Stylus Voltage Boost Circuit for Signal and Battery Trade-off

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Solution Overview

Problem

The challenge is to generate higher voltage levels for effective communication with digitizers using a stylus pen powered by a low-voltage battery while maintaining long battery life, given the limited space and cost constraints in the stylus circuitry.

Innovation Solution

A voltage boost circuit is implemented in the stylus pen, comprising a control module with a boost converter that increases the output voltage from a typical 1.5V battery to 10V-30V, using a combination of charge and discharge circuits with independent timing control, allowing for efficient signal transmission without draining the battery to ground, thus conserving power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If voltage is increased for better signal transmission, then signal-to-noise ratio is improved, but battery life is reduced

Engineering Contradiction:
Improvesignal-to-noise ratioVSAvoidbattery life
Core Design Contradiction:
Measurement precisionVSDuration of action of moving object

Solution Approach 1:

The patent implements periodic voltage boosting where the battery voltage is increased to high voltage levels only during specific transmission intervals when signal communication with the digitizer is required. Between these periodic intervals, the voltage remains at low levels to conserve battery power. This periodic switching between high and low voltage states resolves the contradiction by providing high signal-to-noise ratio only when needed while maintaining extended battery life during non-transmission periods.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent employs dynamic voltage adjustment where the voltage level is continuously adapted based on operational requirements. The system dynamically switches between low voltage (1.5V) for battery conservation and high voltage (10V-30V) for effective signal transmission. This dynamic voltage control allows the system to optimize the balance between signal quality and power consumption in real-time, resolving the static contradiction between these two parameters.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If voltage boost circuit is added to increase transmission voltage, then communication effectiveness is improved, but device complexity increases

Engineering Contradiction:
Improvecommunication effectivenessVSAvoidcircuit complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines the voltage boost functionality with the existing battery and transmission circuitry into an integrated system. The boost converter is designed to work seamlessly with the battery power source and the transmission antenna, merging multiple functions (power storage, voltage conversion, and signal transmission) into a unified circuit architecture. This integration reduces the number of separate components and simplifies the overall device complexity while maintaining improved communication effectiveness.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The voltage boost circuit is designed as a multi-functional component that serves multiple purposes: it boosts voltage for transmission, manages power distribution, and can operate in different voltage modes (low and high) depending on operational needs. This universal design allows a single circuit module to handle various functions that would otherwise require separate components, thereby improving communication effectiveness without proportionally increasing device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If continuous high voltage is used for transmission, then signal quality is improved, but power consumption increases

Engineering Contradiction:
Improvesignal qualityVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system employs periodic high voltage transmission bursts rather than continuous high voltage. The boost converter activates only during scheduled transmission intervals to deliver high-quality signals, then returns to low voltage operation. This periodic operation ensures that signal quality is maintained during communication events while average power consumption is dramatically reduced compared to continuous high voltage operation.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system dynamically changes the voltage parameter based on operational requirements. During transmission intervals, the voltage parameter is changed from low (1.5V) to high (10V-30V) to ensure signal quality. Between transmissions, the voltage parameter is changed back to low to minimize power consumption. This parameter switching allows the system to achieve high signal quality only when necessary while maintaining low power consumption during idle periods.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution enables improved signal-to-noise ratio and longer battery life by generating higher voltage levels for effective communication with digitizers, extending the stylus pen's operational life and reducing the need for frequent battery replacements.

Implementation Method 1

A voltage boost circuit is implemented in the stylus pen, comprising a control module with a boost converter that increases the output voltage from a typical 1.5V battery to 10V-30V

Methodology Applied
Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Data Source

PatentEP3350674B1Voltage boost circuit for a stylus pen
Publication Date: 2021.02.03 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP3350674B1 patent drawingFigure 1
  • EP3350674B1 patent drawingFigure 2
  • EP3350674B1 patent drawingFigure 3

AI summary

A stylus pen is disclosed that can be used as an input device to a digitizer associated with a computer screen on a computing device, such as a computer, mobile device, tablet, etc. The stylus pen can include a voltage boost circuit that generates a stylus output signal on an antenna output. The voltage boost circuit has a charging portion and a discharging portion. Both portions have transistors that are activated and deactivated through pulsed control signals. However, a pulse duration for each control signal is separately controllable through different RC-based circuits. Additionally, the voltage boost circuit provides power savings by draining the output voltage signal to a positive voltage rail, rather than ground.