R2A20112

Renesas Low Noise & High Efficiency PFC Control IC R2A20112 Features April 2010 (2)Reduce recovery diode loss, change from expensive first recovery diode two competitive normal diode. ・Downsizing boost coil, output capacitor ・Downsizing and simplification of common filter and normal filter. ・Efficiency up ・Reduce line noise and radiation noise. Filter (1) Downsizing filter Filter Downsizing boost coil (1)Reduce ripple ＺＣＤ1 ＶＣＣ RT OUT2 OUT1 SGND PGND NC NC AC high voltage line less ZCD2 ＣＯＭＰ Reduce ripple Tolerance up Low standby current FB OCP1 Total Cost Down! ZCS: Zero Current Switching ZVS: Zero Voltage Switching OCP2 VREF RAMP (3)Thermal balance on FET (3)Reduce switching loss by ZCS, ZVS Low noise and Ripple reduction Reducing input current ripple and GND bounce noise by interleaving technology. SINGLE Gate Ave. Current IL1 0A Gate1 Principle power loss reduction CCM Single Recovery loss of boost diode by ZCS Basically, no recovery diode loss by sensing zero current. FET current Drain voltage Big peak current Small loss INTERLEAVE Big loss Gate2 Ave. Current IL1+IL2 IL2 0A IL1 In CCM case, a peak current is small, but switching loss is big at Ton. DCM Single In DCM single case, switching loss is small, but peak current is so large. Output ripple DCM Interleave Small peak current Small loss GND bounce noise To sift DCM interleave, it is possible to keep small loss at Ton, and keep small peak current. Improvement of thermal balance Parallel switching by Single Mode Different of resister factor by each MOSFET Improvement of load regulation by gm Amp Independent control by Interleave (R2A20112) Driver In case of gm Amp, there is no feedback current flow, and load regulation becomes good. Conventional PFC Driver PFC Driver R2A20112 VOUT VOUT Current concentration by different switching timing. R2 FET1 FET2 FET3 FET1 FET2 Error Amp VEO VREF R2 R1 FB Error Amp R1 VREF Current concentration point Reduction of unbalance by independent control. Feedback loop detection Built in over voltage protection. And feedback loop absence detection can stop output pulse and PG signal. Therefore bulk capacitor and MOSFET are not broken if using Renesas RFC IC. Dynamic OVP R2A20112 had “Dynamic” and “Static” OVP. Dynamic OVP is doing discharge error Amp voltage before reaching Static OVP voltage. Therefore peak current is limited. As the result, reduce over voltage cause “No coil vibration”. 200ms/div Vout Conventional PFC cut voltage R2A20112 PFC cut voltage The feedback loop disconnection is detected, and stop pulse! cut Feedback loop is down case, bulk voltage is going up abnormal voltage. Then capacitor is broken. cut Prevention from destruction of bulk capacitor and power MOS! CO MP ILm 20ms/div Reduce coil vibration when change input voltage suddenly by Dynamic OVP. FB General IC w/o this function FB R2A20112 Renesas Electronics URL http://www.renesas.com/pfcic ©2010. Renesas Electronics Corporation, All rights reserved.