ALQ25_03 Datasheet, PDF (9/15 Pages) Astec America, Inc – Single Output Open-Frame DC-DC Converter Module Industry Standard ¼ Brick: 36V-75V Input / 5V Output

Technical Reference Notes
ALQ25 Series
(Open Frame Single Output Quarter Brick)
Basic Operation and Features
INPUT UNDER VOLTAGE LOCKOUT
To prevent any instability to the converter, which may affect the end system, the ALQ25 series have been designed to turn-on
once V_IN is in the voltage range of 34 - 36 VDC. Likewise, it has also been programmed to turn-off when V_IN drops down to 33
- 35 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
+SENSE PIN (Pin 7). Please refer to Equation (1) for the
required external resistance and output adjust
relationship.
Equation (1):
-Vin
ENABLE
+Vin
-Vout
-Sense
Trim
+Sense
+Vout
Radj_up
Rload
R _adj−up
=
5.1×V_o × (100 + ∆%)
1.225 × ∆%
−
510
∆%
− 10.2(KΩ)
Figure 3. External resistor configuration to increase the outputs
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
-Vin
-Vout
required external resistance and output adjust
relationship.
-Sense
ENABLE
Trim
R_{adj− down}
=
510
∆%
− 10.2( KΩ)
+Sense
+Vin
+Vout
Radj_down
Rload
Figure 4. External resistor configuration to decrease the outputs
MODEL: ALQ25 SERIES
Dec 1, 2003 - REVISION B
SHEET 9 OF 15