E-UC3843BD1 Datasheet, PDF (8/15 Pages) STMicroelectronics – HIGH PERFORMANCE CURRENT MODE PWM CONTROLLER

UC2842B/3B/4B/5B - UC3842B/3B/4B/5B
Figure 15 : Error Amp Configuration.
2.5V
+
Z_i
V_FB 2
-
COMP 1
Z_f
1mA
D95IN345
Figure 16 : Under Voltage Lockout.
7
ON/OFF COMMAND
V_i
TO REST OF IC
I_CC
V_ON
V_OFF
UC3842B UC3843B
UC3844B UC3845B
16V
8.4V
10V
7.6V
<17mA
<0.5mA
D95IN346
V_OFF V_ON
V_CC
During UVLO, the Output is low
Figure 17 : Current Sense Circuit .
ERROR
AMPL.
2R
I_S
1
COMP
R
R
3
CURRENT
R_S
C
SENSE
5
GND
D95IN347
Peak current (is) is determined by the formula
IS
max
≈
1.0 V
RS
A small RC filter may be required to suppress switch transients.
8/15
1V
CURRENT
SENSE
COMPARATOR