier including resistors for determining sensitivity, the feedback resistor and at least a part of the resistors for determining sensitivity being made of different resistive elements having different temperature characteristics, the resistive elements varying depending on the types of wavelengths of the optical signals.
- 2. The photoreceptive amplifier circuit as set forth in claim 1, wherein:
the latter-stage amplifiers is provided at a second-stage corresponding to the respective types of wavelengths, so as to operate as a differential amplifier for simultaneously receiving output of the former-stage amplifier and supplying outputs of the photoreceptive amplifier circuit, the differential amplifiers including the resistors for determining sensitivity made up of input resistors, input voltage dividing resistors, and feedback resistors, which differ to each other in temperature characteristics, the differential amplifiers being switched so as to select one of the resistive elements.
- 3. The photoreceptive amplifier circuit as set forth in claim 2, further comprising:
a reference amplifier at a same stage as the former-stage amplifier, the reference amplifier having a same structure as that of the former-stage amplifier but not connected to the photoreceptor, the differential amplifiers individually calculating difference between the former-stage amplifier and the reference amplifier.
- 4. The photoreceptive amplifier circuit as set forth in claim 1, wherein:
the latter-stage amplifiers is provided at a second-stage corresponding to the respective types of wavelengths, so as to operate as a differential amplifier for simultaneously receiving output of the former-stage amplifier and supplying outputs of the photoreceptive amplifier circuit, the differential amplifiers including the resistors for determining sensitivity made up of dividing resistors for dividing output in accordance with a reference voltage which is specified in advance, the dividing resistors having different temperature characteristics in the respective differential amplifiers, the differential amplifiers being switched so as to select one of the resistive elements.
- 5. The photoreceptive amplifier circuit as set forth in claim 2, wherein:
the optical signals have two kinds of wavelengths, the differential amplifiers are provided as two differential amplifiers, each of which includes a pair of transistors constituting a differential pair and constant-current sources for supplying current to the differential pair, the two differential amplifiers further including a single common output transistor, one of the constant-current sources becomes active with a corresponding differential amplifier which is selected according to the type of wavelength, while the other constant-current source becomes inactive.
- 6. The photoreceptive amplifier circuit as set forth in claim 3, wherein:
the optical signals have two kinds of wavelengths, the differential amplifiers are provided as two differential amplifiers, each of which includes a pair of transistors constituting a differential pair and constant-current sources for supplying current to the differential pair, the two differential amplifiers further including a single common output transistor, one of the constant-current sources becomes active with a corresponding differential amplifier which is selected according to the type of wavelength, while the other constant-current source becomes inactive.
- 7. The photoreceptive amplifier circuit as set forth in claim 4, wherein:
the optical signals have two kinds of wavelengths, the differential amplifiers are provided as two differential amplifiers, each of which includes a pair of transistors constituting a differential pair and constant-current sources for supplying current to the differential pair, the two differential amplifiers further including a single common output transistor, one of the constant-current sources becomes active with a corresponding differential amplifier which is selected according to the type of wavelength, while the other constant-current source becomes inactive.
- 8. The photoreceptive amplifier circuit as set forth in claim 1, further comprising:
a reference amplifier at a same stage as the former-stage amplifier, the reference amplifier having a same structure as that of the former-stage amplifier but not connected to the photoreceptor, wherein: the former-stage amplifier and the reference amplifier respectively include feedback resistors which differ to each other in temperature characteristic, corresponding to the plural types of wavelengths the latter-stage amplifier is provided at a second-stage, so as to operate as a differential amplifier for receiving output of the former-stage amplifier and supplying outputs of the photoreceptive amplifier circuit, the former-stage amplifier and the reference amplifier each including a switch for selecting one of the resistive elements, the switch calculating difference between respective outputs from the former-stage amplifier and the reference amplifier so as to select one of the feedback resistors in accordance with the difference.
- 9. The photoreceptive amplifier circuit as set forth in claim 1, wherein:
the feedback resistor and the resistors for determining sensitivity are respectively made of two different kinds of diffused resistor having different temperature characteristics.
- 10. The photoreceptive amplifier circuit as set forth in claim 1, wherein:
the feedback resistor and the resistors for determining sensitivity are respectively made of a diffused resistor and a polysilicon resistor which have different temperature characteristics.
- 11. The photoreceptive amplifier circuit as set forth in claim 1, wherein:
the feedback resistor and the resistors for determining sensitivity are respectively made of two different kinds of polysilicon resistor having different temperature characteristics.
