Programmable PDM Interface for Backward-Compatible Audio Links
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Solution Overview
Problem
Current pulse density modulation (PDM) microphones, sensors, and amplifiers lack full programmability, which limits their configurability and efficiency, and they are not compatible with conventional systems without increasing power consumption or pin count.
Innovation Solution
The introduction of programmable PDM components that enable backwards compatibility with existing systems, allowing for register programming, reduced power consumption, and support for enhanced dynamic range through multi-value symbols and double/triple bandwidth modes, without requiring additional wires or increasing latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If programmability is added to PDM components, then configurability and efficiency are improved, but device complexity increases
Solution Approach 1:
The PDM interface is designed to perform multiple functions: it can operate in conventional PDM mode for audio data transmission and in programmable mode for device configuration. The same two-wire interface handles both audio streaming and register programming, eliminating the need for separate control lines and reducing overall system complexity despite adding programmability features.
Solution Approach 2:
The system dynamically switches between different operational modes (conventional PDM mode and programmable mode) based on the state of the data line. When the data line is held at a specific level, the device interprets subsequent signals as programming commands rather than audio data, allowing flexible reconfiguration without hardware changes.
2Use of energy by moving object
If full clock stop is used for disabling PDM device, then power consumption is reduced, but programmability is lost
Solution Approach 1:
The device provides self-service configuration capabilities through programmable registers that can be set to enable various power management modes. The system can be programmed to automatically enter low-power states or adjust operational parameters based on detected conditions, eliminating the need for external clock stopping while maintaining programmability and enabling flexible power optimization.
Data Source
AI summary
Systems and methods for programmable pulse density modulation (PDM) components enable backwards compatibility while maintaining reasonable tolerances. A system includes a programmable PDM device, a PDM master device and a bus communicably coupling the programmable PDM device to the PDM receiver. The PDM device may include an audio sensor, audio input circuitry, a delta-sigma converter and a PDM transmitter and receiver. The PDM transmitter and receiver may send out PDM data from the PDM device and receive programming data from the PDM Master device. The PDM device may further include register space controlled by the PDM master device, a buffer storing audio data for wakeup word systems that store audio data when the PDM receiver is powered down, a bus holder to hold the previous value on the bus if no device is driving it, and/or a clock multiplier to multiply the incoming clock by a factor.