21 Sep
2018
21 Sep
'18
5:07 p.m.
On 2018-Sep-21, at 4:03 PM, Noel Chiappa via cctalk wrote:
To clarify, bipolars have a fixed MINIMUM drop, which can be used in a switching supply to
as much advantage as possible with bipolars, but have a varying drop in a linear regulator
(that's where the 'linear' comes from) which results in the large losses and
inefficiency of linear regs.
From: Brent
Hilpert
If the heatsinks seem huge compared to modern day
supplies, that's more
likely the result of technology improvements - faster devices, and
moving from bipolar switching transistors to mosfets. Bipolar
transistors have a near-fixed voltage drop which can't be reduced
Right, I knew bipolars had the fixed drop, but I hadn't made the connection
to that being the cause of the large amount of heat needing to be dumped.
Useful enlightenment!