R2A20112 Datasheet, PDF (1/1 Pages) Renesas Technology Corp – Renesas Low Noise & High Efficiency PFC Control IC

Renesas Low Noise & High Efficiency PFC Control IC
R2A20112
April 2010
Features
・Downsizing boost coil, output
Filter
capacitor
・Downsizing and simplification
of common filter and normal filter.
・Efficiency up
・Reduce line noise and radiation noise.
(1) Downsizing filter
Filter
(1)Reduce
ripple
Downsizing boost coil
(2)Reduce recovery diode loss, change
from expensive first recovery diode two
competitive normal diode.
Total Cost Down!
AC high voltage
line less
Low standby current
ZCS: Zero Current Switching
ZVS: Zero Voltage Switching
ＺＣＤ1
ZCD2
ＣＯＭＰ
FB
OCP1
OCP2
VREF
RAMP
ＶＣＣ
RT
OUT2
OUT1
SGND
PGND
NC
NC
Reduce ripple
Tolerance up
(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
INTERLEAVE
Gate
Gate1
Ave. Current
IL1
0A
Gate2
Ave. Current
IL1+IL2
IL2
IL1 0A
Output ripple
Principle power loss reduction
CCM Single
Big loss
In CCM case, a peak current is small,
but switching loss is big at Ton.
DCM Single
Recovery loss of boost
diode by ZCS
Basically, no recovery
diode loss by sensing
zero current.
Big peak current
Small loss
In DCM single case, switching loss is small,
but peak current is so large.
DCM
Interleave
FET current
Drain voltage
GND bounce noise
Improvement of thermal balance
Parallel switching by Single Mode
Different of resister factor by each MOSFET
Independent control by Interleave
(R2A20112)
PFC
Driver
PFC
Driver
Driver
Small peak current
Small loss
To sift DCM interleave, it is possible to keep small loss at
Ton, and keep small peak current.
Improvement of load regulation by gm Amp
In case of gm Amp, there is no feedback current flow,
and load regulation becomes good.
Conventional
R2A20112
VOUT
VOUT
Current
concentration by
different switching
timing.
FET1
FET2
FET3
Current concentration point
FET1
FET2
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.
Conventional
R2A20112
PFC cut voltage
PFC cut voltage
The feedback loop
Feedback loop is down
case, bulk voltage is
disconnection is detected,
and stop pulse!
going up abnormal
cut
voltage. Then
cut
capacitor is broken.
Prevention from destruction of
bulk capacitor and power MOS!
FB ^{General IC}
w/o this function
FB _R2A20112
R2
Error Amp
R1
VEO
VREF
R2
FB _{Error Amp}
R1
VREF
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”.
Vout
2 0 0 m s/ div
COMP
ILm
2 0 ms/ div
Reduce coil vibration when
change input voltage
suddenly by Dynamic OVP.
Renesas Electronics URL http://www.renesas.com/pfcic
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