Abstract: An audio amplifier employs an idle mode to reduce power consumption and improve efficiency of the amplifier. The audio amplifier comprises a modulator configured to receive an analog input signal. The modulator is operable to convert the analog input signal to differential first and second quantized signals, each having a common mode duty cycle. The modulator causes the common mode duty cycle of each of the first and second quantized signals to be shifted when the level of the analog input signal is below a threshold level so that the common mode duty cycle is one of greater than or less than fifty percent (50%). The amplifier further includes a power stage that receives the first and second quantized signals and generates corresponding first and second output signals configured to drive a load, wherein the first and second output signals switched between a supply voltage and a second voltage based on the respective first and second quantized signals.

Abstract: Systems and methods for calibrating a wireless power transmitter is described. A wireless power transmitter can include a controller and an amplifier module. The amplifier module can include an amplifier configured to amplify a voltage converted from a current proportional to power consumed by a wireless power transmitter, and a circuit connected to the amplifier. The circuit can be configured to receive a control signal from the controller. The circuit can be further configured to perform time division multiplexing on an output of the amplifier according to the control signal. A time division multiplexed output of the amplifier can include calibration data of the amplifier. The amplifier can be configured to output the time division multiplexed output to the controller.

Abstract: A monolithic component includes a field-effect power transistor and at least one first Schottky diode inside and on top of a gallium nitride substrate.

Abstract: A digital audio playback circuit includes a noise shaping circuit configured to receive an input digital audio signal, and a digital to analog converter (DAC) configured to convert the input digital audio signal to a pre-amplified output analog audio signal according to a gain ramp defined by a gain control signal. A muting circuit is configured to compare input digital audio signal to a threshold and assert a mute control signal when the input digital audio signal is below the threshold. An analog gain control ramp circuit is configured to generate the gain control signal in response to the mute control signal to cause the gain ramp to ramp down. An amplifier is configured to amplify the pre-amplified output analog audio signal for playback by an audio playback device.

Abstract: Class D amplifier circuitry comprising: input buffer circuitry configured to receive a first digital input signal modulated according to a first modulation scheme in which the digital input signal can take a first plurality N of discrete signal levels; analog modulator circuitry configured to generate an analog modulated signal based on an analog output signal output by the input buffer circuitry; and quantizer circuitry configured to generate an output signal based on the analog modulated signal, wherein the output signal is modulated according to a second modulation scheme in which the output signal can take a second plurality M of discrete signal levels, wherein the second plurality M is greater than the first plurality N.

Abstract: A tool for performing diagnostics on a fire detection system includes an induction coil which includes two halves that may be selectively opened and closed to surround a wire in the system and sense current through the wire. A diagnostic module and a conduit provide communication of data of the sensed current between the induction coil and the diagnostic module. The diagnostic module is configured to decode the data to interpret communications sent through the wire.

Abstract: A level shift transistor of a first conductivity type configured to level shift a signal from a primary side circuit to a secondary side circuit between the primary side circuit having a primary side reference potential as reference and the secondary side circuit having a secondary side reference potential independent from the primary side reference potential as reference, a diode connected in a forward direction between a first main electrode of the level shift transistor and the secondary side circuit, a capacitor connected in parallel to the diode, and an inverter configured to invert the signal are provided. A control electrode of the level shift transistor is connected to a primary side power supply of the primary side circuit, and a second main electrode thereof is connected to an output of the inverter. The inverter operates between the primary side reference potential and the primary side power supply.

Abstract: An amplifier system may include at least one input source, a converter configured to provide voltage rails to an amplifier, the voltage rails including a first voltage rail and a second voltage rail, a MOSFET arranged at a secondary side of the system at the first voltage rail, a second MOSFET arranged at the first voltage rail, a third MOSFET arranged at the second voltage rail, a fourth MOSFET arranged at the second voltage rail; and, a first capacitor arranged at the first voltage rail and a second capacitor arranged at the second voltage rail, the first and forth MOSFETS are configured to operate simultaneously with one another and the second and third MOSFETs are configured to operate simultaneously with one another and opposite of the first and fourth MOSFETs so as to allow synchronous rectification so that the first and second capacitors reciprocally and mutually exclusively charge and discharge.

