Impact of the passive component structure for high efficiency and fast response POL using Power Supply on Chip

Power-SoC, which integrates MCU, power device, control circuits and passive devices on the same chip has been attracted attention. In this paper, we discuss the impact of passive component structure for high efficiency and fast response POL using 3D Power-SoC (Supply on Chip). We propose the optimal structure according to the switching frequency based on simulations

Design of Power Receiving Units for 6.78MHz Wireless Power Transfer Systems

In the last decade, the wireless power transfer (WPT) technology has been a popular topic in power electronics research and increasingly adopted by consumers. The AirFuel WPT standard utilizes resonant coils to transfer energy at 6.78 MHz, introducing many benefits such as longer charging distance, multi-device charging, and high tolerance of the coil misalignment. However, variations in coil coupling due to the change in receiving coil positions alter the equivalent load reactance, degrading efficiency. In recent studies, active full-bridge rectifiers are employed on WPT receivers because of their superior efficiency, controllability, and ability to compensate for detuned WPT networks. In order to take advantage of those characteristics, the rectifier switching actions must be synchronized with the magnetic field. In the literature, existing solutions for synchronizing the active rectifier in WPT systems are mostly not reliable and bulky, which is not suitable for small receivers. Therefore, a frequency synchronous rectifier with compact on-board control is proposed in this thesis. The rectifier power stage is designed to deliver 40 W to the load while achieving full zero-voltage switching to minimize the loss. The inherent feedback from the power stage dynamics to the sensed signal is analyzed to design stable and robust synchronization control, even at a low power of 0.02 W. The control system is accomplished using commercial components, including a low-cost microcontroller, which eliminates the need for bulky control and external sensing hardware. This high power density design allows the receiver to be integrated into daily consumer electronics such as laptops and monitors. Finally, a wide-range and high v resolution control scheme of the rectifier input phase is proposed to enable the dynamic impedance matching capability, maintaining high system efficiency over wide loading conditions. In addition, to increase the WPT technology adoption to low-power consumer electronics, a small wireless receiver replacing conventional AA batteries is developed. This receiver can supply power to existing AA battery-powered devices while providing the benefit of WPT technologies to consumers

Characterizing and modeling methods for power converters

“Stable power delivery is becoming increasingly important in modern electronic devices, especially in applications with stringent requirements of its form factor. With the evolution of technology, the switching frequency in a power converter is pushed to a higher frequency range, e.g., several MHz or even higher, to decrease its size. However, the loss generated in the converter increases drastically due to the high switching frequency. In addition, a wide-band feedback controller is required to accommodate the high switching frequency in the converter. We focus on the characterization or modeling of the feedback control circuits and critical components in a switching power converter. A transient-simulation-oriented averaged continuous-time model is proposed to evaluate the transient output noise of a buck converter. The proposed modeling method is developed with time-domain waveforms, which enables a generalized modeling framework for current-mode controllers with constant and nonconstant switching frequencies. In this work, we mainly focus on characterization for two types of components: the switching components, including Si MOSFETs and GaN High-electron-mobility transistor (HEMT), and the magnetic core in an inductor. For the characterization of switching components, a set of test fixtures are designed to characterize the equivalent circuit of Si MOSFETs and GaN HEMTs. The frequency-dependent behaviors of Si MOSFETs are observed, which invalidate the conventional modeling methods for MOSFETs, especially for radiated emission (RE) prediction. For the characterization of magnetic cores, two different probe calibration methods are demonstrated. Accurate phase discrepancy characterization is allowed with the proposed method, which overcomes the main limitation in the conventional two-winding method. In addition, the proposed method supports wide-band loss measurement without resonance tuning, which supports core loss measurement for non-sinusoidal excitation”--Abstract, page iv

Testing of DC/DC converters for 48 V electric vehicles

DC/DC applications in automotive market are expected to require new system specifications in next years. Because of the spreading of electrical cars, the power line at 48V will be very common. Moreover, the converter chips and external passives are required to occupy less area. A DC/DC solution, meeting such requirements, is presented in this work. The switched capacitors architecture is intended to reduce external passive devices space occupation, whereas sustained electrical power is kept high. This paper discusses a preliminary version of the converter, with experimental results from measurements, and presents the final chip architecture, with some simulation result data

Analysis of an Isolated Bidirectional Ćuk Converter

The objective of this thesis is to perform an analysis of the isolated bidirectional Ćuk dc-dc converter topology and demonstrate the advantages and operation of this configuration through simulations using MATLAB/SimulinkTM and measurements collected from a 1.5-kW prototype tested at the Engineering Research Center (ENRC) laboratory of the University of Arkansas. The idea of integrating an active-clamp snubber circuit on each side of the converter, proposed by Dr. Sudip Mazumder from the University of Illinois, Chicago, limits the additional voltage stresses on the components due to the energy from the transformer’s leakage inductance. This is studied in this thesis to achieve zero voltage switching (ZVS) turn-ON functionality of all active devices, reducing the losses and size of passive components. In addition, this work evaluates three separate control parameters that are utilized for power transfer, ZVS region, and the circulating current of the converter. These three variables are the duty cycle of S_P1, namely d_1; the duty cycle of S_S1, namely d_2; and the phase-shift ratio, by the symbol ∆_∅. The theoretical analysis is validated through simulations using MATLAB/SimulinkTM and through a 1.5-kW prototype converter. In addition to the analysis of the results, conclusions and suggestions for future work are presented to enhance the system’s quality

Merged Two-Stage Power Converter With Soft Charging Switched-Capacitor Stage in 180 nm CMOS

In this paper, we introduce a merged two-stage dc-dc power converter for low-voltage power delivery. By separating the transformation and regulation function of a dc-dc power converter into two stages, both large voltage transformation and high switching frequency can be achieved. We show how the switched-capacitor stage can operate under soft charging conditions by suitable control and integration (merging) of the two stages. This mode of operation enables improved efficiency and/or power density in the switched-capacitor stage. A 5-to-1 V, 0.8 W integrated dc-dc converter has been developed in 180 nm CMOS. The converter achieves a peak efficiency of 81%, with a regulation stage switching frequency of 10 MHz.Interconnect Focus Center (United States. Defense Advanced Research Projects Agency and Semiconductor Research Corporation