R2A20113

Renesas Critical Conduction Mode PFC IC R2A20113 Features April 2010 ((1)AC high voltage line less 1)AC high voltage line less (3) Reduce recovery diode loss Simple External Circuit Best for Small Power Supplies • AC sense line less • ZCD line less No open/short detector, No turn-on at inrush • Feedback loop detection • High efficiency by Zero current switching • Low radiation noise • Small package: SOP8/DIP8 390V (2) ZCD line less 19V FB ＶＣＣ Specification Vcc Maximum Tj operation Drive peak current 2 4V -40 to 150deg. +/-0.9A ＣＯＭＰ OUT R2A2012X ＲＴ GND VREF OCP Applications R2A20113 Best support for power supplies of 1-phase operating products that require low noise and downsizing due to the power factor regulation for flat-screen TV, HDD recorder and AV home electronics. 1. ZCD Line Less Getting ZCD signal pulse from the current sense resistor, therefore ZCD auxiliary winding is unneeded. OCP comp. CS External open short detection circuit is unneeded Unneeded!! Unneeded Open/Short Detector 390V + ZCD comp. R2A20113 Turn-on of MOSFET at inrush timing is prevented ZCD Vth GND Out put Voltage Input Current OUT Previous R2A20113 2. Improvement of Load Reg. Adopting gmAMP In case of adopting gmAMP adopted, there is no feedback current flow, and load regulation becomes good. Conventional VOUT VOUT 3．Dynamic OVP The R2A20113 has “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”. Error Amp Block Vout R2A20113 Acoustic noise Acoustic noise is rreduced. is educed. 200ms/div R2 R1 Error AMP VEO R2 R1 FB Error AMP Feedback input COMP ILm 20ms/div VREF VREF OVP Dynamic OVP 4. Feedback Loop Detector Feedback loop absence detect function can stop output pulse. Therefore Renesas PFC IC prevents the breakings of bulk capacitor and MOSFET. Conventional PFC out voltage Dynamic OVP 5. Principle Power Loss Reduction Recovery Loss of Boost diode by ZCS Basically, no recovery diode In CCM case, switching loss and radiation noise are large. loss by zero current switching too. Critical conduction mode FET current Drain voltage R2A20113 PFC out voltage Detect the feedback loop disconnection, and stop the pulse!! Continue conduction mode In case of feedback loop down, bulk voltage is going up abnormal voltage. Then capacitor is broken. cut Prevent from the breakings of Bulk capacitor & Power MOS!!! FB Convention IC (W ithout the function) FB R2A20113 In CRM case, switching loss and radiation noise are small due to zero current and zero voltage switching. Renesas Electronics URL http://www.renesas.com/pfcic ©2010. Renesas Electronics Corporation, All rights reserved.