ICE3AR0680JZ Datasheet, PDF (14/34 Pages) Infineon Technologies AG – Of f -Line SMPS Cur rent Mode Cont rol ler wi th integrated 800V

CoolSET^®-F3R80
ICE3AR0680JZ
Functional Description
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 CoolMOS^® is
compensated over temperature within a wide input
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%
(Figure 20).
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
s
Figure 20 Overcurrent Shutdown
The Propagation Delay Compensation is realized by
means of a dynamic threshold voltage V_csth (Figure 21).
In case of a steeper slope the switch off of the driver is
earlier to compensate the delay.
V_{OSC max. Duty Cycle}
Similarly, the same concept of propagation delay
compensation is also implemented in burst mode with
reduced level, V_{csth_burst} (Figure 17). With this
implementation, the entry and exit burst mode power
can be very close between low line and high line input
voltage.
3.7 Control Unit
The Control Unit contains the functions for Active Burst
Mode and Auto Restart Mode. The Active Burst Mode
and the Auto Restart Mode both have 20ms internal
blanking time. For the over load Auto Restart Mode, the
20ms blanking time can be further extended by adding
an external capacitor at BBA pin. With the blanking
time, the IC avoids entering into those two modes
accidentally. Those buffer time is very useful for the
application which works in short duration of peak power
occasionally.
3.7.1
Basic and Extendable Blanking Mode
5.0V
Ichg_EB
S1
4.5V
R_BO2
BBA
C11
# _CBK
500
C3
0.9V
S2
Auto
Restart
Mode
Counter
CT1
Spike
Blanking
30us
&
G5
V_Sense
V_csth
off time
Propagation Delay
t
Figure 21
Signal1
Signal2
t
Dynamic Voltage Threshold V_csth
FBB
C4
4.5V
20ms
Blanking
Time
Control Unit
Figure 22 Basic and Extendable Blanking Mode
There are 2 kinds of Blanking mode; basic mode and
the extendable mode. The basic mode is a built-in
20ms blanking time while the extendable mode can
extend this blanking time by connecting an external
capacitor to the BBA pin. For the extendable mode, the
gate G5 remains blocked even though the 20ms
blanking time is reached. After reaching the 20ms
blanking time the counter is activated and the switch S1
is turned on to charge the voltage of BBA pin by the
constant current source, I_{chg_EB}. When the voltage of
BBA pin hits 4.5V, which is sensed by comparator C11,
the counter will increase the counter by 1. Then it
Version 2.1a
14
11 Jan 2012