How to choose a DC power supply for automated test systems

Each automated test systems for testing circuit boards, modules or devices require one or more DC power supply is used to provide power to the device under test and provide test stimulus. In some cases, the power supply provides power not only to the device under test, but also to provide the test excitation source via a simulated work environment. For example, although most automotive electronic equipment in nominal 12VDC, but the maximum input voltage may be as high as 27VDC. Because of this, some car standard requires 12VDC up to 27VDC devices limit testing. Determines the necessity like power requirements. Let us look at the common power supply specifications when selecting the power of automated test systems need to consider what?

Linear power supply or switching power supply?
Decisions when buying a DC power supply is the first to make a choice of linear or switching power supply. Linear power supply with low ripple and noise, and has a fast transient behavior. However, their low efficiency, will produce a lot of heat, and heavy. So most of the engineers found only at lower output power levels (usually 500W or less) when comparing desirable. Most linear DC power supply desktop power supply.

Linear power for the desktop, the application is a very suitable test communications device such as a mobile phone or radio or radar system demodulation module. These devices have a very sensitive discriminator or demodulator circuit, these circuits at low noise figure to play the desired performance. To test the true performance of these units, we need to ensure that the DC power to the test device does not add any spurious noise. Since the linear power with lower than the switching power supply output ripple and noise, so they are a better choice for such applications.

When the power requirements low, linear power supply is also a good choice. The main benefit of switching power supply can only manifested in higher output power level talent. Therefore, the DC output power per channel does not exceed the application requirements of 100W to 200W linear DC power supply used in more cost effective.

From this point of view, considering the total DC power output of all channels of the system is very important. If there are four or four of the following channels, and power requirements are relatively low, then the more sensible choice is to form 19-inch rack mount kit provides four linear power.

If your system requires more output channels, or higher output power, then use the switching power supply is a better choice. Switching power supply can provide a higher power than the linear power density. By using a switching power supply, you can have 12VDC output, and can be installed in the same rack configuration provides up to 4000W of power. Switching power supply is easier to control than the linear, while the cost per channel almost.

Even in requiring low output ripple and noise applications, not just more efficient switching power supply. Recent developments in the field of power electronics (such as zero switch), which greatly improved the ripple and noise performance switching power supply. When you also consider switching power supply is more flexible than linear power supply, and can provide higher power density, then they will become the first choice for almost all applications except for a few applications outside.

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