Application circuit diagram based on L200

The L200 is a monolithic integrated adjustable voltage regulator IC with functions such as current limiting, thermal shutdown, power limiting, and input overvoltage protection.

Maximum power dissipation

The L200 has internal limiting to reduce heat dissipation. This occurs when the internal junction temperature reaches 150°C. The datasheet has a graph of the safe operating area, but if the maximum output current is to reach 2 amps, the difference between the input voltage minus the output voltage must be less than 20 volts.

Specification

DC input voltage: 40V maximum

Peak input voltage: 60V max, 10 ms

Output voltage range: 2.85 to 36V

Output current range: 0.1~2A

Quiescent current: 4.2 mA

Output noise: 80uV

The L200 regulator has many versions: L200, L200C, L200CH, L200CV. These are actually the same regulator, the main difference is the operating temperature and the pinout.

For L200, the operating junction temperature is -55~150°C. For L200C, the operating junction temperature is -25 to 150°C.

L200 adjustable voltage regulator circuit diagram (I)

This is a regulated power supply made using an L200 voltage regulator with variable voltage and limited current regulation.

The 5-pin L200 regulator provides voltage and current regulation. The IC also has thermal shutdown and input overvoltage protection, and the maximum dropout voltage can reach 60V DC. The above circuit has RSC = 0.45 ohms, so the current limit is 1 amp. The output voltage can be adjusted from 2.85V to 36V. The supply voltage must be a few volts greater than the maximum output voltage. For an output voltage of 36V, the input voltage Vcc must be above 40V. If you want to get a 9V output voltage, the input voltage should be at least 12V.

L200 adjustable voltage regulator circuit diagram (II)

Here, the regulator is designed to produce an output adjustable between 2.85V and 15V (1A). Resistors R1 and R2 determine the output voltage. Resistor R3 determines the output current limit, here 1A. Capacitors C1 and C2 provide filtering. Do not apply more than 200V to the input on L40.

Circuit diagram with parts list.

Assemble the circuit on a general-purpose PCB.

Power the circuit with 18V DC

The input voltage always has to be a few volts higher than the maximum regulator output.

Mount IC1 with the heat sink.

The output voltage can be changed by adjusting POTR2.

Design formula

Vout = 2.77 [1 + (R2/R1)]

Current limit (Isc) = 0.45/R3