| 摘要 |
PURPOSE:To secure a high-precision detection of the temperature and then the switching action of high accuracy by forming the temperature sensor consisting of FET and the A/D converter to digitzie the output of the temperature sensor onto the same semiconductor substrate. CONSTITUTION:Reference voltage generator ccircuit 7 featuring the flat temperature characteristics, reference voltage generator circuit 8 featuring the temperature characteristics, differential amplifier 9 and 10, and output buffer 11 are formed on the same Si sbustrate. Circuit 7 is composed of P-channel FET12 and 14 plus N-channel FET13 and 15, and the threshold levels are set identical between FET13 and 15 with the threshold level of FET14 set lower than that of FET12. Furthermore, the conductance coefficient is set equal between those FET's with the flat temperature coefficient. On the other hand, FET pairs of 15 and 16 plus 17 and 19 are provided to circuit 8 with different conductance coefficients as well as the depending property caused to the temperature. In such constitution, the power voltage is divided through resistance 20 and 21 plus amplifier 9 and then delivered through buffer 11 after detecting the fixed temperature at comparator 10. |