- 12. An optical pickup element including a photoreceptive amplifier circuit for amplifying and outputting a signal from a photoreceptor on which optical signals of plural types of wavelength are supplied, comprising:
a former-stage amplifier for receiving the signal from the photoreceptor, a latter-stage amplifier for amplifying output of the first-stage amplifier, the former-stage amplifier including a feedback resistor and the latter-stage amplifier including resistors for determining sensitivity, the feedback resistor and at least a part of the resistors for determining sensitivity being made of different resistive elements having different temperature characteristics, the resistive elements varying depending on the types of wavelengths of the optical signals.
- 13. The optical pickup element as set forth in claim 12, wherein:
the latter-stage amplifiers is provided at a second-stage corresponding to the respective types of wavelengths, so as to operate as a differential amplifier for simultaneously receiving output of the former-stage amplifier and supplying outputs of the photoreceptive amplifier circuit, the differential amplifiers including the resistors for determining sensitivity made up of input resistors and feedback resistors, which differ to each other in temperature characteristics, the differential amplifiers being switched so as to select one of the resistive elements.
- 14. The optical pickup element as set forth in claim 13, further comprising:
a reference amplifier at a same stage as the former-stage amplifier, the reference amplifier having a same structure as that of the former-stage amplifier but not connected to the photoreceptor, the differential amplifiers individually calculating difference between the former-stage amplifier and the reference amplifier.
- 15. The optical pickup element as set forth in claim 12, wherein:
the latter-stage amplifiers is provided at a second-stage corresponding to the respective types of wavelengths, so as to operate as a differential amplifier for simultaneously receiving output of the former-stage amplifier and supplying outputs of the photoreceptive amplifier circuit, the differential amplifiers including the resistors for determining sensitivity made up of dividing resistors for dividing output in accordance with a reference voltage which is specified in advance, the dividing resistors having different temperature characteristics in the respective differential amplifiers, the differential amplifiers being switched so as to select one of the resistive elements.
- 16. The optical pickup element as set forth in claim 13, wherein:
the optical signals have two kinds of wavelengths, the differential amplifiers are provided as two differential amplifiers, each of which includes a pair of transistors constituting a differential pair and constant-current sources for supplying current to the differential pair, the two differential amplifiers further including a single common output transistor, one of the constant-current sources becomes active with a corresponding differential amplifier which is selected according to the type of wavelength, while the other constant-current source becomes inactive.
- 17. The optical pickup element as set forth in claim 14, wherein:
the optical signals have two kinds of wavelengths, the differential amplifiers are provided as two differential amplifiers, each of which includes a pair of transistors constituting a differential pair and constant-current sources for supplying current to the differential pair, the two differential amplifiers further including a single common output transistor, one of the constant-current sources becomes active with a corresponding differential amplifier which is selected according to the type of wavelength, while the other constant-current source becomes inactive.
- 18. The photoreceptive amplifier circuit as set forth in claim 15, wherein:
the optical signals have two kinds of wavelengths, the differential amplifiers are provided as two differential amplifiers, each of which includes a pair of transistors constituting a differential pair and constant-current sources for supplying current to the differential pair, the two differential amplifiers further including a single common output transistor, one of the constant-current sources becomes active with a corresponding differential amplifier which is selected according to the type of wavelength, while the other constant-current source becomes inactive.
- 19. The optical pickup element as set forth in claim 12, further comprising:
a reference amplifier at a same stage as the former-stage amplifier, the reference amplifier having a same structure as that of the former-stage amplifier but not connected to the photoreceptor, wherein: the former-stage amplifier and the reference amplifier respectively include feedback resistors which differ to each other in temperature characteristic, corresponding to the plural types of wavelengths the latter-stage amplifier is provided at a second-stage, so as to operate as a differential amplifier for receiving output of the former-stage amplifier and supplying outputs of the photoreceptive amplifier circuit, the differential amplifiers selecting one of the resistive elements by using a switch, which calculates difference between respective outputs from the former-stage amplifier and the reference amplifier and select one of the feedback resistors in the former-stage in accordance with the difference.
- 20. The optical pickup element as set forth in claim 12, wherein:
the feedback resistor and the resistors for determining sensitivity are respectively made of two different kinds of diffused resistor having different temperature characteristics.
- 21. The optical pickup element as set forth in claim 12, wherein:
the feedback resistor and the resistors for determining sensitivity are made of a diffused resistor and a polysilicon resistor which have different temperature characteristics.
- 22. The optical pickup element as set forth in claim 12, wherein:
the feedback resistor and the resistors for determining sensitivity are respectively made of two different kinds of polysilicon resistor having different temperature characteristics.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2003-019417 |
Jan 2003 |
JP |
|
Parent Case Info
[0001] This Nonprovisional application claims priority under 35 U.S.C. § 119(a) on patent application Ser. No. 2003/019,417 filed in Japan on Jan. 28, 2003, the entire contents of which are hereby incorporated by reference.