Innovative CircuitsSuperpower compared with LM7812
How does the superpower compare with a typical 3 terminal regulator?
Quite well as you can see in the oscillograms below. Both devices were
tested using datasheet recommended application circuits, both devices
use the same input supply.
NOTE: For 1A pulse tests, the Superpower in these photos uses a TO-220
output device rather than the standard surface mount, to allow the
higher current without current limiting. The standard device with
surface mounted components begins to limit current at about 700mA.
Superpower,
1A pulse
Superpower
delivering 1A into 8 Ohms, bottom trace is load voltage. Notice the
clean, fast rise and fall of the load voltage. The top trace shows Vout
transients, which are quite low.
A less demanding test, pulling 250mA from the regulator, shows a
super clean load transient and an output with a very small step and
almost no transient behavior. Notice the 2mV scale on the output trace, vs. the 5mV scale on the LM7812 oscillogram to the right.
LM7812, 1A pulse
The
LM7812 is ok, but with a 0.8V transient at the leading edge (visible in full size view), a 40mV step and, like the LM317, a slew limited, ringing transient
on the trailing recovery edge.The LM7812 transient magnification has so much motion that it's hard to tell what's going on. The output rings for 200µsec and the load has a transient that exceeds ½V.
At 250mA, the LM7812 exhibits a characteristic output ringing on the rising transient, a significant step and has an odd wrinkle at the load. The noise increase at high current is moderate. The test circuit uses a 0.1µF capacitor from output to ground as suggested by the data sheet. Using 10µF output capacitance increases the ringing so that it does not settle within several msec.
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. 