This paper proposes a PFM+PWM hybrid controlled soft-switching half-bridge converter which has both benefit of conventional half-bridge converter and LLC converter. Generally, conventional half-bridge converter has good constant current characteristic due to PWM control, however it has some drawbacks of (1) primary side switches and secondary side diodes operate under hard switching, (2) two magnetic components. Meanwhile, the LLC resonant converter has the benefit of achieving ZVS and ZCS, however it can't realize a constant current (CC) characteristic because of resonant fashion. In order to achieve soft-switching and CC characteristic using half-bridge converter, a DCM operation are employed, which can be controlled by PWM+PFM Hybrid Control. In this paper the operating characteristics of the proposed half-bridge converter are experimentally verified. The experimental results for 48Vin, 16Vo, 80W board achieves 90% efficiency and validated this method is useful practically.
Financed by the National Centre for Research and Development under grant No. SP/I/1/77065/10 by the strategic scientific research and experimental development program:
SYNAT - “Interdisciplinary System for Interactive Scientific and Scientific-Technical Information”.