©2010. Renesas Electronics Corporation, All rights reserved.
Renesas Electronics URL http://www.renesas.com/pfcic
• Small radiation noise
• Small peak current
• Non-influenced of
current change.
• Simple circuit
• A little bit complex
circuit.
Advantages
Weaknesses
Input voltage
Choke coil current
Input average current
Continuous conduction mode
Critical conduction mode
(Discontinuous)
• Large radiation noise
• Large peak current
• Large choke coil
Hold timer (Adjustable)
Large current change
In case of critical current
mode, the peak current
is so large.
In case of continuous
current mode, not so much
change peak current.
lout change case
4. Feed back loop detector
IC operation does not stop for set period, therefore recovery is
faster, available in the area where power supply is not stable.
Possible to set no coil vibration at start up and current limit.
3. Hold function countermeasure to AC temporary blackout
AC input
Bulk voltage
Hold counter
AC blackout
FET OUT
(R2A20111)
FET OUT
(Conventional IC)
FB
Bulk voltage
Built in over voltage protection.
And feedback loop absence detection can stop output pulse and PG.
Therefore bulk capacitor & FET is not broken by R2A20111.
FB
Conventional IC
w/o this function
Bulk voltage
In case of feed back
loop down, bulk
voltage rise up to
abnormal voltage. And
capacitor is broken.
R2A20111
The feed back loop
disconnection is detected,
and stop pulse!
Prevention from destruction
of bulk capacitor and power
MOSFET!
R2A20111
Conventional
cut
cut
5. Soft start period become short by quick soft start function
Triangle wave
Soft start voltage
General soft start period
Renesas
Css=4.7uF
Improved time=4.7uFX1V/25uA=188ms.
6. Improve load regulation by gm Amp at feed back Amp
Error Amp
VREF
R2
R1
VOUT
VEO
Error Amp
FB
VREF
R2
R1
VOUT
In voltage feedback Amp case, feedback current flow
influence to load regulation.
Conventional
R2A20111
Example of Application Circuit
Down sizing trance
Possible to use 500V type FET
HA16150
12V
HA16116
R2A20111
380V
5V
+
RJK5015
RJK5015
Small & high reliability systems
• Target power range is over 300V.
• Realize high reliability on PFC block by R2A20111 and
coordinate next stage by P.G.
• Realize small transformer and high efficiency by using
half bridge topology by HA16150.
V-AMP
C-AMP
CAI
FB
C-limiter
EO
Multi
CLIMIT
VREF
C-AMP
CS
C-limiter
Multi
Conventional
R2A20111
Constant
power
limiter
Features
1. Continuous conduction mode is suitable for the system with large
and high frequency variation of current.
2. Easy design by separate current terminal.
3. Hold function countermeasure to AC temporary blackout.
It is possible to set no soft start time by chip capacitor.
4. Feed back loop detector.
5. Soft start period become short by quick soft start function.
6. Improve the load regulation by gm Amp at feed back Amp.
OUT
GND
DELAY
CGND
CAI
VREF
CAO
CLIMIT
VCC
SS
EO
FB
IAC
PFC-ON
CT
RT
DIP16
or
SOP16
1. Continuous conduction mode suitable for the system
2. Easy design by separate current terminal
Renesas PFC Control IC for Digital-TV
R2A20111
April 2010
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