Technical Reference Notes
AEO_ALO04/12/20/25x48 Series
(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 33 to 36VDC. Likewise, it has also been programmed to turn-off when V
IN
drops down to 31 to
34VDC
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 (1a): 1.5V to 12V
Radj_up
=
-Vin
-Vout
-Sense
Enable
Vadj
Rload
Radj_up
+Sense
+Vin
+Vout
5.1
×
Voset
×
(
100
+ ∆%
)
510
−
−
10.2
∆%
1.225
× ∆%
ΚΩ
Figure 3. External resistor configuration to increase the outputs
Equation (1b): 1.2V
5.1
×
Voset
×
(
100
+ ∆%
)
510
Radj_up
=
−
−
10.2
∆%
0.6
× ∆%
ΚΩ
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
-Vin
-Vout
-Sense
Radj_down
Enable
Vadj
+Sense
Rload
510
−
10.2
⋅
kΩ
∆%
+Vin
+Vout
Where:
∆%
= percent change in output voltage
Figure 4. External resistor configuration to increase the outputs
MODEL: AEO_ALO04/12/20/25x48 SERIES
AUGUST 25, 2005 - REVISION G
SHEET 7 OF 26
ASTEC [ Astec America, Inc ]
