Datasheet

LT1941
9
1941fb
BLOCK DIAGRAM
Inverting/Boost Switching Regulator One of Two Step-Down Switching Regulators
Figure 2. Block Diagram of the LT1941 with Associated External Components
–
+
–
+
–
+
–
+
–
+
R
SQ
SLAVE
OSC
¤
INT REG
AND REF
MASTER
OSC
RUN/SS1
RUN/SS2
2μA
BIAS1
2μA
CLK1
CLK2
CLK3
V
IN
0.628V
54mV
I
LIMIT
CLAMP
1.7V
RUN/SS
PGOOD
C
C
C
F
R
C
GND
ERROR
AMP
SLOPE
V
C
0.9V
0.35V
CLK
R1
C1
C
IN
SW
FB
BOOST
V
IN
V
IN
D2
C3
L1
D1
C1
R2
OUT
1941 F02
RUN/SS3
2μA
–
+
4.5V
5GOOD
V
IN
–
+
–
+
10.8V
12GOOD
1.25V
RUN/SS
0.4V
NFB
FB3
0.6V
1.12V
–
+
–
+
–
+
ERROR
AMP
C2
–
+
–
+
–
+
V
C3
R
CLK3
Q
S
BIAS2
SW3
V
IN
SW3
L3
C4
V
OUT3
D3
BOOST
PGND
Q1
DRIVER
0.01Ω
RAMP
GENERATOR
SLAVE
OSCILLATOR
PGOOD3
V
IN
SW3
L4A
L4B
D4
C6
–V
OUT3
C5
INVERTING
3
–
+
FOR
POSITIVE
OUTPUTS
FOR
NEGATIVE
OUTPUTS
V
OUT3
R3
(EXTERNAL)
FB3
NFB
R4
(EXTERNAL)
FB3
–V
OUT3
R3
(EXTERNAL)
NFB
R4
(EXTERNAL)