how to select the right power modules
What aspects should be considered to select the right power modules ?
Function
DC/DC converter
AC/DC converter
DC/AC converter
AC/AC converter
Output power
It is generally recommended : the operation power is 30~80% of the rated power of the power modules
(All module power supplies have a certain overload capacity, but it is still not recommended to work under overload conditions for a long time. After all, this is a short-term emergency plan.)
3. Packagingtype : SIP/DIP/SMD/quarter-brick /half-brick/Enclosed/open frame/Din rail
case Size: ① The volume should be as small as possible under certain power conditions, so as to give more space and function to other parts of the system;
②As far as possible, choose the products that comply with international standard packaging
4. Temperature range and derating usage
There is general three kinds of temperature range: commercial grade, industrial grade, military grade.
Commercial grade (0 ℃ to +70 ℃)
Industrial grade (-40 ℃ to +85 ℃)
Military grade (-55 ℃ to +125 ℃)
5. Isolated voltageMost circuits must be isolated, that is, the load and the noise of the load to the local power supply are separated from other loads and noise of the power grid.Within a certain time limit (usually 1 second), the highest voltage that the converter can withstand and is applied between the input terminal and the output terminal is called the isolation strength of the converter.
Therefore, when designing a low-noise power supply, a DC / DC converter with high isolation strength and low isolation capacitance should be selected to reduce leakage current.
6. MTTFCommonly used is the "general" reliability prediction method in the US military standard MIL-HDBK-217F, and the telecommunications equipment model in the Bellcore standard TR-NWT-000332.
7. Power consumption and efficiencyAccording to the formula, where Pin, Pout, P consumption are the module power input, output power and its own power loss. It can be seen that under certain conditions of output power, the smaller the loss P of the module, the higher the efficiency, the lower the temperature rise, and the longer the life.
Of course, the smaller the loss, the more energy-saving it is.
