RTC Correction Circuit for Power-Off Temperature Compensation
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Solution Overview
Problem
Existing real-time clock (RTC) systems face challenges in temperature correction when powered off, as they rely on external temperature sensors and MCU resources, leading to inefficiencies and resource wastage.
Innovation Solution
A correction circuit integrated within the chip, featuring a built-in temperature collection circuit, power-on/off detection, and a frequency dividing coefficient operation circuit, which allows for temperature-based frequency correction even when the chip is powered off, using pre-saved temperature and frequency deviation data to calculate the necessary frequency dividing coefficient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an external temperature sensor is used to collect temperature for frequency correction, then temperature correction can be performed, but the chip cannot perform correction when powered off and MCU resources are wasted
Solution Approach 1:
The correction circuit is designed to perform frequency correction autonomously without requiring external temperature sensors or MCU intervention. The circuit includes an internal temperature detection module that automatically detects temperature changes and adjusts the frequency division coefficient accordingly, enabling the system to self-correct frequency deviations while powered off without consuming external power or MCU resources
Solution Approach 2:
The correction circuit is segmented into independent functional modules: a temperature detection module, a frequency division coefficient operation module, and a frequency division module. This segmentation allows the temperature detection and correction functions to operate independently from the main MCU system, enabling autonomous correction when the chip is powered off without involving the MCU
2Device complexity
If frequency correction is performed using an integer frequency dividing circuit, then the circuit structure is simple, but timing precision is insufficient for high-precision timing requirements
Solution Approach 1:
The frequency division coefficient is made dynamically adjustable based on temperature conditions. The circuit can switch between different frequency division coefficients (e.g., 32768, 32769, 32770) according to the detected temperature, allowing the system to adapt to temperature-induced frequency variations and maintain high timing precision without requiring a complex fixed-precision circuit
Solution Approach 2:
The frequency division coefficient parameter is changed based on temperature detection results. When temperature changes cause frequency deviation, the correction circuit adjusts the frequency division coefficient to compensate for the deviation, thereby maintaining accurate timing without requiring a fundamentally more complex circuit structure
Data Source
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AI summary
The present document discloses a correction circuit. The correction circuit includes a frequency dividing circuit (110), a frequency dividing coefficient operation circuit (120), a built-in temperature collection circuit (130), and a power-on and power-off detection circuit (140). The built-in temperature collection circuit (130) is configured to collect a temperature of the chip; the power-on and power-off detection circuit (140) is configured to detect power-on and power-off of the chip; the frequency dividing coefficient operation circuit (120) is configured to calculate, according to the temperature of the chip collected by the built-in temperature collection circuit (130) when the power-on and power-off detection circuit (140) detects that the chip is powered off, a frequency dividing coefficient, and output the frequency dividing coefficient to the frequency dividing circuit (110); and the frequency dividing circuit (110) is configured to provide, according to the frequency dividing coefficient output by the frequency dividing coefficient operation circuit, a timing pulse for a real-time clock (11).