ltc1709eg-trpbf Linear Technology Corporation, ltc1709eg-trpbf Datasheet - Page 25

• Manufacturer Part Number: ltc1709eg-trpbf
• Description: 2-phase, 5-bit Adjustable,high Efficiency, Synchronous Step-down Switching Regulator
• Manufacturer: Linear Technology Corporation

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 V
term from the stage that has its bottom MOSFET on
subtracts current from the (V
resulting from the stage which has its top MOSFET on. The
output ripple current is:
where D is duty factor.
I
RIPPLE
R
IN
V
IN
C
IN
BOLD LINES INDICATE
HIGH, SWITCHING
CURRENT LINES.
KEEP LINES TO A
MINIMUM LENGTH.
+
2
V
fL
OUT
U
Figure 10. Instantaneous Current Path Flow in a Multiple Phase Switching Regulator
1 2
1 2
U
D
IN
D
- V
1
OUT
OUT
1
D
W
/L discharge current
)/L charging current
SW1
SW2
D1
D2
U
L1
L2
The input and output ripple frequency is increased by the
number of stages used, reducing the output capacity
requirements. When V
as illustrated in Figures 3 and 4, very low input and output
ripple currents result.
R
R
SENSE1
SENSE2
IN
is approximately equal to 2(V
+
C
V
OUT
OUT
LTC1709
1709 F10
R
25
L
OUT
)