Hybrid-switching asymmetrical half-bridge flyback DC-DC converter
This paper proposes a hybrid-switching technique for asymmetrical half-bridge flyback converter. In this topology, the duty loss can be minimized because the active switches can achieve zero-voltage-switching (ZVS) and the output diode can be turned off at zero current, which result in higher efficiency, higher power density and universal input voltage range (90-264V). Moreover, this technique doesn't require any addition of components into the original topology and still employ the fixed frequency PWM, therefore the control method is simple and straightforward, while still being highly reliable.
Asymmetrical Half Bridge Flyback Converter with Constant Off Time Control
In previous studies, an asymmetric half bridge (AHB) flyback converter was proposed with the main advantages of the fewer number of components and the soft switching technique. In this paper, a new control method for AHB flyback with constant off time (COT) modulation to provide a wide range of zero voltage switching (ZVS) function.
Design and implementation of zero-voltage-switching flyback converter with synchronous rectifier
A design consideration and circuit implementation of a zero-voltage-switching (ZVS) flyback converter with synchronous rectifier are presented. To reduce the voltage spike due to the transformer leakage inductance when the main switch is turned off at the flyback converter, one auxiliary switch and one clamp capacitor are used in the adopted converter. The resonant circuit, consisting of leakage inductance and output capacitance of switch, is used to achieve ZVS operation for all switches during the transition between the main switch and the auxiliary switch. The synchronous switch is used on the transformer secondary side to reduce the conduction losses further and to increase the circuit efficiency. The operating principle and system analysis of the adopted converter are discussed in detail. The design example of the adopted power converter is presented. Finally experimental results based on a 5 V/20 A prototype circuit are provided to demonstrate the system performance.