Hardware Fuel Gauge Circuit for Portable Device Sleep Mode

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Solution Overview

Problem

Conventional fuel gauge operations for portable device batteries are hindered when the processor enters sleep mode, as software applications are deactivated, preventing accurate power consumption estimation due to ongoing power consumption by peripheral circuits.

Innovation Solution

An apparatus comprising a voltage measuring circuit and a control circuit that periodically measures battery pack voltage, calculates battery characteristics, and triggers an interrupt to wake the processor for updates, ensuring continuous fuel gauge operation even in sleep mode.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the processor enters sleep mode to save power, then power consumption is reduced, but fuel gauge operation cannot be performed since software applications are deactivated

Engineering Contradiction:

Improvepower consumptionVSAvoidfuel gauge operation

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The fuel gauge operation is segmented into two parts: (1) hardware-based voltage measurement and battery characteristic calculation performed by the voltage measuring circuit and control circuit during sleep mode, and (2) software-based fuel gauge computation performed by the processor when awake. This segmentation allows the system to maintain fuel gauge functionality while the processor is in sleep mode by offloading measurement tasks to hardware circuits.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The voltage measuring circuit and control circuit automatically perform voltage measurement and battery characteristic calculation without requiring processor intervention during sleep mode. The control circuit autonomously determines whether to trigger an interrupt based on accumulated battery characteristics, enabling the system to self-monitor battery status even when the processor is deactivated.

Inventive Principle:

Principle #25Self-service

2Use of energy by moving object

If software applications are deactivated in sleep mode, then power consumption is reduced, but power consumption monitoring by peripheral circuits cannot be tracked

Engineering Contradiction:

Improvepower consumptionVSAvoidpower consumption data

Core Design Contradiction:

Use of energy by moving objectVSLoss of information

Solution Approach 1:

The control circuit acts as an intermediary between the voltage measuring circuit and the processor. It accumulates battery characteristics based on voltage measurements and determines when to trigger an interrupt, thereby bridging the gap between hardware measurement capabilities and software processing needs during sleep mode transitions.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The voltage measuring circuit and control circuit perform preliminary voltage measurement and battery characteristic calculation before the processor needs to wake up. This preliminary action ensures that when the processor becomes active, it receives pre-processed data ready for fuel gauge computation, eliminating the need for continuous software monitoring.

Inventive Principle:

Principle #10Preliminary action

3Measurement precision

If the processor remains awake to perform fuel gauge operation, then accurate power consumption estimation is maintained, but power savings from sleep mode are lost

Engineering Contradiction:

Improvepower consumption estimationVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The voltage measuring circuit performs periodic voltage measurements at predetermined time intervals during sleep mode, and the control circuit accumulates battery characteristics periodically. This periodic action maintains measurement precision without requiring continuous processor operation, allowing the system to wake up only when necessary for fuel gauge computation.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS10042004B2Apparatus used with processor of portable device and arranged for performing at least one part of fuel gauge operation for battery by using hardware circuit element(s) when processor enter sleep mode

Publication Date: 2018.08.07 MEDIATEK INC

AI summary

An apparatus used with a processor to perform fuel gauge operation for a battery of a portable device includes a voltage measuring circuit and a control circuit. The voltage measuring circuit periodically measures and records a battery pack voltage for the battery according to time information received from the processor after the processor enters a sleep mode. The control circuit generates an accumulation result by calculating and accumulating at least one value of battery characteristics according to the battery pack voltage, and compares the accumulation result with a reference threshold of battery characteristics to determine whether to trigger an interrupt to wake up the processor, so as to cause the processor to update a battery cell voltage and an internal battery resistance of the battery for performing fuel gauge operation.