Abstract: A system for controlling an electronic device, including an accessory coupled to the device having a control interface for receiving at least one input and a tone generator, the accessory configured to, in response to an input, generate a corresponding control tone using the tone generator, and send the control tone and a calibration sequence to the device. The device is operable to receive the calibration sequence and control tone. The device includes a zero-crossing detector operable to determine at least one of the start or ending of each of the calibration sequence and the control tone and having a circuit operable to determine the periods of the calibration sequence and the control tone based on the zero-crossing detector output.

Abstract: An apparatus for a portable electronic device for receiving a jack of a headset, the jack including a set of lines, the set of lines including at least one audio line, a ground signal and a microphone signal line, the apparatus comprising a set of switches for receiving the ground signal line and the microphone signal line and a sensing circuit for reducing induced noise from the headset, wherein the sensing circuit is located between the set of switches and the microphone signal line and ground signal line.

Abstract: There is provided a single wire bus architecture comprising a single wire bus; a master device coupled to the single wire bus; at least one slave device coupled to the single wire bus; a communication protocol implemented over the single wire bus and employed by the master device and the at least one slave device; wherein when one of the at least one slave devices wishes to communicate with the master device, the one of the at least one slave devices discharges the clock signal during a tri-state stage of the clock signal; and wherein the single wire bus transmits a clock signal, power and data between the master device and the one of the at least one slave device in communication with the master device.

Abstract: There is provided an electret microphone comprising a junction gate-field-effect transistor (JFET) and a bias resistor connected to the JFET and supplying current to the JFET, whereby an electrical output is determined by measuring a differential voltage across the bias resistor.

Abstract: The present disclosure provides a method of determining microphone polarity in a headset. By being able to detect the polarity of the microphone within the headset, a portable electronic device may be compatible with any headset and is not limited to use with a specific headset. By applying a detection signal over one of lines within a headset cable, a return signal may be sensed on one of the other lines to determine which of the lines is the ground line and which line is the microphone line.

Abstract: A circuit, device and method for controlling an output signal of an amplifier are provided. The output signal may be controlled through a first stage located before a digital to analog converter and/or a second stage located after it. The first stage boosts the digital signal to match with the full signal range of the converter. For the second stage, the circuit comprises: a first resistor coupled to an output of the amplifier in series, the first resistor having a resistance value Rs; a second resistor coupled to the first resistor in series, the second resistor having a resistance value Rp; and an output terminal for a transducer connected to the electronic device, the output terminal connected in parallel to the second resistor. In the circuit, the resistance values Rs and Rp are related by an inversely proportional relationship.

Abstract: A MEMS microphone comprising a MEMS transducer having a back plate and a diaphragm as well as controllable bias voltage generator providing a DC bias voltage between the back plate and the diaphragm. The microphone also has an amplifier with a controllable gain, and a memory for storing information for determining a bias voltage to be provided by the bias voltage generator and the gain of the amplifier.

Abstract: The present invention relates to a condenser microphone assembly comprising a capacitive electro-acoustic transducer element comprising a diaphragm and a back-plate operatively connected to a DC bias voltage, a fast charge pump adapted to generate the DC bias voltage, and a controllable or programmable current source operatively connected to the DC bias voltage to draw a predetermined DC current there from. The controllable or programmable current source is responsive to a difference between a representative of a detected DC bias voltage and a DC reference voltage.

Abstract: In use in a battery, a first spiral-wound battery element and associated wiring generates a first magnetic field and a second spiral-wound battery element and associated wiring generates a second magnetic field. The first element, the second element and the wiring may be arranged within a casing so that the first magnetic field is proximate to the second magnetic field and oriented in an opposite polarity. Conveniently, it may be shown that the total magnetic field generated by the battery has significantly lower magnitude than the total magnetic field generated by a conventional battery for the same current drain and same wiring structure.

