公开(公告)号：JP2000341055A

公开(公告)日：2000-12-08

申请号：JP15096299

申请日：1999-05-31

Applicant: SHARP KK

Inventor： OKUDA TAKANORI ,  YOKOGAWA SEIICHI ,  SHIMIZU TAKAYUKI

IPC: H03F1/34 ,  H03F3/08 ,  H04B10/07 ,  H04B10/116 ,  H04B10/40 ,  H04B10/50 ,  H04B10/60 ,  H04Q9/00 ,  H04B10/04 ,  H04B10/06 ,  H04B10/14 ,  H04B10/26 ,  H04B10/28

Abstract: PROBLEM TO BE SOLVED: To provide a DC optical current compensation circuit where the accuracy of the characteristic can be enhanced and a low voltage power supply can be employed and to provide an infrared ray communication equipment using it. SOLUTION: The DC optical current compensation circuit 2 consists of a detection circuit 21 that detects an optical current from a photodiode PD given to an amplifier circuit 1, an input circuit 22 that receives a current detected by the detection circuit 21, a low pass filter 23 that extracts a DC component from the input current to the input circuit 22, and an output circuit 24 that feeds back the extracted DC component current to the input of the amplifier circuit 1.

公开(公告)号：JPH10304471A

公开(公告)日：1998-11-13

申请号：JP11216797

申请日：1997-04-30

Applicant: SHARP KK

Inventor： NODA KAZUO ,  YOKOGAWA SEIICHI

IPC: H03K17/78 ,  H04B10/07 ,  H04B10/112 ,  H04B10/40 ,  H04B10/50 ,  H04B10/60 ,  H04B10/69 ,  H04Q9/00 ,  H04B10/04 ,  H04B10/06 ,  H04B10/14 ,  H04B10/26 ,  H04B10/28

Abstract: PROBLEM TO BE SOLVED: To reduce malfunctions of an infrared-ray data receiver, caused when an infrared-ray signal and a low-frequency external disturbance light noise such as the sun ray or an incandescent light are made incident onto the receiver. SOLUTION: This infrared-ray data receiver consisting of a photodiode 1 which is a photoelectric conversion element, a preamplifier 2, an ABCC circuit 3, an AC coupling capacitor 4, a resistor 5, a post-stage amplifier 6, and a comparator 7, is provided with a malfunction prevention circuit (low-pass filter) 8 that receives an output of the amplifier 2 and adds its output to a detection voltage V1, so as to change the detection voltage in response to the incident external disturbance light.

公开(公告)号：JPH08237207A

公开(公告)日：1996-09-13

申请号：JP3879795

申请日：1995-02-27

Applicant: SHARP KK

Inventor： OKUDA TAKANORI ,  YOKOGAWA SEIICHI

IPC: H03D1/04 ,  H04B1/10 ,  H04B10/07 ,  H04B10/114 ,  H04B10/40 ,  H04B10/50 ,  H04B10/524 ,  H04B10/60 ,  H04B10/69 ,  H04L25/49 ,  H04Q9/00 ,  H04B10/28 ,  H04B10/04 ,  H04B10/06 ,  H04B10/14 ,  H04B10/26

Abstract: PURPOSE: To precisely demodulate a modulated wave from the output of a photoelectric conversion element by preventing the activation of an integration circuit only for time which is previously decided from the restoration time of a pulse outputted from an output circuit. CONSTITUTION: An electric signal from a light-receiving element 22 is amplified by an amplifier circuit 23 and is filtered into only a transportation frequency component by BPF 24. Output from BPF 24 is discriminated from a prescribed level by waveform shaping circuits 25 and 26 and is waveform-shaped. Then, it is inputted to the integration circuit 27 and the component of a modulate wave is extracted by integration. Then, it is waveform-shaped by an output circuit 28 and outputted to a decoding circuit and a control circuit in a poststage. Output is masked by permitting a discharge current switching circuit 33 to short circuit terminals in the capacitor of the integration circuit 27 so as to prevent the activation in response to the output of the output circuit 28, for example. Thus, the malfunction of output by the feedback of the output pulse to the input-side of the amplifier circuit with voltage fluctuation is prevented and the modulated wave can precisely be demodulated.

