A soft‐switching post‐regulator for multi‐outputs dual forward DC/DC converter with tight output voltage regulation

Abstract

An improved soft-switching post-regulator topology for multi-outputs dual forward DC/DC converter is presented. A delay-trailing modulation method is proposed. ZVSZCS on/zero-current-switching off conditions can be realised on both the primary MOSFETs and the secondary rectifying diodes. Excellent decoupling among different outputs and tight output voltage regulation are achieved. The efficiency is improved due to single power-conversion stage and share in the primary components. The operating principle and main feature of this improved topology are analysed. Key design issue including zero-voltageswitching operation, maximum duty ratio of the primary side MOSFETs and parameter determination for the primary magnetising inductor and the secondary additional redistribution capacitor are discussed. Finally, an experimental prototype with two outputs (300-400 V input, 48 V, 6.5 A and 24 V, 11 A outputs) is built to verify the theoretical analysis. The measured efficiency at normal operation input voltage (400 V) is improved by about 0.5-2%, and the measured efficiency under light loads is improved by more than 2%.

Design Methodology of Tightly Regulated Dual-Output LLC Resonant Converter Using PFM-APWM Hybrid Control Method

“…First, the specifications, such as input voltage range, resonant frequency, and output voltages, are required to design the power stage. Second, the magnetizing inductance is designed by considering the resonant frequency, the input voltage, and the parasitic capacitance of the MOSFETs, which was derived in (12). Third, the resonant inductance and capacitance ratio can be designed using (26).…”

“…The secondary side post regulators (SSPR) have been proposed to tightly regulate the output voltage with small output voltage error. They can regulate each output voltage independently, however, additional switches, gate driving circuits, and voltage controllers are required [8][9][10][11][12][13][14][15][16][17][18][19][20].…”

Flyback-Based Multiple Output dc-dc Converter with Independent Voltage Regulation

“…However, leakage inductance and saturated inductance still affect the boundary lines and a minimum load is required to maintain the regulation. Further efforts have been devoted in [13][14][15][16][17][18] to mitigate the cross regulation, where the need for multiple linear regulators at high load current and high frequency would deteriorate the efficiency and increase the control complexity.…”

Implementation of Multiple Output Converters using Time Division Multiple Control with Soft switching and EMI Filter

“…However most of the MOCs developed to date will hardly regulate all of the outputs with a good degree of tight regulation while not the value of quality within the structure and control.Some studies on this subject are conducted and several other strategies are projected like the cross regulation technique [1]- [3], the post regulation technique [4]- [5], and also the PWM/PFM hybrid technique [6]. The cross regulation technique, that regulates solely the most output voltage, is widely used as a result of the simplicity of its structure and control, however the regulation for the rest of the output voltages is not good.…”

“…The cross regulation technique, that regulates solely the most output voltage, is widely used as a result of the simplicity of its structure and control, however the regulation for the rest of the output voltages is not good. In the post regulation technique, an additional switch is employed at every output so as to control all of the output exactly [4]- [6]. However, this technique needs as several controllers because the range of the outputs, that causes complexness within the structure and control.…”