Power analog to digital converter for voltage scaling applications

In order to optimize energy efficiency, some applications require adapting supply voltage according to the work load requirements. For example, in high performance digital systems and in RF systems, voltage scaling and modulation techniques have been adopted in order to achieve a more efficient processing of the energy. These techniques are based in rapidly adjusting the system supply voltage level. In order to achieve this, a topology which is capable of achieving very fast changes of the output voltage is needed. In this paper a PWM multiphase topology whose phases are coupled by using transformers is proposed to be used in an envelope elimination and restoration (EER) technique. The proposed topology can achieve very fast changes between discrete voltage steps so it can be considered as a power analog to digita

Comparación entre dos Arquitecturas para la Implementación de un Convertidor Multinivel para un Amplificación de Envolvente de Alta Eficiencia

Recientemente ha sido presentada una solución que combina un convertidor multinivel en serie con un regulador lineal para obtener un amplificador de envolvente. Este convertidor se emplea para la mejora de la eficiencia en amplificadores de RF mediante la implementación de la técnica de eliminación y restauración de envolvente (EER). La solución propuesta puede reproducir cualquier señal con componentes espectrales de hasta 2 MHz con una potencia instantánea máxima de salida de 50 W. En este artículo se presenta una importante modificación del convertidor multinivel basada en una arquitectura de celda de tres estados. Se presenta una comparación entre estas dos posibles implementaciones de la celda multinivel. La topología de celda de tres estados tiene varias ventajas sobre la de dos estados: menor número de celdas y entradas de tensión y un diseño físico y eléctrico más sencillo. Se ha realizado una comparación de la energía manejada por cada topología de celda para diferentes señales de entrada. Se analiza su influencia en la eficiencia de cada topología de celda y en la optimización del diseño del amplificador de envolvente para ambas topologías. Adicionalmente se ha construido un prototipo para validar los estudios teóricos presentados y poder comparar más detalladamente ambas solucione

Switching capacities based envelope amplifier for high efficiency RF amplifiers

Modern transmitters usually have to amplify and transmit signals with simultaneous envelope and phase modulation. Due to this property of the transmitted signal, linear power amplifiers (class A, B or AB) are usually used as a solution for the power amplifier stage. These amplifiers have high linearity, but suffer from low efficiency when the transmitted signal has high peak-to-average power ratio (PAPR). The Kahn envelope elimination and restoration (EER) technique is used to enhance efficiency of RF transmitters, by combining highly efficient, nonlinear RF amplifier (class E) with a highly efficient envelope amplifier in order to obtain linear and highly efficient RF amplifier. This paper presents a solution for the envelope amplifier based on a multilevel converter in series with a linear regulator. The multilevel converter is implemented by employing voltage dividers based on switching capacities. The implemented envelope amplifier can reproduce any signal with maximum spectral component of 2 MHz and give instantaneous maximum power of 50 W. The efficiency measurements show that when the signals with low average value are transmitted, the implemented prototypes have up to 20% higher efficiency than linear regulator that is used as a conventional solution

Multilevel Power Supply for High Efficiency RF Amplifiers

In radio systems linear power amplifiers (class A, B or AB) are usually used as a solution for the power amplifier stage. These amplifiers have high linearity, but suffer from low efficiency when the transmitted signal has low peak-to-average power ratio. The Kahn envelope elimination and restoration (EER) technique is used to enhance efficiency of RF transmitters, by combining highly efficient, nonlinear RF amplifier (class D or E) with a highly efficient envelope amplifier in order to obtain linear and highly efficient RF amplifier. This paper presents a solution for the envelope amplifier based on a combination of multilevel converter and linear regulator. The proposed solution can reproduce any signal with maximal spectral component of 2 MHz and give instantaneous maximal power of 50 W. The efficiency measurements show that when the signals with low average value are transmitted, it has up to 15% higher efficiency than linear regulator that is used as a conventional solution. Additionally, the algorithm for selection of voltage levels for the multilevel converter is explained, as well

Comparison of Two Different Cell Topologies for a Multilevel Power Supply to Achieve High Efficiency Envelope Amplifier

A solution combining a multilevel converter in series with a linear regulator to obtain an envelope amplifier was presented recently in for EER. Two possible implementations of the multilevel cell are compared. In, a two-state topology for the multilevel cell is proposed for the envelope amplifier. The three-state cell topology, proposed in this paper, has two main advantages: less number of cells and inputs and a simpler electrical and physical design. The comparison of the energy handled by each cell topology confirms several advantages of the three-state cell. Considerations to optimize the design of the multilevel converter for both cell topologies and experimental comparison between both cell architectures are enclosed

