Zero-voltage switching half-bridge DC-DC converter topology by utilizing the transformer leakage inductance trapped energy

摘要

A duty-cycle-shifted pulse-width modulation controlled half-bridge zero-voltage switching DC—DC converter has a primary side, a secondary side and a transformer coupling the primary side to the secondary side. The primary side has first and second primary switches coupled to a primary winding of the transformer and an auxiliary branch having one side coupled to a junction of the first and second primary switches and a second side coupled to common. The auxiliary branch includes a grounded auxiliary switch that is switched on when one of the first and second primary switches is on to trap leakage inductance energy of the transformer when that primary switch is turned off and thereafter switched off to release the trapped leakage inductance energy to provide a zero voltage switching condition for the other primary switch. The one of the first and second primary switches that is on when the auxiliary switch is switched on may be controlled with duty-cycle-shifted pulse width modulation to provide a zero current switching condition for that primary switch.