LM323, LM323A

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Figure 13. Current Regulator

Figure 14. Adjustable Output Regulator

Figure 15. Current Boost Regulator

Figure 16. Current Boost with

Short Circuit Protection

5.0 V

R

Input

0.33µF

LM323, A

R

The LM323,A regulator can also be used as a current source when

connected as above. Resistor R determines the current as follows:

For example, a 2.0 A current source would require R to be a 2.5 Ω,

15W resistor and the output voltage compliance would be the input

voltage less 7.5 V.

Constant

Current to

Grounded Load

Input

Output

1.0k

4

6

7

2

3

-

+

0.1µF

10k

MC1741

The addition of an operational amplifier allows adjustment to higher or

intermediate values while retaining regulation characteristics. The

minimum voltage obtainable with this arrangement is 3.0 V greater

than the regulator voltage.

LM323, A

0.33µF

R

0.1µF

Output

1.0µF

The LM323, A series can be current boosted with a PNP transistor. The

of the PNP determines when the pass transistor begins conducting; this

circuit is not short circuit proof. Input-output differential voltage

2N4398 or Equiv

LM323, A

LM323, A

Input

2N4398

or Equiv.

Output

R

MJ2955

or Equiv.

1.0µF

The circuit of Figure 16 can be modified to provide supply protection

an additional PNP transistor. The current sensing PNP must be able to

handle the short circuit current of the three-terminal regulator.

Therefore, an 8.0 A power transistor is specified.