Analog Control of a 2.5 kW GaN Based CRM PFC with Input Filter Optimization

This paper investigates zero-voltage-switching (ZVS) control of a single-phase GaN-based critical-conductionmode (CRM) totem-pole power factor correction (TPFC) in fully analog domain. Critical mode operation is used by the totem-pole PFC rectifier in order to achieve both high frequency operation and hence smaller magnetics while also achieving high efficiency due to soft switching. A digitally controlled CRM TPFC faces challenges due to current sensing delays and zero-current detection (ZCD) sensitivity to high di/dt noise, which complicates ZVS control. For designing a fully analog controlled CRM TPFC, a deadtime optimization is performed over the entire line cycle to minimize the cycle averaged CRM turn-on loss. Furthermore, the design methodology and volume optimization of input electromagnetic interference (EMI) filter for CRM totem-pole PFC converter is proposed. Finally, a 2.5kW GaN-based 120Vac/240Vac to 400V dc totem-pole PFC is demonstrated with 98.12% peak efficiency operating between 70 kHz (near peak) and 460 kHz (near zero) switching frequency.