文档介绍：华中科技大学
硕士学位论文
基于I<'2>C总线的温度自适应实时时钟芯片的设计
姓名:李奥博
申请学位级别:硕士
专业:软件工程
指导教师:应建华
20090527
华中科技大学硕士学位论文
摘要
实时时钟芯片具有产生秒、分、小时、日、星期、月、年的功能,并且具有闰
年自动调整功能,广泛应用于手机、复费率电表、可编程时间控制器等需要微功耗
和精确计时的场合。
实时时钟的基本功能是保持跟踪时间及日期等信息,必要的特性是走时精确,
而温度对时钟芯片所用晶振的影响难以避免,因此依据温度对时钟进行实时修调是
必不可少的。
本文讨论的基于 IC2 总线的实时时钟芯片除了具备基本的走时功能外,还具备了
主电源掉电情况下的备用电源供电和基于 AD 转换的集成温度补偿修调功能,无需
通过外部 PC 即可依据当前温度及芯片所用晶体温频特性进行 RTC 的时钟修正,真
正实现了温度“自适应”。
本文的设计内容主要分为三个部分:首先进行 RTC 的设计,即时钟计数模块的
设计,包括电源管理模块及 I 2C 总线控制逻辑。其次聚焦于时钟修调模块,介绍其
实现“温度自适应”的原理和电路设计。最后对保证修调系统高效工作的温度传感
器、AD 转换器、存储器以及整个系统进行设计说明。
本芯片采用 CSMC CMOS 工艺,原理图的绘制、仿真及版图的绘制均基
于 Cadence 软件完成。目前该芯片已流片成功,经测试各项结果均满足设计指标。

关键词:实时时钟 I 2C 总线温度自适应 AD转换数字频率修调
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华中科技大学硕士学位论文
Abstract
Real-Time Clock counts seconds, minutes, hours, date of the month, day of the weak,
month and year with leap-pensation. It is widely used in mobile phones, electric
supply meters, programmable controllers and other industrial electronics and consumer
electronics.
The basic function of Real-Time Clock is maintaining time and the calendar
information,so the precision is necessary and important. Because of the effect of the
temperature can not be avoided, the frequency trimming during to the temperature is
essential.
The Real-Time Clock Applied in IC2 -bus discussed in this article not only provides
time as basic function, but also has a built-in power sense circuit that detect power failures
and automatically switches to the battery supply. In addition, it has a frequency trimming
system which can automatically changing the time information during to the temperature
basing on the ADC and the temperature characteristic of the crystal.
This article is divided into three parts: the first is the circuit design of the RTC,
including power management and the control logic of the IC2 protocol. The second part
is the design of the frequency trimming circuit which is adaptive to the temperature. The
final part introduces the other