LTC1709 View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
LTC1709
Linear Technology
'LTC1709' PDF : 28 Pages View PDF
LTC1709
APPLICATIO S I FOR ATIO
The output ripple current is reduced significantly when
compared to the single phase solution using the same
inductance value because the VOUT/L discharge current
term from the stage that has its bottom MOSFET on
subtracts current from the (VIN - VOUT)/L charging current
resulting from the stage which has its top MOSFET on. The
output ripple current is:
( ) ∆IRIPPLE
=
2VOUT
fL
1−
2D
1− D
1− 2D + 1
where D is duty factor.
The input and output ripple frequency is increased by the
number of stages used, reducing the output capacity
requirements. When VIN is approximately equal to 2(VOUT)
as illustrated in Figures 3 and 4, very low input and output
ripple currents result.
VIN
RIN
+
CIN
BOLD LINES INDICATE
HIGH, SWITCHING
CURRENT LINES.
KEEP LINES TO A
MINIMUM LENGTH.
SW1
D1
L1
RSENSE1
SW2
D2
L2
RSENSE2
VOUT
+ COUT
Figure 10. Instantaneous Current Path Flow in a Multiple Phase Switching Regulator
RL
1709 F10
25
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