Abstract: A switching amplifier comprises a controller, configured to receive an input signal and a reference signal, and to generate a control signal according to the input signal and the reference signal; a pulse-width modulation (PWM) modulator, coupled to the controller, configured to generate a PWM signal according to the input signal and the control signal; a power management unit, coupled to the controller, configured to receive a power supply and the control signal, and to provide an adaptive supply voltage according to the power supply and the control signal; and a switching power stage, coupled to the power management unit and the PWM modulator, configured to generate an output signal according to the PWM signal and the adaptive supply voltage.

Abstract: A switched mode amplifier system may include a switched mode amplifier having an amplifier input coupled to an output of an analog integrator and an amplifier output, include a feedback network coupled between the amplifier output and an input of the analog integrator, and a calibration system. The calibration system may be configured to force the input of the analog integrator to a fixed known input value, force the amplifier output to a fixed known duty cycle, measure an analog signal generated at the output of the analog integrator in response to forcing the input of the analog integrator to the fixed value, determine an offset of the switched mode amplifier system based on the analog signal, and correct for the offset.

Abstract: A nuclear magnetic resonance (NMR) power supply system and method are disclosed. The architecture adopts a two-stage topology to reduce the required capacitance by over ten times, leading to a four-fold improvement in power density. The first stage is an isolated converter that only supplies average power, therefore input filter and transformer sizes can be reduced. The second stage is a fast response DC-DC converter followed by a RF transmitter to produce a pulsed RF signal, so that the mid-point voltage after the first stage can be allowed to droop considerably, leading to much smaller sized capacitors. These and other embodiments enforce the isolated converter to only transfer average power, which reduces the power rating and the volume of the system's transformer.

Abstract: Circuits for protecting devices, such as gallium nitride (GaN) devices, and operating methods thereof are described. The circuits monitor a magnitude of the current in a device and reduce the magnitude of the current and/or shut down the device responsive to the magnitude of the current exceeding a threshold. These circuits safeguard devices from damaging operating conditions to prolong the operating life of the protected devices.

Abstract: An apparatus for amplifying an audio source includes a speaker and a chip. The chip includes a processor configured to generate a signal and an amplifier element configured to amplify the signal into an amplified signal. The chip further includes a current monitor configured to monitor the current of the amplified signal prior to the amplified signal being output from the chip to the speaker and a voltage monitor configured to monitor the voltage of the amplified signal prior to the amplified signal being output from the chip to the speaker. The processor of the chip is configured to control a power of the amplified signal output from the chip to the speaker based at least on the current and the voltage.

Abstract: The present disclosure provides a current detection circuit for a loudspeaker 500, comprising a first detection resistor RSP, a second detection resistor RSN, a sampling selection circuit 100, an input selection circuit 200, and a processing circuit 300. By adding the sampling selection circuit 100 and the input selection circuit 200, voltages on two ends of the corresponding detection resistors (RSP, RSN) are sampled according to the fact that potential differences of an output stage VOP and an output stage VON of a class-D audio power amplifier 400 are in different semi-periods, and the current of the loudspeaker 500 is obtained through processing, thereby detecting the current of the loudspeaker 500 without adding an anti-clipping distortion function to the class-D audio power amplifier 400.

Abstract: An adaptive sample and hold circuit for signal amplifier range selection is presented. The adaptive sample and hold circuit has an input for receiving an input signal and an output for providing a sample-and-hold-voltage. It also includes a sample-and-hold-capacitor to generate the sample-and-hold-voltage from the input signal, and a range detector. The range detector is adapted to identify a range of the input signal and to adjust a voltage at the sample-and-hold-capacitor based on the range of the input signal to maintain the sample-and-hold-voltage within a predetermined voltage span.

Abstract: A method for adjusting a parameter of an audio service and a terminal includes obtaining, by the terminal, first information, where the first information includes at least one of a first battery level or a first temperature, and adjusting, by the terminal, a parameter of an audio service of the terminal when a first condition is met, where the first condition includes one or more of the first battery level is less than a first preset threshold or greater than a second preset threshold, or the first temperature is less than a third preset threshold or greater than a fourth preset threshold.

