LSN2-T30-D12 Datasheet, PDF (8/17 Pages) Murata Manufacturing Co., Ltd. – DOSA-SIP, 30A POL DC/DC Converters

LSN2-T/30-D12 Series
DOSA-SIP, 30A POL DC/DC Converters
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Figure 6. Coincident or Simultaneous Phasing (Identical Slew Rates)
The first system (discrete On/Off controls) applies signals from an already-
powered logic sequencer or dedicated microcontroller which turns on each
downstream power section in cascaded series. This of course assumes all
POLs have On/Off controls. A distinct advantage of the sequencing controller
is that it can produce an “All On” output signal to state that the full system is
stable and ready to go to work. For additional safety, the sequencer can moni-
tor the output voltages of all downstream POLs with an A/D converter system.
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Figure 7. Proportional or Ratiometric Phasing (Identical VOUT Time)
Figure 7 shows two POLs with different slew rates in order to reach differing
final voltages at about the same time.
However, the sequencer controller has some obvious difficulties besides
extra cost, wiring and programming complexity. First, power is applied as a
fast-rising all-or-nothing step which may be unacceptable to certain circuits,
especially large output bypass capacitors. These could force POLs into overcur-
rent shutdown. And some circuits (such as many linear regulators and some
POLs) may not have convenient start-up controls. This requires designing and
fabricating external power controls such as high-current MOSFETs.
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Figure 8. Staggered or Sequential Phasing—Inclusive (Fixed Delays)
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Figure 9. Staggered or Sequential Phasing—Exclusive
(Fixed Cascaded Delays)
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Figure 10. Wiring for Simultaneous Phasing
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MDC_LSN2-T/30-D12 Series.B17 Page 8 of 17