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ON-BOARD PULSE LOAD
The on-board pulse loads provide user a quick and easy way to measure transient performance of
paralleling DJT090s. Basically, the pulse load would track an external arbitrary current reference and
apply it on the output rail. Total sixteen channel of pulse load can operate together to achieve 16x
pulse capability. For using on-boar pulse load,
•
Connect input power
•
Connect output DC load if needed (the pulse load can operate on top of external DC load. e.g.
use external DC load to sink 300A and use on-board pulse load to pulse additional 300A
current)
•
Connect IN_IREF to function generator
•
Connect M_VOUT to Oscilloscope Channel 1 via co-
axil cable, use 50Ω input impedance or
use 50Ω attenuator in series with 1MΩ input impedance.
•
Connect ICHECK1 to oscilloscope Channel 2 via co-
axil cable, use 1MΩ input impedance
Now the EVM setup is ready to perform transient analysis. User can simply control the pulse load by
applying an external arbitrary voltage reference on IN_IREF by function generator. Parameters to
setup on the function generator,
•
Switch to pulse mode
•
Set frequency to 100Hz
•
Set duty to 5% MAX! (on-board pulse load can take maximum 40W loss, reduce duty if pulse
load exceeds 40W loss)
•
Set output voltage high level to desired current value using roughly 100A/V ratio (1.0V = 100A)
for 8 channel parallel EVM. 5V maximum. Due to cable losses and other issues, use ICHECK1
as reference to verify actual output current waveform.
•
Set output voltage low level to 10mV (a small current will be applied)
•
Set rising/falling edge of the pulse to the desired value, 100ns minimum.
Upon complete, power the EVM and enable the output of the function generator. Use oscilloscope
to exam the performance.
•
Use M_VOUT to examine undershoot/overshoot of the output, adjust horizontal/vertical
axis to proper range.
•
Use ICHECK1 to see actual load current waveform. Use 166A/V conversion ratio for 8 channel
EVM to interpreting the pulse load current. ICHECK1 is a more accurate way to determine
output current characteristics. For example, regardless high level voltage setting, if
ICHECK1 shows a 1V step with a 1us rising time, it is equivalent to apply a 166A/us trainset
on the output rail. To be noted, noise
can be seen on the measurement due to nearby DJT090, use average
value to measure high level voltage.
