一种新颖的峰值电流模式DC-DC Buck片上快速软启动电路

A fully integrated soft-start circuit for DC-DC buck converters is presented.The proposed high speed soft-start circuit is made of two sections:an overshoot suppression circuit and an inrush current suppression circuit. The overshoot suppression circuit is presented to control the input of the error amplifier to make output voltage limit increase in steps without using an external capacitor.A variable clock signal is adopted in the inrush current suppression circuit to increase the duty cycle of the system and suppress the inrush current.The DC-DC converter with the proposed soft-start circuit has been fabricated with a standard 0.13μm CMOS process.Experimental results show that the proposed high speed soft-start circuit has achieved less than 50μs start-up time.The inductor current and the output voltage increase smoothly over the whole load range.     

A fixed frequency fast transient response DC-DC controller for VRM application Chen Mingyang(陈明阳), Zhao Menglian*(赵梦恋), Wu Xiaobo(吴晓波)

A 2V-10A fast transient response DC-DC buck controller based on fixed frequency hysteresis control is presented. A carefully designed output voltage filter detects the output capacitor current change which helps the controller to respond immediately after load changes. Adaptive hysteresis control guarantees the switching frequency to be the same as the reference frequency by using a CCII-composed circuit and current mirrors. The controller is designed and fabricated in a TSMC 0.35 μm process. Simulation and test results show that this con- troller achieves a 20 μs settling time in one single switching cycle when load current changes from 1 A to the full load condition at 10 A.     

A new interface amplifier concept for fast D/A converters

A new interface amplifier is proposed which can tolerate an appreciable capacitive loading without affecting the settling time. It utilizes a low loop-gain approach with high internal bandwidth and excellent open-loop gain linearity. Most importantly, the amplifier is compensated at the input node rather than somewhat internally. As a result, the amplifier overdrive also can be eliminated, provided that the rise and fall times of the converter's output current stay within prescribed limits. Contrary to the present high-speed D/A converter realizations, in this application only a low-current, low-power D/A converter is required. With an input capacitance of 500 pF and a load capacitance of 12 pF, the measured settling time is less than 70 ns to within /spl plusmn/0.05 percent for output-signal changes of /spl plusmn/10 V.     

High-gain wideband error amplifier topology for DC-DC buck converter switching at 20 MHz

A wideband error amplifier topology with increased DC-gain and reduced quiescent current consumption is presented. The reduction in quiescent current consumption is achieved by lowering the output stage current, which helps to increase the output impedance and hence the overall DC-gain of the amplifier. Simulation results show that the proposed topology has 60 dB DC gain and 540 MHz unity gain bandwidth with 450 muA quiescent current consumption. The experimental result of the loop-gain of a high-frequency (20 MHz) DC-DC buck converter that utilises the proposed topology also confirms the simulation results.     

Design issues for monolithic DC-DC converters

This paper presents various ideas for integrating different components of dc-dc converter on to a silicon chip. These converters are intended to process power levels up to 0.5W. Techniques for integrating capacitors and design issues for MOS transistors are discussed. The most complicated design issue involves inductors. Expressions for trace resistance and inductance estimation of on-chip planar spiral inductor on top metal layer of CMOS process are compared. These inductors have high series resistance due to low metal trace thickness, capacitive coupling with substrate and other metal traces, and eddy current loss. As an alternative, a CMOS compatible three-dimensional (3-D) surface micromachining technology known as plastic deformation magnetic assembly (PDMA) is used to fabricate high quality inductors with small footprints. Experimental results from a monolithic buck converter using this PDMA inductor are presented. A major conclusion of this work is that the 3-D "post-process" technology is more viable than traditional integrated circuit assembly methods for realizing of micro-power converters.     

Current control with fast transient for three-phase AC/DC boost converters

This letter introduces a new synchronous reference frame hysteresis control of a three-phase ac/dc boost converter that is demonstrated to have excellent transient behavior when compared with previous fast methods based on regular proportional plus integral control with cross-coupling terms. Finally, the control software program and a comparison of results are shown.     

