®

BCD20007-G Rev AD, 4-Nov-09

Page 10 of 15

www.power-one.com

IMX7/IMS7 DC-DC Series Data Sheet

7-Watt DC-DC Converters

≥105

0

102

1.6

95

4.5

85

9

75

13

Single-output models with R-input:

The R input (pin 13) is referenced to the secondary side of the

converter. Adjustment of the output voltage is possible by

means of either an external resistor or a voltage source.

Fig. 13

Output voltage control with external resistor

R

Vo+

Vo–

Vi+

Vi–

R

ext2

R

ext1

06131

Fig. 14

Output voltage adjust for single-output models

R

Vo+

Vo-

+

V

ext

-

4 k

Ω

Control

logic

R

ext1

R

ext 2

06029b

Vi–

Vi+

a) Adjustment by means of an external resistor:

Depending upon the value of the required output voltage,

figure below:

≈ 4 kΩ • –––––––––

≈ 4 kΩ • ––––––––––––––––––

Vo– and R pin.

The control voltage is 1.96 to 2.62 V and allows for

≈ ––––––––

Caution: Applying an external voltage >2.75 V may damage the

converter.

Note: Attempting to adjust the output below this range will cause

the converter to shut down (hiccup mode).

Trim

Vo1+

Vo2–

+

V

ext

–

Vi+

Vi–

R

ext

Vo1–

Vo2+

06089a

Control

circuit

Fig. 15

Output voltage adjust for double-output models

Double-output models with Trim input:

The Trim input (pin 4) of double-output models is referenced

to the primary side. The figure below shows the circuitry.

Programming of the output voltage by means of an

4 and Vi –. The following table indicates suitable resistor

values

for

typical

output

voltages

under

nominal

equal load conditions on each output.

Ω

Ω

Ω

Ω

Ω]

105 to 108 (107 typically)

0

105

1.5

104

5.6

103

12

102

27

101

68

100

∞

Adjustment of the output voltage is possible in the range of

For external output voltages in the range of 75 to 105% of

connected to the Trim-input (pin 4) and Vi–. The table

outputs or equal load conditions on each output. Direct

paralleling of the Trim-inputs of converters connected in

parallel is feasible.

Note: Applying a control voltage greater than 20 V will set the

converter into a hiccup mode.