Linear-assisted DC/DC converters with modified current-mode control applied to photovoltaic solar systems

This article shows the proposal of a current-mode one-cycle control for linear-assisted DC/DC converters. Linearassisted DC/DC converters are structures that allow to take advantages of the two classic alternatives in the design of power supply systems: voltage linear regulators (classic NPN topology or LDO –low dropout–) and switching DC/DC converters. The current-mode one-cycle control technique is proposed in order to obtain the duty cycle of the linear-assisted converter switch. The proposed structure can provide an output with suitable load and line regulations. Thus, the paper shows the design and simulation results of the proposed current-mode one-cycle linear-assisted converter.Postprint (published version

Efficient LDO-Assisted DC/DC buck converter for integrated power management system

DC-DC Switching Converters; Voltage Linear Regulators; Linear-Assisted DC-DC Voltage Regulators.Postprint (published version

Capacitorless DC–DC regulator as a candidate topology for photovoltaic solar facilities

Postprint (published version

Comparative aspects in control strategies for hybrid DC-DC converters

Linear-switching hybrid DC/DC converters consist of a voltage linear regulator (classic NPN or nMOS topologies and LDO) connected in parallel with a switching DC/DC converter. In order to control these hybrid structures, different strategies exist, allowing to fix the switching frequency as a function of some parameters of the linear regulator. This article compares two control strategies that, although can be applied to the same circuital structure of linear-assisted converter, are sensibly different. The first one, reported in previous literature, cancels completely the average current through the linear regulator in steady state to achieve a reduction of the losses. Thus the efficiency of the whole system increases and almost equals the one of the standalone switching converter. The proposed approach, in spite of a slightly increment of linear regulator’s losses, reduces the output ripple due to the crossover distortion of linear regulator output stage.Postprint (published version

On capacitor–less linear–assisted DC–DC regulators as candidate topology for photovoltaic solar facilities

Linear-assisted DC/DC converters (or linear-switching hybrid DC/DC converters) consist of a voltage linear regulator (classic NPN or nMOS topologies and LDO) connected in parallel with a switching DC/DC converter. They are good candidates for energy processing in photovoltaic solar facilities. In order to control these hybrid structures, different strategies exist, allowing fixing the switching frequency as a function of some parameters of the linear regulator. This article compares two control strategies that, although can be applied to the same circuital structure of linear-assisted converter, are sensibly different. The first one, reported in previous literature, cancels completely the average current through the linear regulator in steady state to achieve a reduction of the losses. Thus the efficiency of the whole system increases and almost equals the one of the standalone switching converter. The proposed approach, in spite of a slightly increment of linear regulator’s losses, reduces the output ripple due to the crossover distortion of linear regulator output stage.Postprint (published version

Current source for LED drivers based on a linear-assisted DC/DC regulator

This article presents a proposal of current source based on a linear-assisted DC/DC converter, in which a linear voltage regulator assists a switching DC/DC converter in order to obtain a compact circuit with advantages of both alternatives; i.e., high efficiency (similar to the switching converter), and low output ripple and fast reaction to the load changes (similar to the linear regulator). In order to reduce the power dissipation in the linear regulator, it is considered as an assisted circuit for providing just a little fraction of the load current. Furthermore, this stage provides the required clock signal for the switching counterpart, resulting in reduction of the complexity in the design of the control scheme for the switching converter and a compact topology, especially for on-chip practical implementations, since no output capacitors are required. This last advantage provides the possibility of obtaining goodperformance current-source drivers for LED technology in lighting applications. The implementation and results indicate that the proposed linear-assisted DC/DC regulator-based current source can achieve a notably compacting and higher performance, while consuming less power in comparison to linear alternatives.Peer ReviewedPostprint (published version

Linear–Assisted DC/DC Converters with Modified Current-Mode Control Applied to Photovoltaic Solar Systems

Los convertidores DC/DC asistidos linealmente (linear-assisted DC/DC converters) son estructuras que permiten aprovechar las ventajas de las dos alternativas clásicas en el diseño de sistemas de alimentación: reguladores de tensión lineales (ya sean éstos con topología clásica NPN o del tipo LDO –baja tensión de dropout–), y convertidores DC/DC conmutados. En este trabajo se muestra la propuesta de un control de un ciclo en modo corriente modificado (modified current-mode one-cycle control technique) para convertidores DC/DC conmutados asistidos linealmente. Se propone esta técnica de control de un ciclo en modo corriente modificado con el fin de obtener el ciclo de trabajo del interruptor del convertidor conmutado. La estructura propuesta puede proporcionar una salida con adecuadas regulaciones de carga y de línea. El trabajo muestra el diseño de las propuestas del regulador DC/DC asistido linealmente, así como los resultados de simulación que validan la propuesta presentada en el artículo.Peer Reviewe

Four–quadrant linear–assisted DC/DC voltage regulator

This Mixed Signal Letter presents a proposal of four-quadrant linear-assisted DC/DC voltage regulator. In this topology, a class-AB linear voltage amplifier assists a four-quadrant switching DC/DC converter in order to obtain a compact circuit with advantages of both alternatives; i.e., high efficiency, inherent in switching converters, and low output ripple and fast reaction to the load changes that are characteristics of linear regulators. In order to reduce the power dissipation in the linear regulator, it is considered as an assisting circuit for providing just a small fraction of the total load current. Furthermore, this stage provides the required clock signal for the switching counterpart, obtaining a compact topology thanks to the reduction of the complexity in the design of the control scheme for the switching converter. In fact, the proposed topology can be addressed to on-chip practical implementations, since no output capacitors are required. This last advantage provides the possibility of obtaining good-performance power-supply modulators for envelope tracking techniques in power amplifiers. The implementation and results indicate that the proposed four-quadrant linear-assisted DC/DC regulator can achieve a notably compacting and higher performance, while consuming less power in comparison to linear alternatives.Postprint (author's final draft

Current-mode one-cycle control applied to linear–assisted DC/DC converters

This article shows the proposal of an current-mode one-cycle control for linear-assisted DC/DC converters. Linear-assisted DC/DC converters are structures that allow to take advantages of the two classic alternatives in the design of power supply systems: voltage linear regulators (classic NPN topology or LDO –low dropout–) and switching DC/DC converters. The current-mode one-cycle control technique is proposed in order to obtain the duty cycle of the linear-assisted converter switch. The proposed structure can provide an output with suitable load and line regulations. The paper shows the design and simulation results of the proposed current-mode one-cycle linearassisted converter.Postprint (published version

Current-Mode One-Cycle Control Applied to Linear-Assisted DC/DC Converters

This article shows the proposal of an current-mode one-cycle control for linear-assisted DC/DC converters. Linearassisted DC/DC converters are structures that allow to take advantages of the two classic alternatives in the design of power supply systems: voltage linear regulators (classic NPN topology or LDO –low dropout–) and switching DC/DC converters. The current-mode one-cycle control technique is proposed in order to obtain the duty cycle of the linear-assisted converter switch. The proposed structure can provide an output with suitable load and line regulations. The paper shows the design and simulation results of the proposed current-mode one-cycle linear-assisted converter.Postprint (published version