Keysight Technologies N69100 Series, Руководство по эксплуатации и обслуживанию

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In CV operation, large capacitive loads and high inductance leads have the potential to create ringing
and dynamically unstable voltage at the DUT when undergoing sudden load or voltage changes. ESR
tends to mitigate this by dampening the resonance that occurs between the load capacitance and
lead inductance. Lead resistance contributes to the damping effects of ESR but also increases voltage
drop and power dissipation in the load leads. The
Capacitive Load Boundary characteristic graphs
have guidelines for minimum required ESR as a function of DUT capacitance. This is a function of the
voltage
compensation mode .
For a DUT that has internal capacitance with low ESR as shown in the Capacitive Load Boundary
graphs, such as film capacitor or ceramic capacitors, additional capacitance and series resistance can
be added in parallel to dampen the effects of ringing, as shown in the following figure. The additional
capacitance should be at least 1 to 4 times the value of C
DUT
and the desired ESR should be chosen
based on the Capacitive Load Boundary plots for C
DUT
. This can be implemented through the addition
of a high-voltage film capacitor and a series resistor. The parallel capacitance and ESR must be able
to handle DUT-specific requirements such as current or voltage ripple. In addition, parallel
capacitance will limit the ability of the power supply to measure fast current edges sourced directly
from the DUT, as well as slow down the voltage programming speed and bandwidth.
Typical external
damping network
Transient Voltage Deviation
The specified voltage transient response to a load current step for the power supply may become
degraded when remote sensing with long load leads, especially with low bypass capacitance at the
DUT. This can be manifested as a poorly dampened ringing or even as a well dampened response with
very large peak deviation. This issue can be most problematic when operating at lower voltage with
higher current. To mitigate this, parallel capacitance can be added at the terminals of interest to
reduce the amplitude of voltage deviation. It is likely an external parallel damping network, as
previously illustrated, would be needed in place of or in addition to a pure capacitor. Generally, a
capacitor with low ESR in parallel with a capacitor with high ESR allows for good stability, minimized
transient response voltage deviation, as well as good voltage noise filtering.
2 Installing the Instrument
70 Keysight N69100 Series Operating and Service Guide