A single-inductor multiple output (SIMO) switched-power DC-DC converter for a class-D amplifier provides outputs that are symmetric about a common-mode input voltage of the amplifier, while remaining asymmetric about a return terminal of the amplifier and switching converter. The DC-DC converter includes an inductive element, a switching circuit that energizes the inductive element from an input source, and a control circuit that controls the switching circuit. The control circuit may have multiple switching modes, and in one of the multiple switching modes, the switching circuit may couple the inductive element between outputs of the converter so that stored energy produces a differential change between the voltages of the outputs. The control circuit may implement a first control loop that maintains a common mode voltage of the pair of outputs at a predetermined voltage independent of the individual voltages of the pair of outputs.

In some embodiments, a low voltage system can include a capacitor between an output node of an amplifier and ground, with the output node connectable to a load, and the amplifier configured to operate with a series of pulses. The low voltage system can further include a monitoring circuit configured to monitor a voltage at the capacitor against a desired low voltage value, and a control system configured to generate the series of pulses for the amplifier, and to control charging and discharging of the capacitor based on an output of the monitoring circuit to regulate the voltage at the output node at approximately the desired low voltage value.

An audio signal amplification device of the disclosure includes: a delta-sigma modulation part configured to resample an input digital audio signal with a quantization number smaller than a quantization number of the digital audio signal; a pulse-width modulation part configured to convert an output signal from the delta-sigma modulation part into a pulse-width modulation signal which sets a gradation of the output signal in an amplitude direction at a gradation of a pulse width; a power amplification part configured to perform power amplification on an output signal from the pulse-width modulation part; a low-pass filter configured to diminish a component higher than a predetermined cutoff frequency, in an output signal from the power amplification part, and to output the resultant signal; and a correction processing part configured to generate a correction signal for correcting the digital audio signal. The correction processing part includes a switch configured to control coupling of the correction processing part to the low-pass filter. When the switch is on, the correction processing part couples a loudspeaker to the low-pass filter, and generates the correction signal.

A power supply system for a plasma process includes two separate power supplies of essentially identical performance characteristics, including a first power supply and a second power supply, and a data transfer connection operably coupling the two power supplies for data communication between the two power supplies. The first power supply is configured to: receive, in a standby mode, data via the data transfer connection from the second power supply supplying power to a plasma process in a normal operating mode, and supply, in an active backup mode, power to the plasma process in place of the second power supply, as a function of the received data. The first power supply can supply in the active backup mode to the plasma process the power having one or more characteristics that are substantially the same as those of the power provided by the second power supply in the normal operating mode.

Various embodiments of the invention provide for an AC-coupling method and systems that utilize a nested loop circuit to generate a differential mode output that facilitates an offset compensation and a common mode output that facilitates DC-biasing of an active circuit. In embodiments, the nested loop circuit comprises a differential amplifier and a differential mode loop that generates a differential mode output and a common mode loop that uses a common mode voltage and a reference voltage to generate the common mode output.

This invention enables to efficiently improve the signal-to-noise power ratio of a delta-sigma modulator without increasing the operating frequency. A digital modulation device 40 includes: a setting unit 41 that sets mutually different default values for N delta-sigma modulation units 42-1 to 42-N; N delta-sigma modulation units 42-1 to 42-N that input signals for each clock cycle indicated in a first clock signal and then perform delta-sigma modulation on the input signals to output modulated signals including noise signals having values that change in accordance with default values; and a serial output unit 43 that inputs, in order, the modulated signals output by the delta-sigma modulation units 42-1 to 42-N for each clock cycle indicated in a second clock signal, the second clock signal having a clock cycle that is 1/N of the clock cycle of the first clock signal, and then serializes and outputs the modulated signals.

An audio amplifier circuit for providing an output signal to an audio transducer may include a power amplifier and a control circuit. The power amplifier may include an audio input for receiving an audio input signal, an audio output for generating the output signal based on the audio input signal, and a power supply input for receiving a power supply voltage, wherein the power supply voltage is variable among at least a first supply voltage and a second supply voltage greater than the first supply voltage. The control circuit may be configured to predict, based on one or more characteristics of a signal indicative of the output signal, an occurrence of a condition for changing the power supply voltage, and responsive to predicting the occurrence of the condition, change, at an approximate zero crossing of the signal indicative of the output signal, the power supply voltage.

In accordance with embodiments of the present disclosure a control circuit may include at least one input for monitoring a respective signal for each of a plurality of amplifiers, an output for outputting at least one control signal for controlling a power supply level of the single signal-variant power supply configured to deliver electrical energy to the plurality of amplifiers, and decision and control logic. The decision and control logic may be configured to monitor the respective signals for each of the plurality of amplifiers and, based on the respective signals, and a respective requirement associated with each of the plurality of amplifiers, setting a power supply level of the single signal-variant power supply and outputting the at least one control signal to control the power supply level such that the respective requirements are satisfied.

For generating quantized signals, a quantized phase domain related to quantized phases of an input signal is generated. Vectors that the input signal may occupy are calculated based on the quantized phase domain. A first quantized phase of a first component of the input signal is generated per the quantized phase domain, and a second quantized phase of a second component of the input signal is generated per the quantized phase domain.

An amplifier includes an input circuit configured to receive an analog input signal and a feedback signal, and output an analog error signal based on the analog input signal and the feedback signal. An ADC is configured to convert the analog error signal into a digital signal in a phase domain. A digital control circuit is configured to generate a digital control signal based on the digital signal in the phase domain. An output circuit is configured to generate an amplified output signal based on the digital control signal, and a feedback circuit is configured generate the feedback signal based on the amplified output signal.