FEATURE DESCRIPTIONS (CON.)
The amount of power delivered by the module is the
voltage at the output terminals multiplied by the output
current. When using the trim feature, the output voltage
of the module can be increased, which at the same
output current would increase the power output of the
module. Care should be taken to ensure that the
maximum output power of the module must not exceed
the maximum rated power (Vo.set x Io.max ≤ P max).
Table 1 provides Rtrim values required for some common
output voltages, while Table 2 provides values of external
voltage source, Vtrim, for the same common output
voltages. By using a 1% tolerance trim resistor, set point
tolerance of ±2% can be achieved as specified in the
electrical specification.
Table 1
Voltage Margining
VO (V)
0.7525
1.0
1.2
1.5
1.8
2.0
2.5
3.3
Rtrim (KΩ)
Open
41.424
22.464
13.047
9.024
7.416
5.009
3.122
1.472
Output voltage margining can be implemented in the DNL
modules by connecting a resistor, R margin-up, from the Trim
pin to the ground pin for margining-up the output voltage
and by connecting a resistor, Rmargin-down, from the Trim pin
to the output pin for margining-down. Figure 37 shows
the circuit configuration for output voltage margining. If
unused, leave the trim pin unconnected. A calculation
tool is available from the evaluation procedure, which
computes the values of Rmargin-up and Rmargin-down for a
specific output voltage and margin percentage.
5.0
Table 2
VO (V)
0.7525
1.0
Vtrim (V)
Open
0.6835
0.670
Vo
Vin
1.2
Rmargin-down
Q1
1.5
0.650
1.8
0.630
2.0
0.6168
0.583
Trim
GND
On/Off
2.5
Rmargin-up
Q2
3.3
0.530
Rtrim
5.0
0.4167
Figure 34: Circuit configuration for output voltage margining
Voltage Tracking
The DNL family was designed for applications that have
output voltage tracking requirements during power-up
and power-down. The devices have a TRACK pin to
implement three types of tracking method: sequential
start-up, simultaneous and ratio-metric. TRACK simplifies
the task of supply voltage tracking in a power system by
enabling modules to track each other, or any external
voltage, during power-up and power-down.
By connecting multiple modules together, customers can
get multiple modules to track their output voltages to the
voltage applied on the TRACK pin.
DS_DNL10SMD_07182012
10
DELTA [ DELTA ELECTRONICS, INC. ]
