专利快速检索-快速检索全球专利，免费商用专利数据库-IPRDB

1. 发明专利

JP2002260348A MEDIUM RECORDING/REPRODUCING SYSTEM 失效
公开(公告)号：JP2002260348A
公开(公告)日：2002-09-13
申请号：JP2001055477
申请日：2001-02-28
申请人： HITACHI LTD
发明人： YOSHIZAWA HIROYASU , KOBAYASHI YOICHIRO , SHINOMIYA TOSHIO , FUJII NOBUYUKI , YOSHINAGA MAKI
IPC分类号： G11B33/14 , G11B5/012 , G11B5/02 , G11B5/035 , G11B5/48 , G11B21/02 , G11B25/04 , G11B33/12
摘要： PROBLEM TO BE SOLVED: To solve the problem that the power consumption of a chip is increased when the IC chip is provided at the tip part of an arm, heat generation becomes large, a suspension holding a head is thermally deformed, and as a result, positioning accuracy is lowered. SOLUTION: In the medium recording/reproducing system equipped with medium drive circuits 110, 140, a head supporting means arm 120, a head moving means carriage 130, a head drive circuit 220, a signal processing circuit 230 and a controller which controls these components, a head drive circuit is divided into a first semiconductor integrated circuit 300 which has a circuit to amplify a read signal by a head, and a second semiconductor integrated circuit which has a circuit to generate the driving signal of a write head in response to write data from a signal processing circuit while transferring read data, the first semiconductor integrated circuit is provided in the region near the tip part of the head supporting means arm 120, and the second semiconductor integrated circuit is provided at the head moving means side.

2. 发明专利

JP2001060303A MAGNETIC DISK DEVICE 失效
公开(公告)号：JP2001060303A
公开(公告)日：2001-03-06
申请号：JP23488299
申请日：1999-08-23
申请人： HITACHI LTD
发明人： FUJII NOBUYUKI , YAMAKIDO KAZUO
IPC分类号： G11B5/09 , G11B5/02
摘要： PROBLEM TO BE SOLVED: To make adjusting operation easy by operating a first MOSFET in which a first constant current and an input signal current are applied to a drain and first voltage is applied to a gate and a second MOSFET in which a constant current of square or root of the first constant current is applied to a drain and second voltage is applied to a gate in a non-saturation region and a saturation region respectively. SOLUTION: When gate voltage V1, V2 of MOSFET M1, M2 are equalized, current flowing in MOSFET M3, M4 are equalized, and it is made I1+Iin. Assuming that voltage V1 is lowered gradually and voltage V2 is raised gradually an operation region of the MOSFET M3 is made a non-saturation region, and an operation region of the MOSFET M4 is made a saturation region, a current flowing in the MOSFET M4 is made k (I1+Iin), and a square waveform generating circuit is formed. Then, a coefficient (k) depends on variation quantity of voltage V1, V2. Upper and lower asymmetry distortion of a signal can be compensated by using this waveform generating circuit.

3. 发明专利

JPH11273013A Magnetic disk device 失效
标题翻译：磁盘设备
公开(公告)号：JPH11273013A
公开(公告)日：1999-10-08
申请号：JP7515798
申请日：1998-03-24
申请人： Hitachi Ltd , Hitachi Vlsi Eng Corp , 日立超エル・エス・アイ・エンジニアリング株式会社 , 株式会社日立製作所
发明人： OTA MORIYOSHI , KURAISHI MAMORU , FUJII NOBUYUKI
IPC分类号： G11B5/09
摘要： PROBLEM TO BE SOLVED: To provide a magnetic disk device provided with an offset cancel circuit capable of reducing the offset of an automatic gain control(AGC) loop circuit without increasing current consumption and an occupied area.
SOLUTION: The magnetic disk device is constituted of a signal processing circuit provided with a reading circuit for amplifying a signal read out by a magnetic head and an AGC loop circuit consisting of a variable gain amplifier 11, a low pass filter(LPF) 12, a post stage amplifier 13, and a gain controlling voltage generation circuit 14 and capable of extracting necessary data based on a signal outputted from the reading circuit and generating a servo signal for a head driving motor and a control circuit for controlling the rotary driving motor. The AGC loop circuit is also provided with an offset cancel circuit 16 consisting of a voltage input/current output type amplifier and capable of adjusting a current drawn out from a current route in the amplifier 11 based on the output voltage of the amplifier 11 or the LPF 12 differently from an offset cancel circuit 15 for the amplifier 13.
COPYRIGHT: (C)1999,JPO
摘要翻译：要解决的问题：提供一种具有能够在不增加电流消耗和占用面积的情况下减少自动增益控制（AGC）回路电路的偏移的偏移消除电路的磁盘装置。解决方案：磁盘装置由设置有用于放大由磁头读出的信号的读取电路和由可变增益放大器11，低通滤波器（LPF）12组成的AGC环路电路的信号处理电路构成，后级放大器13和增益控制电压产生电路14，并且能够基于从读取电路输出的信号提取必要的数据，并产生用于磁头驱动电机的伺服信号和用于控制旋转驱动电动机的控制电路。 AGC环路电路还设置有由电压输入/电流输出型放大器组成的偏移消除电路16，其能够根据放大器11的输出电压或放大器11的输出电压来调节从放大器11中的当前路径引出的电流 LPF12与放大器13的偏移消除电路15不同。

