Fact, a linear voltage regulator (ex. 7805) gets hotter if the input voltage is higher (with a constant load).
Would the heat dissipation be similar for a DC to DC converter?
I am trying to get my head around the frequency of the converter at low then at higher input voltages.
(I assume low i/p voltage high freq. Higher i/p voltage lower freq.)
Using ebay converters similar to the one below:
A linear voltage regulator is a DC to DC converter. I think you mean a switching converter.
A linear voltage regulator is a DC to DC converter. I think you mean a switching converter.
Yes, "Switching", similar to the DC to DC converters I mentioned from ebay.
Would the heat dissipation be similar for a DC to DC converter?
For a switching converter, usually no. These converters are typically 90% or more efficient, the difference from 100% is converted to heat.
To expand a bit, a switching buck converter draws less current from the source than it delivers to the load. Linear regulators always draw slightly more current from the source than they deliver to the load.
Small converters are rarely as good as 90%, but generally much better
than a linear regulator.
For any particular device the heat dissipation will be a complex function of
input voltage, the load current and temperature of the ferrite inductor (ferrite
properties vary a lot with temperature).
LarryD:
I am trying to get my head around the frequency of the converter at low then at higher input voltages.
(I assume low i/p voltage high freq. Higher i/p voltage lower freq.)
The frequency of the converter will not change, like the one that you link it operated at 150KHz, will not change with the input voltage, only the duty cycle change like PWM.
They actually run cooler as the efficiency increases with the voltage differential.
This is because at higher input voltages, less current is drawn (on average) and it is after all, that current which heats up the switching device.
Small converters are rarely as good as 90%, but generally much better
than a linear regulator.
I suppose, if you shop on eBay.
Thank you: Paul__B, BillHo, MarkT, jremington and KeithRB.
I like what Paul just said, will do some testing when I receive some of these converters from eBay.
Side issue, I was going to glue a heat sink to a ceramic I.C.
In the past I used something called liquid steel which worked great and had good heat transfer.
However I am unable to get this locally any more.
Do you have any recommendations on what you use?