8
LT1575/LT1577
BLOCK DIAGRAM
W
LT1575 Adjustable Voltage
SW2
NORMALLY
CLOSED
I2
5µA
–
+
ERROR AMP
COMP
1575/77 BD1
–
+
COMP1
Q6
SHDN
V
IN
GND
FB
R2
5k
SW1
NORMALLY
OPEN
100mV
HYSTERESIS
I1
15µA
I3
100µA
–
+
I
LIM
AMP
V
TH1
50mV
+
–
V
TH2
1V
+
–
D1
IPOS
INEG
GATE
D2
–
+
COMP2
–
+
COMP3
OR2
START-UP V
REF
1.21V
R1
50k
OR1
Q4
Q3
Q2Q1
Q5
