The power requirements imposed on the amplifier by piezoelectric actuators is discussed. We consider a two-degree-of-freedom mechanical system driven by a piezoelectric stack for the purpose of analyzing power flow and power dissipation of four amplifiers. Two of the amplifiers are benchtop linear amplifiers. The other two amplifiers are based on switching topologies. The power consumption of a...

Since the xDSL specifications impose stringent linearity requirements to ensure the integrity of the data transferred, current line drivers use linear amplifiers. The downside of these solutions is their power consumption, as the xDSL modulation has a high peak to average ratio, forcing the amplifier to operate in its least efficient region. An alternative is the use of switching amplifiers, wh...

Class D audio amplifiers have gained significant influence in sound reproduction due to their high efficiency. One of the most commonly used control methods in class D amplifiers is known as self-oscillation. An parameter of key interest in self-oscillating class D amplifiers is the switching frequency, which can be directly related to the performance of the amplifier. This paper will clearify ...

A Class-E/Fodd high power amplifier (PA) using the distributed active transformer (DAT) is demonstrated at 29MHz. The DAT combines the output power from four VDMOS push-pull pairs. The zero voltage switching (ZVS) condition is investigated and modified for the Class-E/Fodd amplifier with a non-ideal output transformer. All lumped elements including the DAT and the transistor package are modeled...

Abstract In this paper a promising novel output voltage filtering concept for multi-cell switch-mode power amplifiers is analyzed. The proposed hybrid filtering concept is based on a passive LC filter enhanced by a linear-mode correction stage of small rated power. Using this principle, also "sub-harmonic" (i.e. low-frequency) switching noise distortions (typically appearing in real interleaved...

Co-design of digital signal-processing (DSP) algorithms and power-amplifier characteristics can lead to improved efficiency and linearity through a variety of strategies including: predistortion, DSP control over bias conditions, particularly the power supply voltage, and DSP generation of digital input signals for switching amplifiers. This paper discusses several amplifier architectures that ...

We present a transfer-matrix method capable of simulating the effects of nonuniform gratings on the filtering, amplification, and bistability characteristics of distributed feedback (DFB) semiconductor laser amplifiers. The linewidth enhancement factor is incorporated in a way that allows direct gaintuning of the bistability hysteresis. As an example, we compare a /4 phase-shifted DFB amplifier...

This paper deals with the design techniques of power efficient switching regulators intended for linear power amplifiers (PAs) employing envelope tracking techniques in wideband wireless standards. The bottlenecks involve a tradeoff between ripple voltage, slew rate and bandwidth. The slew rate limitation is identified as the main challenge; thus a ‘bang-bang’ slew-enhancement technique is prop...

Semiconductor optical amplifiers (SOAs) are a versatile core technology and the basis for the implementation of a number of key functionalities central to the evolution of highly wavelength-agile all-optical networks. We present an overview of the state of the art of SOAs and summarize a range of applications such as power boosters, preamplifiers, optical linear (gain-clamped) amplifiers, optic...