Dynamic Sampling Battery Fuel Gauge Circuit
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Solution Overview
Problem
Battery fuel gauge circuits in electronic devices face high power consumption due to increased sampling frequency requirements for precise detection of intermittent battery current bursts during communication periods, leading to undesirable energy usage.
Innovation Solution
A battery fuel gauge circuit with a detection circuit that dynamically adjusts sampling frequency and amplifier operation speed based on control data from the processor, using an A/D converter and integrator circuit to optimize power usage by increasing sampling frequency only during current increases and reducing it during stable periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sampling frequency is increased to improve detection precision of intermittent battery current bursts, then the measurement precision is improved, but the power consumption increases
Solution Approach 1:
The sampling frequency is made dynamically adjustable rather than fixed. The control unit changes the sampling frequency based on the operational state of the electronic device, using high sampling frequency during communication periods when current bursts occur and low sampling frequency during standby periods, thereby resolving the contradiction between detection precision and power consumption
Solution Approach 2:
The sampling frequency parameter is changed according to operational conditions. The system switches between high sampling frequency (for precise detection during communication) and low sampling frequency (for power saving during standby), allowing the system to optimize both detection precision and power consumption under different operating conditions
2Measurement precision
If the sampling frequency is increased to accurately detect current bursts during transmission and reception periods, then the measurement precision is improved, but the power consumption of the detection circuit increases
Solution Approach 1:
The detection circuit operates with periodic variation in sampling frequency. During communication periods (transmission and reception), the sampling frequency is increased to capture current bursts accurately. During standby periods, the sampling frequency is reduced, creating a periodic pattern that balances detection precision with power consumption of the detection circuit
Data Source
AI summary
A detection circuit is mounted on an electronic device having a communication function, including at least a battery, a CPU, and a communication unit, and is configured to detect the remaining battery charge. An A/D converter performs sampling of a magnitude of a current IBAT discharged from the battery, and converts the current IBAT thus sampled into a digital current value. An interface circuit receives, from the CPU, control data which indicates a period in which there is an increase in the current discharged from the battery. Based upon the control data, a control unit raises the sampling frequency of the A/D converter in the period in which there is an increase in the current IBAT.