ALO25F24 Datasheet, PDF (6/13 Pages) Astec America, Inc – Single Output 8th Brick: Open-Frame Module

Technical Reference Notes
ALO25F24
(Single Output 8^th Brick)
Basic Operation and Features
INPUT UNDER VOLTAGE LOCKOUT
To prevent any instability to the converter, which may affect the end system, the converter have been designed to turn-on once
V_IN is in the voltage range of 17.2-17.95 VDC. Likewise, it has also been programmed to turn-off when V_IN drops down to
15.8-16.5 VDC.
OUTPUT VOLTAGE ADJUST/TRIM
The converter comes with a TRIM pin (PIN 6), which is used to adjust the output by as much as 90% to 110% of its set point.
This is achieved by connecting an external resistor as described below.
To INCREASE the output, external R_{adj_up} resistor
should be connected between TRIM PIN (Pin6) and
-Vin
+SENSE PIN (Pin 7). Please refer to Equation (1) for the
required external resistance and output adjust
relationship.
Enable
Equation (1a):
+Vin
-Vout
-Sense
Vadj
+Sense
+Vout
Radj_up
Rload
Radj_up
=
^{5.1 ×}


Voset × (100 +
1.225× ∆%
∆%)
−
510
∆%

− 10.2

ΚΩ
Figure 3. Trim UP test configuration (Pin Side Up).
To DECREASE the output, external R_{adj_down} resistor
should be connected between TRIM pin (Pin 6) and
-SENSE PIN (Pin 5). Please refer to Equation (2) for the
required external resistance and output adjust
relationship.
Equation (2):
Radj_down

510
∆%
−
10.2^{}⋅kΩ
Where: ∆% = percent change in output voltage
-Vin
Enable
+Vin
-Vout
-Sense
Vadj
+Sense
+Vout
Radj_down
Rload
Figure 4. Trim DOWN test configuration (Pin Side Up).
MODEL: ALO25F24
AUGUST 23, 2005 - REVISION H
SHEET 6 OF 13