Forward-type converter

A type of non-resonant converter. It is a transformer-isolated converter with multiple switch elements, a driven oscillation method, and PWM control. It is mainly used as an AC-DC converter. The structure is such that the primary and secondary sides of a step-down converter are isolated by a transformer. Its basic operation is the same as that of a step-down converter, serving as a constant voltage power supply circuit that keeps the output voltage stable by changing the pulse width in response to input voltage variations. On the secondary side, the output voltage is rectified to its average value using a choke coil. It also has a structure similar to a flyback converter with an added choke coil. Although it requires many windings, it offers relatively superior high-frequency switching characteristics due to its high efficiency. Since one transformer is incorporated, it can output a higher voltage than the input voltage by boosting through the turns ratio. When the switch is off, a large kickback voltage is applied to the switch, so it is necessary to use components such as transient voltage suppressors to keep the voltage within the withstand limit. Compared to flyback converters, it is widely used as a small to large-capacity power supply in general circuits for electric and electronic devices with larger power demands.