Acoustic Transducer Supply Switching for Wide Dynamic Range

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Solution Overview

Problem

Modern transducer systems, such as MEMS microphones, face challenges in balancing performance and power consumption, requiring innovative solutions to manage energy efficiently while maintaining system performance across varying sound pressure levels.

Innovation Solution

A controllable power supply system that switches between different voltage modes based on sound pressure levels, reducing power consumption at lower levels and increasing it at higher levels, allowing the transducer system to operate effectively across a wide dynamic range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a fixed supply voltage is provided to the buffer circuit, then the circuit operation is simple, but the power consumption cannot be optimized across varying sound pressure levels

Engineering Contradiction:
Improvepower consumptionVSAvoidsupply circuit complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The supply circuit dynamically switches between a first supply voltage and a second supply voltage based on the sound pressure level detected by the feedback signal. This dynamic adjustment allows the buffer circuit to operate with optimized power consumption at different operating conditions while maintaining simple circuit architecture

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the supply voltage parameter based on the operating conditions (sound pressure level). By switching between different voltage levels, the system optimizes power consumption without requiring complex circuit redesign, directly addressing the contradiction between energy efficiency and device simplicity

Inventive Principle:
Principle #35Parameter changes

2Productivity

If a high supply voltage is always provided to the buffer circuit, then the dynamic operating range is maximized, but the power consumption increases unnecessarily at lower sound pressure levels

Engineering Contradiction:
Improvedynamic operating rangeVSAvoidpower consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The supply circuit dynamically adjusts the voltage level based on the feedback signal representing sound pressure level. When high sound pressure levels are detected, the higher supply voltage is provided to maintain full dynamic operating range. When lower sound pressure levels are detected, the lower supply voltage is provided to reduce power consumption, thus resolving the contradiction between maintaining productivity and reducing energy use

Inventive Principle:
Principle #15Dynamics

3Use of energy by moving object

If a low supply voltage is always provided to the buffer circuit, then the power consumption is minimized, but the dynamic operating range is reduced

Engineering Contradiction:
Improvepower consumptionVSAvoiddynamic operating range
Core Design Contradiction:
Use of energy by moving objectVSProductivity

Solution Approach 1:

The supply voltage parameter is changed based on operating conditions. The system uses a lower voltage to minimize power consumption during normal operation, but switches to a higher voltage when high sound pressure levels are detected to maintain the required dynamic operating range. This parameter adaptation resolves the contradiction between energy efficiency and productivity

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 approach enables reduced power consumption while maintaining a large dynamic operating range, allowing the transducer system to efficiently handle both low and high sound pressure levels, thereby optimizing performance and energy management.

Implementation Method 1

Many MEMS devices use capacitive sensing techniques for transducing the physical phenomenon into electrical signals. In such applications, the capacitance change in the sensor is converted to a voltage signal using interface circuits.

Methodology Applied
Scientific EffectCapacitive sensing: Capacitance

Implementation Method 2

buffering, by a buffer circuit, a first electrical signal from an acoustic transducer to produce a second electrical signal

Methodology Applied
Scientific EffectElectrical signal buffering:

Implementation Method 3

based on comparing the feedback signal to the first threshold, switching between a first mode and a second mode, supplying a first supply voltage to the buffer circuit during the first mode, and supplying a second supply voltage to the buffer circuit during the second mode

Methodology Applied
Scientific EffectVoltage switching:

Data Source

PatentUS10008990B2System and method for acoustic transducer supply
Publication Date: 2018.06.26 INFINEON TECHNOLOGIES AG

AI summary

According to an embodiment, a method of operating an acoustic device includes buffering, by a buffer circuit, a first electrical signal from an acoustic transducer to produce a second electrical signal, receiving a feedback signal at a supply circuit, and comparing the feedback signal to a first threshold. The feedback signal is based on the first electrical signal. The method further includes, based on comparing the feedback signal to the first threshold, switching between a first mode and a second mode, supplying a first supply voltage to the buffer circuit during the first mode, and supplying a second supply voltage to the buffer circuit during the second mode. The first supply voltage is different from the second supply voltage.