The present disclosure provides a gradient amplifier driver stage circuit, a gradient amplifier system and a control method thereof. The gradient amplifier driver stage circuit includes: a gradient coil and a plurality of gradient driver modules electrically cascaded with each other and forming an output end, the output end being electrically connected to the gradient coil, wherein each gradient driver module includes a pre-stage power supply and a bridge amplifier connected in parallel, output voltage of the pre-stage power supplies of the plurality of gradient driver modules are the same, and each gradient driver module is configured to provide an inductive voltage drop and a resistive voltage drop on the gradient coil.

The present invention relates to an amplification device (10) of an input signal comprising: a first amplification stage (12), a second amplification stage (14), each amplification stage (12, 14) comprising: a switching circuit (22), the switching circuit (22) being able to generate, as output (22A, 22B), a switched signal having at least two states, and an inductive element (24) able to smooth the switched signal to obtain a smoothed signal (I1, I3), the smoothed signal (I1, I3) having a useful component and a stray component.

The amplification device (10) further comprises a compensation circuit (16), for each amplification stage (12, 14), able to generate a compensation signal (I2, I4) of the stray component of the smoothed signal (I1, I3) generated in the inductive element (24) of the corresponding amplification stage (12, 14).

Shoot-through condition in a component containing an amplifier with a push-pull output stage is managed. A first current in a first transistor of the output stage is mirrored to generate a first mirrored current. A second current in a second transistor of the output stage is mirrored to generate a second mirrored current. A sum of the first mirrored current and said second mirrored current is generated. When a magnitude of the sum exceeds a first pre-determined threshold, a respective control voltage of the first transistor and the second transistor is adjusted to reduce the first current and the second current at least until the sum falls below a second pre-determined threshold. In an embodiment, the first pre-determined threshold equals the second pre-determined threshold. In an embodiment, the component is a class-L power amplifier.

Shoot-through condition in a component containing an amplifier with a push-pull output stage is managed. A first current in a first transistor of the output stage is mirrored to generate a first mirrored current. A second current in a second transistor of the output stage is mirrored to generate a second mirrored current. A sum of the first mirrored current and said second mirrored current is generated. When a magnitude of the sum exceeds a first pre-determined threshold, a respective control voltage of the first transistor and the second transistor is adjusted to reduce the first current and the second current at least until the sum falls below a second pre-determined threshold. In an embodiment, the first pre-determined threshold equals the second pre-determined threshold. In an embodiment, the component is a class-L power amplifier.

Systems and methods according to one or more embodiments are provided for correcting a current measurement through a speaker in an audio system. In one example, a system for driving a speaker includes an output stage configured to drive a current through the speaker. The system further includes a first and second current sensor coupled to the output stage and configured to measure a positive current including a first measurement error and a negative current including a second measurement error through the speaker, respectively. The system further includes a processing block coupled to the first and second current sensors to receive the measured positive and negative current signals and configured to add a positive offset value to an input of each first and second current sensors, determine the first and second measurement errors, and correct a measured current using the positive and negative currents and the determined first and second measurement errors.

A circuit includes an active balun having an RF signal input and having differential signal outputs, the active balun including a first pair of transistors coupled to the RF signal input, the first pair of transistors including a first transistor of a first type and a second transistor of a second type, wherein the first type and second type are complementary; and an intermodulation distortion (IMD) sink circuit having an operational amplifier (op amp) coupled between a first node and a second node, wherein the first transistor and second transistor are coupled in series between the first node and the second node.

A circuit includes an active balun having an RF signal input and having differential signal outputs, the active balun including a first pair of transistors coupled to the RF signal input, the first pair of transistors including a first transistor of a first type and a second transistor of a second type, wherein the first type and second type are complementary; and an intermodulation distortion (IMD) sink circuit having an operational amplifier (op amp) coupled between a first node and a second node, wherein the first transistor and second transistor are coupled in series between the first node and the second node.

To reduce signal output and wiring to a D/A converter (DAC). A DAP 1 comprises a DAC 7 that D/A-converts LR 2 channels digital audio data into LR 2 channels analog audio data, an amplification circuit 9 that amplifies the LR 2 channels analog audio data that the DAC 7 D/A-converts, a DAC 8 that D/A-converts the LR 2 channels digital audio data into the LR 2 channels analog audio data, and an amplification circuit 10 that amplifies inverted LR 2 channels analog audio data that the LR 2 channels analog audio data that the DAC 8 D/A-converts is inverted.

In a class-D amplifier, oscillation phenomenon is suppressed in a high RF range and surge voltage is reduced. An oscillation absorption circuit is connected on the power supply side of the class-D amplifier circuit, and the class-D amplifier circuit and thus connected oscillation absorption circuit equivalently configure an oscillation circuit. Resistance provided in the oscillation absorption circuit is assumed as damping resistance of the oscillation circuit, thereby suppressing the oscillation phenomenon and reducing the surge voltage. The oscillation absorption circuit is made up of the RL parallel circuit of resistance and inductance. The oscillation absorption circuit and the class-D amplifier circuit constitute the oscillation circuit, and the resistance of the oscillation absorption circuit constitutes the damping resistance of the oscillation circuit in the high RF range.

To reduce signal output and wiring to a D/A converter (DAC).

A DAP 1 comprises a DAC 7 that D/A-converts LR 2 channels digital audio data into LR 2 channels analog audio data, an amplification circuit 9 that amplifies the LR 2 channels analog audio data that the DAC 7 D/A-converts, a DAC 8 that D/A-converts the LR 2 channels digital audio data into the LR 2 channels analog audio data, and an amplification circuit 10 that amplifies inverted LR 2 channels analog audio data that the LR 2 channels analog audio data that the DAC 8 D/A-converts is inverted.