Section 4: Theory of operation Model 2657A High Power System SourceMeter® Instrument Reference Manual
4-10 2657A-901-01 Rev. B/December 2012
V-source sink operating boundaries
The quadrant within which the Model 2657A operates depends on the device-under-test (DUT)
connected to the Model 2657A output. The following example illustrates this operation by using the
Model 2657A configured as a voltage source to discharge a 1000 V power source (a battery).
Figure 75: Sourcing voltage while sinking current
The current compliance limit applies both to positive and negative currents. For example, if you set
the current compliance limit to 50 mA, the current limit applies to ±50 mA.
For this example, the Model 2657A is programmed to source 200 V and to limit current to 50 mA.
When the SMU turns on, the battery voltage is higher than the programmed voltage source value.
Since the SMU is unable to deliver the programmed voltage, the SMU is placed in current compliance
and begins to sink current. Sink operation continues until the battery voltage equals the programmed
voltage source level and the current in the circuit drops to nearly 0 A.
In the following figure, as the battery drains, the battery voltage is lowered (shown by the green arrow
in the figure). Operation will continue in this direction until the SMU is able to deliver the programmed
voltage source value.
I
DUT
1000 V200 V
2657A
+
-
+
-
SMU
NOTE