| 摘要 |
PURPOSE:To attain an oscillating circuit not effected by temperature fluctuation, by charging/discharging a capacitor intermittently from a constant current source and generating a reference voltage, in an oscillation circuit repeating the charge/discharge of the capacitor depending on the voltage of the charge/discharge capacitor and the reference voltage. CONSTITUTION:A frequency division circuit 6 frequency-divides a clock pulse V3 of a prescribed period, turns on/off switches 32, 33 alternately, turns on a switch 34 when both switches 32, 33 are turned off and transfers the charge of the capacitor C1 charged during the turning-on of the switch 32 to a capacitor C2. The capacitor C2 holds the voltage and becomes a reference voltage source. As a result, a Schmitt trigger 5 turns on/off a charge/discharge switch 43 to a capacitor C0 taking the voltage as the threshold value and determining the frequency. When oscillation current sources 41, 42 are changed due to the dispersion in the ambient temperature and products, the reference voltage current source is similarly changed and the values of both capacitors are similarly changed, allowing to attain temperature compensation. |
