61 / 84
cost parts.
A single instrument
solution for multiple
measurement challenges
Obviously, most design and test
engineers would prefer a solution
that’s less complicated to implement
than configuring a test setup with a
DC power supply to provide the source
voltage, a sense resistor, a DMM, an
oscilloscope, an SMU instrument,
and a switching system to tie them
all together. If they can make the
measurements they need with only a
single instrument, testing can begin
sooner because there is less equipment
to set up (Figure 2). Automating the
measurement is simpler as well with
only one instrument to program. This
eliminates the need to synchronize
multiple instruments and allows the
engineer to focus on making the
measurement. However, instrument
designers are only beginning to
take on the challenge of creating
instruments capable of providing the
level of power needed to energize a
wireless IoT device without sacrificing
the ability to measure both very low
load currents and much higher active
load currents accurately and with high
resolution. Such instruments are only
now entering the market in the form
of power supplies with integrated
precision measurement capabilities
(Figure 3).
In order to measure very low standby
or sleep mode currents accurately,
a
power
supply/measurement
instrument must be capable of
DMM-quality measurements with
up to 6½ digits of resolution. When
making high current measurements,
it has to capture current pulses as
short as hundreds of microseconds.
Also, because some devices, such as
implantable medical sensors or other
portable, battery-powered devices,
have a power-up load sequence and a
power-down sequence, similar to the
one shown in Figure 4, the instrument
chosen must have the triggering
capabilities needed to make multiple,
synchronized measurements at each
state of the power-up or power-down
cycle.
New-Tech Magazine Europe l 61