4. 发明专利

JPH11186861A VARIABLE GAIN AMPLIFIER 失效
公开(公告)号：JPH11186861A
公开(公告)日：1999-07-09
申请号：JP36440397
申请日：1997-12-19
申请人： HITACHI LTD
发明人： OOTA MORIYOSHI , FUJII NOBUYUKI
IPC分类号： H03G3/10 , H03F3/45
摘要： PROBLEM TO BE SOLVED: To simplify a circuit, to lower power consumption and to lower noise by using a differential amplification transistor and specifying the constitution of the circuit for distributing a current by a gain control voltage. SOLUTION: For transistors Q5 and Q6, by forming the at least practical emitter size to be double to the transistors Q3, Q4, Q7 and Q8, a double current is made to flow at the time of the same input condition. The collector DC current I of the differential amplification transistor Q1 is distributed by 1/2 each by the differential transistors Q3 and Q4 in an ON state and made to flow to load resistors R1 and R2. The collector DC current I of the differential amplification transistor Q2 is distributed by 1/2 each by the differential transistors Q7 and Q8 in the ON state and made to flow to the load resistors R1 and R2. Thus, the equal current of I/2+I/2=I is respectively made to flow to the load resistors R1 and R2 and the change of a DC bias voltage is not generated.

5. 发明专利

JP2002117501A MEDIUM RECORDING AND REPRODUCING SYSTEM 失效
公开(公告)号：JP2002117501A
公开(公告)日：2002-04-19
申请号：JP2000307850
申请日：2000-10-06
申请人： HITACHI LTD
发明人： FUJII NOBUYUKI , KOBAYASHI YOICHIRO , YOSHINAGA MAKI , YOSHIZAWA HIROYASU
IPC分类号： G11B5/09 , G11B5/012
摘要： PROBLEM TO BE SOLVED: To provide a medium recording and reproducing system capable of reading and writing data at high speed by transferring the data at high speed without deteriorating the S/N ratio. SOLUTION: In the medium recording and reproducing system furnished with medium driving circuits (110, 140), a head driving circuit (220), a signal processing circuit (230) and a controller (230) for controlling these circuits, the head driving circuit (220) is composed of a 1st semiconductor integrated circuit (300) which is provided with an amplifier circuit (RAMP) for amplifying a read-out signal by the above head and a circuit (WAMP) for producing a driving signal of a head for write-in, and a 2nd semiconductor integrated circuit (400) for performing the receipt and delivery of read data and write data, which are arranged between the 1st semiconductor integrated circuit and the signal processing circuit (230), then the constitution is made in such a manner that the 1st semiconductor integrated circuit is provided at the tip side of a head holding means and the 2nd semiconductor integrated circuit is provided at the base side of the head holding means (120) to enable the transfer of the write-in data to the 1st semiconductor integrated circuit from the 2nd semiconductor integrated circuit by a current signal.

6. 发明专利

JP2000286648A SEMICONDUCTOR INTEGRATED CIRCUIT DEVICE 失效
公开(公告)号：JP2000286648A
公开(公告)日：2000-10-13
申请号：JP9061099
申请日：1999-03-31
申请人： HITACHI LTD
发明人： FUJII NOBUYUKI , KAJIYAMA SHINYA
IPC分类号： H03K19/0944 , H03F3/45
摘要： PROBLEM TO BE SOLVED: To obtain a semiconductor integrated circuit provided with an amplifier circuit which has realized a high operating speed and a high gain. SOLUTION: Two single end differential amplifiers, in each of which a second-conductivity first MOSFET the gate and drain of which are connected to the drain of a first-conductivity first amplifying MOSFET is connected and the drain of a second MOSFET which is formed in a current mirror shape with the above-mentioned first MOSFET is connected to the drain of a second amplifying MOSFET which is formed in a differential shape with the above- mentioned first amplifying MOSFET, are connected in series. Small amplitude inverted phase input signals are supplied to the preceding-stage single end type differential amplifier and the drain output signal of the second amplifying MOSFET is inputted to the gate of the MOSFET corresponding to the first amplifying MOSFET of the succeeding-stage differential amplifier. In addition, the drain output signal of the first amplifying MOSFET is inputted to the gate of the MOSFET corresponding to the second amplifying MOSFET and output signals are obtained from the drain of the MOSFET corresponding to the second amplifying MOSFET.

