An Adaptive Multi-Mode PWM Control PSR Flyback Converter

Author(s):  
Chang Chen ◽  
Lei Wang ◽  
Changyuan Chang ◽  
Xiong Han

In this paper, an adaptive multi-mode PWM control PSR flyback converter is proposed. In constant voltage (CV) mode, the converter adopts primary-side regulate (PSR) scheme to detect load information through the auxiliary winding, which reflects the load information on the voltage of [Formula: see text]. The converter adjusts the switching frequency according to the voltage of [Formula: see text] under different load conditions, realizing adaptive multi-mode PWM control to significantly improve light- load efficiency and thus the overall average efficiency. Besides, it does not give compromise to other system performance, such as audible noise, standby power consumption, and regulation. To verify the feasibility and performance of the proposed circuit, the converter has been designed and fabricated in HHGRACE_0.35[Formula: see text][Formula: see text]m BCD process and verified in a 5V/1A circuit prototype. The experimental results show that 25% load power efficiency of the proposed converter is 78.1%, which is improved by up to 3.4% compared to the conventional converter.

2017 ◽  
Vol 26 (11) ◽  
pp. 1750175
Author(s):  
Changyuan Chang ◽  
Chao Hong ◽  
Yang Xu ◽  
Hailong Sun ◽  
Yao Chen

A constant voltage AC–DC converter based on the digital assistant technology is proposed in this paper, which has the advantage of high output precision. In this paper, a novel digital exponential wave generator is adopted in Constant Voltage (CV) mode to replace the normal triangle waveform to obtain a wider range of switching frequency, increasing the accuracy of output voltage under light load. The control chip is implemented based on NEC 1[Formula: see text][Formula: see text]m 5[Formula: see text]V/40[Formula: see text]V HVCMOS process, and a 5[Formula: see text]V/1.2[Formula: see text]A prototype has been built to verify the proposed control method. In PFM mode the deviation of output voltage is within [Formula: see text]% and the load regulation is [Formula: see text]%. Meanwhile, when the load jumps from light to heavy, the minimum output voltage could be maintained above 4.16[Formula: see text]V.


Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 960
Author(s):  
Myeong Woo Kim ◽  
Jae Joon Kim

This paper presents a dual-mode DC-DC buck converter including a load-dependent, efficiency-controllable scheme to support multi-purpose IoT applications. For light-load applications, a selectable adaptive on-time pulse frequency modulation (PFM) control is proposed to achieve optimum power efficiency by selecting the optimum switching frequency according to the load current, thereby reducing unnecessary switching losses. When the inductor peak current value or converter output voltage ripple are considered in some applications, its on-time can be adjusted further. In heavy-load applications, a conventional pulse width modulation (PWM) control scheme is adopted, and its gate driver is structured to reduce dynamic current, preventing the current from shooting through the power switch. A proposed dual-mode buck converter prototype is fabricated in a 180 nm CMOS process, achieving its measured maximum efficiency of 95.7% and power density of 0.83 W/mm2.


2013 ◽  
Vol 336-338 ◽  
pp. 1186-1189
Author(s):  
Zhu Lei Shao ◽  
San Tang

Aiming at the problem of switching power supply stable output, a push-pull switching power supply was designed. the switching frequency is 100kHZ and the output voltage is 5V. System model of the push-pull switching power supply is established on PSpice, and research on the output performance of the push-pull switching power supply. By the parameter sweep analysis of load, the push-pull switching power supply can stabilize output in full load and light load conditions, and load regulation rate comply with the design requirements.


2015 ◽  
Vol 9 (1) ◽  
pp. 553-559
Author(s):  
HU Xin-xin ◽  
Chen Chun-lan

In order to optimize the electric energy quality of HVDC access point, a modular multilevel selective harmonic elimination pulse-width modulation (MSHE-PWM) method is proposed. On the basis of keeping the minimum action frequency of the power device, MSHE-PWM method can meet the requirement for accurately eliminating low-order harmonics in the output PWM waveform. Firstly, establish the basic mathematical model of MMC topology and point out the voltage balance control principle of single modules; then, analyze offline gaining principle and realization way of MSHEPWM switching angle; finally, verify MSHE-PWM control performance on the basis of MMC reactive power compensation experimental prototype. The experimental result shows that the proposed MSHE-PWM method can meet such performance indexes as low switching frequency and no lower-order harmonics, and has verified the feasibility and effectiveness thereof for optimizing the electric energy quality of HVDC access point.


Electronics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 355
Author(s):  
Yeu-Torng Yau ◽  
Chao-Wei Wang ◽  
Kuo-Ing Hwu

In this paper, two light-load efficiency improvement methods are presented and applied to the ultrahigh step-down converter. The two methods are both based on skip mode control. Skip Mode 1 only needs one half-bridge driver integrated circuit (IC) to drive three switches, so it has the advantages of easy signal control and lower cost, whereas Skip Mode 2 requires one half-bridge driver integrated circuit IC, one common ground driver IC, and three independent timing pulse-width-modulated (PWM) signals to control three switches, so the cost is higher and the control signals are more complicated, but Skip Mode 2 can obtain slightly higher light-load efficiency than Skip Mode 1. Although the switching frequency used in these methods are reduced, the transferred energy is unchanged, but the output voltage ripple is influenced to some extent.


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