公开(公告)号：JPH0766648A

公开(公告)日：1995-03-10

申请号：JP21261293

申请日：1993-08-27

Applicant: SHARP KK

Inventor： YOKOGAWA SEIICHI

IPC: H03G3/02

Abstract: PURPOSE:To enable a gain adjustment without using an exterior resistance and increasing the number of terminal and space. CONSTITUTION:A cascade connection is performed for two differential amplifiers 1 and 2 by AC coupling via capacity C1 and C2. Supposing that Vc and Vd has anti-phases and the voltage change amount of Vc and Vd is equal, 'Vc=(Va-Vb)XA1/2...(4)...' is established, and further, 'v2=(Vc-Vd)XA 2=(Va-Vb)XA1XA2...(5) is established. Because terminal voltage Vd becomes '0' when a pad P1 provided on an output terminal d is shorted to a power source or GND, 'v2=VcXA2...(6)' is established by formula (5). If formula (4) is substituted for formula (6), 'v2=(Va-Vb)XA1XA2/2...(7)' is established. Namely, when the pad 1 is shorted to the power source or GND, gain can be made '1/2'.

公开(公告)号：JPH0645838A

公开(公告)日：1994-02-18

申请号：JP253693

申请日：1993-01-11

Applicant: SHARP KK

Inventor： YOKOGAWA SEIICHI ,  OKABAYASHI NAONORI ,  HANABUSA KOICHI

IPC: G11B7/13 ,  H03F3/08 ,  H03F3/343 ,  H03F3/347

Abstract: PURPOSE:To easily extend the operation range of an AC component with a low cost without much increasing the size of a light receiving amplifier. CONSTITUTION:Plural photo diodes PDA, PDB, PDC, and PDD and amplifying circuits AMPA, AMPB, AMPC, and AMPD which receive the inputs from anodes of these photo diodes are provided. A first current mirror circuit 1 is provided which receives the sum total of currents flowing to cathodes of photo diodes PDA, PDB, PDC, and PDD and outputs a current I2 having the same magnitude as the received current I1. This current I2 is divided into currents I4, I5, I6, and I7 having the same magnitude for respective photo diodes, and a second current mirror circuit 2 is provided which branches and removes these currents I4, I5, I6, and I7 from anodes of photo diodes.

公开(公告)号：JPH0645536A

公开(公告)日：1994-02-18

申请号：JP15482192

申请日：1992-06-15

Applicant: SHARP KK

Inventor： HANABUSA KOICHI ,  YOKOGAWA SEIICHI ,  OKABAYASHI NAONORI

IPC: H01L27/082 ,  H01L21/8222 ,  H03F3/343 ,  H03F3/347

Abstract: PURPOSE:To reduce the influence of light on the operation of a PNP transistor of a monolithic integrated circuit constituted so as to contain the PNP transistor. CONSTITUTION:A first PNP transistor Q1 is connected with a peripheral circuit and functions. Both of the bases of a second and a third PNP transistors Q2, Q3 are connected with the emitter of a fourth PNP transistor Q4. The collector of the second PNP transistor Q2 is connected with the base of the fourth PNP transistor Q4. The collector of the fourth PNP transistor Q4 is connected with the base of the first PNP transistor Q1. The second, the third and the fourth PNP transistors Q2, Q3, and Q4 constitutes a current mirror circuit, and correct the photo current generated in a parasitic photodiode of a PNP transistor.

公开(公告)号：JPH0314311A

公开(公告)日：1991-01-23

申请号：JP15095489

申请日：1989-06-13

Applicant: SHARP KK

Inventor： OKABAYASHI NAONORI ,  KIHARA SEIICHIRO ,  YOKOGAWA SEIICHI

IPC: H03H11/12 ,  H03H11/54

Abstract: PURPOSE:To reduce the cost and size of the filter circuit by constituting a 1st constant current supply circuit of a reference voltage generating circuit and a current mirror circuit and setting up the temperature characteristics of a temperature characteristics correcting resistor so as to be inversely proportional to the temperature characteristics of an emitter resistor in a 1st operational amplifier. CONSTITUTION:The temperature characteristics of a 1st constant current supply circuit 24 is set up so as to be reversely proportional to that of the emitter resistor in the 1st operational amplifier to resolve the temperature characteristics of the whole filter circuit. Namely, the 1st circuit 24 is constituted of a resistor R7 having temperature characteristics reversed to that of the emitter resistor R5 and belonging to the same kind as a resistor R5, the current mirror circuit consisting of a semiconductor and the reference voltage generating circuit 241 for generating a prescribed reference voltage Vref and can be included in an IC. Thereby, the number of parts can be reduced by integrating the 1st circuit 24 in one IC together with respective amplifiers and a 2nd constant current supply circuit 25. Thus, the cost and size of the filter circuit can be reduced.

