The flyback converter is another DC/DC topology used in HVAC systems. Diode bridge rectification is first used to rectify 120V or 230VAC input, which is then chopped by a switching power device, and then finally goes through the transformer to be converted into lower voltage rails. In a flyback converter, the switching power device used to chop the primary side DC voltage is referenced to ground, requiring a low-side driver. Figure 4-2 shows an example of a flyback converter.

Figure 4-2 Flyback Converter with UCC27614

The UCC27614 can be used to drive the switching power device in a flyback converter. The UCC27614 features a high VDD rating of 30V to allow for flexibility in system design, and the UCC27614 also has a high drive strength of 10A peak source and sink current to increase switching efficiency. The driver also has a negative voltage capability for added robustness. The UCC44273 can also be used as a low quiescent option for designs that require a lower power consumption or smaller footprint.