ltc3728legn-trpbf Linear Technology Corporation, ltc3728legn-trpbf Datasheet - Page 14
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ltc3728legn-trpbf
Manufacturer Part Number
ltc3728legn-trpbf
Description
Dual, 550khz, 2-phase Synchronous Step-down Switching Regulator
Manufacturer
Linear Technology Corporation
Datasheet
1.LTC3728LEGN-TRPBF.pdf
(36 pages)
OPERATION
LTC3728
A fi nal question: If 2-phase operation offers such an ad-
vantage over single-phase operation for dual switching
regulators, why hasn’t it been done before? The answer
is that, while simple in concept, it is hard to implement.
Constant-frequency current mode switching regula-
tors require an oscillator derived “slope compensation”
signal to allow stable operation of each regulator at over
50% duty cycle. This signal is relatively easy to derive in
single-phase dual switching regulators, but required the
development of a new and proprietary technique to allow
2-phase operation. In addition, isolation between the two
channels becomes more critical with 2-phase operation
because switch transitions in one channel could potentially
disrupt the operation of the other channel.
These 2-phase parts are proof that these hurdles have
been surmounted. They offer unique advantages for the
ever-expanding number of high effi ciency power supplies
required in portable electronics.
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(Refer to Functional Diagram)
Figure 4. RMS Input Current Comparison
3.0
2.5
2.0
1.5
1.0
0.5
0
0
V
V
O1
O2
= 5V/3A
= 3.3V/3A
10
INPUT VOLTAGE (V)
DUAL CONTROLLER
SINGLE PHASE
DUAL CONTROLLER
2-PHASE
20
30
3728 F04
40
3728fd