Power Sequence Detection Circuit for Memory Systems
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Solution Overview
Problem
Existing power sequence detection methods in semiconductor processing face challenges in accurately determining voltage transitions due to variations in decoupling capacitance, leading to potential clock glitches and data corruption during power mode transitions, especially when relying on bandgap threshold voltages for battery backup systems.
Innovation Solution
A power sequence detection circuit that monitors and compares voltage levels using comparators and flip-flop circuits to ensure correct sequencing of power modes during standby transitions, providing fault indicators for corrective actions and isolating components as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the bandgap threshold voltage is kept in the core power supply domain to save power consumption on the coin cell battery, then power consumption on the battery is reduced, but the reliability of power sequence detection deteriorates due to unknown threshold voltage before core supply crosses the threshold
Solution Approach 1:
The power supply system is segmented into two independent domains: the core power supply domain containing the core power supply and first bandgap circuit, and the always-on power supply domain containing the coin cell battery and second bandgap circuit. This segmentation allows each domain to operate independently with its own threshold voltage references, ensuring reliable power sequence detection while minimizing battery power consumption.
Solution Approach 2:
A power sequence detection circuit acts as an intermediary between the two power supply domains. It receives voltage level indicators from both domains, compares their sequences, and detects mismatches. This intermediary mechanism ensures that power sequence reliability is maintained even when the bandgap threshold voltages are kept separate in different power domains.
2Reliability
If the bandgap threshold voltage is run on the always ON coin cell battery to avoid improper voltage sequence, then power sequence detection reliability is improved, but the risk of threshold voltage mismatch increases leading to clock glitches and data corruption
Solution Approach 1:
The power sequence detection circuit implements feedback by continuously monitoring voltage level indicators from both the core power supply domain and always-on power supply domain, comparing their assertion sequences, and generating mismatch detection signals. This feedback mechanism ensures that any threshold voltage mismatches are detected and can be corrected before causing clock glitches or data corruption.
Solution Approach 2:
The system performs preliminary comparison of voltage level indicator sequences before power mode transitions are completed. By detecting sequence mismatches in advance, the system can prevent clock glitches and data corruption from occurring, rather than reacting after they have already happened.
3Measurement precision
If multiple voltage levels are monitored to determine power mode transitions, then the accuracy of power sequence detection is improved, but the device complexity increases due to additional comparators and detection circuits
Solution Approach 1:
The power sequence detection circuit is designed with multi-functionality to handle multiple voltage level monitoring tasks. It can detect voltage levels from both power supply domains, compare their sequences, and generate mismatch detection signals all within a single integrated circuit structure. This universal design reduces overall system complexity compared to having separate circuits for each function.
Solution Approach 2:
The monitoring and comparison functions for multiple voltage levels are merged into a single power sequence detection circuit. Instead of having separate comparison circuits for each voltage level, the patent combines them into one unified circuit that efficiently handles all voltage level indicators from both power supply domains, thereby reducing device complexity.
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
Ensures reliable detection of power mode transitions, preventing data corruption and clock glitches by accurately determining the sequence of power levels and providing timely corrective actions, thus maintaining system integrity during power up and down cycles.
Implementation Method 1
Several voltages typically need to be detected to determine transitions from one power mode to the next
Implementation Method 2
a difference in decoupling capacitance on the printed circuit board to which the components are mounted
Data Source
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AI summary
A memory system includes a core power supply node configured to provide a core power supply; backup regulator configured to provide a backup power supply; memory configured to be powered by the core power supply or the backup power supply; threshold detection circuitry configured to provide a first indicator that when asserted indicates the core power supply has fallen to a first threshold, a second indicator that when asserted indicates the core power supply has fallen to a second threshold, and a third indicator that when asserted indicates the core power supply has fallen to a third threshold. The memory system also includes power sequence detection circuitry is configured to determine, upon the core power supply falling and based on which of the first, second, and third indicators are asserted, whether the asserted indicators have been asserted in a correct sequence and provide a first test result accordingly.