Renesas Low Noise & High Efficiency PFC Control IC R2A20112 April 2010 Features ・Downsizing boost coil, output capacitor ・Downsizing and simplification of common filter and normal filter. ・Efficiency up ・Reduce line noise and radiation noise. Downsizing boost coil (1) Downsizing filter Filter (2)Reduce recovery diode loss, change from expensive first recovery diode two competitive normal diode. Filter (1)Reduce ripple AC high voltage line less Low standby current ＺＣＤ1 ＶＣＣ ZCD2 RT ＣＯＭＰ OUT2 FB OUT1 OCP1 SGND OCP2 PGND VREF NC RAMP NC Total Cost Down! ZCS: Zero Current Switching ZVS: Zero Voltage Switching Low noise and Ripple reduction Reduce ripple Tolerance up (3)Thermal balance on FET (3)Reduce switching loss by ZCS, ZVS Principle power loss reduction Reducing input current ripple and GND bounce noise by interleaving technology. CCM Single INTERLEAVE SINGLE Recovery loss of boost diode by ZCS Basically, no recovery diode loss by sensing zero current. Gate1 Gate Big loss Gate2 Ave. Current IL1+IL2 IL2 0A IL1 Ave. Current IL1 0A In CCM case, a peak current is small, but switching loss is big at Ton. DCM Single FET current Drain voltage Big peak current Small loss In DCM single case, switching loss is small, but peak current is so large. Output ripple DCM Interleave Small loss Small peak current To sift DCM interleave, it is possible to keep small loss at Ton, and keep small peak current. GND bounce noise Improvement of load regulation by gm Amp Improvement of thermal balance Independent control by Interleave Parallel switching by Single Mode (R2A20112) Different of resister factor by each MOSFET In case of gm Amp, there is no feedback current flow, and load regulation becomes good. Conventional R2A20112 Driver PFC VOUT PFC Driver VOUT Driver Current concentration by different switching timing. R2 FET1 FET1 FET2 FET2 R2 Feedback loop detection VREF Dynamic OVP Conventional R2A20112 PFC cut voltage General IC w/o this function Error Amp Reduction of unbalance by independent control. 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. Feedback loop is down case, bulk voltage is going up abnormal voltage. Then capacitor is broken. FB R1 VREF Current concentration point FB VEO R1 FET3 cut Error Amp 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”. PFC cut voltage The feedback loop disconnection is detected, and stop pulse! cut Prevention from destruction of bulk capacitor and power MOS! FB 200ms/div Vout CO MP ILm R2A20112 Renesas Electronics URL http://www.renesas.com/pfcic ©2010. Renesas Electronics Corporation, All rights reserved. 20ms/div Reduce coil vibration when change input voltage suddenly by Dynamic OVP.