l6611 STMicroelectronics, l6611 Datasheet - Page 25

• Manufacturer Part Number: l6611
• Description: Digitally Programmable Secondary Housekeeping Controller
• Manufacturer: STMicroelectronics

7
In fig. 23 a circuit is suggested to obtain the regulated +3.3V output with a linear configuration instead of the
Magamp circuitry.
In this case the output of the E/A modulates the gate-source voltage of a power MOS in series with the power
stage.
In fig. 24 a simple and cheap latch circuit is showed to manage an OV fault on the Auxiliary output in the same
way of an OC (UV) fault, without having recourse to a (expensive) power crowbar. By tuning the value of R
it is possible to set the voltage value that triggers the latch circuit; C
nected between the collector of Q1 and Cout pulls down the output of the auxiliary E/A: this has the same effect
of the OCP_bounce internal signal that guarantees the reduction of duty cycle.
Figure 23. Controlling a Linear Regulator with the Error Amplifier B
Figure 24. Auxiliary OVP without Crowbar
APPLICATION IDEAS
L6611
L6611
DMON
DMON
Cout
Cout
+12V
+12V
L
L
BAT42
BAT42
R
R
D1
D1
B
B
BC548
BC548
Q1
Q1
+5V
+5V
C
C
1
1
L6611
L6611
Bout
Bout
5K6
5K6
C
C
DEL
DEL
100
100
BC558
BC558
DEL
Q2
Q2
_
_
+
+
+1.25V
+1.25V
Z
Z
defines the turn-on delay. A diode con-
C
C
Binv
Binv
C
C
R
R
5K6
5K6
2
2
SET
SET
V
V
AUX
AUX
+3.3V
+3.3V
R
R
R
R
H
H
L
L
L6611
25/28
SET