| 摘要 |
<p>A temperature sensor includes a pair of transistors each connected in series with a respective one of a pair of resistors across a source of voltage. The emitters of the transistors are connected together and the collectors are connected to a respective input of a differential amplifier. An output of the amplifier drives a voltage divider circuit having a pair of outputs each connected to the base of a respective one of the transistors. The transistors are operated at different current densities and the ratio of such current densities is maintained constant with changes in temperature by feedback from the amplifier which has an output which is porportional to absolute temperature. In a second embodiment the supply voltage is generated by a current source, such that it will vary with changes in the load thereon. An output of the amplifier is connected to the base of a transistor which is connected across the voltage supply lines and the voltage divider, such that the voltage across the divider varies in accordance with the output of the amplifier. In a third embodiment the two sensing transistors each have a second emitter. The emitter areas of one of the transistors are unequal, such that a potentiometer connected from the first emitters of the transistors to the second emitters of the transistors permits calibration of the ratio of the current density of one transistor to the current density of the other transistor.</p> |
