CET Technology

Half-Bridge Transformers

Half-Bridge Transformers

An advantage of the half-bridge (and others like Push-Pull, Full Bridge) is the effective duty cycle is twice that of the transistor duty cycles. This means the duty cycle essentially can approach 100% which is unlike that of the flyback or forward converter.  This means a smaller transformer can be used for the same energy delivered per unit time compared with a flyback or forward converter; or more power can be delivered size for size. Smaller input and output filtering is also a plus.

Also, because the flux density changes from some positive max to some negative min the turns required can be reduced a fair amount which means fewer layers of windings and fewer winding layers means lower proximity losses due to the reduced eddy currents.

Disadvantages may be they operate at half the supply voltage and they are incompatible with current mode control.