MCU Low Voltage Detection Block for Data Retention
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Solution Overview
Problem
Microcontroller units (MCUs) in battery-powered electronic devices malfunction when voltage levels deviate from predetermined ranges, leading to reduced data retention time due to unnecessary reset operations.
Innovation Solution
The MCU operates in a stop mode when the battery voltage is within a low voltage range and performs a normal operation without resetting when the voltage increases, using a low voltage detection block and reset signal generation unit to control operation modes based on detected voltage levels, thereby avoiding power consumption associated with reset operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the MCU performs a reset operation when voltage recovers from low voltage range, then the MCU can ensure normal operation, but the data retention time is reduced due to unnecessary reset operations
Solution Approach 1:
The patent introduces a new parameter - the low voltage range threshold - to distinguish between different voltage conditions. By defining a specific voltage range (between first reference voltage level VLVD and second reference voltage level VPOR) as the low voltage range, the system can make intelligent decisions about whether to perform reset operations or maintain stop mode, thereby resolving the contradiction between ensuring normal operation and preserving data retention time.
Solution Approach 2:
The low voltage detector continuously monitors the battery voltage level and provides feedback to the control logic. Based on this feedback, the system dynamically adjusts its behavior: when voltage is in the low voltage range, it enters stop mode without resetting; when voltage recovers above the range, it performs normal operation without unnecessary resets. This feedback mechanism eliminates unnecessary reset operations while ensuring reliable operation when needed.
2Use of energy by moving object
If the MCU enters stop mode when battery voltage is low, then power consumption is reduced, but the MCU cannot perform normal operations during low voltage conditions
Solution Approach 1:
The patent implements a dynamic operation mode that adapts to voltage conditions. The MCU transitions between stop mode (when voltage is in the low voltage range) and normal operation mode (when voltage recovers). This dynamic behavior allows the system to minimize power consumption during low voltage conditions while maintaining the capability to perform normal operations when voltage is sufficient, resolving the contradiction between power saving and operational capability.
3Reliability
If the MCU performs reset operation to prevent malfunction at low voltage, then reliability is improved, but data retention time is reduced
Solution Approach 1:
The patent changes the voltage parameter threshold to define a low voltage range between first reference voltage level VLVD and second reference voltage level VPOR. By using this intermediate voltage range threshold, the system can prevent malfunctions that occur at very low voltages while avoiding unnecessary reset operations in the intermediate range, thereby preserving data retention time while maintaining reliability.
Solution Approach 2:
The patent prepares for potential malfunctions by monitoring voltage levels in advance. When voltage enters the low voltage range, the system proactively enters stop mode to prevent malfunction before it occurs. This beforehand cushioning approach ensures reliability by preventing malfunctions while avoiding the need for reset operations that would waste time and reduce data retention.
Data Source
AI summary
A method of operating a micro controller unit including maintaining a stop mode operation when a battery level detected in response to a first interrupt signal input from an external source is in a predetermined low voltage level range during the stop mode operation, and performing a normal operation corresponding to a second interrupt signal input from the external when a battery voltage level detected in response to the second interrupt signal is higher than the highest voltage level belonging to the predetermined low voltage level range.