Design And Implementation Of Low-power Digital Real Time Clock Based On Asynchronous Circuit

To reduce the power consumption of the chip,meanwhile ensuring the reliability of other performances,has become an important topic in a chip designation in the current integrated circuit development.Real time clock(RTC)chips have been widely used in all systems that require micro-power consumption and provide a time base.Thus,they are usually required to be low-power consumption in practical applications.So far,most RTC chips are designed with the synchronous circuits.Some problems followed with synchronous circuits as the size of the circuit becomes larger,such as the inevitable clock skew,increased power consumption,and etc.On the other hand,the asynchronous circuit has many characteristics such as low-power consumption,low noise,high speed and good robustness,and moreover,it does not encounter the clock distribution problem.Therefore,I devote to design a RTC chip by adopting the asynchronous circuit.In this thesis,the SMIC’s 55 nm process is adopted to designate a digital RTC chip with low-power consumption.Firstly,the basic theory of asynchronous circuits and the asynchronous circuit design method(link-joint self-timed systems)are outlined.According to the principle of desynchronization,a scheme for the asynchronous circuit designation using the mainstream EDA tools is proposed.Then,according to the function of the RTC system,the overall structure of the RTC is designed,and the circuit design of each part is completed by modules,and its perpetual calendar module is fully asynchronously designed.After the design of each part of the module is completed,the RTL-level simulation,logic synthesis and automatic placement and routing are carried out successively for the asynchronous RTC.For the convenience of comparison,a synchronous RTC with the same function is also implemented using the same process.Finally,by comparing and analyzing power consumption and area of the asynchronous RTC and the synchronous RTC,it is found that although the area of the asynchronous RTC is increased by 8.2% compared with the synchronous RTC,the power consumption is reduced by about 9.2%.By further comparing the fully asynchronous perpetual calendar and the synchronous perpetual calendar,it can be found that the power consumption of the former is reduced by 53.2% compared with the latter,and the area is only increased by 17.6%.These results suggest that the proposed asynchronous circuit based RTC chips have potential applications for practice.