(1) Output-Temperature: We need to reduce the output power depending on the operating temperature and the direction that the S.P.S. is allocated.
Example: If the S.P.S. is vertically installed, output power can be 100% between 0 ~ 50℃, and between 50 ~60℃ the output power should be derated. At 60℃ we need to reduce the output power to 60% of load. Above 60℃, we can not guarantee proper operation and lifetime of the unit.
(2) Output Power to Input Voltage
When the input voltage is low, S.P.S. will have higher power loss because of the PFC circuit, therefore we need to reduce the output power. Refer to figure 7.5, between 110V ~ 264V the S.P.S. can output full load, but between 90V~110V we need to reduce the output power. At 90V, the output power will be derated to 80% of full load.