ICE3AS03LJG Datasheet, PDF (8/25 Pages) Infineon Technologies AG – Off-Line SMPS Current Mode Controller with integrated 500V Startup Cell ( Latched and frequency jitter Mode )

F3 PWM controller
ICE3AS03LJG
Functional Description
reset. Thus it is ensured that at every startup cycle the _3.3
Improved Current Mode
soft start starts at zero.
Soft-Start Comparator
HV
VCC
Startup Cell
FB
C8
PWM-Latch
RQ
Driver
Power Management
Internal Bias
Latched Off Mode
Reset
V_VCC < 6.23V
Power-Down Reset
Soft Start block
Undervoltage Lockout
18V
10.5V
Voltage
Reference
5.0V
Auto Restart
Mode
Active Burst
Mode
Latched Off
Mode
0.67V
PWM OP
x3.3
Improved
Current Mode
SQ
CS
Figure 4 Current Mode
Current Mode means the duty cycle is controlled by the
slope of the primary current. This is done by comparing
the FB signal with the amplified current sense signal.
Figure 3 Power Management
The internal bias circuit is switched off if Latched Off
Mode or Auto Restart Mode is entered. The current
consumption is then reduced to 250µA.
Amplified Current Signal
FB
Once the malfunction condition is removed, this block
will then turn back on. The recovery from Auto Restart
Mode does not require re-cycling the AC line. In case
0.67V
Latched Off Mode is entered, VCC needs to be
dropped below 6.23V to reset the Latched Off Mode. Driver
t
This is done usually by re-cycling the AC line.
When Active Burst Mode is entered, the internal Bias is
switched off most of the time but the Voltage Reference
is kept alive in order to reduce the current consumption
below 450µA.
t_on
t
Figure 5 Pulse Width Modulation
In case the amplified current sense signal exceeds the
FB signal, the on-time t_on of the driver is finished by
resetting the PWM-Latch (see Figure 5).
The primary current is sensed by the external series
resistor R_Sense inserted in the source of the external
power MOSFET. By means of Current Mode
regulation, the secondary output voltage is insensitive
Version 2.0
8
3 Jul 2009