RC oscillator and temperature compensation method thereof

Abstract

The invention relates to the field of integrated circuits, and in particular relates to an RC oscillator and a temperature compensation method thereof. The RC oscillator comprises a charge circuit which is controlled by a charge switch to charge a charge-discharge capacitor, a discharge circuit which is controlled by a discharge switch to discharge the charge-discharge capacitor, the charge-discharge capacitor which outputs voltage to a comparator, and the comparator which is used for comparing the output voltage with a threshold voltage and outputting a high-level voltage or a low-level voltage; the high-level voltage controls the charge switch to be switched off and the discharge switch to be switched on; the low-level voltage controls the charge switch to be switched on and the discharge switch to be switched off; the charge-discharge capacitor comprises a control capacitor and an MOS capacitor array with selectable capacitance values. According to the invention, the MOS capacitor with the negative temperature coefficient is used for performing temperature drift compensation on the comparator with the positive temperature coefficient, so that the temperature drift of the RC oscillator is reduced; a digital control word is designed to select a certain MOS capacitance value, so that frequency change caused by temperature drift of comparator delay can be quickly and accurately compensated.

Description

technical field [0001] The invention relates to the field of integrated circuits, and relates to a temperature compensation technology of a low-temperature drift RC oscillator, in particular to an RC oscillator and a temperature compensation method thereof. Background technique [0002] For communication and control chips, a clock with low temperature drift is required in some states. Although the traditional crystal oscillator has a low temperature drift coefficient, it requires off-chip components and has high power consumption. Especially under the requirements of low power consumption design, it cannot To meet the demand, the RC oscillator with low temperature drift is especially suitable for this kind of scene. The RC oscillator consists of capacitors, resistors, comparators and switches, forming a delay loop. The power supply voltage charges the capacitor through the resistor and the switch, and the voltage on the capacitor rises. When the threshold voltage of the com...

AI Technical Summary

Problems solved by technology

If the oscillator frequency is high, the delay of the comparator will account for a large proportion, which will cause a large proportional coefficient of the temperature drift of the comparator to be transferred to the temperature drift of the oscillator, thus affecting the actual use.

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