7. 发明专利

JP2000207858A MAGNETIC DISK DEVICE 失效
公开(公告)号：JP2000207858A
公开(公告)日：2000-07-28
申请号：JP356299
申请日：1999-01-11
申请人： HITACHI LTD
发明人： FUJII NOBUYUKI , KAJIYAMA SHINYA
IPC分类号： G11B21/10
摘要： PROBLEM TO BE SOLVED: To reduce the offset of a differential amplifier circuit and to improve the positioning accuracy of a head by providing an offset compensating circuit including a switch circuit adding a minute current to an output current of the differential amplifier circuit and a variable current source circuit adjusting a minute current by detecting an offset of the differential amplifier circuit at the time of no input signal, and controlling an offset compensating circuit. SOLUTION: The offset compensating circuit 1 consisting of a current source I3 and transistors Q3-Q5 is provided with respect to transistors Q1, Q2 of an input differential circuit. An offset detecting circuit 2 comparing the reference voltage V2 formed by a band gap circuit 4 with a monitor output voltage V1 of a differential amplifier at the time of no input signal, forms a control signal LK, and controls the switch S1 so that V1>V2 is made. Also, the offset detecting circuit 2 generates a control signal IT from potential difference between the monitor output voltage V1 and the reference voltage V2, and sets a current of a current source I3 so that a current I3 is made zero at the time of no input signal.

8. 发明专利

JP2000049610A AD CONVERSION CIRCUIT AND MAGNETIC DISK DEVICE 失效
公开(公告)号：JP2000049610A
公开(公告)日：2000-02-18
申请号：JP21663198
申请日：1998-07-31
申请人： HITACHI LTD , HITACHI ULSI SYS CO LTD
发明人： FUJII NOBUYUKI , SAITO TAKESHI
IPC分类号： H03M1/44
摘要： PROBLEM TO BE SOLVED: To provide the AD conversion circuit of a MAG amplifier system, in which an input waveform distortion to a MAG amplifier is small and a highly precise AD conversion operation can be executed. SOLUTION: A buffer circuit 12 in the former stage of a MAG amplifier circuit 13a in an initial stage is formed of a differential amplifier stage 21, a first emitter follower stage 22 connected to the output side of the differential amplifier stage and a second emitter follower stage 23. The differential amplifier 32 of the MAG amplifier circuit in the initial stage is driven by the first emitter follower stage and the comparator 31 of the MAG amplifier circuit in the initial stage by the second emitter follower stage 23.

9. 发明专利

JPH11238330A MAGNETIC DISK DEVICE 失效
公开(公告)号：JPH11238330A
公开(公告)日：1999-08-31
申请号：JP4162698
申请日：1998-02-24
申请人： HITACHI LTD
发明人： FUJII NOBUYUKI
IPC分类号： G11B21/10 , G11B7/09
摘要： PROBLEM TO BE SOLVED: To provide a correctable offset correction circuit so that a desired output waveform can be obtained even when an input offset voltage to a differential amplifier circuit is largely deviated. SOLUTION: This magnetic disk device is comprised of a rotary drive motor for driving to rotate a magnetic disk, a magnetic head for reading data from the magnetic disk, a head drive motor for positioning the magnetic head, a read-out circuit for amplifying a signal read by the magnetic head, a signal processing circuit for extracting necessary data and generates a servo signal for a head drive motor based on a signal from this read-out circuit, and a control circuit for controlling the rotary drive motor. In this case, the circuit to generate the servo signal for the head drive motor is provided with a differential amplifier circuit 20 for amplifying the read signal and an offset correction circuit 10 for detecting an error of an output signal of the differential amplifier circuit 20 with respect to a predetermined center potential and correcting the offset of the differential amplifier circuit 20 so that the error is eliminated.

你已经成功收藏专利！

检索式保存成功!

IPRDB

热门服务

关于我们

友情链接

联系方式