Abstract: An analog front end circuit with pulse width modulation current compensation comprises sensing a current condition and determining if the current condition is a positive or negative current condition. An appropriate control signal is determined according to the current condition and sent to turn on a positive current electronic switch if the current condition is a negative current condition or sent to turn on a negative current electronic switch if the current condition is a positive current condition. A positive compensation current flows to offset negative parasitic current when the positive current electronic switch is turned on and a negative compensation current flows to offset positive parasitic current when the negative current electronic switch is turned on. A master control unit utilizes pulse width modulation signals of various widths associated with various current conditions to be sent to turn on the positive electronic switch or the negative electronic switch.

Abstract: An assembly for powering a first circuit, including at least one ferrite bead in series with a diode between a first terminal of application of a first voltage and a first terminal of said first circuit.

Abstract: The application describes a switched driver (401) for outputting a drive signal at an output node (402) to drive a load such as a transducer. The driver receives respective high-side and low-side voltages (VinH, VinL) defining an input voltage at first and second input nodes and has connections for first and second capacitors (403H, 403L). A network of switching paths is configured such that each of the first and second capacitors can be selectively charged to the input voltage, the first input node can be selectively coupled to a first node (N1) by a path that include or bypass the first capacitor, and the second input node can be selectively coupled to a second node (N2) by a path that includes or bypasses the second capacitor. The output node (402) can be switched between two switching voltages at the first or second nodes. The driver is selectively operable in different operating modes, where the switching voltages are different in each of said modes.

Abstract: A switching power amplifier includes logic circuitry that generates first and second components of a differential signal, based on received amplitude code and a delayed version of the same. The amplitude code includes a sign and a magnitude. When the sign is positive, a first logic path is configured to generate the first component based on the received amplitude code and the second logic path is configured to generate the second component based on the delayed amplitude code. When the sign is negative, the first logic path is configured to generate the first component based on the delayed amplitude code and the second logic path is configured to generate the second component based on the received amplitude code. The switching power amplifier further includes a differential-to-single ended conversion circuit configured to generate a single-ended signal based on the differential signal.

Abstract: A method for powering an audio amplifier includes receiving an input audio signal in an audio signal processor, delaying the input audio signal in the audio signal processor to generate a delayed audio signal, predicting a power demand estimate by analyzing the input audio signal to calculate the power demand estimate in the audio signal processer, and selecting, by the audio signal processor, power conversion settings for a DC to DC converter on the basis of the power demand estimate. The method further includes supplying power input to the DC to DC converter, converting the power input in accordance with the power conversion settings to provide a power output, powering the audio amplifier using the power output, and supplying the delayed audio signal to the audio amplifier from the audio signal processor to generate an amplified audio signal.

Abstract: Examples of amplifiers and nth-order loop filters thereof are configured to enable fast and robust recovery from saturation, while limiting signal distortion at or near full power delivery across multiple process and temperature corners. An example nth-order loop filter comprises n series-coupled resistor-capacitor (RC) integrators. In an example, each of the second RC integrator to the (n?1)th RC integrator has a reset mechanism responsive to a reset signal output from a reset controller when an input signal overload condition is detected at the input. Upon detecting the overload condition, each of the third RC integrator to the (n?1)th RC integrator is hard reset, the nth RC integrator is not reset, and a controlled reset is performed on the second RC integrator to recover from saturation caused by the signal overload condition, while maintaining the output signal below the 1% total harmonic distortion (THD) level at or near full power delivery.

Abstract: Provided are a frame configuring unit configured to configure a frame using a plurality of orthogonal frequency-division multiplexing (OFDM) symbols, by allocating time resources and frequency resources to a plurality of transmission data, and a transmitter which transmits the frame. The frame includes a first period in which a preamble which includes information on a frame configuration of the frame is transmitted, a second period in which a plurality of transmission data are transmitted by time division, a third period in which a plurality of transmission data are transmitted by frequency division, and a fourth period in which a plurality of transmission data are transmitted by time division and frequency division.

