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公开(公告)号：JPH11203612A
公开(公告)日：1999-07-30
申请号：JP788698
申请日：1998-01-19
Applicant: SONY CORP
Inventor： NARISAWA KEIJI , SHOJI NORIO
Abstract: PROBLEM TO BE SOLVED: To realize the amplifier circuit for a magneto-resistive(MR) head in which the adverse effect on an input resistor caused by the change in the head resistance is reduced, the gain is very precisely controlled and the power supply voltage is reduced. SOLUTION: A bias current iB is supplied to a head resistor RMR by a current source ISB and the change in the resistive value of the resistor RMR is transformed into the change in a voltage during a reproducing of recorded data. The direct current components of the voltage generated accross the resistor RMR are cutoff by a capacitance element C2, only the direct current components of the voltage change corresponding to the resistive value change of the resistor RMR are inputted to a differential amplifier circuit AMP2, an amplification voltage Vout is outputted to the external and recorded data are discriminated in accordance with the voltage Vout . Moreover, the adverse effect on the input resistor of the circuit AMP2 caused by the change in the resistive value of the resistor RMR is reduced, the gain fluctuation of the amplifier circuit caused by the change in the resistor RMR is reduced and the voltage of the power supply is reduced.
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公开(公告)号：JPH0253320A
公开(公告)日：1990-02-22
申请号：JP20502188
申请日：1988-08-18
Applicant: SONY CORP
Inventor： NARISAWA KEIJI , SHOJI NORIO
IPC: H03K17/64
Abstract: PURPOSE:To set a value of an output current optionally by using an output setting means so as to set a setting current supplied by a current mirror to a current source being a component of a current output means. CONSTITUTION:A current I2 of a variable current source 36 is set freely by a base potential applied to a base of a PNP transistor(TR) 30 in a head drive circuit 10. Thus, the head drive circuit 10 varies the current I2 of the variable current source 36. Then a collector-emitter voltage VCE of an NPN TR 14 being the output stage of a current source 12 whose write current (I0=n.m.I2) is adjusted to an optional value is set as small as possible to increase the output dynamic range.
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公开(公告)号：JP2002304701A
公开(公告)日：2002-10-18
申请号：JP2001110841
申请日：2001-04-10
Applicant: SONY CORP
Inventor： SAKO MICHIYA , TOGUCHIDA KAZUE , NARISAWA KEIJI
Abstract: PROBLEM TO BE SOLVED: To solve a problem that it takes long time for moving a mode from the recording mode to the reproducing mode in the case the fogging of the output voltage of a recording head to the side of a reproducing amplifier is in existence. SOLUTION: In the reproducing amplifier provided with an amplifier circuit part 13 including differential pair transistors Q2, Q3, a switch circuit 16 constituted so as to connect the switches SW1, SW2 respectively in parallel is arranged with respect to resistors R5, R6 applying a bias voltage to each base of the differential pair transistors Q2, Q3, then the input impedance is made to be lowered by turning this switch circuit 16 ON in the specified period when in the recording mode and when the mode is changed over to the reproducing mode from the recording mode.
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公开(公告)号：JPH09245302A
公开(公告)日：1997-09-19
申请号：JP7836996
申请日：1996-03-06
Applicant: SONY CORP
Inventor： NARISAWA KEIJI , NAKAGUCHI MASATOSHI
Abstract: PROBLEM TO BE SOLVED: To provide a circuit capble of securing the outputting of a reproduced signal while suppressing the fluctuation of a signal level due to a thermal asperity phenomenon. SOLUTION: This circuit is provided with a magnetic resistor 17 whose resisrance is changed according to the change of the magnetic density on a disk surface, an amplifier 13 amplifying the read-out signal voltage to be generated by the magnetic resistor 17, a resistor 12, an amplifier 14, a capacitor 16 and a feedback loop consisting of the magnetic resistor 17 and a transistor 18 and a thermal asperity circuit 20 consisting of a high-pass filter 21, a comparator 22, a monostable multivibrator 23, a switch 24 and a constant current power source 25. When the comparator 22 detects that the read-out signal voltage passing through the high-pass filter 21 exceeds a threshold value voltage VTH, the responsiviness of the feedback look is fastened by raising the gain of the amplifier 14 for a fixed period while closing the switch 24 by the output of the monostable multvibrator 23.
