Real Time Clock Event Data Reliability via Voltage and Oscillation Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing real-time clocks lack reliability in recording event data due to lack of countermeasures against voltage reductions and oscillation stops, leading to uncertain data correctness.
Innovation Solution
Incorporating a voltage reduction detection circuit and an oscillation stop detection circuit to record additional data indicating power supply voltage levels and oscillator status, enhancing data reliability by providing threshold comparisons and edge detection modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a real time clock records event data without voltage reduction detection, then the device complexity is low, but the reliability of stored event data deteriorates due to inability to detect voltage reductions causing erroneous data
Solution Approach 1:
The voltage reduction detection circuit operates in advance to detect voltage reductions before they cause erroneous data recording. By detecting the voltage reduction condition beforehand and storing this information with the event data, the system prevents unreliable data from being recorded while maintaining normal operation flow.
Solution Approach 2:
The voltage reduction detection circuit acts as an intermediary between the power supply and the event recording system. It monitors the power supply voltage and provides status information to the control circuit, which then decides whether to record event data or not, thereby filtering out potentially erroneous data before storage.
2Reliability
If a real time clock does not include oscillation stop detection, then the device complexity is low, but the reliability of recorded time data deteriorates when oscillator stops
Solution Approach 1:
The oscillation stop detection circuit continuously monitors oscillator status in advance and detects when the oscillator stops. This preliminary detection allows the control circuit to identify and exclude time data recorded during oscillation stop periods, preventing unreliable time data from being stored.
Solution Approach 2:
The oscillation stop detection circuit provides feedback information about oscillator status to the control circuit. This feedback mechanism allows the system to adjust its recording behavior based on real-time oscillator performance, storing time data only when the oscillator is functioning correctly.
3Reliability
If additional data indicating operating state is recorded with event data, then the reliability of event data improves, but the quantity of stored information increases
Solution Approach 1:
Instead of recording complete operational status information continuously, the system records only the critical voltage reduction status and oscillation stop status at the time of event data recording. This selective recording approach adds necessary reliability information while minimizing the increase in stored information quantity.
Solution Approach 2:
The system records only the essential operating state information (voltage reduction status and oscillation stop status) rather than all possible operational parameters. This partial recording approach provides sufficient reliability data without excessive information storage.
Data Source
AI summary
A real time clock for outputting data indicating a time of day includes: an event detection circuit for detecting that an event detection signal has been inputted from outside; a timing circuit for generating the time-of-day data according to a signal outputted from an oscillator circuit; a memory; and a control circuit for, if the event detection circuit detects input of the event detection signal, recording event data in the memory, the event data including additional data indicating an operating state of the real time clock and the time-of-day data generated by the timing circuit.