ICE3BR1065J_11 INFINEON [Infineon Technologies AG], ICE3BR1065J_11 Datasheet - Page 11

• Manufacturer Part Number: ICE3BR1065J_11
• Manufacturer: INFINEON [Infineon Technologies AG]

3.4
Figure 9
In the Startup Phase, the IC provides a Soft Start
period to control the 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.
.
Figure 10
Version 2.0
V
V
V
SoftS2
SoftS1
SoftS
Startup Phase
0 .6 7 V
S o ftS
Soft Start
Soft Start Phase
S o ft S ta rt c o u n te r
C 7
P W M O P
S o ft S ta rt
S o ft S ta rt
C o m p a ra to r
S o ft-S ta rt
x 3 .3
G 7
&
G a te D riv e r
C S
11
When the V
IC starts the Soft Start mode (see Figure 10).
The function is realized by an internal Soft Start
resistor, an current sink and a counter. And the
amplitude of the current sink is controlled by the
counter (see Figure 11).
Figure 11
After the IC is switched on, the V
controlled such that the voltage is increased step-
wisely (32 steps) with the increase of the counts. The
Soft Start counter would send a signal to the current
sink control in every 600us such that the current sink
decrease gradually and the duty ratio of the gate drive
increases gradually. The Soft Start will be finished in
20ms (t
the Soft Start period, the current sink is switched off.
Figure 12 Gate drive signal under Soft-Start Phase
V
Gate
Driver
Soft Start
SOFTS32
Counter
Soft-Start
V
SoftS
VCC
Soft Start Circuit
) after the IC is switched on. At the end of
32I
exceeds the on-threshold voltage, the
t
Soft-Start
Functional Description
8I
4I
CoolSET
ICE3BR1065J
SoftS
SFOFTS
2I
28 Dec 2011
voltage is
R
®
SoftS
5V
I
-F3R
t
t