Innovative CircuitsBeware of Imitators!
What is a "super regulator" exactly? In some circles the phrase has come to mean a "boot–strapped" regulator, one that is internally powered by its own regulated voltage. This is a design popularized by Walt Jung in articles in The Audio Amateur, Electronic Design and EDN magazines. As seen here, a self–powered regulator existed at least as far back as 1961.
Of course there is no law that says a regulator must be self–powered to be called "super." There is a law of physics that says to get the best performance from a regulator it should be self–powered. How else can you get the least noise, the best output dynamics, the lowest output impedance and the best line regulation all together? Go ahead, find another way. We dare you.
Belleson have evaluated some so–called super regulators on the
market and uncovered some imitators. We found one regulator that is not
self–powered, although it is a pretty good regulator. This one we
call the "Clark Kent."
We found another device that is also not self–powered and, based on the output dynamics, can hardly be called a regulator at all. This one we call "Lex Luthor" because of the evil it can do.
The original Jung super regulator used a green LED as a bias
voltage. Both Clark and Lex have an LED on the board (albeit blue). But
neither uses the LED for anything except to drain power or perhaps to
provide a static load on the output. So beware, all regulators with
LEDs are not truly super. The
Belleson Superpower is truly super and does not have an LED. What it
does have is better performance:
Clark Kent, 625mA pulse
Fuzzy trace is Vout at 9VDC, vertical = 5mV/div. Bottom trace is
V(load) = 5V across 8 Ohms (625mA) for 0.8msec. Good performance but
not super.
Superpower,
625mA pulse
Top trace is Vout at 9VDC, vertical = 5mV/div. Bottom trace is V(load) = 5V across 8 Ohms (625mA) for 0.8msec. Fast, clean, quiet, super.
Clark Kent is a good regulator, with decent dynamic performance. Clark has a step of 22mV and fast clean step response. The step is caused by internal resistance and the lack of a sense connection. What you cannot see here is the noise performance, which is good but not as good as Superpower.
Lex Luthor, as you can see, does not have very good dynamic
response. Notice how both time and voltage scales
are compressed to show the signal, which rings for nearly 200msec when
current is requested and then has a nearly 0.2V recover step that takes
0.3 seconds(!) to settle. The load voltage rings and has a
corresponding recovery tail.
If used to regulate an audio supply, Lex will certainly change the sound of the system, but not because it is true to the source signal. More likely because it keeps things moving after the signal has stopped.
Belleson® has introduced a small form factor, high output current Superpower™
regulator. The new SPJ78 and SPJ17 devices are available with Vout of +3.3V, +5V
and +6.25V, at current to 2 amps.