Delta Electronics Series S48SA Rtrim − down = ∆1089Vo% −104ΚΩ, Output Voltage Adjustment Trim

Output Voltage Adjustment (TRIM)

To increase or decrease the output voltage set point, the modules may be connected with an external resistor between the TRIM pin and either the Vo+ or Vo -. The TRIM pin should be left open if this feature is not used.

Figure 15: Circuit configuration for trim-down (decrease output voltage)

If the external resistor is connected between the TRIM and Vo- pins, the output voltage set point decreases. The external resistor value required to obtain a percentage of output voltage change △Vo% is defined as:

Rtrim − down = ∆1089Vo% −104[ΚΩ]

Ex. When trim-down –10% (1.8V X 0.9 = 1.62V)

Rtrim − down = 108910 −104 = 4.9[ΚΩ]

Figure 16: Circuit configuration for trim-up (increase output voltage)

If the external resistor is connected between the TRIM and Vo+ the output voltage set point increases. The external resistor value required to obtain a percentage output voltage change △Vo% is defined as:

DS_S48SA1R812_06012006

Rtrim − up = 23.8(100 + ∆Vo%) −1089 −104[ΚΩ] ∆Vo%

Ex. When trim-up +10% (1.8V X 1.1 = 1.98V)

Rtrim − up = 23.8(100 +10) −1089 −104 = 48.9[ΚΩ] 10

Care should be taken to ensure that the maximum output power of the module remains at or below the maximum rated power.

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