NEW PERTURBATION TECHNIQUE FOR TRANSIENT ANALYSIS AND ITS APPLICATIONS IN DC-DC PWM SWITCHING POWER CONVERTERS

An improved perturbation technique proposed in a recent paper (Int. J. Electronics, vol. 63, pp.403-414) has been successfully applied to steady-state analysis of PWM switching converters. This paper extends the algorithm to transient analysis of a broader class of non-linear systems. As an example, the transient response of a Boost PWM switching converter is analyzed to demonstrate its simplicity and accuracy.     

Active-clamp snubbers for isolated half-bridge DC-DC converters

In conventional isolated half-bridge dc-dc converters, the leakage-inductance-related losses degrade converter efficiency and limit the ability to increase the converters' switching frequencies. In this paper, a novel active-clamp snubber circuit for half-bridge dc-dc converters is proposed to recycle the energy stored in the leakage inductance by transferring this energy to a capacitor with zero-voltage zero-current-switching switched auxiliary switches, such that body-diode conduction of primary-side main switches are prevented and primary side ringing are attenuated resulting in improved converter efficiency. Principles of operation and simulation analysis are presented and supported by experimental results that show significant improvement in efficiency.     

PWM-switch modeling of DC-DC converters

The introduced PWM-switch modeling method is a simple method for modeling pulse-width-modulated (PWM) DC-DC converters operating in the continuous conduction mode. The main advantage of this method is its versatility and simple implementation compared to other methods. The basic idea is the replacement of the switches in the converter by their time-averaged models. These switch models have been developed in such a way that the converter model provides the same results as the state-space-averaging technique but not including nonlinear effects. Simple rules for determination of the switch models are obtained. The resulting model is a time-averaged equivalent circuit model where all branch currents and node voltages correspond to their averaged values of the corresponding original currents and voltages. The model also includes parasitics, second-order effects and nonlinearities, and can be implemented in any circuit-oriented simulation tool. The same model is used for the simulation of the steady-state and the transient behavior     

Duty-cycle control boosts DC-DC converters

An improved design for a switched-capacitor pulsewidth modulated (PWM) DC-DC converter with adjustable conversion ratios is presented. The converter provides a nominal power of 40 W and nominal voltage conversion ratio of 12/5. The same structure can provide other conversion ratios, as required. Such low power supplies use relatively small, low-value capacitors, and could conceivably be realized with IC technology     

Novel zero-Voltage-transition PWM DC-DC converters

A new family of zero-voltage-switching (ZVS) pulsewidth-modulated (PWM) converters that uses a new ZVS-PWM switch cell is presented in this paper. Except for the auxiliary switch, all active and passive semiconductor devices in the ZVS-PWM converters operate at ZVS turn ON and turn OFF. The auxiliary switch operates at zero-current-switching (ZCS) turns ON and OFF. Besides operating at constant frequency, these new converters have no overvoltage across the switches and no additional current stress on the main switch in comparison to the hard-switching converter counterpart. Auxiliary components rated at very small current are used. The principle of operation, theoretical analysis, and experimental results of the new ZVS-PWM boost converter, rated 1 kW, and operating at 80 kHz, are provided in this paper to verify the performance of this new family of converters.     

An improved LQR-based controller for switching DC-DC converters

A general approach for controlling pulse-width-modulated (PWM) -type switching DC-DC converters digitally using state-feedback techniques and linear optimal control theory is reported. The methodology for redesigning the state estimator is investigated, and a method derived from the general linear-quadratic-regulator (LQR) problem, is proposed. The method is found to offer better transient responses and robustness to uncertainties in plant parameters when compared with the typical eigenvalue-assignment method. Special attention is directed to plant models with possible migrations of the open-loop zeroes across the stability boundary during operation. Results of applying these techniques to a published Cuk converter are reported to illustrate different points of interest     