Abstract: An audio amplifier system is described herein, comprising: an amplifier adapted to amplify an audio signal and comprising an output enable/disable input, the amplifier further adapted to receive an output enable signal at the output enable/disable input that enables/disables an output of the amplifier; a Zobel network connected to the output of the audio amplifier and comprising a Zobel capacitor and a Zobel resistor arranged such that they form a high pass frequency filter function and wherein the Zobel network is adapted to be substantially resistive when a frequency of an audio signal output from the audio amplifier is within a first frequency range; a mirroring resistor connected in parallel to the Zobel resistor and adapted to mirror a power that is dissipated in the Zobel resistor, and wherein a printed circuit board upon which the mirroring resistor is located is adapted to conduct heat generated by the mirroring resistor; a negative temperature coefficient (NTC) resistor located in close proximity to

Abstract: An audio amplifier that implements current mode control without the use of an explicit or separate current mode sensor is disclosed. The audio amplifier may include a pair of feedback loops that provide current from a node located before an inductor of an output filter and current from a node located after the inductor of the output filter to an integrator circuit. The integrator circuit may be formed from existing circuitry of the audio amplifier controller. Thus, current mode control can be implemented without a separate current mode sensor.

Abstract: A power supply system controls the source impedance of a generator utilizing two amplifiers having asymmetrical power profiles in reference to a nominal load impedance that are diametrically opposite in reference to the nominal load impedance. Variations in power profiles may be achieved by using different topologies for each of the amplifiers or implementing a phase delay network. The output power from the first and second amplifiers may be combined using a combiner circuit or device and the output power from the combiner is transmitted to a plasma load. The output power of each amplifier may be independently controlled to alter one or more characteristics of the output power signal provided by the individual amplifiers. By changing the ratio of the output power of the first amplifier to the output power of the second amplified, the source impedance of the generators may be varied.

Abstract: A control method includes sequentially updating a next cycle pulse width modulation command for each of an upper switch and lower switch of a phase leg of a power converter according to an order defined by timing of a rising edge of the next cycle pulse width command for one of the switches relative to a rising edge of a previous cycle pulse width command for the one of the switches.

Abstract: The present disclosure relates to amplifier circuitry (300) that includes a linear amplifier stage (110) that receives an input signal and outputs a first drive signal to an output node (302) and a switching amplifier stage (130) operable to output a second drive signal to the output node (302). A controller (340) is selectively operable in a first dual-amplifier mode, in which switching of the switching amplifier stage is controlled based on a current of the first drive signal, such that the current of the first drive signal does not exceed a first current threshold magnitude; and at least one other mode, in which the controller controls the switching amplifier stage such that the current of the first drive signal may exceed the first current threshold magnitude. The controller (340) selectively controls the mode of operation based on an indication (SSL) of signal level of the output signal.

Abstract: A power control system for audio power amplifiers, especially in the automotive segment, dynamically controlling the output voltage through the reading of the input and output currents, and other parameters, automatically adjusting the amplifier to the load and to the operation conditions, allowing that the amplifier always operates within the safe operation range.

Abstract: An audio system includes an H-bridge. The audio system implements one or more techniques for ensuring a transistor within the H-bridge does not turn on in the event of the detection of a short-circuit on the output of the H-bridge. Other transistors within the H-bridge can turn and thus audio can still be played to a speaker.

Abstract: An exemplary system and method is disclosed employing a floating inverter amplifier comprising an inverter-based circuit comprising an input configured to be switchable between a floating reservoir capacitor during a first phase of operation and to a device power source during a second phase of operation. In some embodiments, the floating inverter amplifier is further configured for current reuse and dynamic bias. In other embodiments, the floating inverter amplifier is further configured with a dynamic cascode mechanism that does not need any additional bias voltage. The dynamic cascode mechanism may be used in combination with 2-step fast-settling operation to provide high-gain and high-speed noise suppression operation.

Abstract: In one aspect, a magnetic field sensor includes a plurality of tunneling magnetoresistance (TMR) elements that includes a first TMR element, a second TMR element, a third TMR element and a fourth TMR element. The first and second TMR elements are connected to a voltage source and the third and fourth TMR elements are connected to ground. Each TMR element has a pillar count of more than one pillar and the pillar count is selected to reduce the angle error below 1.0°.

