ICE3PCS01G Datasheet, PDF (14/24 Pages) Infineon Technologies AG – Standalone Power Factor Correction (PFC) Controller in Continuous Conduction Mode (CCM)

CCM-PFC
ICE3PCS01G
Functional Description
90 ~ 270 Vac
Line
Filter
DBRO1 DBRO2
RBRO1
RBRO2
BOP
RBRO3
CBRO
1.25V
C8b
C8a
1V
Brownout
Latch
RQ
Brownout
SQ
Figure 12
Input Brownout Protection
3.8.2 Peak Current Limit (PCL)
The IC provides a cycle by cycle peak current limitation
(PCL). It is active when the voltage at pin 2 (ISENSE)
reaches -0.2V. This voltage is amplified by a factor of -
5 and connected to comparator with a reference
voltage of 1.0V as shown in Figure 13. A deglitcher with
200ns after the comparator improves noise immunity to
the activation of this protection.
Full-wave
rectifier
ISENSE
RCS
Rshunt
Iin
SGND
G=-5
AO2
200ns
PCL
C5
1V
Figure 13 Peak Current Limit (PCL)
3.8.3 Open Loop Protection (OLP)
Whenever VSENSE voltage falls below 0.5V, or
equivalently V_OUT falls below 20% of its rated value, it
indicates an open loop condition (i.e. VSENSE pin not
connected) or an insufficient input voltage V_IN for
normal operation. It is implemented using comparator
C2a with a threshold of 0.5V as shown in the IC block
diagram in Figure 6.
3.8.4 First Over-Voltage Protection (OVP1)
Whenever V_OUT exceeds the rated value by 8%, the
over-voltage protection OVP1 is active as shown in
Figure 6. This is implemented by sensing the voltage at
VSENSE pin with respect to a reference voltage of
2.7V. A VSENSE voltage higher than 2.7V will
immediately turn off the gate, thereby preventing
damage to bus capacitor. After bulk voltage falls below
the rated value, gate drive resumes switching again.
3.8.5 Second Over Voltage Protection (OVP2)
The second OVP is provided in case that the first one
fails due to the aging or incorrect resistors connected to
the VSENSE pin. This is implemented by sensing the
voltage at pin OVP with respect to a reference voltage
of 2.5V. When voltage at OVP pin is higher than 2.5V,
the IC will immediately turn off the gate, thereby
preventing damage to bus capacitor.
When the bulk voltage drops out of the hysteresis the
IC can be latched further or begin auto soft-start. These
two protection modes are distinguished through
detecting the external equivalent resistance connecting
to VBTHL_EN pin after Vcc is higher than UVLO
threshold as shown in Figure 3. If the equivalent
resistance is higher than 100kΩ the IC selects latch
mode for second OVP, otherwise auto soft-start mode.
In normal operation the trigger level of second OVP
should be designed higher than the first. However in
the condition of mains transient overshoot the bulk
voltage may be pulled up to the peak value of mains
that is higher than the threshold of OVP1 and OVP2. In
this case the OVP1 and OVP2 are triggered in the
same time the IC will shut down the gate drive until bulk
voltage falls out of the two protection hysteresis, then
resume the gate drive again.
3.8.6
Bulk Voltage Monitor and Enable
Function
The IC monitors the bulk voltage through VSENSE pin
and output a TTL signal to enable PWM IC or control
inrush relay. During soft-start, once the bulk voltage is
higher than 95% rated value, pin VB_OK outputs a high
level. The threshold to trigger the low level is decided
by the pin VBTHL_EN voltage which can be adjustable
externally.
When pin VBTHL_EN is pulled down externally lower
than 0.5V, IC will enters into standby mode and most of
the function blocks are turned off. When the disable
signal is released the IC recovers by soft-start.
3.8.7 Boost Follower
The IC provides adjustable lower bulk voltage in case
of low line input and light output power. The low line
condition is determined when pin BOP voltage is less
than 2.3V. Pin BOFO is connected to PWM feedback
voltage through a voltage divider, representing the
output power. The light load condition is determined
when pin BOFO voltage is less than 0.5V. Once these
two conditions are met in the same time, a 20µA
current source is flowing out of pin VSENSE so that the
bulk voltage should be reduced to a lower level in order
Version 2.0
14
5 May 2010