Methods, apparatus, systems, and articles of manufacture are disclosed to generate a modulation protocol to output audio. An example apparatus includes a modulation circuit including a first input, a second input, a first output, and a second output; a first gate coupled to the first output of the modulation circuit; a second gate coupled to the second output of the modulation circuit; a first multiplexer including a first input coupled to the first output of the modulation circuit, a second input coupled to the output of the second gate, and an output coupled to a first switch; and a second multiplexer including a first input coupled to the second output of the modulation circuit, a second input coupled to the output of the first gate, and an output coupled to a second switch.

An audio system has an amplifier for driving an audio actuator and includes a switched-mode power supply that draws power from a power source (e.g., battery) to supply power to the amplifier, a capacitor charged by the switched-mode power supply to supply power to the amplifier, and a feed-forward compressor that performs dynamic range compression of an audio input to provide an audio output for amplification by the amplifier. The compressor includes a sidechain frequency-biasing filter that generates a frequency-biased version of the audio input that is attenuated as frequency increases which causes the compressor to decrease the compression as frequency increases. A control block limits current drawn from the battery by the switched-mode power supply independent of audio input frequency, but the frequency-biasing filter enables the amplifier to service audio power transients greater than the current-limited power supply can supply by advantageously concurrently sourcing extra power from the capacitor.

An apparatus and method for providing a musical instrument effects unit with transistor bias voltage visualization are disclosed. An example embodiment includes a musical instrument effects apparatus with transistor bias voltage visualization, the apparatus comprising: a transistor amplifier; a bias control coupled to the transistor amplifier to adjust an active bias voltage setting for the transistor amplifier; and a bias voltage meter coupled to the transistor amplifier to monitor, measure, and enable visualization of the active bias voltage setting, the bias voltage meter including a visualization device to produce a visual representation of the active bias voltage setting.

An apparatus and method for providing a musical instrument effects unit with transistor bias voltage visualization are disclosed. An example embodiment includes a musical instrument effects apparatus with transistor bias voltage visualization, the apparatus comprising: a transistor amplifier; a bias control coupled to the transistor amplifier to adjust an active bias voltage setting for the transistor amplifier; and a bias voltage meter coupled to the transistor amplifier to monitor, measure, and enable visualization of the active bias voltage setting, the bias voltage meter including a visualization device to produce a visual representation of the active bias voltage setting.

A method and system for controlling power delivery to an electronic device having default and proprietary power modes. A default power delivery protocol between the power delivery adapter and the electronic device is completed upon connecting the power delivery adapter to the electronic device. When a proprietary power mode is available, it is verified and communicated to the power delivery adapter, wherein the power delivery adapter delivers power to the electronic device according to the proprietary power mode. When a proprietary power mode is not available, the power delivery adapter continues to deliver power in the default mode.

A method and system for controlling power delivery to an electronic device having default and proprietary power modes. A default power delivery protocol between the power delivery adapter and the electronic device is completed upon connecting the power delivery adapter to the electronic device. When a proprietary power mode is available, it is verified and communicated to the power delivery adapter, wherein the power delivery adapter delivers power to the electronic device according to the proprietary power mode. When a proprietary power mode is not available, the power delivery adapter continues to deliver power in the default mode.

A solid state relay and a method for controlling a signal path between an AC-signal output and a load in a power amplifier assembly are disclosed. The relay comprises a first and a second MOSFET having a common gate junction, a common source junction and wherein and wherein a drain terminal of a first MOSFET and a drain terminal of a second MOSFET form relay terminals. The solid state relay further comprises a control circuit comprising a positive side comprising a first controlled current generator configured to provide a first control current to the gate junction, and a negative side comprising a current mirror circuit configured to sink a second current from the source junction. Hereby, a generic solid state speaker relay has been disclosed. The relay performs up to the most stringent demands regarding pop/click on high quality products. It can be used to ground wire break, hot wire break and BTL (Bridge Tied Load) break. The design is rather tolerable to different MOSFETs and very competitive in quality and price.

The disclosure presents a method and an amplifier system for minimizing variation in an acoustical signal caused by variation in gain of an amplifier, comprising a battery for providing a supply voltage to the amplifier, a digital signal processor for providing the acoustical signal to the amplifier, a controller unit receiving an enablement signal when the supply voltage is in an offset mode, and based on the enablement signal requesting a measured voltage during a time period, and a first analog-to-digital converter configured for measuring the supply voltage to the amplifier when receiving the request from the controller unit or the first analog-to-digital converter is configured for measuring the supply voltage to the amplifier continuously, and where variations in the measured voltage relates to variations in the supply voltage during the time period. Furthermore, the controller unit is configured to predict offset modes (i.e. changes) in the supply voltage based on the enablement signals and a fitting of the measured voltages, and wherein the controller unit is configured to generate a compensating signal based on the fitting and transmit the compensating signal to the digital signal processor, the digital signal processor is then configured to minimize variation in the acoustical signal at the output of the amplifier by compensating the variation in gain of the amplifier based on the compensating signal.

The disclosure presents a method and an amplifier system for minimizing variation in an acoustical signal caused by variation in gain of an amplifier, comprising a battery for providing a supply voltage to the amplifier, a digital signal processor for providing the acoustical signal to the amplifier, a controller unit receiving an enablement signal when the supply voltage is in an offset mode, and based on the enablement signal requesting a measured voltage during a time period, and a first analog-to-digital converter configured for measuring the supply voltage to the amplifier when receiving the request from the controller unit or the first analog-to-digital converter is configured for measuring the supply voltage to the amplifier continuously, and where variations in the measured voltage relates to variations in the supply voltage during the time period. Furthermore, the controller unit is configured to predict offset modes (i.e. changes) in the supply voltage based on the enablement signals and a fitting of the measured voltages, and wherein the controller unit is configured to generate a compensating signal based on the fitting and transmit the compensating signal to the digital signal processor, the digital signal processor is then configured to minimize variation in the acoustical signal at the output of the amplifier by compensating the variation in gain of the amplifier based on the compensating signal.

Brownout management for an audio amplification system. An audio amplification system includes audio volume control circuitry, audio sample interpolation circuitry, and brownout management circuitry. The brownout management circuitry includes brownout detection circuitry and brownout response circuitry. The brownout detection circuitry is configured to determine whether a voltage of a battery that powers the audio amplification system is below a brownout threshold, and to generate a brownout detection signal that indicates the voltage is below the brownout threshold. The brownout response circuitry is coupled to an audio output of the audio sample interpolation circuitry. The brownout response circuitry is configured to attenuate the audio samples output by the audio sample interpolation circuitry responsive to the brownout detection signal indicating that the voltage is below the brownout threshold.