Abstract: The present invention relates to a condenser microphone assembly comprising an electro-acoustic transducer element comprising a diaphragm and a back plate, signal processing circuitry operatively connected to the transducer element so as to process signals generated by the transducer element, and a mode-setting circuitry for selectively setting the condenser microphone assembly in a test mode or an operational mode. The electro-acoustic sensitivity of the condenser microphone assembly, when operated in the test mode, is at least 40 dB lower than the corresponding electro-acoustic sensitivity of the assembly when operated in the operational mode. The present invention further relates to a method for determining a performance parameter of a signal processing circuitry mounted inside a housing of an assembled condenser microphone assembly.

Abstract: The invention relates to a digital microphone comprising an integral analog-to-digital converter based on a multi-level quantizer in cascade with a digital signal converter which is adapted to provide a single-bit output signal. Digital microphones in accordance with the invention are particularly well adapted for use in mobile terminals and compact portable communication equipment such as mobile or cellular phones, headsets, hearing prostheses etc.

Abstract: A condenser microphone is provided having a transducer element. A diaphragm has an electrically conductive portion. A back-plate has an electrically conductive portion. A DC bias voltage element is operatively coupled to the diaphragm and the back-plate. A collapse detection element is adapted to determine a physical parameter value related to a separation between the diaphragm and the back-plate. A collapse control element is adapted to control the DC bias voltage element based on the determined physical parameter value.

Abstract: A MEMS microphone comprising a MEMS transducer having a back plate and a diaphragm as well as controllable bias voltage generator providing a DC bias voltage between the back plate and the diaphragm. The microphone also has an amplifier with a controllable gain, and a memory for storing information for determining a bias voltage to be provided by the bias voltage generator and the gain of the amplifier.

Abstract: In a first aspect the present invention provides a compact high efficiency driver suitable for driving a loudspeaker, such as a miniature loudspeaker for mobile phones or hearing aids. The driver comprising an interface for receiving an input signal, a three-level modulator, and a three-level H-bridge. The interface may be adapted to receive a digital input signal. In a preferred embodiment of the driver the H-bridge is controlled by a correction circuit which is operated by a Return-To-Zero scheme. In a further preferred embodiment the driver comprises a supply voltage step-up circuit for increasing a voltage supplied to the H-bridge. In a second aspect the present invention provides a miniature loudspeaker assembly having a built-in driver. In a third aspect the present invention provides a mobile device with a built-in miniature loudspeaker assembly.

Abstract: The present invention relates to miniature transducer assemblies arranged within an assembly housing having a plurality of external terminals on the assembly housing in order for the assembly to be able to receive and transmit electrical signals to and from the assembly, wherein at least one of the plurality of external terminals is adapted to receive and/or transmit at least two electrical signals so as to reduced the number of external terminals on the assembly housing. The principles apply, for example, to miniature microphone or telecoil assemblies having built-in analog-to-digital converters so as to be able to provide a digital output signal according to a sensed acoustic pressure.

Abstract: A microphone assembly comprising; a transducer for receiving acoustic waves through a sound inlet port, and for converting received acoustic waves to analog audio signals, a pre-amplifier having an input and an output terminal, the input terminal being connected to the transducer so as to receive analog audio signals from the transducer, switching means having one or more input terminals, and an output terminal, a first input terminal of the one or more input terminals being connected to the output terminal of the pre-amplifier so as to receive amplified analog audio signals from the pre-amplifier, and an analog-to-digital converter having an input and an input/output terminal, the input terminal being connected to the output terminal of the switching means so as to convert received analog audio signals to digital audio signals. Preferably the switching means is configured so as to be controlled by a characteristic of a received auxiliary analog audio signal, such as its DC level or its AC amplitude level.

Abstract: In a first aspect the present invention provides a compact high efficiency driver suitable for driving a loudspeaker, such as a miniature loudspeaker for mobile phones or hearing aids. The driver comprising an interface for receiving an input signal, a three-level modulator, and a three-level H-bridge. The interface may be adapted to receive a digital input signal. In a preferred embodiment of the driver the H-bridge is controlled by a correction circuit which is operated by a Return-To-Zero scheme. In a further preferred embodiment the driver comprises a supply voltage step-up circuit for increasing a voltage supplied to the H-bridge. In a second aspect the present invention provides a miniature loudspeaker assembly having a built-in driver. In a third aspect the present invention provides a mobile device with a built-in miniature loudspeaker assembly.