Battery Power Calculation for Variable CPU Clocks
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Solution Overview
Problem
Current battery monitoring systems in mobile terminals, such as notebook computers, lack accurate measurement of maximum power supply from batteries during variable frequency CPU operations, especially when sudden changes in discharge current occur, leading to inaccuracies in determining optimal clock frequencies for high-speed operations.
Innovation Solution
A semiconductor device with a voltage measurement unit, current measurement unit, and controller that estimates internal battery resistance and calculates the maximum power amount by comparing discharge currents and voltages in different measurement modes, ensuring accurate power calculations even during sudden changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the CPU operates at high clock frequency for extended periods, then calculation performance is improved, but power consumption increases and reliability deteriorates due to overheating
Solution Approach 1:
The patent implements periodic switching between high-speed clock operation and normal clock operation. The control unit monitors battery temperature and power supply voltage, and when thresholds are exceeded, it periodically switches the CPU to normal operation mode to allow cooling, then returns to high-speed mode when conditions permit, thereby maintaining reliability while achieving calculation performance
Solution Approach 2:
The patent employs feedback control by continuously monitoring battery temperature and power supply voltage, and using this information to dynamically adjust CPU clock frequency. The control unit receives feedback from temperature and voltage detection circuits, and adjusts the clock frequency accordingly to prevent overheating and ensure reliable operation
2Productivity
If the CPU frequently switches between normal and high-speed clock operation, then optimal performance is achieved, but accurate determination of maximum battery power becomes difficult due to discharge current variations
Solution Approach 1:
The patent performs preliminary measurement of power supply voltage at multiple discrete discharge current values before determining maximum power. The control unit stores voltage measurements taken at predetermined current levels, and uses this pre-collected data to accurately calculate maximum power without being affected by transient current variations during mode switching
Solution Approach 2:
The patent dynamically adapts the power measurement process to operating conditions. The control unit determines whether to perform voltage measurement based on current operation mode and battery state, and adjusts measurement timing and current values according to actual discharge conditions, enabling accurate maximum power determination despite frequent mode transitions
3Measurement precision
If voltage measurement is performed at high discharge current values, then maximum power calculation accuracy is improved, but power supply voltage may fall below minimum operating voltage
Solution Approach 1:
The patent changes the discharge current parameter dynamically based on battery state and operation mode. The control unit selects appropriate current values for voltage measurement from a set of predetermined values, adjusting the measurement current according to battery charge level, temperature, and current operation mode to ensure both accuracy and operational safety
Solution Approach 2:
The patent uses feedback control to monitor power supply voltage during measurement and adjust measurement parameters accordingly. The control unit continuously checks voltage levels and compares them against minimum operating thresholds, terminating or adjusting measurements when voltage approaches critical levels to prevent operation failure
Data Source
AI summary
A semiconductor device includes a voltage measurement unit that measures an output voltage of a battery, a current measurement unit that measures a discharge current of the battery; and a controller that determines, in a first measurement mode, whether to employ a first discharge current as a power calculation current based on a difference between the first and a second discharge current, the second discharge current being the discharge current measured by the current measurement unit before the first discharge current is measured, in which the controller estimates an internal resistance of the battery based on the power calculation current and the output voltage measured in the first measurement mode and the discharge current and the output voltage measured in a second measurement mode, and calculates, based on the internal resistance that is estimated, a maximum power amount that can be output by the battery in the second measurement mode.