AT1396A/B/C/D
Preliminary Product Information
6-Channel DC-DC Converter for DSC
generating 3.3V from Li-Ion, boost-buck operation may be needed so a regulated
output can be maintained for input voltages above and below 3.3V. The efficiency is
best than SEPIC or ZETA structure. In this case, it may be configure the CH3 as a
step-down and connect its input PVCC3 to the CH1 output, set to a voltage at or
above 4.2V. The output efficiency with this topology is typically up to 90%. Note that
the step-up output (CH1) supplies both the step-up(CH1) load and the step-down
(CH2) input current when the CH3 is powered from the CH1. The CH3 input current
reduces the available step-up output (CH1) current for other loads.
Figure 1. Using /SDOK to drive external MOSFET that gates 3.3V power to DSP after 1.8V core voltage is in regulation
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4/2/2007 REV:1.1
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