| 摘要 |
PROBLEM TO BE SOLVED: To prevent a heater from overheating when the value of a control voltage becomes abnormal in a heater device which is provided with a heater whose heat generation is controlled by a control voltage from a heater control circuit.SOLUTION: Provided is an oscillation device in which the temperature of a crystal vibrator 10, for example, is stabilized at, for example, 80°C by using a heater 5, wherein a control voltage for the heater 5 is generated by an IC chip 3 on the basis of a temperature detection value. Meanwhile, the heater 5 is configured so that its output is reduced along with an increase in the control voltage. A positive characteristic thermistor 71 is interposed in a voltage supply path 61 which is a supply line of the control voltage for the heater 5, and a pull-up resistor 73 is provided between the positive characteristic thermistor 71 and the heater 5, and between it and a DC power supply 72. When the control voltage abnormally drops, the control voltage is limited to a prescribed voltage by an increase in the resistance value of the positive characteristic thermistor 71, whereby overheating is prevented. |
