lm317 is a linear adjustable three-terminal voltage regulator integrated circuit, and its hot means that the load current is large and the power consumption is large.
There are two ways to solve this:
one. Reduce its power consumption by:
1. Reduce the load current as much as possible.
2, reduce the pressure drop at both ends as much as possible. Among them, 1 is difficult, and a high-power resistor can be properly strung into 2 when it cannot be carried out.
two. To increase its heat sink or improve the ventilation and heat dissipation conditions
LM317 is a linear voltage regulator circuit, and heating is normal.
To reduce its working temperature, it must be added a suitable heat dissipation device, such as heat sink, profile radiator, etc.
Or give up the linear circuit and use DC-DC modules such as 3R33.