ALQ40_03 Datasheet, PDF (8/16 Pages) Astec America, Inc – Industry Standard ¼ Brick: 36V-75V Input / 50A Output Current

Technical Reference Notes
ALQ40/50 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 ALQ50 series have been designed to turn-on
once V_IN is in the voltage range of 33-35 VDC. Likewise, it has also been programmed to turn-off when V_IN drops down to 32-
34 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.
3.3V/2.5V/1.8V
Equation (1a):
Radj_up

5.1⋅Vo(100 + ∆%)
1.225⋅∆%
−
510
∆%
−
10.2^{} ⋅ kΩ
1.2V
Equation (1b):
Radj_up

5.1⋅Vo(100 +
0.6⋅∆%
∆%)
−
510
∆%
−
10.2^{} ⋅ kΩ
-Vin
Enable
+Vin
-Vout
-Sense
Vadj
+Sense
+Vout
Radj_up
Rload
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
required external resistance and output adjust
relationship.
Equation (2)
Radj_down

510
∆%
−
10.2^{}⋅kΩ
-Vin
Enable
+Vin
-Vout
-Sense
Vadj
+Sense
+Vout
Radj_down
Rload
Figure 4. External resistor configuration to increase the outputs
MODEL: ALQ50 SERIES
APRIL 21, 2003 - REVISION A (PRELIMINARY)
SHEET 8 OF 16