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公开(公告)号：JPH0877504A
公开(公告)日：1996-03-22
申请号：JP23233694
申请日：1994-08-31
Applicant: SONY CORP
Inventor： NARISAWA KEIJI
Abstract: PURPOSE: To prevent the lowering of a frequency of a reproducing amplifier by connecting a head reading out a recording signal to an emitter side of a transistor, connecting an inductance and a load resistor of a base grounded amplifier to the collector side and processing a signal. CONSTITUTION: The reproducing amplifier 10 for an MR head is constituted of the MR head 2, the transistor 3, a bias current source 4, the load resistor 5, a coil 11, a capacitor 6 for compensating a phase of a feedback loop and a current amplifier 7. The coil 11 is connected to the load resistor 4 in series. In such a case, when the resistance value of the head 2 is defined R1 , the value of the resistor 5 is R2 , the small signal resistance value of the transistor 3 is r0 , a wiring inductance is L1 and the inductance of the coil 11 is L2 , L2 = L1 (R2 /(R1 +r0 )). That is, the wiring inductance L1 occurring between the head 2 and the transistor 3 is canceled by the inductance L2 of the coil 11, and a high band gain Av =(R2 +ωL2 )/(R1 +r0 +ωL1 ) is held.
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Patent Agency Ranking
公开(公告)号：JPH0766640A
公开(公告)日：1995-03-10
申请号：JP21310793
申请日：1993-08-27
Applicant: SONY CORP
Inventor： NARISAWA KEIJI
IPC: H03F3/343
Abstract: PURPOSE:To improve accuracy and stability and to enable an operation by low voltage by composing each transistor composing a base voltage transformation circuit and a feedback circuit of a specified connection circuit. CONSTITUTION:The emitter of a transistor 2 composing a base voltage transformation circuit is connected with the base of a transistor 3 composing a feedback circuit and is connected with a transistor 9 composing a constant current source, and constant current I1 is allowed to flow through the emitter of the transistor 2 by a current source 11 and a transistor 10. When current Ic1 is allowed to flow through the collector of a transistor 1 composing an input circuit, Ic1=I1/beta2-I2/beta2.beta3 is established, an error ratio epsilon=I2/I1X1/beta3 is established and accuracy is improved when the current amplification factors of the transistors 2 and 3 are defined as beta3 and beta2, respectively. By increasing the emitter current I2 of the transistor, stability can be improved. Operating voltage becomes low voltage by voltage VBE between the emitter and base of the transistor 1.
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公开(公告)号：JPS6115415A
公开(公告)日：1986-01-23
申请号：JP13623784
申请日：1984-06-30
Applicant: Sony Corp
Inventor： TAKEDA HITOSHI , SHIYOUJI NORIO , NARISAWA KEIJI
IPC: H03K3/286 , H03K3/0233 , H03K3/2885
CPC classification number: H03K3/2885
Abstract: PURPOSE:To reduce a delay time by constituting an RSFF of a logical circuit not requiring a reference voltage to decrease the number of components. CONSTITUTION:One logical circuit consists of transistors (TRs) 1, 2, 3, 7, 10, the other logical circuit consists of TRs 21, 22, 23, 27, 30 and each circuit consists of a differential amplifier. Then a set input S and set input control signals A, B are supplied to one NOR gate and a reset input R and reset input control signals C, D are supplied to the other NOR gate. Then terminals A, B, C, D constitute an inhibiting gate ro realize a synchronous type. In this case, the terminals A- D have high/low levels shifted lower to a half of logical amplitude (VL) of the output and have identical VL to each other.
Abstract translation: 目的：通过构成不需要参考电压的逻辑电路的RSFF来减少组件数量来减少延迟时间。 构成：一个逻辑电路由晶体管（TRs）1,2,3,4,10组成，另一个逻辑电路由TR 21,22,23,27,30组成，每个电路由差分放大器组成。 然后将设定输入S和设定输入控制信号A，B提供给一个或非门，复位输入R和复位输入控制信号C，D提供给另一个或非门。 然后端子A，B，C，D构成禁止门，实现同步型。 在这种情况下，终端A-D具有从输出的逻辑振幅（VL）的下半部分移位的高/低电平，并且具有彼此相同的VL。
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公开(公告)号：JP2006260772A
公开(公告)日：2006-09-28
申请号：JP2006183267
申请日：2006-07-03
Inventor： NARISAWA KEIJI , SHOJI NORIO
IPC: G11B5/09
Abstract: PROBLEM TO BE SOLVED: To realize an amplifier circuit for MR head which allows power consumption to be reduced, a circuitry to be simplified by including capacitive elements, and external parts to be reduced.
