ICE3A1065LJ Datasheet, PDF (8/26 Pages) Infineon Technologies AG – Power Management Supply

CoolSET™-F3
ICE3A1065LJ
Functional Description
to charge the external capacitor C_VCC which is
connected to the VCC pin. This VCC charge current is
controlled to 0.9mA by the Startup Cell. When the V_VCC
exceeds the on-threshold V_CCon=18V, the bias circuit
are switched on. Then the Startup Cell is switched off
by the Undervoltage Lockout and therefore no power
losses present due to the connection of the Startup Cell
to the Drain voltage. To avoid uncontrolled ringing at
switch-on a hysteresis start up voltage is implemented.
The switch-off of the controller can only take place after
Active Mode was entered and V_VCC falls below 10.5V.
The maximum current consumption before the
controller is activated is about 250μA.
When V_VCC falls below the off-threshold V_CCoff=10.5V,
the bias circuit switched off and the soft start counter is
reset. Thus it is ensured that at every startup cycle the
soft start starts at zero.
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.
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
Latched Off Mode is entered, VCC needs to be lowered
below 6.23V to reset the Latched Off Mode. 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.
In the Startup Phase, the IC provides a Soft Start
period to control the maximum primary current by
means of a duty cycle limitation. The Soft Start function
is a built-in function and it is controlled by an internal
counter.
When the V_VCC exceeds the on-threshold voltage, the
IC starts the Soft Start mode. The function is realized
by an internal Soft Start resistor, a current sink and a
counter. And the amplitude of the current sink is
controlled by the counter.
V_SoftS
V_SoftS2
V_SoftS1
3.3
Startup Phase
Soft Start counter
Figure 5 Soft Start Phase
S oftS
S oft S tart
Soft Start
S oft-Start
C om parator
C7
&
G7
G ate D river
SoftS
5V
R_SoftS
0 .6 V
PWM OP
x3.2
Figure 4 Soft Start
Soft Start ^{32I 8I 4I 2I}
I
Counter
CS
Figure 6 Soft Start Circuit
Version 2.4
8
19 Nov 2012