IMX35 Series: 35W DC-DC Converters
9-36V, 18-75V, 40-121V & 60-150V Inputs
Dual/Triple/Quad Outputs 3.3V, 5V, 12V & 15V
Product Specifications
Aug 2002
Functional Description
The quadruple output type consists of 4 outputs and two
power trains. Vo1, Vo4 derive from the first power train and
Vo2, Vo3 from the second one (thus each pair of outputs is
independent from the other one). Voltage regulation for
each pair of outputs is achieved with passive transformer
feedback from the main transformer of each power train.
Each pair of outputs are restricted to being of the same out-
put voltage type (i.e. D05, D12, etc.). If both power trains
have the same output voltage, all outputs may be adjusted
by means of the Trim input. (In case of different output volt-
ages, the Trim1 input influences only Vo1 and Vo4. See:
Block diagram, quadruple output types.)
The IMX35 family of DC-DC converters consists of two
feedback controlled interleaved switching flyback power
trains using current mode PWM (pulse width modulation).
Functionally the converters are of two main types.
The triple output types consist of 3 outputs Vo1, Vo2, Vo3.
Vo1 (3.3 V or 5.1 V) is generated by a power train using
synchronous rectifier technology thus enabling high effi-
ciency. Also there is active magnetic feedback on this out-
put via a pulse transformer which results in very tight and
reliable regulation of the output voltage. The other two out-
puts Vo2 and Vo3 are electrically isolated double outputs.
Vo2, Vo3 are restricted to being of the same output voltage
(i.e. D05, D12, etc.). Voltage regulation is achieved with a
passive transformer feedback from the main transformer
of that power train.
The dual output types consist of two electrically isolated
outputs Vo1, Vo2. Vo1 and Vo2 derives from two power
trains and are electrically isolated. Voltage regulation for
each output is achieved with passive transformer feedback
from the main transformer of each power train. Adjustment
of the outputs voltages in the range of 90...105% of Vo nom is
possible via Trim input on the primary side.
Adjustment of the output 1 (Vo1) is provided by the Trim1
pin referenced to the secondary side and allows for pro-
gramming of the voltage of output 1 in the range of approx.
90...105% of Vo nom. (See: Block diagram, triple output
types)
03097a
03098
4
Vi+
17 Vo1+
Vi+
4
16
Vo1+
1
5
6
7
8
2
3
PUL
n.c.
W
16
15
n.c.
1
5
6
7
8
2
3
PUL
Trim
Control
15
Vo1—
Vo1—
Trim1
PWM
17 Vo4+
18 Vo4—
13 Vo2+
PWM
W
Ref
Ref
18
13
SD
Vi—
n.c.
SD
Vi—
n.c.
Vo2+
14
12
Vo2—
Vo3+
14
12
Vo2—
Vo3+
11
19
Vo3—
n.c.
11 Vo3—
19 n.c.
Fig. 2
Block diagram, quadruple output types
Fig. 1
Block diagram, triple output types
Current limitation is provided by the primary circuit for each
power train and limits the possible output power for each
pair of outputs. In the case of an overload on either of the
power trains which causes the output voltage to fall less
than typically 60% of Vo nom, the entire converter will shut
down and automatically restart in short intervals.
Overtemperature protection is provided, this will shut down
the converter in excessive overload conditions with auto-
matic restart approximately in short intervals.
AUG 13, 2002
Rev 1.0
www.power-one.com
Page 3 of 15