Sinrace Power Supply Technology (Shenzhen) Co., Ltd.

AC/DC power supplies are typically universal in nature, meaning that they operate over a wide range of input voltages, normally from 85 or 90 VAC up to 264VAC. This feature allows a single product to operate world-wide without changes in configuration of the input stage. Some products utilize automatic input voltage range selection giving two operating ranges; typically 90 to 132VAC & 180 to 264VAC. Universal input power supplies provide better immunity to supply disturbances in some circumstances and this may be a benefit.

If the power supply is to be used close to its full power capability within the application it is important to check the specification details on the available output power in the low input voltage area, where some products de-rate by as much as 20 or 30%, meaning that they may be operating outside of specification when operating from nominal 100VAC or 115/120VAC supplies or at the very least may infringe the design margins of the end equipment. Ignoring this de-rating in the available output power will seriously affect the reliability and life time of the power supply and therefore the end equipment.

De-rating the power supply output power at low input voltages is common in lower cost universal input power supplies and is normally due to the limitations of the active power correction boost converters employed.