Voltage regulation circuit schematics

AN3399

8/24

Doc ID 018824 Rev 2

1.4

Voltage regulation and current limitation with external NPN

The Figure 4 is the slightly modified circuit from Figure 1 for voltage regulation with current

limitation using external NPN.

Figure 4.

Voltage regulation and current limitation with external NPN

This circuit is a modification of circuit from Figure 2 extended with the current limitation

feature provided by resistor R5 and transistor T2 (BC856). The output voltage is possible

adjust like in original schematics by change or R1 and R2 resistors without impact on the

output voltage.

Parameters of circuit from Figure 4 are following:

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Output voltage = 5 V

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Output current limited at 200 mA

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