A Low-power Digital Temperature Compensation Design Of Real-time Clock Chips

Real-time clocks(RTC)plays an important role in industrial applications since all time-based systems and applications require a stable and accurate time benchmark.However,higher accuracy and stability will lead to higher power consumption from the perspective of clock chip design technology.Hence,we designed a low-power temperature compensated real-time clock chip in this article.This thesis studies and designs a low-power temperature-compensated real-time clock chip.The RTC designed in this thesis is based on analog design.The main work of this thesis is to design the power supply part and oscillator of the analog part of the whole chip.The power supply circuit mainly includes the reference circuit(Bias)and the Low Dropout Regulator circuit,Clock Detection circuit.The design of the power supply circuit is the basis for realizing low power consumption.For this reason,transistors operating in the sub-threshold region are used to design the entire power supply circuit,so that the power consumption performance of the n A level can be achieved.The chip has a built-in32.768 KHz crystal,and the internal oscillation circuit adopts the pulse freewheeling oscillation circuit designed based on the Pierce oscillator,and the built-in temperature sensor and compensation algorithm enable the analog part to provide a stable and accurate32768 Hz clock.The chip can achieve In a typical case(power supply voltage 3V,temperature 25?),the current consumption is 0.35?A.Through the precise clock provided by the analog part to the digital part,the digital part can realize the conventional real-time clock functions,such as calendar function(accurate to the second),timing function,alarm function,etc.The chip designed in this thesis adopts a standard 0.18 ? m process.The experimental data shows that this chip can achieve a performance of ± 3ppm in frequency offset in the temperature range of-40? to 85?.