ICE3AR10080CJZ Datasheet, PDF (12/33 Pages) Infineon Technologies AG – Off-Line SMPS Current Mode Controller with integrated 800V CoolMOS® and Startup cell (brownout & CCM) in DIP-7

CoolSET^®-F3R80
ICE3AR10080CJZ
Functional Description
In addition to Start-Up, Soft-Start is also activated at _3.5
each restart attempt during normal Auto Restart.
PWM Section
V _SoftS
V_SOFTS32
t_Soft-Start
0.75
Oscillator
Duty Cycle
max
PWM Section
Clock
V_FB
Frequency
t
Jitter
4.5V
V_OUT
t
V_OUT
t_{S ta rt-U p}
t
Figure 14 Start Up Phase
The Start-Up time t_Start-Up before the converter output
voltage V_OUT is settled, must be shorter than the Soft-
Start Phase t_Soft-Start (Figure 14). By means of Soft-Start
there is an effective minimization of current and voltage
stresses on the integrated CoolMOS^®, the clamp circuit
and the output rectifier and it helps to prevent
saturation of the transformer during Start-Up.
Soft Start
Block
Soft Start
Comparator
PWM
Comparator
Current
Limiting
FF1
1
S
Gate Driver
G8
RQ
&
G9
CoolMOS^®
Gate
Figure 15 PWM Section Block
3.5.1
Oscillator
The oscillator generates a fixed frequency of 100KHz
with frequency jittering of ±4% (which is ±4KHz) at a
jittering period of 4ms.
A capacitor, a current source and current sink which
determine the frequency are integrated. The charging
and discharging current of the implemented oscillator
capacitor are internally trimmed in order to achieve a
very accurate switching frequency. The ratio of
controlled charge to discharge current is adjusted to
reach a maximum duty cycle limitation of D_max=0.75.
Once the Soft Start period is over and when the IC goes
into normal operating mode, the switching frequency of
the clock is varied by the control signal from the Soft
Start block. Then the switching frequency is varied in
range of 100KHz ± 4KHz at period of 4ms.
3.5.2
PWM-Latch FF1
The output of the oscillator block provides continuous
pulse to the PWM-Latch which turns on/off the
integrated CoolMOS^®. After the PWM-Latch is set, it is
reset by the PWM comparator, the Soft Start
comparator or the Current -Limit comparator. When it is
in reset mode, the output of the driver is shut down
immediately.
Version 2.0
12
11 Jan 2012