New high-efficiency 2.5 V/0.45 W RWDM class-D audio amplifier for portable consumer electronics

2007 18th European Conference on Circuit Theory and Design

2007

Switching power amplifiers offer the potential for superior efficiencies if used at radio frequencies. However many existing bandpass architectures require a switching frequency four times that of the signal, making implementation difficult. In this paper we propose to use a high-pass sigma-delta modulator to reduce the switching rate to only twice of the signal. We will present a solution to the problem of the reflected image and demonstrate it's viability for use in mobile telephony.

Section: Introductionmentioning

confidence: 99%

Using high pass sigma-delta modulation for Class-S power amplifiers

Ralph

2007 18th European Conference on Circuit Theory and Design

2007

“…In comparison to Class E, F and other harmonic switching amplifiers the class D amplifier can be designed with a wide pass band while maintain efficiency. Class-D amplifiers have a theoretical drain efficiency of 100%, practical demonstrations of between 85% -90% have been realized [3]. For this reason a class D switch-mode PA can be used to realize the power amplification stage corresponding to block 'C' in Figure 1.…”

Section: Figure 1 Class S Amplification Systemmentioning

confidence: 99%

FPGA SerDes Capability as Switch mode PA Modulator

Finnerty

Dooley

25th IET Irish Signals &Amp; Systems Conference 2014 and 2014 China-Ireland International Conference on Information and Communi

2014

Abstract-This paper demonstrates the ability of current commercially available FPGA hardware to generate radio frequency pulsed modulated signals. This work is carried out to determine the suitability of integrated SerDes devices for use in frequency flexible transmitters capable of modulating switch mode power amplifiers (SMPA's). The paper shows that it is possible to meet spectral mask requirements of -50dBc for WCDMA signals at carrier frequencies in digital dividend from 750MHz to 1GHz.

“…In practice this is not possible as yet at high frequencies. For audio applications however efficiencies of 85-90% [1] have been realized. In these low frequency applications amplifiers such as Class-D amplifiers are widely used today.…”

Section: Introductionmentioning

confidence: 99%

Digital quadrature mixing of lowpass sigma-delta modulators for switch-mode power amplifiers

Finnerty

Dooley

2011 20th European Conference on Circuit Theory and Design (ECCTD)

2011

Abstract-In this paper a phase compensation technique for the digital upconversion of a quadrature signal for amplification with switch mode power amplifiers is proposed. When a digital signal generator is used to generate the complex envelope signal care must be taken to compensate for the phase skew between the two paths. If phase compensation is not implemented an image caused by up converting the complex envelope of the modulation signal is created. By compensating for phase skew between the I and Q signal paths it is possible to remove this image signal and enable the transmission of multi carrier signals. As a direct result of this technique there is a reduction in the filtering effort at the output of the power amplifier to meet spectral mask requirements.