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1.1.5. Dynamic Waveform Definition
Along with static operation the 3110 load modules are built with a Dynamic mode for
operation in Constant Current (CC), Constant Resistance (CR) or Constant Power (CP).
This allows the test engineer to simulate real world pulsing loads or implement a load profile
that varies with time.
A dynamic waveform can be programmed from the front panel of the 3110 load module. The
user would first set a High and low value of load current using the Level button. The
Dynamic Setting then allows for the rise and fall time between these 2 current values to be
adjusted. The time period that the waveform is high (Thigh) along with the time period that
the waveform is low (Tlow) can also be set.
The dynamic waveform is illustrated below in Fig 1-10.
I
LOAD
CURRENT
RISE
SLEW RATE
The dynamic waveform can also be set up via the optional computer interface. Dynamic
waveform settings made from the front panel of the load module can also be saved in the
memory of the mainframe. For the store/recall procedure and the computer command set
please refer to the relevant operating manual for the 3300G/3302G/3305G mainframes.
Further dynamic waveform definitions are:
•
The period of dynamic waveform is Thigh + Tlow
•
The dynamic frequency = 1 /( Thigh + Tlow )
•
The duty cycle = Thigh / ( Thigh + Tlow )
1.1.6. Slew Rate
Slew rate is defined as the change in current or voltage over time. A programmable slew
rate allows for a controlled transition from one load setting to another. It can be used to
minimize induced voltage drops on inductive power wiring, or to control induced transients
on a test device (such as would occur during power supply transient response testing).
In cases where the transition from one setting to another is large, the actual transition time
can be calculated by dividing the voltage or current transition by the slew rate. The actual
transition time is defined as the time required for the input to change from 10% to 90% or
from 90% to 10% of the programmed excursion.
T
HIGH
Fig 1-10 Dynamic Wave form
3110 Series Operation Manual 5
FALL SLEW RATE
T
LOW
HIGH LOAD
LOAD
LOW LOAD
LEVEL
V
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