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    Write driver circuit having programmable overshoot and undershoot
    4.
    发明授权
    Write driver circuit having programmable overshoot and undershoot 有权
    写入具有可编程过冲和下冲的驱动电路

    公开(公告)号：US06297921B1

    公开(公告)日：2001-10-02

    申请号：US09292502

    申请日：1999-04-15

    申请人： John J. Price, Jr. ,  Donald J. Schulte

    发明人： John J. Price, Jr. ,  Donald J. Schulte

    IPC分类号： G11B502

    CPC分类号： G11B5/022 ,  G11B5/012 ,  G11B5/02 ,  G11B5/035 ,  G11B5/09 ,  G11B2005/0013

    摘要： Undershoot and overshoot control circuitry is provided in a write driver circuit to enhance its efficiency and ability to quickly change directions of write current through a write head. The undershoot and overshoot control circuitry includes: (1) an undershoot reduction circuit, which adds current to the write current when one head terminal has a voltage higher than the opposite head terminal and the input signals are in a certain state, indicating that the write current waveform is about to experience some level of undershoot; (2) an overshoot enhancement circuit, which adds current to the write current when one of the head terminals has a voltage lower than a predetermined threshold, indicating that the write current waveform is about to experience some level of overshoot; and (3) an overshoot reduction circuit, which provides a resistance between the head terminals in parallel with the write head to damp overshoot, when one of the head terminals has a voltage lower than a predetermined threshold, indicating that the write current waveform is about to experience some level of overshoot. The predetermined thresholds, the currents added to the write current, and the resistance provided are all programmable in one embodiment, so that the undershoot and overshoot of the write driver circuit may be precisely controlled for efficient operation.

    摘要翻译： 在写驱动器电路中提供下冲和过冲控制电路，以增强其效率和快速改变通过写头的写入电流方向的能力。 下冲和过冲控制电路包括：（1）下冲还原电路，当一个头端子的电压高于相对的头端并且输入信号处于一定状态时，该电路将电流加到写入电流上， 电流波形即将经历一定程度的下冲; （2）过冲增强电路，当一个头端子具有低于预定阈值的电压时，将电流加到写入电流，指示写入电流波形即将经历一定程度的过冲; 和（3）过冲减少电路，当头部端子中的一个具有低于预定阈值的电压时，其提供与写入头并联的头部端子之间的电阻以抑制过冲，指示写入电流波形为约 经历一定程度的超调。 预定阈值，添加到写入电流的电流和提供的电阻在一个实施例中都是可编程的，使得可以精确地控制写入驱动器电路的下冲和过冲以进行有效的操作。

    Breakdown voltage compensation circuit for write driver transistors
    5.
    发明授权
    Breakdown voltage compensation circuit for write driver transistors 有权
    用于写驱动晶体管的击穿电压补偿电路

    公开(公告)号：US6133768A

    公开(公告)日：2000-10-17

    申请号：US292557

    申请日：1999-04-15

    申请人： John J. Price ,  Donald J. Schulte

    发明人： John J. Price ,  Donald J. Schulte

    IPC分类号： H03K17/66 ,  H03B1/00 ,  H03K3/00

    CPC分类号： H03K17/662

    摘要： A simulation circuit has a simulation circuit path that simulates operation of the write current circuit path of a write current driver. A simulation transistor simulates operation of the driver transistor and a monitor circuit monitors current at the base of the simulation transistor to derive a compensation current based on variations in base current, including breakdown of the simulation transistor. The compensation current is combined with the driver current to derive the write driver current for the driver transistor of the write current driver. In another form, the simulation circuit path is a scaled-down electrical equivalency of the write current circuit path so that the simulation current is a scaled fraction of the write current and power requirements are reduced. In one form, current is added to the compensation current to accommodate unidirectional nature of current mirrors in the monitor circuit.

    摘要翻译： 模拟电路具有模拟写入电流驱动器的写入电流电路路径的操作的仿真电路路径。 模拟晶体管模拟驱动晶体管的操作，监控电路监视模拟晶体管底部的电流，以基于基极电流的变化（包括模拟晶体管的击穿）导出补偿电流。 补偿电流与驱动器电流组合以得出写入电流驱动器的驱动晶体管的写入驱动器电流。 在另一种形式中，模拟电路路径是写入电流电路路径的按比例缩小的电当量，使得模拟电流是写入电流的比例分数，并且功率需求降低。 在一种形式中，电流被添加到补偿电流以适应监视器电路中电流镜的单向性质。