C1

0.1 µF

C2

1 µF

R1

240 Ω

INPUT

OUTPUT

ADJUST

LM317

INPUT

OUTPUT

ADJUST

LM317

R2

720 Ω

R3

120 Ω

R4

1 kΩ

Output

Adjust

ADJUST

OUTPUT

INPUT

R1

LM317

I

limit

1.2

R1

C1

0.1 µF

C3

1 µF

R1

240 W

INPUT

OUTPUT

ADJUST

LM317

D1

1N4002

R2

5 kW

C2

10 µF

LM317

SLVS044W – SEPTEMBER 1997 – REVISED OCTOBER 2014

www.ti.com

System Examples (continued)

9.3.2 Adjustable Regulator Circuit With Improved Ripple Rejection

C2 helps to stabilize the voltage at the adjustment pin, which will help reject noise. Diode D1 exists to discharge

C2 in case the output is shorted to ground.

Figure 13. Adjustable Regulator Circuit with Improved Ripple Rejection

9.3.3 Precision Current-Limiter Circuit

Figure 14. Precision Current-Limiter Circuit

9.3.4 Tracking Preregulator Circuit

This application keeps a constant voltage across the second LM317 in the circuit.

Figure 15. Tracking Preregulator Circuit

12

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