Summary of six basic DC/DC converter topologies

There are six basic DC/DC converter topologies, namely buck, boost, buck-boost, cuk, zeta, and sepic converters.

The half-bridge converter is also a double-ended converter. The above are two topologies.

The voltage stress of the half-bridge switch tube is the input voltage. And because of the capacitor on the other bridge arm, it has the ability to resist magnetic bias. However, for the above topology, a DC blocking capacitor is usually added to improve the ability to resist magnetic bias. However, if peak current control is used, one problem should be noted, which is that it may cause the problem of capacitor ampere-second imbalance. Other methods are needed to solve it. The half-bridge converter can achieve ZVS through asymmetric control, that is, the two tubes are turned on alternately, one with a duty cycle of D and the other with a duty cycle of 1-D. This is the so-called asymmetric half-bridge, which usually adopts the following topology. Peak current control can be used for asymmetric half-bridge.

Forward Converter

Winding Reset Forward Converter

LCD reset forward converter

 RCD reset forward converter

Active Clamp Forward Converter

Dual-Tube Forward

Absorption Dual Forward

Active Clamp Dual Forward

Primary side clamped dual forward

Soft Switching Dual Forward

Push-Pull Converter

Lossless Absorption Push-Pull Converter

Push-pull converter: Push-pull converter is a double-ended converter. In fact, it is two forward converters coupled by a transformer. The basic advantage of push-pull converter is that the drive does not need to be isolated, the transformer is magnetized at both ends, and only two switch tubes are needed. However, the transformer winding utilization rate is low, and the switch tube voltage stress is twice the input, so it is generally only suitable for low-voltage input occasions. And there is a problem that there will be magnetic bias, so current-type control and other methods should be used to avoid it. If two double-tube forwards are coupled in the same way, a push-pull converter with four switch tubes can be formed, which is the so-called double double-tube forward. Its tube voltage stress drops to the input voltage. Others are the same.

Push-pull forward is a new topology that has recently emerged. It uses a capacitor to solve problems such as converter leakage inductance spikes and bias magnetism. It is used in VRM.

The half-bridge converter is also a double-ended converter. The above are two topologies.

The voltage stress of the half-bridge switch tube is the input voltage. And because of the capacitor on the other bridge arm, it has anti-magnetic bias capability. However, for the above topology, a DC blocking capacitor is usually added to improve the anti-magnetic bias capability. However, if peak current control is used, one problem should be noted, which is that it may cause capacitor ampere-second imbalance. Other methods are needed to solve this problem.

 The half-bridge converter can achieve ZVS through asymmetric control, that is, the two tubes are turned on alternately, one with a duty cycle of D and the other with a duty cycle of 1-D. This is the so-called asymmetric half-bridge, which usually adopts the following topology. For an asymmetric half-bridge, peak current control can be used.

Full-bridge converter

Full-bridge converters are the most commonly used in high-power applications, especially ZVS and ZVZCS. Next, I will collect some three-level converters and post them. In the future, I will give the boost family of isolated converters...flyback converters...forward-flyback converters...APFC...PPFC...single-stage PFC...resonant converters, etc....

Three level converter

I chose two topologies that look more comfortable. These three-level converters are evolved from half-bridge converters, and can also be evolved into multi-level converters, which are suitable for high-voltage input applications. Moreover, soft switching can be achieved through full-bridge phase-shift control.