Datasheet

0
20
40
60
80
100
EFFICIENCY (%)
0
1 2 3 4 5 6
LOAD CURRENT (A)
8
7
V
IN
= 48V
V
IN
= 78V
V
IN
= 36V
Both outputs loaded equally,
simultaneously
LM5032
SNVS344A –MARCH 2005–REVISED APRIL 2013 www.ti.com
If the current sense circuits employ sense resistors in the drive transistor sources, low inductance resistors
should be used. In this case, all the noise sensitive low current ground tracks should be connected in common
near the IC, and then a single connection made to the power ground (sense resistor ground point). The outputs
of the LM5032 should have short direct paths to the power MOSFETs in order to minimize inductance in the PC
board traces.
The two ground pins (GND1, GND2) must be connected together with a short direct connection to avoid jitter due
to relative ground bounce in the operation of the two regulators.
If the internal dissipation of the LM5032 produces high junction temperatures during normal operation, the use of
wide PC board traces can help conduct heat away from the IC. Judicious positioning of the PC board within the
end product, along with use of any available air flow (forced or natural convection) can help reduce the junction
temperatures.
APPLICATION CIRCUIT EXAMPLE
Figure 33 shows an example of an LM5032 controlled 200W dual interleaved regulator which provides two
independent regulated outputs. The input voltage range (V
PWR
) is 36V to 78V, and the output voltages are 12V
each. The output current capability is 8.3A from each output. Current sense transformers T1 and T2 provide
information to the CS2 and CS1 pins for the current mode control, and error amplifiers U5 and U6 provide
voltage feedback to COMP2 and COMP1 via optocoupler U2. Auxiliary power is provided to VCC from the
primary side snubbers when the LM5032 outputs are enabled. The UVLO levels are ≊ 34.3V for increasing V
PWR
,
and ≊ 32.3V for decreasing V
PWR
. The circuit can be shutdown by forcing the ON/OFF input (J2) below 1.25V. An
external synchronizing frequency can be applied to the SYNC input (J3). Each regulator output is current limited
at ≊ 9A.
Efficiency measurements for this circuit are shown in Figure 32.
Figure 32. Total Board Efficiency
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