Abstract: Isolated circuit systems are provided. The systems include a primary side circuit and a secondary circuit, electrically isolated from each other. The primary side and secondary side circuits each utilize a direct current (DC) reference signal. The primary side circuit may use the DC reference signal in a modulation operation. The secondary side circuit may use the DC reference signal in a demodulation operation. The DC reference signal may be sent from the primary side circuit to the secondary side circuit, or from the secondary side circuit to the primary side circuit.

Abstract: Various techniques are provided to reduce common mode disturbance associated with an amplifier, such as a class D amplifier. In one example, an amplifier includes a power stage configured to generate first and second PWM signals. The amplifier further includes an integration stage comprising input nodes configured to receive an input differential analog signal. The integration stage is configured to generate an output differential analog signal in response to the PWM signals and the input differential analog signal. The amplifier further includes an active compensation circuit configured to provide a compensation signal to the integration stage to reduce disturbances at the input nodes associated with the PWM signals switching between a common mode and a differential mode. Additional devices, systems, and methods are also provided.

Abstract: An audio device includes a network interface, an amplifier that amplifies an audio signal received through the network interface, and a processor configure to obtain an output value of a signal from the amplifier and sends the output value of the signal through the network interface.

Abstract: Current monitoring techniques are included in an electronic system that provides power to a load from a power output stage that supplies power to a load. Multiple current control devices form the power output stage in series with multiple sense resistors that provide corresponding sense voltages indicative of current provided through the multiple current control devices to the load in the same or different time intervals. A calibration control circuit controls injection of current through the multiple sense resistors individually and measures the corresponding sense voltages generated by the current to determine resistance values of the multiple sense resistors. A correction subsystem computes a first ratio of a first resistance to a second resistance and a second ratio of a third resistance to a fourth resistance of the multiple sense resistors, and controls compensation for a difference between the first ratio and the second ratio to remove the measurement error.

Abstract: A switch circuit provides a first output signal and a second output signal for switching between ternary modulation and quaternary modulation for a target device. A first output signal is provided from one of a first signal, a second signal and a ground signal according to an input signal and a duty signal, wherein the first signal is generated through performing a one-bit left-shift operation for the input signal, and the second signal is generated through adding the input signal and the duty signal. A second output signal is provided from one of a third signal, a fourth signal and the ground signal according to the input signal and the duty signal, wherein the third signal is generated through subtracting the input signal from the duty signal, and the fourth signal is generated through performing a two's-complement transformation and the one-bit left-shift operation for the input signal.

Abstract: An amplifier system may include a first stage having a plurality of inputs configured to receive a differential pulse-width modulation input signal and generate an intermediate signal based on the differential pulse-width modulation input signal, a quantizer configured to generate a modulated signal based on the intermediate signal, a single-ended class-D output stage configured to generate a single-ended output signal as a function of the differential pulse-width modulation input signal, a feedback network configured to feed back the single-ended output signal to a first input of the plurality of inputs and to feed back a ground voltage to a second input of the plurality of inputs, a plurality of buffers, each particular buffer configured to receive a respective component of the differential pulse-width modulation input signal and generate a respective buffered component, and an input network coupled between the plurality of buffers and the first stage.

Abstract: A method and apparatus is provided for control of plural optical phase shifters in an optical device, such as a Mach-Zehnder Interferometer switch. Drive signal magnitude is set using a level setting input and is used for operating both phase shifters, which may have similar characteristics due to co-location and co-manufacture. A device state control signal selects which of the phase shifters receives the drive signal. One or more switches may be used to route the drive signal to the selected phase shifter. Separate level control circuits and state control circuits operating at different speeds may be employed. When the phase shifters are asymmetrically conducting (e.g. carrier injection) phase shifters, a bi-polar drive circuit can be employed. In this case, the phase shifters can be connected in reverse-parallel, and the drive signal polarity can be switchably reversed in order to drive a selected one of the phase shifters.

Abstract: An electronic actuator device and a control method thereof are provided. The electronic actuator device includes a plurality of first and second power switches and a driving circuit. The first power switches respectively provide a first reference voltage to a plurality of voltage receiving ends of a motor respectively according to a plurality of first control signals. The second power switches respectively provide a second reference voltage to the voltage receiving ends respectively according to a plurality of second control signals. The driving circuit generates the first and second control signals. In a braking operation, the first power switches are turned on during a plurality of first time periods, and the second switches are turned on during a plurality of second time periods that are alternate and non-overlapped with the first time periods. An interval time period is present between each adjacent two of the first and second time periods.

