Specifications
6
Tip
5
Simplify setup with autoranging
power supplies
With bench and rack space at a
premium, having the ability to
produce a wide range of voltage
and currents with one power supply
is beneficial. Applications that
require many voltage and current
combinations require many power
supplies or a very large power
supply to span the largest voltage
and current combination. For
example, a dc/dc converter is tested
under several voltage and current
combinations at about the same
power level.
A very basic dc power supply has a
rectangular output (Figure 1). It has
a maximum voltage setting (Vmax)
and a maximum current setting (Imax)
with a single maximum power point
(Pmax) which equals Vmax * Imax.
This creates a rectangular output
characteristic.
More advanced power supplies
have multi-range outputs. For
example, a dual-range power supply
(Figure 2) has two rectangular output
characteristics, each having a
different Vmax and Imax. However,
both output characteristics have
the same Pmax but at two different
points. The power supply can switch
between the different ranges to
satisfy both rectangular output
characteristics.
Autoranging outputs (Figure 3) satisfy
many different voltage and current
combinations that are limited by
Pmax. The output characteristic
follows a constant Pmax curve
allowing for several different power
curves rated at the same power
level, Pmax.
Using autoranging outputs simplifies
the test setup by eliminating the
need for many power supplies.
Supplies such as the Agilent N675xA
and N676xA have autoranging
outputs that help do this and
drive the cost of test down.
Figure 1: Rectangular output characteristic
Figure 2: Dual-range output characteristic
Figure 3. Autoranging output characteristic