Envelope Amplifier for RF Amplifier based on Multilevel Converter

Modern transmitters usually have to amplify and transmit signals with simultaneous envelope and phase modulation. Due to this property of the transmitted signal, linear power amplifiers (class A, B or AB) are usually used as a solution for the power amplifier stage. These amplifiers have high linearity, but suffer from low efficiency when the transmitted signal has low peakto-average power ratio. The Kahn envelope elimination and restoration (EER) technique is used to enhance efficiency of RF transmitters, by combining highly efficient, nonlinear RF amplifier (class D or E) with a highly efficient envelope amplifier in order to obtain linear and highly efficient RF amplifierThis paper presents a solution for the envelope amplifier based on a combination of multilevel converter and linear regulator. The proposed solution can reproduce any signal with maximal spectral component of 2 MHz and give instantaneous maximal power of 50 W. The efficiency measurements show that when the signals with low average value are transmitted, it has up to 15% higher efficiency than linear regulator that is used as a conventional solution. Additionally, the algorithm for selection of voltage levels for the multilevel converter is explained, as wel

Comparison of Two Multilevel Architectures for Envelope Amplifier

Modern transmitters usually have to amplify and transmit signals with simultaneous envelope and phase modulation. Due to this property of the transmitted signal, linear power amplifiers (class A, B or AB) are usually used as a solution for the power amplifier stage. These amplifiers have high linearity, but suffer from low efficiency when the transmitted signal has low peak-to-average power ratio. The Kahn envelope elimination and restoration (EER) technique is used to enhance efficiency of RF transmitters, by combining highly efficient, nonlinear RF amplifier (class D or E) with a highly efficient envelope amplifier in order to obtain linear and highly efficient RF amplifier. This paper compares two solutions for the envelope amplifier based on a combination of multilevel converter and linear regulator. The solutions are compared regarding their efficiency, size and weight. Both solutions can reproduce any signal with maximal spectral component of 1 MHz and give instantaneous maximal power of 50 W. The efficiency measurements show that when the signals with low average value are transmitted, the implemented prototypes have up to 19% higher efficiency than linear regulator that is used as a conventional solution

Transformer-coupled converter for voltage modulation techniques

In high performance digital systems as well as in RF systems, voltage scaling and modulation techniques have been adopted to achieve a more efficient processing of the energy. The implementation of such techniques relies on a power supply that is capable of rapidly adjusting the system supply voltage. In this paper, a pulsewidth modulation multiphase topology with magnetic coupling is proposed for its use in voltage modulation techniques. Since the magnetic coupling in this topology is done with transformers instead of coupled inductors, the energy storage is reduced and very fast voltage changes are achieved. Advantages and drawbacks of this topology have been previously presented in the literature and in this paper, the design criteria for implementing a power supply for the envelope elimination and restoration technique in an RF system are presented along with an implementation of the power supply

Modulador de amplitude para amplificadores de rádio frequência

Mestrado em Engenharia Electrónica e TelecomunicaçõesEste trabalho enquadra-se na área de Electrónica para Telecomunicações. A alteração dinâmica da fonte de alimentação do amplificador de potência é uma das actuais soluções para ultrapassar o compromisso linearidade rendimento. A construção do modulador para gerar a alimentação dinâmica é crucial para a obtenção de um conjunto que cumpra os requisitos de linearidade e rendimento. Os requisitos chave deste bloco são a largura de banda e rendimento. Neste trabalho foi feito o estudo das diversas abordagens e técnicas para melhoramento da eficiência num amplificador de potência para rádio frequência em particular as que recorrem a modelação da amplitude da fonte de Alimentação (Seguidor de envolvente (SE), eliminação e restauro de envolvente (EER) e modulação polar). Efectuou-se o estudo dos moduladores de amplitude, seus requisitos chave e técnicas de construção. Foi implementado um modulador de amplitude capaz de fornecer 12W, uma largura de banda para sinal fraco de 6MHz e um rendimento médio para um sinal de CDMA2000FW de 57%. Este modulador permite a sua utilização em outros standards tais como o EDGE e CDMA2000RV com rendimento respectivamente de 73% e 67% respectivamente.This work is included in the area of electronics for telecommunications. The dynamic shifting of the supply source of the power amplifier is one of the nowadays solutions to overcome the efficiency linearity compromise. The modulator construction to generate the dynamic supply is crucial to obtain a set that meets the linearity and efficiency requirements. A study of several approaches and techniques for improvement of efficiency in a radio frequency power amplifier, particularly the ones that use the power supply amplitude modulation (envelope tracking (ET), envelope elimination and restoration (EER) e Polar modulation) was made. The study of the amplitude Modulators, its key requirements and construction techniques was be made. An amplitude modulator able to supply 12W, a small signal bandwidth of 6MHz and a 57% average efficiency for a CDMA2000RV signal was implemented. This modulator allows it application in other standards like EDGE and CDMA2000RV with respectably efficiency of 73% e 67%