Datasheet
LT1158
18
1158fb
TYPICAL APPLICATIONS
Figure 13. 90% Effi ciency 24V to 5V 10A Switching Regulator
95% Effi ciency 24V to 12V 10A Low Dropout Switching Regulator
Figure 14. Potentiometer-Adjusted Open Loop Motor Speed Control with Short-Circuit Protection
330pF
LT1158 F13
0.01μF
4.7k
1μF
1000μF
LOW ESR
500μF EA
LOW ESR
R
S
0.007Ω
L1
70μH
SHORT-CIRCUIT
CURRENT = 15A
5V OR
12V
*
INPUT
30V MAX
IRFZ44
330k
0.1μF
10k
30k
10μF
* ADD THESE COMPONENTS TO IMPLEMENT
LOW-DROPOUT 12V REGULATOR
L1: MAGNETICS CORE #55585-A2
30 TURNS 14GA MAGNET WIRE
MBR340
27k
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
BOOST
T GATE DR
T GATE FB
T SOURCE
SENSE
+
SENSE
–
V
+
B GATE DR
BOOST DR
V
+
BIAS
ENABLE
FAULT
INPUT
GND
B GATE FB
LT1158
510Ω
1N4148
1N4148
1N4148
1μF
2.2nF
0.1μF
3.4k
*
*
EXT
SYNC
0.01μF
0.01μF
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
LT3525
4.7k
SHUTDOWN
R
S
: DALE TYPE LVR-3
ULTRONIX RCS01
(2) IRFZ44
+–
f = 25kHz
+
+
+
+
+
+
2.2nF
LT1158 F14
0.01μF
5.1k
1000μF
LOW ESR
24Ω
START CURRENT
= 15A MINIMUM
10V TO 30V
24Ω
0.1μF
10μF
THE CMOS 555 IS USED AS A 25kHz TRIANGLE-WAVE
OSCILLATOR DRIVING THE LT1158 INPUT PIN. THE
D.C. LEVEL OF THE TRIANGLE WAVE IS SET BY THE
POTENTIOMETER ON THE CMOS 555 SUPPLY PIN, AND
ALLOW ADJUSTMENT OF THE LT1158 DUTY CYCLE
FROM 0 TO 100%.
CMOS 555: LMC555 OR TLC555
Q1, Q2: MTP35N06E
13k
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
BOOST
T GATE DR
T GATE FB
T SOURCE
SENSE
+
SENSE
–
V
+
B GATE DR
BOOST DR
V
+
BIAS
ENABLE
FAULT
INPUT
GND
B GATE FB
LT1158
510Ω
1N4148
1μF
MOTOR SPEED
0 TO 100%
0.33μF
10k
+
–
1
2
3
4
8
7
6
5
CMOS
555
1N5231A
Q1
Q2
0.02Ω
7.5k
1k
-
+
+
+