Lm317 current spreading circuit (complete works)

Probe current voltage pin 420*4450 head diameter 5.0 over current current and voltage pin

Lm317 current spreading circuit (complete works)

When the load current is greater than the nominal current value of the three-terminal adjustable integrated regulator, it can be solved by expanding the current.

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. Use three to expand to 18A.

The circuit shown in Fig. 2 is an example in which an NPN-type high-power tube is used for current expansion. At this time, a 3DD15 can supply a load of 5A, a LM317 can provide 1.5A, and an output of about 6.5A. At this time, the two diodes are isolated, and two or more high-power tubes are connected in parallel to expand the current to a larger extent.

When the nominal current of the LM regulator is 0.1A, and the load current needs to be large, the method of current expansion is: the LM317 can first drive a power tube with a smaller power, and then the power of a smaller power. The tube drives one or several more powerful tubes.

As shown in Figure 3, the LM317 first drives BG1-3D15, and then GBl drives BG2, BG3 - two 3DDl70 tubes. At this time, the regulator can output 20A current.