| 摘要 |
<p>PURPOSE:To sufficiently draw out the performance of a circuit by switching a clock signal supplied to a microprocessor according to the change of an environmental temperature, and driving the microprocessor by means of the optimal clock signal. CONSTITUTION:A thermister 1 generates a thermister output voltage 101 corresponding to the environmental temperature, a voltage comparing circuit 2 compares the voltage 101 with a reference voltage, when the voltage 101 is larger, a clock selective A signal 102 at a logic '1' is outputted. A clock A generating circuit 3 outputs a clock A signal 103, and a clock B generating circuit 4 generates a clock B signal 104 having a higher frequency than that of the clock A signal 103. A clock switching circuit 5 selects the clock A signal 103 when the signal 102 is at the logic '1', the circuit 5 selects the clock B signal 104 when the signal 102 is not at the logic '1', and outputs the signal to a microprocessor 6. Thus the maximal speed performance of the microprocessor allowable in the environmental temperature is drawn out.</p> |
