ICE3B0365L Datasheet, PDF (11/28 Pages) Infineon Technologies AG – Off-Line SMPS Current Mode Controller with integrated 650V Startup Cell/Depletion CoolMOS™ and Latched off Mode

CoolSET™-F3
ICE3xxx65L
Functional Description
current. That means the propagation delay time
between exceeding the current sense threshold V_csth
and the switch off of the internal CoolMOS™ is
compensated over temperature within a wide range.
Current Limiting is now possible in a very accurate way.
E.g. I_peak = 0.5A with R_Sense = 2. Without Propagation
Delay Compensation the current sense threshold is set
to a static voltage level V_csth=1V. A current ramp of
dI/dt = 0.4A/µs, that means dV_Sense/dt = 0.8V/µs, and a
propagation delay time of i.e. t_{Propagation Delay} =180ns
leads then to an I_peak overshoot of 14.4%. By means of
propagation delay compensation the overshoot is only
about 2% (see Figure 12).
V
1,3
1,25
1,2
1,15
1,1
1,05
1
0,95
0,9
0
with compensation
without compensation
0,2 0,4 0,6 0,8
1 1,2 1,4 1,6 1,8
dV_Sense
dt
2_V
µs
3.6
Control Unit
The Control Unit contains the functions for Active Burst
Mode, Auto Restart Mode and Latched Off Mode. The
Active Burst Mode and the Auto Restart Mode are
combined with an Adjustable Blanking Window which is
depending on the external Soft Start capacitor. By
means of this Adjustable Blanking Window, the IC
avoids entering into these two modes accidentally.
Furthermore it also provides a certain time whereby the
overload detection is delayed. This delay is useful for
applications which normally works with a low current
and occasionally require a short duration of high
current.
3.6.1
Adjustable Blanking Window
SoftS
5kΩ ^RSoftS
6.5V
4.4V
1
&
S1
G2
G4
Figure 12 Overcurrent Shutdown
The Propagation Delay Compensation is realized by
means of a dynamic threshold voltage V_csth (see Figure
13). In case of a steeper slope the switch off of the
driver is earlier to compensate the delay.
V_{OSC max. Duty Cycle}
C3
5.4V
4.8V
C4
&
Auto
Restart
G5
Mode
Active
Burst
Mode
V_Sense
V_csth
off time
Propagation Delay t
Figure 13
Signal1
Signal2
t
Dynamic Voltage Threshold V_csth
FB
C6
1.30V
&
G6
Control Unit
Figure 14 Adjustable Blanking Window
V_SoftS is clamped at 4.4V by the closed switch S1 after
the SMPS is settled. If overload occurs V_FB is
exceeding 4.8V. Auto Restart Mode can’t be entered as
the gate G5 is still blocked by the comparator C3. But
after V_FB has exceeded 4.8V the switch S1 is opened
via the gate G2. The external Soft Start capacitor can
now be charged further by the integrated pull up
resistor R_SoftS. The comparator C3 releases the gates
G5 and G6 once V_Softs has exceeded 5.4V. Therefore
there is no entering of Auto Restart Mode possible
during this charging time of the external capacitor
Version 2.0
11
8 May 2006