The Tips to Choose Power Modules
DC/DC power module with its small volume, high performance, and easy to use characteristics, in communication, network, industrial control, railway, military, etc are getting widely used. Power module selection should consider several aspects
Rated power
Generally recommend that the actual use of power, 30% to 80% of the rated power module is appropriate. In the power range, power module various aspects performance is stable and reliable. All power modules all have certain overload ability, but still we don’t suggest long time working in overload condition.
Packaging form
The difference of DC/DC converter size and the shape of the output form are very big. Small power products use sealing shell, appearance is very tiny. High power products often use quarter-brick or half-brick. The encapsulation of the module is variable. How to choose the right packaging form? There are three main aspects:
Under the condition of certain power volume must be as low as possible, thus to provide more space and more functions to other parts of the system;
Try to choose accord with international standard products, because of the encapsulation compatibility is better, not limited to one or two supply manufacturers;
It should be extensible, facilitate to system upgrades.
Temperature range and derating
General factory power module has several temperature range alternative products: commodity level, industrial, and military level, etc. In choosing power module, we must consider the actual demand of the operating temperature range, because different temperature level, material and manufacturing process, prices are very different, improper selection will also affect use. There are two kinds of methods: it is according to the service power and packaging format, if the volume in certain conditions the actual service power has been close to power rating, so the temperature range of module must be strictly meet the practical needs. The other is based on temperature range to choose, if we choose smaller temperature range of products based on the considering of cost, we can select power or packaging larger product.
Commodities (0 ℃ to + 70 ℃)
Industrial (-40 ℃to + 85 ℃)
Military level (-55 ℃ to + 125 ℃)
Frequency conversion and fixed frequency
Like all switch type device, DC/DC converter can produce the noise as in work, so filtering performance is also the important basis for the selection. Integrated DC/DC converter is usually used frequency conversion switch technology or fixed frequency switch technology. And fixed frequency switch converter in this respect is simple, which can even use LC filters.
Working frequency
In general, the higher the frequency, the smaller the work output ripple noise, the better the power dynamic response, but also it has high requirements on components especially magnetic materials. In high request application occasion, we should consider using high switching frequency products. On the other hand when module power switch frequency close to the signal working frequency, it’s easy to cause bad beat oscillation.