A hybrid single-switch power factor correction pre-regulator

Power factor correction converters are widely used as the pre-regulator for the downstream DC-DC converter in order to comply with IEC 1000-3-2 specifications. However, for power supplies with hold-up time requirement, when the input drops out the energy stored in the capacitor of the pre-regulator cannot be fully transferred to the next stage due to the limit of duty cycle in the downstream DC-DC converter. This paper proposes a new pre-regulator that can reduce the bulky capacitor and suppress the voltage across it below 450 V. Basic operation of the converter is discussed and experimental results are provided for verification.