On/off reference voltage switch for multiple I/O standards
    5.
    发明授权
    On/off reference voltage switch for multiple I/O standards 有权
    用于多个I / O标准的开/关参考电压开关

    公开(公告)号:US06911860B1

    公开(公告)日:2005-06-28

    申请号:US10037716

    申请日:2001-11-09

    IPC分类号: H03K17/35

    摘要: A switch circuit selectively provides a reference voltage, needed in some I/O standards, to a logic device. The circuit receives a dedicated power supply that is different from the device's I/O supply. It may also include a level shifting circuit for converting a master control signal having a logic level determined by a first supply to a first control signal having a logic level determined by the dedicated supply. The switch circuit also includes a transmission switch that passes the reference voltage to an output in response to at least the first control signal. The transmission switch may be a CMOS transmission gate with at least one NMOS transistor controlled by the first control signal in parallel with at least one PMOS transistor controlled by a second control signal, complementary to the first. The second control signal may be generated by another level shifting circuit and have a logic level determined by the I/O supply.

    摘要翻译: 开关电路选择性地将某些I / O标准所需的参考电压提供给逻辑器件。 该电路接收与设备的I / O电源不同的专用电源。 其还可以包括电平移位电路,用于将具有由第一电源确定的逻辑电平的主控制信号转换成具有由专用电源确定的逻辑电平的第一控制信号。 开关电路还包括传输开关,其响应于至少第一控制信号将参考电压传递到输出。 传输开关可以是CMOS传输门,其中至少一个NMOS晶体管由第一控制信号控制,与由与第一控制信号互补的第二控制信号控制的至少一个PMOS晶体管并联。 第二控制信号可以由另一电平移位电路产生并具有由I / O电源确定的逻辑电平。

    Schmitt trigger circuit with adjustable trip point voltages
    7.
    发明授权
    Schmitt trigger circuit with adjustable trip point voltages 有权
    施密特触发电路具有可调跳闸点电压

    公开(公告)号:US06870413B1

    公开(公告)日:2005-03-22

    申请号:US10017933

    申请日:2001-12-14

    IPC分类号: H03K3/3565 H03K3/012

    CPC分类号: H03K3/3565

    摘要: A Schmitt trigger circuit has an adjustable hysteresis characteristic by providing a plurality of feedback circuits that differently affect at least one, and preferably both, of the circuit's upper trip point level and lower trip point level. The upper trip point level can be adjusted by selecting a desired feedback circuit from a first set of feedback circuits, and/or the lower trip point level can be adjusted by selecting a desired feedback circuit from a second set of feedback circuits. Feedback circuit selection is achieved by one or more control signals that may be programmable. The hysteresis characteristic can be adjusted to meet desired noise margin, delay, and input recognition criteria at different VCC levels. The Schmitt trigger circuit may be a CMOS Schmitt trigger with two input stage NMOS, two input stage PMOS transistors, a first set of NMOS feedback circuits, and a second set of PMOS feedback circuits.

    摘要翻译: 施密特触发电路具有可调滞后特性,通过提供多个反馈电路,其不同地影响电路的上跳点电平和较低跳变点电平的至少一个,优选两者。 可以通过从第一组反馈电路中选择所需的反馈电路来调整上跳点电平,和/或可以通过从第二组反馈电路中选择所需的反馈电路来调整下跳变点电平。 反馈电路选择由一个或多个可编程的控制信号来实现。 可以调节滞后特性,以满足不同VCC电平下的所需噪声容限,延迟和输入识别准则。 施密特触发电路可以是具有两个输入级NMOS,两个输入级PMOS晶体管,第一组NMOS反馈电路组和第二组PMOS反馈电路的CMOS施密特触发器。