SOLUTION: A bias current source IS
B supplies current to an MR head resistor R
MR , and a variation of the head resistance R
MR is converted into voltage change in reproducing magnetic recording data. DC component in voltage drop across the head resistance R
MR is cut off by the capacitive elements C3, C4 and only AC component is input to a differential amplifier circuit AMP2 which consists of transistors Q1, Q2. Since recording data can be discriminated in response to amplified output voltage V
out , capacity values of the capacitive elements C3, C4 for DC cutoff can be reduced, and since they are included in an IC chip, the external parts can be reduced. Furthermore, since base bias voltage of transistors Q1, Q2 can be set independent of the MR head, power consumption can be reduced.
COPYRIGHT: (C)2006,JPO&NCIPIAbstract translation: 要解决的问题：为了实现减少功耗的MR磁头放大器电路，通过包括电容元件和要减少的外部部件来简化电路。
解决方案：偏置电流源IS
B 向MR头电阻R SB SB提供电流，磁头电阻R SB SB 的变化 在再现磁记录数据时转换为电压变化。 磁头电阻R MR 之间的电压降中的直流分量被电容元件C3，C4截止，只有AC分量输入到由晶体管Q1，Q2组成的差分放大器电路AMP2。 由于可以响应于放大的输出电压V 输出来鉴别记录数据，所以可以减小用于DC截止的电容元件C3，C4的电容值，并且由于它们被包括在IC芯片中，所以外部 零件可以减少。 此外，由于可以将晶体管Q1，Q2的基极偏置电压设置为与MR头无关，所以可以降低功耗。 版权所有（C）2006，JPO＆NCIPI -
公开(公告)号：JP2001084502A
公开(公告)日：2001-03-30
申请号：JP26450899
申请日：1999-09-17
Applicant: SONY CORP
Inventor： NARISAWA KEIJI , SHOJI NORIO
Abstract: PROBLEM TO BE SOLVED: To obtain a reproducing circuit for MR head capable of holding an MR head at the grounding potential without connecting to the grounding potential and capable of preventing the dielectric breakdown by setting a bias voltage using a current source. SOLUTION: A current i2 supplied to the terminal ND2 of the MR head RMR is controlled by a voltage bias circuit 10 in accordance with a reference voltage VR supplied by a constant voltage source VS1 so that a terminal voltage ΔV of the MR head RMR is controlled to be nearly equal to the reference voltage VR. A current i1 supplied to a terminal ND1 of the MR head RMR is controlled by a potential setting circuit 20 to hold a potential of a middle point of the MR head RMR to a nearly grounding potential GND, then a resistance value of the MR head RMR is changed in accordance with the recording information at the time of reproduction, and since the change of the terminal voltage according thereto is amplified by an output circuit 30 and outputted, the potential of the middle point can be held to the grounding potential GND without grounding the MR head RMR, then the breakdown due to the static electricity is prevented.
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公开(公告)号：JPH09259404A
公开(公告)日：1997-10-03
申请号：JP6604096
申请日：1996-03-22
Applicant: SONY CORP
Inventor： NARISAWA KEIJI , SAKO MICHIYA
Abstract: PROBLEM TO BE SOLVED: To prevent the delay of the rise and fall time of write current and to make write frequency higher so as to speed up the recording operation of an HDD by directly switching a current source to make the write current flow. SOLUTION: When signals CTLA and CTL1 are 'H', while signals CTLB and CTL2 are 'L', a transistor Q1 and a switch circuit S1 are kept in the on-state, while a transistor Q2 and a switch circuit S2 in the off-state. By turning on the circuit S1, a current to flow via a resistor element R4 is made to flow via the circuit S1 into a ground line GND. As a result, a current mirror circuit consisting of transistors Q13 and Q10 does not function as a current source. On the contrary, a current to flow via an element R3 with off-state of the circuit S2 is made to flow into transistors Q12 and Q11, and hence a current mirror circuit of these transistors Q12 and Q11 functions as a current source. Consequently, the write current Iw flows from one end side (HX) of a head LHD to the other end side (HY).
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