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    1.
    发明专利
    未知

    公开(公告)号：DE69231141D1

    公开(公告)日：2000-07-13

    申请号：DE69231141

    申请日：1992-07-01

    Applicant: ST MICROELECTRONICS INC

    Inventor： CAMERON SCOTT W

    IPC: H02M7/5387 ,  H02P6/08 ,  H02P27/06 ,  H02P27/08 ,  H02P7/62

    Abstract: Pulse Width Modulation (PWM) techniques, often used to reduce the power dissipation in polyphase motors, chop the current in the coils of the motor at their peak current levels, to achieve maximum torque, to allow rapid accelerations, and to reduce the power dissipated in the chip to a level proportional to the duty cycle. During the time the current is switched off, the current which has been established in the coils of the motor is allowed to be dissipated. Accordingly, when the switching transistors of the active coils are turned off during PWM mode chopping, a non-rectifying ground return path is provided for flyback energy in the active driving coil. This non-rectifying ground return path is provided by switching transistors in parallel with flyback diodes, operated in a form of synchronous rectification. This gives an alternate current path for the coil current to reduce the voltage drop across the diodes, and thereby reduce the power dissipation and heat in the chip.

    2.
    发明专利
    未知

    公开(公告)号：DE69521877D1

    公开(公告)日：2001-08-30

    申请号：DE69521877

    申请日：1995-12-22

    Applicant: ST MICROELECTRONICS INC

    Inventor： CAMERON SCOTT W

    IPC: G11B5/09 ,  G11B5/00 ,  G11B5/012 ,  G11B5/02 ,  G11B5/39 ,  G11B5/40 ,  G11B19/04 ,  H03F3/45

    Abstract: An innovative differential amplifier circuit, which can control the midpoint potential of a load which does not itself have any midpoint connection. This is achieved by using a proxy load element (RP1,RP2) in parallel with the primary load. The proxy load is of much higher impedance value than the primary load, and does have a center tap. The potential of the center tap of the mirrored load is used for a feedback connection to a control loop (A2) which regulates the output to both the primary load and the proxy load.

    4.
    发明专利
    未知

    公开(公告)号：DE69529968T2

    公开(公告)日：2004-02-12

    申请号：DE69529968

    申请日：1995-12-22

    Applicant: ST MICROELECTRONICS INC

    Inventor： CAMERON SCOTT W ,  ALEGRE DE LA SOUJEOLE AXEL

    IPC: G11B5/09 ,  G11B5/00 ,  G11B5/02 ,  G11B5/39 ,  H03F3/72 ,  H03F1/30

    Abstract: The present application discloses an innovative improved circuit, in which the long transient at write-to-read transitions is avoided by using a shorting switch (M1) to short the inputs of the first amplifier stage (A1) together when the read amplifier is activated. This speeds up write-to-read transition. Moreover, since read mode can now be entered more quickly after a power-down condition, this circuit also permits the use of other power-saving tricks to idle the read amplifier momentarily.

    5.
    发明专利
    未知

    公开(公告)号：DE69231141T2

    公开(公告)日：2001-02-15

    申请号：DE69231141

    申请日：1992-07-01

    Applicant: ST MICROELECTRONICS INC

    Inventor： CAMERON SCOTT W

    IPC: H02M7/5387 ,  H02P6/08 ,  H02P27/06 ,  H02P27/08 ,  H02P7/62

    Abstract: Pulse Width Modulation (PWM) techniques, often used to reduce the power dissipation in polyphase motors, chop the current in the coils of the motor at their peak current levels, to achieve maximum torque, to allow rapid accelerations, and to reduce the power dissipated in the chip to a level proportional to the duty cycle. During the time the current is switched off, the current which has been established in the coils of the motor is allowed to be dissipated. Accordingly, when the switching transistors of the active coils are turned off during PWM mode chopping, a non-rectifying ground return path is provided for flyback energy in the active driving coil. This non-rectifying ground return path is provided by switching transistors in parallel with flyback diodes, operated in a form of synchronous rectification. This gives an alternate current path for the coil current to reduce the voltage drop across the diodes, and thereby reduce the power dissipation and heat in the chip.

    8.
    发明专利
    未知

    公开(公告)号：DE69529968D1

    公开(公告)日：2003-04-24

    申请号：DE69529968

    申请日：1995-12-22

    Applicant: ST MICROELECTRONICS INC

    Inventor： CAMERON SCOTT W ,  ALEGRE DE LA SOUJEOLE AXEL

    IPC: G11B5/09 ,  G11B5/00 ,  G11B5/02 ,  G11B5/39 ,  H03F3/72 ,  H03F1/30

    Abstract: The present application discloses an innovative improved circuit, in which the long transient at write-to-read transitions is avoided by using a shorting switch (M1) to short the inputs of the first amplifier stage (A1) together when the read amplifier is activated. This speeds up write-to-read transition. Moreover, since read mode can now be entered more quickly after a power-down condition, this circuit also permits the use of other power-saving tricks to idle the read amplifier momentarily.

    9.
    发明专利
    未知

    公开(公告)号：DE69521877T2

    公开(公告)日：2002-04-11

    申请号：DE69521877

    申请日：1995-12-22

    Applicant: ST MICROELECTRONICS INC

    Inventor： CAMERON SCOTT W

    IPC: G11B5/09 ,  G11B5/00 ,  G11B5/012 ,  G11B5/02 ,  G11B5/39 ,  G11B5/40 ,  G11B19/04 ,  H03F3/45

    Abstract: An innovative differential amplifier circuit, which can control the midpoint potential of a load which does not itself have any midpoint connection. This is achieved by using a proxy load element (RP1,RP2) in parallel with the primary load. The proxy load is of much higher impedance value than the primary load, and does have a center tap. The potential of the center tap of the mirrored load is used for a feedback connection to a control loop (A2) which regulates the output to both the primary load and the proxy load.

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