Theory of Operation

The following figure represents the block diagram for a single output channel on the NI PXI-4130.

Each output channel on the NI PXI-4130 has a preregulation switching stage and a linear regulation stage. To improve efficiency and to reduce heat dissipation on the power supply, the preregulation stage controls the voltage level across the control element in the linear regulation stage.

The voltage and current control loops work together through the linear regulation stage to provide the constant voltage mode and constant current mode. In constant current mode, the NI PXI-4130 acts as a precision current source. Thus, regardless of the output voltage, the current through the load is held constant at the programmed value.

The isolated output (channel 1) on the NI PXI-4130 can operate from the PXI chassis power (internal power) or from an auxiliary DC power supply. When operating from internal power, the isolated output channels are restricted to lower power levels. When operating from an auxiliary power source, the isolated output channel can increase the current to 2 A, delivering a maximum of 40 W.