Microphone Sigma-Delta Circuit With Switchable Resolution and Power
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Solution Overview
Problem
Digital microphones in portable devices face challenges in balancing performance and power consumption across different applications, such as voice commands and high-quality video recording, where power efficiency is critical for continuous operation but not always a priority.
Innovation Solution
An electronic circuit with a sigma-delta modulator and a mode selector that allows for configurable resolution and power consumption by operating in multiple modes, including cascading sigma-delta modulators and adjusting clock frequencies, supply currents, and voltages, to optimize performance and power usage based on external control signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sigma-delta modulator operates in high-resolution mode with cascaded modulators and higher clock frequencies, then measurement precision and dynamic range are improved, but power consumption increases
Solution Approach 1:
The sigma-delta modulator is designed to dynamically switch between different operation modes (single modulator or cascaded modulators) and adjust clock frequencies based on the required dynamic range. This dynamic reconfiguration allows the system to optimize power consumption by using only the necessary processing power for each specific application scenario.
Solution Approach 2:
The system changes key operating parameters including the number of cascaded sigma-delta modulators (1 or 2), clock frequencies (variable within ranges), and resolution settings. These parameter changes enable the modulator to adapt between low-power voice command mode and high-performance video recording mode, resolving the contradiction between measurement precision and power consumption.
2Measurement precision
If the sigma-delta modulator operates in high-resolution mode with cascaded modulators, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The high-resolution sigma-delta modulator is segmented into two separate modulator stages that can be independently configured. Each stage has its own clock frequency and resolution settings, allowing the system to achieve high dynamic range when needed while maintaining the option to use only a single stage for simpler applications, thus managing device complexity effectively.
3Measurement precision
If the clock frequency is increased to improve dynamic range, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The clock frequency of each sigma-delta modulator stage is made dynamically adjustable rather than fixed. The system can set different clock frequencies (e.g., first modulator: 0.7-2.8 MHz, second modulator: 1.4-5.6 MHz) based on the required dynamic range, allowing optimization of power consumption by using lower frequencies when high dynamic range is not required.
Data Source
AI summary
An electronic circuit for a microphone and a microphone are disclosed. In an embodiment, the electronic circuit includes a sigma-delta modulator having a configurable resolution and a mode selector, wherein the sigma-delta modulator is selectively operable in at least two operation modes and the mode selector is configured to determine a desired operation mode dependent on an externally provided control signal and to select the resolution of the sigma-delta modulator according to the determined operation mode.