| 摘要 |
PURPOSE:To detect temperature by reading a clock signal frequency, by providing a comparing circuit, which compares the outpus of both a 1/N dynamic frequency divider and a 1/N static frequency divider that divide the same clock signal. CONSTITUTION:The outputs of the divided frequencies from a 1/N static frequency divider 302 and a 1/N dynamic frequency divider 303, which divide the same clock signal, are applied to a comparing circuit 304, which is constituted by, e.g., an exclusive OR circuit. A clock is set to the lower limit frequency, at which the dynamic frequency divider 303 is not erroneously operated. When temperature is increased, the dynamic frequency divider 303 begins to operate erroneously, the state of a memory circuit 305 is changed into the direction the frequency of the clock signal is increased, the clock signal frequency is increased by one step and this is repeated until the normal operation is obtained. Temperature data is stored in the state memory circuit 305. By reading the state of the state memory circuit 305 or by reading the clock signal frequency, the temperature can be found. |
