Cirrus Logic Inc.

Ziyan Zou

Ning Li

John L Melanson

Anthony Stephen Doy

Kaichow Lau

George E Hardy

Emmanuel A Marchais

Carl Lennart Ståhl

Chin Huang Yong

Sandeep Prasad Sira

K Joshua Bodon

The impedance of a connector, such as a flex cable, between a source and load affects the temperature and power consumption within an electronic system, such as a mobile device. According to embodiments described in this disclosure, the impedance of the flex cable may be separately tracked from the impedance of the source, which provides for improved power management within the electronic system. The impedance of the flex cable may be factored into determining a maximum available power to the load. The impedance of the flex cable may also be mapped to a temperature and used to manage power to maintain operation within temperature limits. Additional aspects of power management and impedance tracking for a connector are described herein.

Impedance tracking for connector between source and load

An integrated circuit may include an output for providing an output signal to a transducer including both a source audio signal for playback to a listener and an anti-noise signal for countering the effect of ambient audio sounds in an acoustic output of the transducer, an error microphone input for receiving an error microphone signal indicative of the output of the transducer and the ambient audio sounds at the transducer, and a processing circuit. The processing circuit may implement a feedback path comprising a feedback filter having a response that generates a feedback anti-noise signal based on the error microphone signal, the feedback filter comprising a plurality of biquad filters and wherein the anti-noise signal is generated from the feedback anti-noise signal and an event detection and oversight control that detects that an ambient audio event is occurring that could cause the feedback filter to generate an undesirable component in the anti-noise signal, and controls filter coefficients of one or more of the plurality of biquad filters to reduce the undesirable component.

Systems and methods for modifying biquad filters of a feedback filter in feedback active noise cancellation

Methods, systems, circuits and computer program products provide an output signal to drive an electromechanical transducer that selectively contains a cooling component when a thermal limit of a voice coil of the electromechanical transducer is exceeded and which air-cools the transducer by convection. An indication of a temperature of a voice coil of the electromechanical transducer is determined and compared with a thermal limit of the transducer. If the thermal limit of the transducer is exceeded by the indication of the temperature of the voice coil, the cooling component is introduced to the output signal that drives the transducer. The cooling component is a signal having a frequency within a low-frequency resonance portion of the response of the electromechanical transducer, so that additional air convection is caused at the transducer to remove heat from the voice coil due to the cooling component of the output signal.

Transducer cooling by introduction of a cooling component in the transducer input signal

An audio output system for providing an output signal to a micro-speaker provides energy reduction and thermal protection by removing components of an input signal from which the output signal is generated, so that the audio power output system does not expend power reproducing portions of the audio information that would not be perceived by a listener. The micro-speaker has a resonant frequency such that substantial content of the audio information lies below the resonant frequency. A processing subsystem receives the audio information and generates the output signal by filtering the audio information with a response simulating the micro-speaker and an acoustic path to the listener, and comparing the filtered audio information with a frequency-dependent threshold of hearing. The processing subsystem then removes portions of the audio information that have an amplitude below the frequency-dependent threshold of hearing.

Micro-speaker audio power reproduction system and method with reduced energy use and thermal protection using micro-speaker electro-acoustic response and human hearing thresholds

Embodiments described herein relate to methods and apparatus for limiting the excursion of a transducer. The method comprises receiving a transducer signal; and limiting the transducer signal or a signal derived therefrom to generate a limited transducer signal for input into the transducer such that an electrical response caused by the limited transducer signal in an electrical model of the transducer would be less than a threshold electrical response, wherein the threshold electrical response has been determined by: inputting a stimulus input signal into the electrical model of the transducer, wherein the stimulus input signal is designed to cause the transducer to reach a maximum excursion; and determining the threshold electrical response as a maximum of the electrical response caused by the stimulus input signal in the electrical model of the transducer.

Growing community of inventors

Austin, TX, United States of America

Ziyan Zou