公开(公告)号：JP2008187540A

公开(公告)日：2008-08-14

申请号：JP2007020128

申请日：2007-01-30

Applicant: SHARP KK

Inventor： YOKOGAWA SEIICHI ,  NABA MASARU

IPC: H04B10/2507 ,  H04B10/116 ,  H04B10/40 ,  H04B10/50 ,  H04B10/516 ,  H04B10/524 ,  H04B10/54 ,  H04B10/58 ,  H04B10/60 ,  H04B10/61 ,  H04B10/69 ,  H04J1/00

Abstract: PROBLEM TO BE SOLVED: To provide a reception demodulating circuit, reception demodulation method and electronics which are materialized without requiring a band pass filter that irreducibly requires frequency adjustment for selecting and extracting a frequency domain of a sub-carrier. SOLUTION: An infrared reception circuit 100 according to one embodiment of the invention demodulates a modulated signal that has been modulated in the frequency domain of the sub-carrier into a signal of a frequency domain prior to modulation, and the infrared reception circuit 100 is equipped with: a rectifier circuit 105 which converts the frequency domain of the modulated signal from a frequency domain in which the relevant modulated signal exists, to a frequency domain prior to the modulation at least; and a low-pass filter 106 which removes a signal in a frequency domain higher than the frequency domain prior to the modulation, among the signal converted by the rectifier circuit 105. COPYRIGHT: (C)2008,JPO&INPIT

公开(公告)号：JP2003152509A

公开(公告)日：2003-05-23

申请号：JP2001348675

申请日：2001-11-14

Applicant: SHARP KK

Inventor： INOUE TAKAHIRO ,  YOKOGAWA SEIICHI ,  NISHINO TAKESHI

IPC: H03K3/0233 ,  H03K3/2897 ,  H03K5/08 ,  H03K5/24

Abstract: PROBLEM TO BE SOLVED: To facilitate the control of the pulse width of an output by operating a limiter circuit properly, even when power supply voltage is made low. SOLUTION: A limiter circuit 13 is provided on the input side of a hysteresis comparator circuit 12, for preventing the hysteresis comparator circuit from saturating. A limit voltage Vlimit is set by a bias circuit 17, such that it changes in response to the operation of the hysteresis comparator circuit 12. Provided that the limit voltage Vlimit is also lowered to interlock with the lowering of hysteresis threshold voltage Vth, when input voltage Vsig exceeds the hysteresis threshold voltage Vth, the limit voltage Vlimit keeps a higher condition higher than the hysteresis threshold voltage Vth.

公开(公告)号：JPH11112286A

公开(公告)日：1999-04-23

申请号：JP26698497

申请日：1997-09-30

Applicant: SHARP KK

Inventor： OKUDA TAKANORI ,  YOKOGAWA SEIICHI

IPC: H03H11/12 ,  H04B10/112 ,  H04B10/40 ,  H04B10/50 ,  H04B10/60 ,  H04B10/69 ,  H04B10/04 ,  H04B10/06 ,  H04B10/14 ,  H04B10/26 ,  H04B10/28

Abstract: PROBLEM TO BE SOLVED: To prevent a dynamic range from being reduced due to a power supply voltage drop in the band pass filter used in a receiver of an infrared ray remote controller and provided with a trans conductance amplifier. SOLUTION: A reference voltage Vref is shifted lower than a half of a power supply voltage Vcc with respect to trans conductance amplifiers GM1, GM2 that output an output current corresponding to an input voltage to suppress the lower component of a filter input Vin. Furthermore, a clamp circuit CLP is used to clamp the filter output Vout so as not to be a prescribed clamp voltage VCLP or below. Thus, most of a range of a dropped power supply voltage is used by its upper component with respect to a post-stage circuit such as a detection circuit using only the upper side component only to suppress reduction in the dynamic range.