How should I measure the efficiency of a DC/DC converter?
What should be taken into consideration for the measurement?

DC/DC Switching RegulatorsHow to use

The efficiency of a DC/DC converter is calculated by the formula below:

Efficiency : η (％)
＝ Output Power (W) / Input Power (W) x 100
＝ (Output Voltage x Output Current) / (Input Voltage x Input Current) x 100 ＝ (Output Voltage x Output Current) / (Input Voltage x Input Current) x 100

By measuring the parameters above respectively and applying them to the formula, the efficiency can be calculated.

Points you should take care of at measurement are as follows:

• Use a high precision source meter for the measurement of efficiency at light load of VFM (PFM) mode DC/DC converters.
• Take care of the wire length between the DC/DC converter and the meters for the measurement of efficiency at heavy load of DC/DC converters unless otherwise the affect of the wire length is cancelled by the equipment.
• Be careful if the measurement should be at the conditions under high temperature and too heavy load. The IC may be turned OFF by protection functions such as current limit or thermal shutdown. Depending on the setting of the measurement equipment, the IC may be damaged by forced negative voltage.