150 W Power Factor Corrected LLC Power Supply Using HiperPLC (PLC810PG)
Summary and Features
Integrated PFC and LLC controller
Continuous mode PFC using small low-cost ferrite core and magnet wire
Frequency and Phase locked PFC and LLC for ripple cancellation in bulk capacitor for reduced ripple current, reduced bulk capacitor size and reduced EMI filter cost
Tight LLC duty-cycle matching
Tight LLC dead-time control
>95% full load PFC efficiency at 140 VAC using conventional ultrafast rectifier
>95% full load LLC efficiency
>92% full load system efficiency
This engineering report describes a 150 W reference design power supply for 230 VAC input LED street lights and also serves as a general purpose evaluation board for the PLC810PG
The design is based on the PLC810PG controller IC which integrates both continuous current mode (CCM) boost PFC and resonant half-bridge (LLC) control functions together with high-side and low side drivers for the LLC stage MOSFETs. To allow optimum design of the LLC transformer (T1) for high efficiency (high k factor–the ratio of parallel to series inductance) the design operates in burst mode at zero load. The supply is thus protected against output overvoltage at low/zero load, but it will not deliver a steady output voltage at zero load. A practical LED street light power supply design that includes an auxiliary output winding to power the LED driver circuitry may not have this limitation.
DER-212 demonstrates a design using the commonly employed single transformer and resonant inductor magnetic component (integrated magnetics) for the LLC stage (common in display applications). However, the PLC810 may as easily be used with separated transformer and resonating inductor. PI design materials support both approaches.