Two‐switch flyback PWM DC–DC converter in discontinuous‐conduction mode

Abstract

SUMMARYThe two-switch flyback DC-DC converter is an extended version of the conventional single-switch flyback converter. An additional switch and two clamping diodes serve as a simple, but an effective way to limit the switch overvoltages, which occur in the conventional single-switch flyback converter due to the ringing of the resonant circuit formed by the transformer leakage inductance and the transistor output capacitance. The clamping diodes in the two-switch flyback topology clamp the maximum voltage across each switch equal to the DC input voltage. This paper presents a detailed analysis and design procedure of the diode-clamped two-switch flyback converter operated in discontinuous-conduction mode (DCM). A comparison of power losses of the two-switch and the single-switch flyback converters is given. The two-switch flyback converter was bread-boarded to validate the theoretical analysis. Experimental results from a 20-V/30-W, 100-kHz laboratory prototype verified that the maximum switch voltage is limited to the DC input voltage.

Pulse current generator for driving tubular field emission lamp based on DCM flyback converter

“…Furthermore, the parasitic capacitance C p , which is resulted from the considerable turns in the secondary side, of the flyback transformer is considered in this paper. Besides, the proposed system is operated in DCM to raise the system efficiency 18–25. The sketch waveforms of the proposed pulse generator are shown in Figure 6, where the three operating states are described as follows, respectively.…”

“…Furthermore, the parasitic capacitance C p , which is resulted from the considerable turns in the secondary side, of the flyback transformer is considered in this paper. Besides, the proposed system is operated in DCM to raise the system efficiency [18][19][20][21][22][23][24][25].…”

An Isolated High Step-Up Converter with Non-Pulsating Input Current for Renewable Energy Applications

“…Even though the input current is non-pulsating, this converter involves two stages and comprises six switches, which increase the complexity of the overall circuit and the number of drivers. In [19] and [20], a two-switch flyback is presented. An additional MOSFET switch and two additional diodes are added to the classic single-switch flyback converter to provide a recycling path for leakage inductance energy.…”

A novel variable frequency modulation technique to improve light‐load efficiency for multiphase synchronous rectified VRM

“…This should be the preferred solution to improve efficiency without extra elements or devices. Furthermore, in the proposed variable frequency modulation control scheme, the switching frequency will be increased as the load current decreases to gain benefits from zero voltage switching (ZVS) [26][27][28][29][30][31][32][33][34][35][36] and higher frequency switching, including reducing both conduction loss and switching loss and ripple. Compared with the conventional method, the proposed technique absolutely differs from the prior arts with decreasing switching frequency control or burst-mode control at light-load condition because the technique increases the switching frequency at light load to benefit the lower ripple and lower conduction loss as discussed below.…”