LT1158

17

Figure 14. Potentiometer-Adjusted Open Loop Motor Speed Control with Short-Circuit Protection

330pF

LT1158 F13

+

0.01

µF

4.7k

1

µF

+

1000

µF

LOW ESR

500

µF EA

LOW ESR

0.007

Ω

L1

70

µH

SHORT-CIRCUIT

CURRENT = 15A

5V OR

12V

*

INPUT

30V MAX

IRFZ44

330k

0.1

µF

10k

30k

10

µF

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

B GATE DR

BOOST DR

BIAS

ENABLE

FAULT

INPUT

GND

B GATE FB

LT1158

510

Ω

1N4148

1N4148

1N4148

1

µF

2.2nF

0.1

µF

3.4k

*

*

EXT

SYNC

0.01

µF

0.01

µF

+

16

15

14

13

12

11

10

9

1

2

3

4

5

6

7

8

LT3525

4.7k

SHUTDOWN

+

ULTRONIX RCS01

(2) IRFZ44

+–

f = 25kHz

2.2nF

LT1158 F14

+

0.01

µF

5.1k

1000

µF

LOW ESR

24

Ω

START CURRENT

= 15A MINIMUM

10V TO 30V

24

Ω

0.1

µF

10

µF

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

B GATE DR

BOOST DR

BIAS

ENABLE

FAULT

INPUT

GND

B GATE FB

LT1158

510

Ω

1N4148

1

µF

MOTOR SPEED

0 TO 100%

0.33

µF

+

10k

+

+

–

1

2

3

4

8

7

6

5

CMOS

555

1N5231A

Q1

Q2

0.02

Ω

7.5k

1k

Μ

Figure 13. 90% Efficiency 24V to 5V 10A Switching Regulator

95% Efficiency 24V to 12V 10A Low Dropout Switching Regulator