ice3ar4780jz Infineon Technologies Corporation, ice3ar4780jz Datasheet - Page 10

• Manufacturer Part Number: ice3ar4780jz
• Description: Off-line Smps Current Mode Controller With Integrated 800v Coolmos And Startup Cell Brownout & Frequency Jitter In Dip- 7
• Manufacturer: Infineon Technologies Corporation

Figure 7
3.3.1
The input of the PWM-OP is applied over the internal
leading edge blanking to the external sense resistor R
connected to pin CS. R
a sense voltage. The sense voltage is amplified with a gain of
3.25 by PWM OP. The output of the PWM-OP is connected
to the voltage source V
superimposed amplified current signal is fed into the positive
inputs of the PWM-Comparator C8 and the Soft-Start-
Comparator (Figure 8).
3.3.2
The PWM-Comparator compares the sensed current signal
of the integrated CoolMOS
(Figure 8). V
external transistor in combination with the internal pull-up
resistor R
feedback circuitry. When the amplified current signal of the
integrated CoolMOS
Comparator switches off the Gate Driver.
Version 2.0
Voltage
Ramp
Gate
Driver
0.6V
FBB
V
OSC
FB
PWM-OP
PWM-Comparator
Light Load Conditions
FBB
and provides the load information of the
is created by an external optocoupler or
Duty Cycle
®
156ns time delay
Sense
exceeds the signal V
max.
1
®
. The voltage ramp with the
converts the source current into
with the feedback signal V
FBB
the PWM-
t
Sense
FBB
t
t
10
Figure 8
3.4
Figure 9
Optocoupler
SoftS
Startup Phase
PWM Controlling
0.6V
FBB
Soft Start
Soft Start counter
C 7
PW M OP
Soft Start
Soft Start
5V
R
FB
Soft-Start Comparator
Functional Description
PWM OP
0.6V
C om parator
PWM Comparator
Soft-Start
CoolSET
Improved
Current Mode
x3.25
C8
G 7
X3.25
&
ICE3AR4780JZ
PWM-Latch
CS
26 Aug 2010
G ate Driver
®
-F3R80
C S