R2A20113 Datasheet, PDF (1/1 Pages) Renesas Technology Corp – Critical Conduction Mode PFC IC

Renesas Critical Conduction Mode PFC IC
R2A20113
April 2010
Features
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
Specification
Vcc Maximum
Tj operation
Drive peak current
24V
-40 to 150deg.
+/-0.9A
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(3) Reduce recovery diode loss
390V
(2) ZCD line less
FB
ＣＯＭＰ
ＲＴ
VREF
ＶＣＣ
OUT
GND
OCP
R2A2012X
19V
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
ZCD comp.
External open short detection circuit is unneeded
UUnnnneeeeddeedd!!
Open/Short Detector
R2A20113
390V
+
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.
VOUT
Conventional
VOUT
R2A20113
R2
Error AMP
R2
FB _{Error AMP}
R1
VEO
R1
VREF
VREF
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
In case of feedback
loop down, bulk
voltage is going up
abnormal voltage.
Then capacitor is
cut
broken.
FB ^{Convention IC}
(Without the
function)
R2A20113
PFC out voltage
Detect the feedback loop
disconnection, and stop
the pulse!!
Prevent from the breakings of
Bulk capacitor & Power MOS!!!
FB _R2A20113
Renesas Electronics URL http://www.renesas.com/pfcic
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”.
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Error Amp Block ^Vout
200ms/div
Feedback
input
OVP
Dynamic
OVP
Dynamic
OVP
COMP
ILm
20ms/div
5. Principle Power Loss Reduction
Continue conduction mode
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
Critical conduction mode
FET current
switching too.
Drain voltage
In CRM case, switching loss and radiation noise are small
due to zero current and zero voltage switching.
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