GE Industrial Solutions QW010-015-020 Series User Manual
Page 14
Tyco Electronics Power Systems
14
Data Sheet
August 22, 2006
36 Vdc to 75 Vdc Input; 1.2 Vdc to 5.0 Vdc Output; 10 A to 20 A
QW010/015/020 Series Power Modules: dc-dc Converters;
Feature Descriptions
(continued)
Output Voltage Set-Point Adjustment (Trim)
(con-
tinued)
Table 1
For example, to trim-down the output voltage of 2.5 V mod-
ule (QW020A0G) by 8% to 2.3 V, Rtrim-down is calculated
as follows:
F= 0.08, A = 5.11, & B = 45.31
Figure 42. Circuit Configuration to Decrease Output
Voltage.
The QW010/015/020 modules have a fixed current-limit set
point. As the output voltage is trim-down, the available out-
put power is reduced.
With an external resistor Rtrim-up, connected between the
TRIM and SENSE(+) pins, the output voltage set point VO,
set increases (see Figure 42). The following equation deter-
mines the required external-resistor value to trim-up and out-
put voltage:
Rtrim-up is the external resistor in kW
∆%
is the percentage change in voltage
A and B values are defined in Table 2 for various
models
Table 2
For example, to trim-up the output voltage of 1.5 V module
(QW020A0M) by 8% to 1.62 V, Rtrim-up is calculated as fol-
lows:
F= 0.08, A = 3.946, & B = 11.454
Figure 43. Circuit Configuration to Increase Output
Voltage.
The voltage between the VO(+) and VO(–) terminals must
not exceed the minimum output overvoltage protection value
shown in the Feature Specifications table. This limit includes
any increase in voltage due to remote-sense compensation
and output voltage set-point adjustment trim.
Although the output voltage can be increased by both the
remote sense and by the trim, the maximum increase for the
output voltage is not the sum of both. The maximum
increase is the larger of either the remote sense or the trim.
The amount of power delivered by the module is defined as
the voltage at the output terminals multiplied by the output
current. When using remote sense and trim, the output volt-
age of the module can be increased, which at the same out-
put current would increase the power output of the module.
Care should be taken to ensure that the maximum output
power of the module remains at or below the maxi mum
rated power.
V
O
A
B
5.0
5.11
45.31
3.3
5.11
45.31
2.5
5.11
45.31
1.8
3.248
18.645
1.5
2.312
17.711
1.2
2.315
17.711
R
trim-down
5.11
0.08
----------
45.31
–
⎩
⎭
⎨
⎬
⎧
⎫
k
Ω
=
R
trim-down
18.565k
Ω
=
V
I
(+)
V
I
(–)
ON/OFF
V
O
(+)
V
O
(–)
SENSE(+)
TRIM
SENSE(–)
R
trim-down
R
LOAD
R
trim-up
A
F
----
B
–
⎩
⎭
⎨
⎬
⎧
⎫
k
Ω
=
F
∆%
100
---------
=
Output Voltage
(V)
A
B
C
1.2
15.9
1089
62.0
1.5
19.8
1089
104
1.8
23.8
1089
104
2.5
34.5
1690
73.1
3.3
45.5
1690
73.1
5.0
69.0
1690
73.1
R
trim-up
3.946
0.08
-------------
11.454
–
⎩
⎭
⎨
⎬
⎧
⎫
k
Ω
=
R
trim-up
37.871k
Ω
=
V
I
(+)
V
I
(–)
ON/OFF
V
O
(+)
V
O
(-)
SENSE(+)
TRIM
SENSE(–)
R
trim-up
R
LOAD