HW006/010/012 Series Power Modules; dc-dc Converters
36-75 Vdc Input; 1.2 Vdc to 5 Vdc Output; 6.6A to 12A
Data Sheet
June 26, 2009
Output Voltage Set-Point Adjustment (Trim)
Design Considerations
Output voltage trim allows the user to increase or decrease
the output voltage set point of a module. This is accom-
Input Source Impedance
plished by connecting an external resistor between the TRIM
pin and either the VO(+) or VO(–) pins. The trim resistor
should be positioned close to the module. If not using the trim
feature, leave the TRIM pin open.
The power module should be connected to a low
ac-impedance source. A highly inductive source impedance
can affect the stability of the power module. For the test con-
figuration in Figure 37, a 33µF electrolytic capacitor
(ESR<0.7W at 100kHz), mounted close to the power module
helps ensure the stability of the unit. Consult the factory for
further application guidelines.
With an external resistor Trim-down between the TRIM and
VO(–) pins, the output voltage set point VO, set decreases
(see Figure 41). The following equation determines the
required external-resistor value to trim-down the output volt-
age from VO, set to VO:
Feature Descriptions
⎧
⎨
⎩
⎫
A
Δ%
Remote On/Off
R
=
-------- – B kΩ
⎬
trim-down
⎭
Two remote On/Off options are available. Positive logic
remote On/Off turns the module on during a logic-high volt-
age on the remote ON/OFF pin, and off during a logic low.
Negative logic remote On/Off, device code suffix "1", turns
the module off during logic-high voltage and on during a logic
low.
Rtrim-down is the external resistor in kW
D% is the % change in output voltage
A & B are defined in Table 1 for various models
Table 1
To turn the power module on and off, the user must supply a
switch to control the voltage between the
Output Voltage
A
B
(V)
ON/OFF pin and the VI(–) terminal. The switch may be an
open collector or equivalent (see Figure 40). A logic low is
Von/off = –0.7 V to 1.2 V. The maximum Ion/off during a logic
low is 1 mA. The switch should maintain a logic-low voltage
while sinking 1 mA. During a logic high, the maximum Von/off
generated by the power module is 15 V. The maximum allow-
able leakage current of the switch at Von/off = 15 V is 50 µA.
1.2
1.5
1.8
2.5
3.3
5.0
1089
1089
1089
1690
1690
1690
62.0
104
104
73.1
73.1
73.1
If not using the remote on/off feature, do one of the following:
For positive logic, leave the ON/OFF pin open.
For example, to trim-down the output voltge of 2.5 V module
(HW010A0G) by 8% to 2.3 V, Rtrim-down is calculated as fol-
lows:
For negative logic, short the ON/OFF pin to VI(–).
D% = 8
A = 1690
B = 73.1
Ion/off
ON/OFF
+
Von/off
–
⎧
⎨
⎩
⎫
1690
8
VO(+)
VO(–)
R
=
----------- – 73.1 kΩ
⎬
trim-down
LOAD
⎭
VI(+)
VI(–)
R
= 138.15kΩ
trim – down
Figure 40. Remote On/Off Implementation.
Lineage Power
13
LINEAGEPOWER [ LINEAGE POWER CORPORATION ]
