High-precision frequency deviation compensation method for RTC chip by combination of variable capacitance

Abstract

The invention discloses a high-precision frequency deviation compensation method for an RTC (Real-Time Clock) chip by combination of variable capacitance, and relates to a high-precision micro processor frequency deviation compensation method for the RTC chip by the combination of the variable capacitance. The high-precision frequency deviation compensation method comprises the following steps: building a mathematical model between temperature and a frequency deviation by adopting the least square method and a Lagrange interpolation algorithm through a piecewise function mode, and calculating an optimal fitting coefficient; then on the basis of the model, designing a high-precision capacitance compensation and accumulative error-based digital compensation combination frequency deviation compensation mode; and finally, completing corresponding compensation work under the control of an MCU module according to an actual temperature condition measured by a temperature sensor. The method provided by the invention can efficiently and intensively complete the frequency deviation compensation work of the RTC chip, and a design basis can be supplied to implementation of high-precision timekeeping of an intelligent electric meter in the field of electricity utilization of a power system.

Description

Technical field [0001] The invention relates to a high-precision frequency offset compensation method for an RTC chip, in particular to a high-precision frequency offset compensation method for an RTC chip combined with a variable capacitor. Background technique [0002] The RTC chip is an application specific integrated circuit that can provide functions such as calendar, clock and data storage. One of its core components is a 32.768kHz tuning fork quartz crystal oscillator, which can be used for smart meters such as electric energy metering, electricity bill settlement, and events. Important functions such as recording provide accurate time reference. The timing accuracy of the RTC chip is largely restricted by the ambient temperature of the electrical appliance, the aging effect of the chip, and other secondary factors. Among them, the environmental temperature is the most important factor affecting the frequency change of the quartz crystal resonator, that is, the resonant f...

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Problems solved by technology

However, due to the error of the thermistor's own parameters, fine-tuning is quite difficult, and the design of the compensation network and parameter optimization calculations are also very complicated, which restricts its application in the field of high-precision timing

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