Novel Control Method For Multiphase Low-Voltage High-Current Fast-Transient Vrms

High-current high-density multiphase DC-DC converters controllers require high performance current sharing functionality in order to keep almost equal division of the load current between the phases at all load conditions while retaining voltage regulation. Usually, this functionality adds complexity to the closed loop controller design and it is only accurate at full load condition. Moreover, the available current sharing methods regulate the current in each phase by controlling the ON time of the switches, which forces the current sharing functionality to be dependent on the control method being used. In this paper, a simple and effective current sharing method that is independent of the regulation control method being used will be presented. The presented method will be applied to a voltage-mode hysteretic-controlled multiphase DC-DC converter for next generation of microprocessors and communication devices that requires high-density high-current fast transient and low output voltage deviation converters. Simulation and experimental results verified the proposes current sharing method

Piecewise Digital Control Method For Dc-Dc Converter

A Piecewise Digital Control method is presented in this paper to improve the converter characteristics especially the efficiency. By combining more than one control method or/and compensators in a single converter controller, improved performance may be achieved. Piecewise control opens the possibility of combining advantages of different control schemes and preventing or minimizing their disadvantages. In this paper, by combining the asymmetric control and the duty-cycle-shifted control in a new piecewise control scheme, the performance and efficiency of half-bridge DC-DC converter with high switching frequency and wide Input voltage range can be Improved, without adding additional components. The proposed control is theoretically analyzed and its implementation considerations are discussed. Experimental results are also presented. © 2005 IEEE

A New Duty-Cycle-Shifted Pwm Control Scheme For Half-Bridge Dc-Dc Converters To Achieve Zero-Voltage-Switching

Asymmetric control scheme is an approach to achieve ZVS for half-bridge isolated DC-DC converter. However, it is not suited for wide-range input voltage due to the uneven voltage and current components stresses. This paper presents a new duty-cycle-shifted PWM control scheme for half-bridge isolated dc-dc converters to achieve ZVS operation without asymmetric penalties and without adding additional components. Because the duty cycle width is kept identical for both switches, the asymmetric current and voltage stresses problem is eliminated. The principles of operation and key features are illustrated. Experimental results verify that higher efficiency is achieved with the proposed duty-cycle-shifted control method, especially at higher switching frequency

New Coupled-Inductors Current-Doubler Topology

Point-of-load DC-DC converters for current and next generation of ICs for communication systems and microprocessors are increasingly becoming stricter than ever. This is due to the required tight dynamic tolerances allowed for supply voltages and high dynamic performance demand coupled with very high power density. A new coupled-inductors current-doubler topology is proposed in this paper. The advantages of the proposed topology include higher voltage step-down ratio suitable for lower output voltages, better current ripple cancellation resulting in lower output current ripple, smaller isolation transformer turns ratio and lower secondary turns current when used in isolated topology, and can be designed to achieve symmetric transient response at both step-up and step-down transients when used in non-isolated topology. Theoretical analysis and simulation results are presented, and verified by experimental results

Unified Analog And Digital Models For Half Bridge Dc-Dc Converter With Current Doubler Rectifier

The half bridge DC-DC topology with current doubler rectification is suitable for high current low voltage applications. In this paper, both analog and digital unified state space models and small signal models valid for symmetric, asymmetric and duty cycle shifted controlled half bridge DC-DC converter are derived. The discretized analog model and derived digital model are compared based on the digital controller design. In addition, a digital controller is designed based on the digital model for symmetric half bridge DC-DC converter. The results are verified by experiment ©2005 IEEE