Okay. I am designing a device that will adjust the signals read from a map sensor from a vehicle's engine.
I had some trouble using a 7805 linear regulator with another project, (iPhone charger), the 7805 kept getting hot and going into shutdown. This, I believed to be caused by the fact that the 7805 had to dissipate 4-7W of power through it's case. I did not want to put a heatsink on it since it would be too large.
I solved this problem by purchasing a cheap USB power adapter that put out 5V. I noticed that the internals were of a "switching" variety.
So I set out to design a power supply around a switching regulator for my automotive design.
It is all designed, the gerbers are sent to the fab house, should be in Monday. So I had a thought today to crack open a device that measures and logs different sensors in my car, to see what that designer used for a power supply. Great timing! Should have waited on those gerbers. They used a linear regulator, in d2pak form. I have never noticed this device get excessively warm where the regulator was. I believe this was possibly due to the fact that the copper pour of the pcb is being used as a heatsink.
Due to the fact that I require 12V, analog and digital 5v, 3.3v and -5v sources, it would be more cost effective to use a linear regulator than a switching variety. My question is, if I use linear VRs, attached to the copper layer they should be fine for dissipation, no? Has anyone used linear regulators in a vehicle environment without thermal shutdown?
I had some trouble using a 7805 linear regulator with another project, (iPhone charger), the 7805 kept getting hot and going into shutdown. This, I believed to be caused by the fact that the 7805 had to dissipate 4-7W of power through it's case. I did not want to put a heatsink on it since it would be too large.
I solved this problem by purchasing a cheap USB power adapter that put out 5V. I noticed that the internals were of a "switching" variety.
So I set out to design a power supply around a switching regulator for my automotive design.
It is all designed, the gerbers are sent to the fab house, should be in Monday. So I had a thought today to crack open a device that measures and logs different sensors in my car, to see what that designer used for a power supply. Great timing! Should have waited on those gerbers. They used a linear regulator, in d2pak form. I have never noticed this device get excessively warm where the regulator was. I believe this was possibly due to the fact that the copper pour of the pcb is being used as a heatsink.
Due to the fact that I require 12V, analog and digital 5v, 3.3v and -5v sources, it would be more cost effective to use a linear regulator than a switching variety. My question is, if I use linear VRs, attached to the copper layer they should be fine for dissipation, no? Has anyone used linear regulators in a vehicle environment without thermal shutdown?