Delta Electronics Series S48SP manual Features Descriptions CON, Output Voltage Adjustment

FEATURES DESCRIPTIONS (CON.)

Output Voltage Adjustment

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.

ON/OFF Vo (-)

Vi (-) Trim

Vi (+)

Vo (+)

R

trim-up

R

Load

ON/OFF Vo (-)

Vi (-) Trim

R

Figure 18: Circuit configuration for trim-up (increase output voltage)

R

Load

Vi (+)

Vo (+)

trim-down

If the external resistor is connected between the TRIM and Vo(-) the output voltage set point increases (Fig. 18). The external resistor value required to obtain an

Figure 17: 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 (Fig. 17). The external resistor value required to obtain an output voltage change from 3.3V to the desired Vo_adj is defined as:

Rtrim_down	( Vo_adj		− 2.5 ) ⋅ 5110		− 2050
		3.3 − Vo_adj
Ex. When Trim-down -10%
Vo_adj=3.3V×(1-10%)=2.97V
Rtrim_down		( 2.97 −	2.5 ) ⋅ 5110	−	2050
	3.3		− 2.97

Rtrim_down = 5.228⋅ 103 ohm

DS_S48SP3R310_05222008

output voltage change from 3.3V to the desired Vo_adj is defined as:

Rtrim_up	2.5 ⋅ 5110	− 2050
	Vo_adj − 3.3

Ex. When Trim-up +10%

Vo_adj=3.3V×(1+10%)=3.63V

Rtrim_up	2.5 ⋅ 5110	− 2050
	3.63 − 3.3

Rtrim_up = 3.666⋅ 104 ohm

When using trim function, the output voltage of the module is usually increased, which increases the power output of the module with the same output current.

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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