BCD20007-G Rev AE, 14-May-2012

Page 10 of 14

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IMX7, IMS7 Series Data Sheet

7-Watt DC-DC Converters

Fig. 12

Output voltage adjust for single-output models

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.

Trim

Vo1+

Vo2–

+

V

ext

–

Vi+

Vi–

R

ext

Vo1–

Vo2+

06089a

Control

circuit

V

Fig. 13

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 15 shows the circuitry.

Adjustment of the output voltage is possible in the range of

Programming of the output voltage by means of an

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.

4 and Vi –. The following table indicates suitable resistor

values for typical output voltages under nominal

equal load conditions on each output.

Caution:

R

Vo+

Vo–

+

V

ext

–

4 k

Ω

V

Control

logic

R

ext1

R

ext 2

06029e

Vi–

Vi+

+

a) Adjustment by means of an external resistor:

Depending upon the value of the required output voltage,

figure below:

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).

Ω

Ω

Ω

Ω]

105 to 108 (107 typically)

0

105

1.5

104

5.6

103

12

102

27

101

68

100

∞

Note:

Applying a control voltage greater than 20 V will set the

converter into a hiccup mode.

≥105

0

102

1.6

95

4.5

85

9

75

13