| 摘要 |
PURPOSE: To detect a stable temperature signal of which offset is low even in a boundary section having much noise in a simple and low cost structure by a method wherein a value of a forward current flowing in a P-N diode is greater than that in the proximity of a boundary between an exponential function region of a forward current/voltage characteristic and a region out of the exponential function region. CONSTITUTION: A constant current source 23 allows a high level forward current, of which value is greater than that in the proximity of a boundary between an exponential function region of a P-N diode 2 and a region out of the exponential function region, to flow in the diode 2. In the boundary of both of the regions, assuming that an inner resistance of a forward direction of the diode 2 at a room temperature (about 300deg.K) is Ri (Ω), the current roughly corresponds to a forward current IF1 (A) designated by an equation of IF1 =1/(1000×Ri) under examination so that the constant current source 23 is actualy set such that the current of which value is not lower than IF1 flows. In order word, it is preferable that a product of an inner resistance value of the forward direction of the diode 2 with the forward current flowing in the diode 2 by the constant current source 23 is set to a value not lower than 1mV. |
