High-precision real-time clock chip

Abstract

The invention discloses a high-precision real-time clock chip which comprises a clock timing module, an I2C interface module, an alarming and periodic interrupt module, a power management module and a digital temperature compensation crystal oscillator; the clock timing module comprises a second register, a minute register, an hour register, a week register, a day register, a moon register, a year register and a square wave output control register; the hour register, the day register, the moon register and the year register are connected with a combinational logic circuit; and the digital temperature compensation crystal oscillator comprises a temperature sensor, an analogue digital converter, a storage cell, a capacitor array and a crystal oscillator. The high-precision real-time clock chip provided by the invention can be repaired and adjusted within an industrial temperature range, can achieve self calibration, greatly improves the accuracy of RTC, meanwhile the problem of electromagnetic interference on macroscopic circuit wiring can be solved, and more I / O resources of the main system are saved.

Description

technical field [0001] The invention relates to a high-precision real-time clock chip. Background technique [0002] Ammeter is the product with the largest production capacity in my country's electrical instrumentation industry. At present, China is the world's largest producer and exporter of ammeters, with an annual production of about 200 million meters. At present, the country is building a smart grid, of which smart meters are an important part. The field of meters has entered the era of smart meters, and traditional mechanical meters have been completely eliminated. [0003] The main market for electricity meters is the civilian electricity meter market. The national policy is one meter for each household. Civil electricity meters are mainly purchased and installed by China Power Grid Corporation. China Power Grid is divided into State Grid and South Grid, including Guangdong, Hainan, Guangxi, Yunnan and Guizhou is the South Grid, and the others are the State Grid. ...

AI Technical Summary

Problems solved by technology

The analog temperature-compensated crystal oscillator (TCXO) uses a varactor diode to control the final frequency of the oscillator, and uses a thermistor network to provide the temperature-voltage value required to compensate the oscillator. Generally, a temperature-compensated crystal oscillator of the order of magnitude can be obtained. However, the disadvantage of this analog temperature compensation method is that it requires a varactor diode with good linearity and a large number of thermistors with small tolerance, and there is mutual interference in network adjustment, and it is very difficult to calculate component parameters and debug.

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