Abstract: An embodiment pulse-width modulation (PWM) modulator circuit comprises a first half-bridge stage having a first output node and a second half-bridge stage having a second output node. The first output node and the second output node are configured to have an electrical load coupled therebetween to apply thereto a PWM-modulated output signal. The circuit comprises a differential stage having input nodes configured to receive an input signal applied between the input nodes and produce a differential control signal for the first half-bridge stage and the second half-bridge stage. A current comparator is arranged intermediate the differential stage and the first and second half-bridge stages. The current comparator is configured to produce a PWM-modulated drive signal to drive the half-bridge stages as a function of the input signal applied between the input nodes in the differential stage.

Abstract: This application is generally related to methods and systems for improving amplifier performance. For example, the system includes two or more gain and phase modulators. The system also includes two or more component amplifiers operably coupled to, and downstream of, the power splitter, where each of the two or more component amplifiers is operably coupled to a respective one of the two or more gain and phase modulators. The system further includes a power combiner operably coupled to, and downstream of, the two or more component amplifiers, configured to output a power signal. The system even further includes a Walsh generator configured to generate and transmit first and second Walsh codes to each of the two or more gain and phase modulators. The first Walsh code is orthogonal to the second Walsh code. A first set of the first and second Walsh codes is inverted with respect to a second set of the first and second Walsh codes.

Abstract: An improved method of providing high burst power to audio amplifiers from limited power sources, using parallel power paths to increase system efficiency without need for a power path controller, thus utilizing a simplified circuit operation and maximizing average power available for both the amplifier and supporting circuitry.

Abstract: A class-D amplifier with low pop-click noise is shown. A loop filter, a control signal generator, a first power driver, and a first feedback circuit are provided within the class-D amplifier to establish a first loop for signal amplification. The class-D amplifier further has a settling circuit and a pre-charging circuit. The settling circuit is configured to be combined with the loop filer and the control signal generator to establish a second loop to settle the loop filter and the control signal generator before the first loop is enabled. The pre-charging circuit is configured to pre-charge a positive output terminal and a negative output terminal of the first power driver.

Abstract: One embodiment provides a system comprising a single DC voltage source and a Class-D amplifier comprising at least one DC/DC converter operated by the single DC voltage source. The amplifier is configured to receive an input signal for power amplification, and generate, via the at least one DC/DC converter, a DC output voltage that approaches or exceeds a DC supply voltage from the single DC voltage source. A gain of the amplifier is a ratio of the output voltage level to the input signal. A steady-state operating point of the at least one DC/DC converter is zero output.

Abstract: This invention provides compact Power Amplifiers with improved efficiency of the circuitry and improved heat dissipation, together achieved much smaller enclosure size for use in modern installations requiring reduced height such as between the thin flat TV and wall, under the table or on the projector pole or in ceiling box and the like.

Abstract: 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.

Abstract: Amplifier architecture that allows low-cost class-D audio amplifiers to be compatible with ultrasonic signals, as well as loads presented by thin-film ultrasonic transducers. The amplifier architecture replaces the traditional capacitor used as an output filter in the class-D amplifier with the natural capacitance of the ultrasonic transducer load, and employs relative impedance magnitudes to create an under-damped low-pass filter that boosts voltage in the ultrasonic frequency band of interest. The amplifier architecture includes a secondary feedback loop to ensure that correct output voltage levels are provided.

Abstract: An amplifier, such as a Class D amplifier, having one or more feedback loops comprising a path from the input to the primary amplifier input, where the paths comprise a low pass filter and a compensator which is disabled when the primary amplifier clips.

Abstract: A semiconductor device includes: a first buffer at which a predetermined signal is input and that outputs a first output signal; a second buffer at which an inverted signal of the predetermined signal is input and that outputs a second output signal; and a short circuit detection circuit that, in accordance with a potential difference between the first output signal and the second output signal, outputs a short circuit evaluation signal evaluating whether or not there is a ground fault in at least one of a first terminal at an output side of the first buffer or a second terminal at an output side of the second buffer or evaluating whether or not there is a short circuit between the first terminal and the second terminal.