ICE2PCS04 Datasheet, PDF (8/19 Pages) Infineon Technologies AG – Standalone PFC Controller in CCM with Input Brown-Out Protection

CCM-PFC
ICE2PCS04/G
Functional Description
.
Window Detect
Max Vcomp current
V_OUT
95%rated
83%rated
Normal Control
V_OUT =rated
t
av(I_IN) ^{Level-shifted VCOMP}
V_OUT
V_OUT,Rated
Supply
related
Current
related
Output
related
OLP
UVLO / IBOP
PCL / SOC
OVP
108%
100%
20%
t
OLP
VCOMP
t
Figure 5 Startup with controlled maximum current
3.4 System Protection
The IC provides several protection features in order to
ensure the PFC system in safe operating range:
• VCC Undervoltage Lockout (UVLO)
• Input Brown-out Detection (IBOP)
• Soft Over Current Control (SOC)
• Peak Current Limit (PCL)
• Open-Loop Detection (OLP)
• Output Over-Voltage Protection (OVP)
After the system is supplied with the correct level of
VCC and V_IN, the system will enter into its normal mode
of operation. Figure 6 shows situation when these
protections features are active, as a function of the
output voltage V_OUT.
An activation of the UVLO, IBOP and OLP results in the
internal fault signal going high and brings the IC into the
standby mode.
As the function of UVLO has already described in the
earlier “Power Supply” section, the following sections
continue to describe the functionality of these
protection features.
Figure 6 Protection Features
3.4.1 Input Brown-Out Protection (IBOP)
Brown-out occurs when the input voltage V_IN falls below
the minimum input voltage of the design (i.e. 85V for
universal input voltage range) and the VCC has not
entered into the V_CCUVLO level yet. For a system without
IBOP, the boost converter will increasingly draw a
higher current from the mains at a given output power
which may exceed the maximum design values of the
input current.
ICE2PCS04/G provides a new IBOP feature whereby it
senses directly the input voltage for Input Brown-Out
condition via an external resistor/capacitor/diode
network as shown in Figure 7. This network provides a
filtered value of V_IN which turns the IC on when the
voltage at pin 4 (VINS) is more than 1.5V. The IC enters
into the standby mode when VINS goes below 0.71V.
The hysteresis prevents the system to oscillate
between normal and standby mode. Note also that V_IN
needs to at least 20% of the rated V_OUT in order to
overcome OLP and powerup the system.
D2 ... D5
Vin
85 ... 265 VAC
C1
brown-out
Brown-Out Detection
0.71V
C4
80k
S
R
C5
1.5V
3.5V
R8
VINS ^D7
C6 R9
ICE2PCS04/G
Figure 7 Input Brown-Out Protection (IBOP)
Version 2.0
8
10 October 2007