Method and apparatus for generating ratiometric control signals
    24.
    发明授权
    Method and apparatus for generating ratiometric control signals 失效
    用于生成比例控制信号的方法和装置

    公开(公告)号:US5650608A

    公开(公告)日:1997-07-22

    申请号:US359306

    申请日:1994-12-19

    摘要: A ratiometric sensor is formed of a first photodiode connected in series with an electronic component, such as a second photodiode or a resistor, between a source of first voltage and a source of second voltage. The ratiometric sensor supplies a "ratiometric voltage" on a ratiometric sensor output line that is connected to a junction between the first photodiode and the electronic component. The ratiometric voltage is proportional to the ratio of the equivalent resistance of the first photodiode to the sum of the equivalent resistances of the first photodiode and the electronic component. A ratiometric sensor that uses a photodiode and a resistance has a large dynamic range because the ratiometric voltage can vary between the first voltage and the second voltage. A ratiometric sensor that uses two photodiodes is less sensitive to noise than a conventional circuit that uses a single photodiode, because noise can get canceled from the numerator and denominator of the ratio. The ratiometric signal can be digitized by an analog-to-digital converter that can include, for example, a 555 timer, a Darlington transistor or a combination of a resistor and a capacitor.

    摘要翻译: 比率传感器由在第一电压源和第二电压源之间的电子部件(例如第二光电二极管或电阻器)串联连接的第一光电二极管形成。 比例传感器在连接到第一光电二极管和电子部件之间的连接处的比例传感器输出线上提供“比例电压”。 比例电压与第一光电二极管的等效电阻与第一光电二极管和电子元件的等效电阻之和的比例成比例。 使用光电二极管和电阻的比例传感器具有大的动态范围,因为比例电压可以在第一电压和第二电压之间变化。 使用两个光电二极管的比例传感器比使用单个光电二极管的常规电路对噪声的敏感性较低,因为噪声可以从该比率的分子和分母中消除。 比例信号可以由模数转换器数字化,模数转换器可以包括例如555定时器,达林顿晶体管或电阻器和电容器的组合。