Real-Time Clock Frequency Scaling for Low-Power Standby MCUs
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Solution Overview
Problem
Conventional micro-controller units (MCUs) face challenges in power management during standby mode, leading to inefficiencies and reduced battery life in always-on systems, as they continue to consume power even when in low power modes.
Innovation Solution
Implementing a hardware power management scheme that dynamically adjusts the real-time clock frequency based on application-specific wake-up resolution, using logic circuitry and timer circuitry to selectively scale the oscillating frequency of the real-time clock signal, allowing for power conservation without affecting usability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the real-time clock operates at full frequency in standby mode, then timekeeping precision is maintained, but power consumption increases
Solution Approach 1:
The patent applies dynamics by making the clock frequency adjustable rather than fixed. The system dynamically switches between full frequency operation (for precision) and reduced frequency operation (for power savings) based on whether wake-up events are pending. This resolves the contradiction by allowing the clock to adapt its operating state to current system needs.
Solution Approach 2:
The patent changes the frequency parameter of the real-time clock based on operational requirements. When no wake-up events are scheduled, the clock frequency is reduced to conserve power. When wake-up events are pending, the frequency is restored to maintain precision. This parameter adjustment directly resolves the contradiction between precision and power consumption.
2Use of energy by moving object
If the clock frequency is reduced to save power, then standby power consumption decreases, but timekeeping precision deteriorates
Solution Approach 1:
The system dynamically adjusts clock frequency based on the presence of wake-up events. When events are pending, the clock runs at full frequency to maintain precision. When no events are pending, it reduces frequency for power savings. This dynamic adaptation resolves the contradiction by ensuring precision is maintained only when necessary.
Solution Approach 2:
The frequency parameter is changed based on system state. The patent monitors for wake-up events and adjusts the clock frequency accordingly - full frequency when events are scheduled, reduced frequency when they are not. This conditional parameter change resolves the precision-power contradiction.
3Ease of operation
If the MCU remains fully operational, then system responsiveness is maintained, but power consumption increases
Solution Approach 1:
The patent applies dynamics by transitioning the MCU between different operational states - fully operational when wake-up events are pending, and in low-power standby when they are not. The clock frequency adjustment enables this dynamic state transition, allowing the system to balance responsiveness and power consumption based on actual needs.
Solution Approach 2:
The system uses periodic monitoring of wake-up event status to determine when to activate full operational mode. The clock frequency is adjusted periodically based on whether events are scheduled, creating a rhythm of high-power/high-responsiveness and low-power/low-responsiveness states that resolves the contradiction.
Data Source
AI summary
Various implementations described herein refer to a method for providing an integrated circuit with a real-time clock source. The method may include generating a real-time clock signal for the integrated circuit with the real-time clock source. The method may include selectively adjusting clock frequency of the real-time clock signal to save power in the integrated circuit.