2.2kW Bridgeless Totem-Pole PFC with Cree SiC FETs and Infineon Analog Control
The CRD-02AD065N 2.2kW bridgeless totem-pole PFC reference design features Cree's latest (C3M™) 650V 60mΩ SiC MOSFETs and the ICE3PCS01G analog PFC controller from Infineon Technologies. This design satisfies the Titanium efficiency standard by having >98.5% efficiency while total harmonic distortion is less than 4% under all load conditions.
This design has an input voltage range of 180- to 264-Vac and provides a 385-Vdc output. With a switching frequency of 64kHz, it is rated for 2.2kW at 264-Vac input and for 1.5kW at 180-Vac input (the design is thermally limited at low-line). Main target applications of this demo board include: server, telecom and industrial power supply units.
- Innovative resistor based current sensing solution
- Distortion less inductor current at zero crossing during all load conditions
- Reduced Bill of Material (BOM) by the use of general-purpose diodes in place of low frequency switches
SiC MOSFETs based Totem-Pole PFC Topology
The main limitation of bridgeless totem-pole PFC topology is the use of conventional silicon devices. The large reverse recovery charge of silicon devices limits the totem-pole PFC circuit to critical conduction mode (CrM). During CrM, bridgeless totem-pole topology suffers from large electromagnetic interference noise, which restricts the use of this topology to low power levels.
These issues can be mitigated by using SiC MOSFETs. Their fast switching speed, low on-state resistance, low reverse recovery charge and low capacitance makes them an ideal choice to enable a continuous conduction mode (CCM) bridgeless totem-pole PFC configuration.
In addition, one of the major problems of totem-pole PFC topology is the inductor current spike at input voltage zero crossing. This problem is less severe with FRED diode line rectification than with a MOSFET solution because of the FRED's low output capacitance and low Qrr compared to those of the body diode of a MOSFET.