Why a uC does not make a heat while running

Using Arduino Microcontrollers
1

Hi all,

I'm not a really Arduino beginner and have a little experience with Arduino platform. But I don't know why when a uC is running it does not make any heat for even those boards with very high speed likes Teensy 3.6 up to 120MHz. In contrast, the CPU always does with a chip just about 200MHz.

Thanks all

2

They do!

Microprocessors are built to handle electric power very efficiency. However, all machines waste some energy by heating up. This is true for microprocessor chips. In the picture above, the glowing chip in the center of the picture is a ATTiny 85 running on 5 volts at 16MHz.

The picture was made with an FLIROne camera on an iPad.

3

ChrisTenone:
Microprocessors are built to handle electric power very efficiency. However, all machines waste some energy by heating up. This is true for microprocessor chips. In the picture above, the glowing chip in the center of the picture is a ATTiny 85 running on 5 volts at 16MHz.

The picture was made with an FLIROne camera on an iPad.

Thanks ChrisTenone.

I just touch it by hand so that can not detect any heat. Anyway that's reasonable.

4

:slight_smile:

It's hard to feel any increased heat output from a single component. If you can, maybe it's time to redesign the circuit. I take these heat pictures to identify inefficiencies. Once I get it all in the µP, I'm happy, because when I use a microP, every problem looks like a software nail.

The heat usually first shows up in a trim pot or switch. If that's the case, it means the software is moving current sinks/sources around too much. Change pin states as seldom as you can - same for reading & converting analog values. Think about sleeping the processor as much as possible - slower is cooler. lower voltage, lower speed. Your eyelids are getting heavy ...

Note: I like the Narcoleptic library.

5

Some ATmegas have on-chip internal temperature sensor. ATmega328P has. You can try to detect if the temperature is increasing after 'cold start'.

6

I used to work at Nexteer in the electrical validation department. They used a giant 144 pin microcontroller from TI clocked at 180 MHz. The aluminum case needed to be molded to that it touched the top of the microcontroller and acted as a heatsink. There were 2 or 3 other chips that needed that treatment too.

Any electrical power that doesn't make something blink (light), beep (sound), or buzz (motion) will make something burn (heat).

7

Thanks all Guys.

8