Sample-and-Hold Amplifier Bias Switching for Lower Optical Navigation Power

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Solution Overview

Problem

Conventional optical navigation devices, such as optical mice, consume excessive power due to multiple amplifiers, leading to reduced battery operating time.

Innovation Solution

An amplifying circuit that operates in both sample and hold modes, utilizing a current providing circuit to adjust bias currents, with a smaller first bias current during power-saving intervals and a larger second bias current during hold mode, reducing overall power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If multiple amplifiers are used in the optical navigation device, then the signal amplification capability is improved, but the power consumption increases

Engineering Contradiction:

Improvesignal amplification capabilityVSAvoidpower consumption

Core Design Contradiction:

PowerVSUse of energy by moving object

Solution Approach 1:

The patent applies dynamics by making the bias current adjustable based on operating mode. The amplifier receives different bias currents (first bias current in sample mode, second bias current in hold mode) depending on the operational requirements, allowing the system to dynamically optimize between performance and power consumption.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of bias current to resolve the contradiction. By providing different bias current levels corresponding to different operating modes (sample mode vs. hold mode), the system achieves both adequate signal amplification when needed and reduced power consumption when full amplification capability is not required.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If amplifiers operate continuously with high bias current, then the signal processing performance is improved, but the battery operating time decreases

Engineering Contradiction:

Improvesignal processing performanceVSAvoidbattery operating time

Core Design Contradiction:

ProductivityVSDuration of action of moving object

Solution Approach 1:

The patent implements periodic action by alternating between sample mode and hold mode operations. The amplifier operates with higher power consumption during sample mode for accurate signal acquisition, then switches to lower power consumption during hold mode, creating a periodic operation pattern that balances performance and battery life.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent applies partial action by providing full amplification capability only when necessary (during sample mode), rather than continuously. During hold mode, reduced amplification with lower bias current is sufficient, allowing the system to achieve required performance with partial power consumption.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS11405006B1Amplifying circuit and optical navigation device

Publication Date: 2022.08.02 PIXART IMAGING INC

AI summary

An amplifying circuit, which can operate in one of a sample mode and a hold mode, comprising: an amplifier; a current providing circuit, configured to provide a first bias current to the amplifier in a power saving time interval when the amplifying circuit operates in the sample mode, and configured to provide a second bias current to the amplifier when the amplifying circuit operates in the hold mode; wherein the first bias current is smaller than the second bias current.