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This paper proposes a LLC type resonant forward converter using adjustable turning-off time control for low power and voltage applications. The new circuit is derived from the conventional LLC converter, and it has simple structure while maintaining decent soft-switching characteristics. The switching losses are reduced by ZVS (zero voltage switching) and ZCS (zero current switching). Also, regulation of the output voltage does not require a small ratio between magnetizing inductor and resonant inductor, so the leakage inductor of transformer can be utilized instead of an external inductor to realize resonance, which makes it possible to use only one magnetic component in the resonant topology. Besides, the adjustable turning-off time control strategy is adopted in the scheme, which optimizes the switching condition while ensuring the wide range operation. In comparison to the traditional PWM (pulse width modulation) control, the proposed control strategy can further reduce the switching loss and improve power efficiency. This is also suitable for the utilization of GaN (gallium nitride) devices due to the requirement of higher switching frequencies at wide input applications. In addition to the detailed theoretical analysis, the validity of the proposed concept is confirmed by the experimental results of a prototype. [ABSTRACT FROM AUTHOR]

This paper presents a novel control technique for a wide output voltage range digitally controlled SIDO boost converter. It employs minimum phase conditions reported in refid="ref1"/ , refid="ref2"/ and extends the same to SIDO boost converter to eliminate the effect of RHP zero. Further, the proposed work employs input-output linearization technique refid="ref3"/, refid="ref4"/ to linearize the control-to-output transfer function across different operating points to achieve improved stability under unbalanced loads and a wide output voltage range on each output of the proposed SIDO boost power converter. The SIDO boost regulator was verified experimentally for an input voltage of 3.3 V and a maximum simultaneous load current of 350 mA on each output. Measurement results demonstrate that the proposed design achieves a wide output voltage range of 4.8 V–13.75 V, with ability to dynamically transition across these different output voltages in both small and big voltage steps. [ABSTRACT FROM AUTHOR]

In this paper the stability and sensitivity function of three basic dc-dc converter with the consideration of circuit parasitics has been analyzed for analog and digital controller implementation. The steady state and small-signal analysis has been used to derive the mathematical expressions for uniformly sampled voltage-mode controlled converters. The effect of digital controller using the ratio of sampling to carrier frequency has been analyzed. The sampling frequency limits the voltage gain in the stepped manner and also affects the stability of the digitally controlled converter. The sensitivity function has been defined for voltage gain with respect to various system parameters. The maximum affected regions on duty ratio scale with corresponding parasitic variable have been discussed. The detailed stability analysis has been carried out for digitally implemented three basic dc-dc converters, i.e., buck, boost, and buck-boost circuits. The analytical results are verified with the simulations performed in PSCAD/EMTDC. An FPGA controller is considered as digital controller for the dc-dc converter and verification of the results through experiment. [ABSTRACT FROM PUBLISHER]

A floating buck controlled multi-mode dimmable light-emitting diode (LED) driver that uses a stacked NMOS switch is presented, which reduces static operational current and eliminates auxiliary winding to simplify design and cost. The accuracy of the output current benefits from the use of a line-voltage compensation technique which can mitigate the effect of line-voltage fluctuation on current consistency. The proposed LED driver is implemented in 0.5 \mum 5V/40 V backend 2P2M CMOS process and occupies a die size (with pads) of 1.17\times 0.84\ mm^2. The experimental results show that the proposed LED driver achieves peak power efficiency of 95.4% across a wide range of input voltage from 85 to 264 Vac and a wide range of series-connected load LEDs from 11 to 27. The worst-case line regulation and load regulation of the output current are 0.28% and 0.25%, respectively. Measurements further show that the startup time is only 34.8 ms at 220 Vac with 50 Hz-input and multi-mode dimming can be easily implemented. [ABSTRACT FROM AUTHOR]

An output voltage ripple aware design of different voltage ramp signal of voltage-mode CCM random frequency buck converter for conductive EMI reduction is presented. A mathematical analysis has been carried out to model the output voltage ripple of random switching converter. Simulations of the converter have been undertaken and measured results from the converter fabricated with a standard 0.35 \mum CMOS process verify the proposed design approach. From experimental results, a carefully designed ramp can reduce the output voltage ripple by more than 8 times without significant influence on the inductor current spectrum spread and any increment on the output filtering inductance and capacitance comparing to the conventional design. [ABSTRACT FROM AUTHOR]

A dual modulation technique to improve power conversion efficiency with minimal increase in output voltage ripple is presented. The worsening switching noise caused by parasitic resistance and inductance due to high-switching operation can also be alleviated by the proposed ac ripple detector. Furthermore, the dual modulation method can speed up the load transient response since the switching frequency can increase to 5 MHz during the transient period. At very light loads, the switching frequency is always kept higher than the acoustic frequency to avoid noisy sound. Experiment results show that the converter operates at 5 MHz using a small inductor of 1 \mu \H. The load transient response time is shorter than 3 \mu \s when load current changes from 150 to 450 mA or vice versa. Power efficiency is kept higher than 85% over a wide load current range. Specifically, light efficiency can be raised to about 45% above that of the conventional design. [ABSTRACT FROM PUBLISHER]