Datasheet

ULS 100-Watt Series
Sixteenth-brick DOSA-Compatible,
Isolated DC-DC Converters
MDC_ULS-100 Series.A09 Page 26 of 28
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DOWN
RT (k:) =
Where ∆%  _(  × 100 )_
– 10.22
∆%
511
Trim Down
Trim Equations
Trim Up
UP
RT (k:) =
–
1.225 × ∆%
5.11 × VNOM × (100 + ∆%)
∆%
511
– 10.22
VNOM – VDES
VNOM
Note: “∆%” is always a positive value.
“V
NOM” is the nominal, rated output voltage.
“V
DES” is the desired, changed output voltage.
Figure 10. Trim Connections To Increase Output Voltages
Connect sense to its respective VOUT pin if sense is not used with a remote load.
LOAD
R
TRIM UP
+VOUT
+VIN
–VIN
ON/OFF
CONTROL
TRIM
+SENSE
–VOUT
–SENSE
LOAD
R
TRIM DOWN
+VOUT
+VIN
–VIN
ON/OFF
CONTROL
TRIM
+SENSE
–VOUT
–SENSE
Figure 11. Trim Connections To Decrease Output Voltages
OUTPUT VOLTAGE ADJUSTMENT
Dynamic control of the remote on/off function is best accomplished with a
mechanical relay or an open-collector/open-drain drive circuit (optically isolated
if appropriate). The drive circuit should be able to sink appropriate current (see
Performance Specifi cations) when activated and withstand appropriate voltage
when deactivated. Applying an external voltage to pin 2 when no input power is
applied to the converter can cause permanent damage to the converter.
+Vcc
13V CIRCUIT
5V CIRCUIT
–VIN
O N /O F F
C O N TR O L
+VIN
Figure 9. Driving the Negative Logic On/Off Control Pin
(simplifi ed circuit)