| 摘要 |
PROBLEM TO BE SOLVED: To allow operation at a low temperature, of such device which is available easily but no operable at a low temperature, by providing a heater for raising the temperature for a device which is not operable at a low temperature, if a device operable at a low temperature and a device not operable at a low temperature are comprised together. SOLUTION: Related to a PLL wherein a device which is not operable at a low temperature supplies a clock to a circuit, a reference power source 108 and a resistor 110 are set so that the output of a comparator 109 is at a high level when the temperature of a thermister is lower than that at which PLL 104 is operable. At high level, an FET 107 becomes on, a current flows in a heater 105, the temperature of a thermister 106 rises, a PLL 104 operates, the resistance of the thermister 106 falls, and the output of the comparator 109 drops to a low level. A controller 103 releases the reset signal of a CPU 101 and inhibits a current to flow in the heater 105, resulting in the output of the comparator 109 at a high level. Then a current flows in the heater 105 again for operation.
|
