ICE1CS02 Datasheet, PDF (9/27 Pages) Infineon Technologies AG – Combi PFC/ PWM Controller

Combi PFC/ PWM Controller
ICE1CS02
Functional Description
3 Functional Description
All values which are used in the functional description
are typical values. For calculating the worst cases the
min/max values which can be found in section 4
Electrical Characteristics have to be considered.
3.1
Introduction
The ICE1CS02 comprises the complete control for
power factor controlled switched mode power sup-
plies. With its PFC and PWM section being internally
synchronized, applies for off-line converters with input
voltages ranging from 90 V to 270 V.
The topology of the PFC preconverter is boost.
The minimal line current gaps for the maximum duty
cycle of the PFC is about 95%. The selectable maxi-
mum duty of the PWM, however, is limited to 47% or
60% to prevent transformer saturation.
The external RC-filter in the feedback line after the
optocoupler is integrated into the IC in order to reduce
the external component count.
The Soft-Start function is integrated into the IC.
An internal precise peak current control is integrated
into the IC. With this function, the costs of the power
transformer and the secondary rectifier diode can be
reduced and the max power can also be limited. The
maximum power is almost independent from the input
voltage. Hence, it can avoid to over-size the critical
components of the SMPS such as the power
transformer or the secondary rectifier diode.
The Undervoltage Lockout monitors the external
supply voltage V_VCC. When the V_VCC exceeds the on-
threshold V_CCon=12V, the internal bias circuit is
switched on. A hysteresis sequence is implemented to
avoid the uncontrolled rings during switch-on. The
switch-off of the controller will take place when V_VCC
falls below 11V. The maximum current consumption
before the controller is activated is around 1.3mA.
When V_VCC falls below the off-threshold; V_CCoff=11.0V,
the internal bias circuit is switched off .
3.3 Internal Synchronization
CLK OUT
PFC OUT
PWM OUT
Figure 4
Internal Synchronisation between PFC
and PWM Out
The clock rising edge will trigger a turn-off of PFC OUT
and falling edge will trigger a turn-on of PWM OUT.
3.2
Power Management
Power Management
Internal Bias
VCC
Undervoltage Lockout
12V
11V
Power-Down
Reset
5V
Voltage
Reference
Soft start
Figure 3 Power Management
Version 1.0
9
25 July 2008