Knowles Electronics, Inc.

Andrzej Pawlowski

Henrik Thomsen

Kim Spetzler Berthelsen

Kasper Strange

David P Rossum

Niel David Warren

Dibyendu Nandy

Robert A Popper

Ramanujapuram Raghuvir

Yang Li

Rene Rye Larsen

The present disclosure relates to an integrated circuit connectable to a microelectromechanical system (MEMS) transducer. The MEMS transducer is configured to generate a transducer audio signal in response to sound. The integrated circuit comprises a digital scrambling circuit coupled to a data communication interface. The digital scrambling circuit is configured to convert a digital audio stream, representative of the transducer audio signal, into a corresponding scrambled data stream. The integrated circuit additionally comprises a data bus interface coupled to the digital scrambling circuit and configured to output the scrambled data stream.

Digital transducer interface scrambling

The disclosure describes devices and methods for implementing impedance matching. The device may be implemented on an integrated circuit that includes a communication protocol interface circuit, a first signal output terminal, a first output driver circuit, and a controller. The first output driver circuit is coupled to the controller and has a corresponding plurality of parallel driver stages, each driver stage including a driver and a configurable resistance coupling an output of the driver to the first signal output terminal (e.g., first contact). The configurable resistances of the first output driver form a first series terminated resistance. The controller is configured to adjust the configurable resistances to adjust the first series terminated resistance.

Microphone assembly

The disclosure relates to a microphone assembly including a multibit analog-to-digital converter configured to generate N-bit samples representative of a microphone signal. The microphone assembly also includes a first digital-to-digital converter configured to generate a corresponding M-bit digital signal based on N-bit digital samples, wherein N and M are positive integers and N&#x3e;M. The microphone assembly may include a data interface configured to repeatedly receive samples of the M-bit digital signal and write bits of the M-bit digital signal to a data frame.

Microphone assembly with pulse density modulated signal

The disclosure relates to a microphone assembly comprising a multibit analog-to-digital converter configured to receive, sample, and quantize a microphone signal to generate N-bit digital microphone samples representative of the microphone signal at a first sampling frequency. The microphone assembly also comprises a first digital-to-digital converter configured to receive, quantize, and noise-shape the N-bit digital microphone samples to generate a corresponding M-bit Pulse Density Modulated (PDM) signal, wherein N and M are positive integers, and N&#x3e;M. The microphone assembly may comprise a SoundWire compliant data interface configured to repeatedly receive samples of the M-bit PDM signal and write bits of the M-bit PDM signal to a SoundWire data frame.

At a microphone, voice activity is detected in a data stream while simultaneously buffering audio data from the data stream to create buffered data. A signal is sent to a host indicating the positive detection of voice activity in the data stream. When an external clock signal is received from the host, the internal operation of the microphone is synchronized with the external clock signal. Buffered data stream is selectively sent through a first path, the first path including a buffer having a buffer delay time representing the time the first data stream takes to move through the buffer. The data stream is continuously sent through a second path as a real-time data stream, the second path not including the buffer, the real-time data stream beginning with the extended buffer data at a given instant in time. The buffered data stream and the real-time data stream are multiplexed onto a single data line and transmitting the multiplexed data stream to the host.

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Virum, Denmark

Andrzej Pawlowski