ICE3AR10080CJZ Datasheet, PDF (10/33 Pages) Infineon Technologies AG – Off-Line SMPS Current Mode Controller with integrated 800V CoolMOS® and Startup cell (brownout & CCM) in DIP-7

CoolSET^®-F3R80
ICE3AR10080CJZ
Functional Description
7). It allows the duty cycle to be reduced continuously
till 0% by decreasing V_FBB below that threshold.
V_OSC
max.
Duty Cycle
5V
R_FB
Soft-Start Comparator
FBB
PWM-Latch
C8
Voltage
Ramp
0.6V
FBB
Gate
Driver
156ns time delay
t
Optocoupler
t
PWM Comparator
0.6V
PWM OP
CS
X3.25
Improved
Current Mode
t ^{Figure 8 PWM Controlling}
Figure 7 Light Load Conditions
3.3.1 PWM-OP
The input of the PWM-OP is applied over the internal
leading edge blanking to the external sense resistor
R_Sense connected to pin CS. R_Sense converts the source
current into 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 V₁.
The voltage ramp with the 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 PWM-Comparator
The PWM-Comparator compares the sensed current
signal of the integrated CoolMOS^® with the feedback
signal V_FBB (Figure 8). V_FBB is created by an external
optocoupler or external transistor in combination with
the internal pull-up resistor R_FB and provides the load
information of the feedback circuitry. When the
amplified current signal of the integrated CoolMOS^®
exceeds the signal V_FBB the PWM-Comparator
switches off the Gate Driver.
3.3.3 Slope Compensation
Due to the sub harmonic oscillation of CCM operation
when duty cycle is larger than 50%, the slope
compensation is added.
The slope Mc; 50mV/ms is added to the current sense
pin when gate is on.
During burst mode operation, the Mc slope is shut
down and no slope added into the current sense signal.
This can save the power consumption at burst mode.
C8
FB
PWM
comparator
PWM latch
Slope
compensation
5.0V
Gate Drive
signal
0.62V
x3.25
PWM OP
Active burst
mode
Mc=50mV/us
S5
LEB
180/220ns
R_slope
10k
1pF D2
CS
Figure 9 Slope compesnation
Version 2.0
10
11 Jan 2012