Random discrete PWM method for DC-DC power converters

A random discrete pulse-width modulation (RDPWM) scheme is examined and compared with the randomised pulse-position modulation (RPPM) method for DC-DC power conversion. The RDPWM method has no switching harmonics while the RPPM method has significant switching harmonics. Power spectral characteristics of the two methods are presented and discussed     

Control features of dual-channel DC-DC converters

This paper presents the steady-state behavior of a two-channel resonant converter family in symmetrical operation. Six configurations will be investigated, including step-down, step-up/down, and step-up ones in continuous conduction mode (CCM) and in discontinuous conduction mode (DCM). Exploring the conditions of transition from CCM to DCM or back, it becomes evident that the CCM operation is definitely restricted, that is, sometimes the converter cannot he operated in CCM at all. The most important relations among the input, output, and control variables are derived and verified by simulation and experimental results.     

降压PWM DC/DC开关稳压系统仿真分析

集成CMOS脉冲宽度调制开关电源系统因为高效率、高集成度等优点在通信、计算机系统方面被广泛应用.文中通过分析建立一个PWM DC/DC稳压系统的闭环响应传输函数,研究如何在瞬态响应速度和稳定性方面进行取舍;在此基础上用Matlab建立小信号模型仿真,并通过Hspice 实现仿真验证.     

Automatic modeling of PWM DC-DC converters

Different small-signal models are available for describing the dynamics of pulse width modulators (PWM) dc-to-dc converters. Discrete time models reach the best compliance in real life situations. Some converter control modes, in particular phase shifting, provide advantages of modeling in discrete time. On the other hand, the burden of getting such exact models is often tedious. Currently, automatic tools are available that are able to provide the state-space model in discrete time of any PWM dc-dc converter switching at constant frequency. The authors claim that the use of these tools is advisable for the analysis and control optimization of switching power supplies. To support their opinion, this letter refers to a new, very accurate small-signal model of a phase-shifting converter which has been published recently. Its excellent performance, as well as the difficulties of the derivation procedure, are compared with the precise forecasts and the short processing time of an automatic modeling tool. The paper concludes in favor of automatic modeling.     

High-performance NMOS operational amplifier

A high performance operational amplifier 300 mil/SUP 2/ in area has been designed and fabricated in a standard n-channel silicon-gate enhancement/depletion MOS process. Specifications achieved include open-loop gain, 1000; power consumption, 10 mW; common-mode range within 1.5 V of either supply rail; unity-gain bandwidth, 3.0 MHz with 80/spl deg/ phase margin; RMS input noise (2.5 Hz-46 kHz), 25 /spl mu/V; C-message weighted noise -5 dBrnC; and 0.1-percent settling time, 2.5 /spl mu/s.     

Quasi-linear modeling and control of DC-DC converters

A quasi-linear approach is proposed for modeling and control of DC-DC power converters. The method presented is derived by perturbing an approximate large signal equation around a varying operating point in a reduced variable space. This differs from the usual practice of applying the perturbation technique around a fixed operating condition. In the proposed algorithm, the control equation and the control parameter are constantly adjusted according to environmental changes to meet the specified dynamical requirement     

Unified steady-state analysis of soft-switching DC-DC converters

In this paper, based on the switching cell approach, a unified steady state analysis for families of soft-switching DC-DC converters with complete unified design equations will be presented. The concept of the unified approach and step by step procedure for a generalized process are discussed and applied to selected soft-switching families such as zero-voltage-switching (ZVS) and zero-current-switching (ZCS)-quasi-resonant converter families, ZVS-clamped voltage quasi-square-wave (QSW) family, ZCS-clamped-current (CC) QSW family, and zero-voltage-transition and zero-current-transition pulse-width modulation families. Also, it has been noted that all the analyzed families have one generalized transformation table. The basic unified equations are summarized and the cell-to-cell comparison will be introduced. It will be shown that the unified analysis leads to several advantages such as improving the computer-aided analysis and design, simplified mathematical modeling, and giving more insight into the converter-cell operation.