FEATURES DESCRIPTIONS (CON.)
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(+)
Trim
Rtn
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 a percentage of output voltage change △% is defined
as:
⎡ 749 | − 9.46 | ⎤ | (KΩ ) | |
Rtrim − down = ⎢ | Δ | ⎥ | ||
⎣ |
| ⎦ |
|
Ex. When
⎡ 749 |
| ⎤ | (KΩ ) = 20 .5(KΩ ) | ||
Rtrim − down = ⎢ |
| − 9.46 | ⎥ | ||
25 | |||||
⎣ |
| ⎦ |
|
Vo(+)
Trim
Rtn
Figure 18: Circuit configuration for trim-up (increase output voltage)
DS_Q48DC12003_03112008
If the external resistor is connected between the TRIM and Rtn the output voltage set point increases (Fig.18). The external resistor value required to obtain a percentage output voltage change △% is defined as:
Rtrim − up = 197Δ (KΩ)
Ex. When
Rtrim − up = 1975 = 39.4(KΩ)
When using trim, 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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