Multichannel Power Supplies vs. Single Channel Power Supplies: Is More Necessarily Better?
Power supplies are such basic tools, with many options commonly available to consumers, that it’s easy to overlook their finer points. For example, many include multiple outputs. Also, multichannel units with high output accuracy are available at increasingly economical prices. Still, no equipment budget can afford every “bell and whistle” so it makes sense to determine which applications really demand a multichannel power supply and which ones don’t.  Here, several questions to ask when determining your power supply needs: 

Does the device you are working with have both digital and analog circuitry or bipolar circuitry?

If the device has both, then you’ll want a multichannel power supply. Triple-channel power supplies typically have two higher voltage channels for analog circuits (to power multi-voltage circuits or to create bipolar power supplies for testing bipolar analog circuits) and a third channel intended to power a digital circuit. More often than not, the voltage for this third channel will be 10V or less (for testing digital circuits operating at 5V or less). When making your purchase, pay close attention to how the power supply’s vendor specifies that channel. Some supplies have fixed (non-programmable) voltage output channels, which are often 5V channels. If the application requires testing digital circuitry that operates at 3.3V or 1.8V, a programmable third channel is essential.

Does your device require individual isolated power supply sections?

If the answer to this question is yes, you’ll need to configure isolated supplies (which can be expensive and problematic to operate in some cases) or buy a multichannel supply. One thing to be aware of here is that multichannel units can either have isolated outputs or they can have output channels that are tied to a common point on their low side. When the channels are connected with the same common point, they aren’t suitable for powering circuits that are isolated from each other. For applications like these, look for multichannel supplies with isolated outputs.

Do you need to power circuits up and down in a specific sequence?

Sometimes multichannel power supplies can do much more than a set of individual supplies. Digital board designs often have circuits that operate at different voltages. When you test such circuits with external power supplies, it’s important to power the circuits in the correct order to avoid stressing and damaging the low voltage circuits. When you choose a multichannel supply for sequential applications, you have to make sure it allows for independent control of each channel so that the channels can be powered on in the desired sequence – and powered down in the opposite sequence when testing is complete.

Do you sometimes require sourcing more voltage or current than what an individual channel can provide?

Some multichannel power supplies allow you to combine channels in a series or in parallel to extend the ranges of the output voltage and current. In some cases, a multichannel supply may allow you to connect two channels in series to increase voltage output but not allow you to combine the channels in parallel. To get the maximum flexibility of the total voltage and current that’s available, look for a multichannel power supply with isolated output channels.

Do you need tracking functionality?

It’s essential to confirm the circuit operates within its performance specification over the defined voltage operating range. Multichannel supplies with tracking functionality offer a convenient way to test a bipolar circuit by linking both channels (a positive-configured output and a negative-configured output) so that they charge synchronously with each other. Previously, multichannel supplies could only track with both channels outputting voltages of the same magnitude, however some of the newer models allow tracking with a variable ratio between the two channels.

If you would like help determining which power supplies best suit your needs, contact us. We’re here to help with your testing, calibration, and all of your equipment needs - throughout the equipment lifecycle. .