RTC Sensing Circuit for Battery Status Detection Under Diode Leakage
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Solution Overview
Problem
Existing electronic systems face challenges in accurately determining the working status of real-time clock circuits due to reverse leakage current from Schottky diodes, leading to potential misjudgment of the validity of the real-time signal generated, especially when the battery powering the real-time clock circuit is malfunctioning or running out of power.
Innovation Solution
A sensing circuit comprising a comparator module and a storage module is used to compare the initial voltage of the real-time clock module with a threshold voltage, generating a comparison result that is stored and delivered to a host circuit to determine whether the real-time clock module is functioning normally or abnormally, thereby preventing incorrect real-time signals from being used.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a Schottky diode is used for switching the power source in the real-time clock circuit, then the real-time clock circuit can operate using electricity from the electronic system when turned on and from the battery when turned off, but the reverse leakage current of the Schottky diode makes it difficult to identify whether the battery is normal and may cause misjudgment of the validity of the real-time signal
Solution Approach 1:
The sensing circuit detects the voltage at the real-time clock circuit at an initial moment before the Schottky diode's reverse leakage current has time to significantly affect the voltage level. By performing the detection preliminarily, the system captures the battery voltage in its relatively undistorted state, enabling accurate determination of battery status and real-time signal validity before the leakage current causes measurement errors
Solution Approach 2:
A sensing circuit is introduced as an intermediary between the real-time clock circuit and the host circuit. This sensing circuit includes a voltage detection unit that measures the voltage at the real-time clock circuit and a determination unit that judges whether the real-time signal is valid based on the detected voltage and a predetermined threshold. The intermediary sensing circuit isolates the detection process from the harmful reverse leakage current effects while providing accurate status information to the host circuit
2Loss of information
If the electronic system uses computation resources to generate real-time signals, then real-time information can be provided, but computation resources for other tasks are occupied and power consumption increases
Solution Approach 1:
The real-time clock circuit operates independently using its own battery power source, generating real-time signals without requiring computation resources from the main electronic system. The circuit serves itself by maintaining autonomous operation through the battery, especially when the electronic system is turned off, thereby eliminating the need for continuous CPU intervention and reducing overall power consumption of the system
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed solution allows the host circuit to accurately determine the working status of the real-time clock module, preventing errors in the electronic system by correctly identifying abnormal conditions and alerting the user, ensuring continuous and correct real-time signal generation.
Implementation Method 1
comparing the initial voltage with a threshold voltage, to generate a comparison result
Data Source
AI summary
The present invention provides a sensing circuit, for sensing a working status of a real-time clock (RTC) module, comprising a comparator module, coupled to the real-time clock module, for receiving an initial voltage of the real-time clock module, and comparing the initial voltage with a threshold voltage, to generate a comparison result; and a storage module, coupled to the comparator module, for storing the comparison result and delivering the comparison result to a host circuit; wherein the host circuit determines whether the working status of the real-time clock module is normal or abnormal according to the comparison result.