Three-terminal voltage regulator current expansion circuit

[url=../Upload/2005527171649144.jpg] When the load current is greater than the nominal current value of the three-terminal adjustable integrated voltage regulator, current expansion can be used to solve the problem. The circuit shown in Figure 1 uses a PNP high-power tube to expand the current. A 3AD53 high-power tube can expand the current to 6A. When one is not enough, two or more high-power tubes can be connected in parallel, such as It can be expanded to 18A with three. The circuit shown in Figure 2 is an example of using NPN high-power tubes to expand current. At this time, a 3DD15 can provide a load current of 5A, an LM317 can provide a current of 1.5A, and the output terminal can provide approximately 6.5A current. At this time, two diodes play an isolation role, and two or more high-power tubes can be connected in parallel to expand the current to a larger value. When the nominal current of the LM regulator is 0.1A and the load current needs to be very large, the current expansion method is: LM317 can first drive a smaller power tube, and then use a smaller power tube to The tube drives one or more more powerful tubes. In the circuit shown in Figure 3, LM317 first drives BG1-3DDl5, and then GB1 drives BG2 and BG3 - two 3DDl70 tubes. At this time, the voltage regulator can output a current of 20A.