Cascading the Outputs of a DC Power Supply to Extend Voltage and Current Ranges

This tutorial is part of the National Instruments Measurement Fundamentals series. Each tutorial in this series, will teach you a specific topic of common measurement applications, by explaining the theory and giving practical examples. This tutorial describes how increase the voltage and current output by cascading the outputs of a multi-channel power supply or supplies.

For additional power supply only concepts, refer to the Power Supply Fundamentals main page.
For the complete list of tutorials, return to the NI Measurement Fundamentals Main page.

Cascading Power Supply Channels to Increase Voltage Output

Sometimes an application requires more voltage than a single channel of a programmable power supply can output. If your power supply offers isolated outputs or a combination of isolated and non-isolated channels, you can easily extend the maximum output range by cascading channels in series.

For example, the NI PXI-4110 triple output power supply offers default configuration shown in figure 1.

NOTE: When cascading modules, be sure to not exceed the maximum common mode of a power supply. For example, the PXI-4110 has a maximum common-mode of +60VDC from ground

Cascading Power Supply Channels to Increase Current Output

If your power supply offers isolated outputs or a combination of isolated and non-isolated channels, you can easily extend the maximum output range by cascading channels in parallel. This type of configuration is sometimes quicker or even costs less than purchasing a new higher-current power supply.

For example, you can extend the current output of a single NI PXI-4110 power supply by cascading an isolated and non-isolated channel, as shown in figure 2. 
Customers interested in this topic were also interested in the following NI products:

• Programmable DC Power Supplies and Precision Sources
• Modular Instruments (digital multimeters, digitizers, switching, etc...)
• LabVIEW Graphical Programming Environment
• SignalExpress Interactive Software Environment

For the complete list of tutorials, return to the NI Measurement Fundamentals Main page

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