ICE3A1065LJ Datasheet, PDF (11/26 Pages) Infineon Technologies AG – Power Management Supply

CoolSET™-F3
ICE3A1065LJ
Functional Description
The overshoot of Signal2 is larger than of Signal1 due
to the steeper rising waveform. This change in the
slope is depending on the AC input voltage.
Propagation Delay Compensation is integrated to
reduce the overshoot due to dI/dt of the rising primary
current. Thus the propagation delay time between
exceeding the current sense threshold V_csth and the
switching off of the integrated internal Depl.
CoolMOS™ is compensated over temperature within a
wide range. Current Limiting is then very accurate.
For example, I_peak = 0.5A with R_Sense = 2. The current
sense threshold is set to a static voltage level V_csth=1V
without Propagation Delay Compensation. A current
ramp of dI/dt = 0.4A/µs, or dV_Sense/dt = 0.8V/µs, and a
propagation delay time of t_{Propagation Delay} =180ns leads
to an I_peak overshoot of 14.4%. With the propagation
delay compensation, the overshoot is only around 2%
(see Figure 13).
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
Figure 13 Overcurrent Shutdown
The Propagation Delay Compensation is realized by
means of a dynamic threshold voltage V_csth
(seeFigure.14). In case of a steeper slope the switch off
of the driver is earlier to compensate the delay.
V _{OSC m ax. Duty Cycle}
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 both
have 20ms internal Blanking Time. For the Auto
Restart Mode, a further extendable Blanking Time is
achieved by adding external capacitor at BL pin. By
means of this Blanking Time, the IC avoids entering
into these two modes accidentally. Furthermore those
buffer time for the overload detection is very useful for
the application that works in low current but requires a
short duration of high current occasionally.
3.6.1
Basic and Extendable Blanking Mode
BL
# ^CBK
I_BK
5.0V
0.9V
1
S1
G2
Soft Start
block
C3
4.0V
4.5V
C4
20ms
Blanking
Time
Spike
Blanking
8.0us
&
G5
Auto
Restart
Mode
FB
C5
1.35V
20ms
Blanking
Time
&
Active
G6
Burst
Mode
Control Unit
V _Sense
V _csth
off time
Propagation Delay t
Figure 14
S ig n a l1
S ig n a l2
t
Dynamic Voltage Threshold V_csth
Figure 15 Basic and Extendable Blanking Mode
There are 2 kinds of Blanking mode; basic mode and
the extendable mode. The basic mode has an internal
pre-set 20ms blanking time while the extendable mode
has extended blanking time to basic mode by
connecting an external capacitor to the BL pin. For the
extendable mode, the gate G5 is blocked even though
the 20ms blanking time is reached if an external
capacitor C_BK is added to BL pin. While the 20ms
blanking time is passed, the switch S1 is opened by
G2. Then the 0.9V clamped voltage at BL pin is
charged to 4.0V through the internal I_BK constant
current. Then G5 is enabled by comparator C3. After
Version 2.4
11
19 Nov 2012