參數(shù)資料
型號: LTC3701EGN
廠商: LINEAR TECHNOLOGY CORP
元件分類: 穩(wěn)壓器
英文描述: 2-Phase, Low Input Voltage, Dual Step-Down DC/DC Controller
中文描述: 1 A DUAL SWITCHING CONTROLLER, 890 kHz SWITCHING FREQ-MAX, PDSO16
封裝: 0.150 INCH, PLASTIC, SSOP-16
文件頁數(shù): 9/20頁
文件大?。?/td> 250K
代理商: LTC3701EGN
9
LTC3701
3701fa
Single Phase
Dual Controller
2-Phase
Dual Controller
SW1 (V)
SW2 (V)
I
L1
I
L2
I
IN
3701 F03
Figure 3. Example Waveforms for a Single Switching
Regulator Channel vs 2-Phase LTC3701 System with
Both Channels Switching
OPERATIOU
Why the need for 2-phase operation Until recently, con-
stant frequency dual switching regulators operated both
channels in phase (i.e., single phase operation). This
means that both topside MOSFETs are turned on at the
same time, causing current pulses of up to twice the
amplitude of those from a single regulator to be drawn
from the input capacitor. These large amplitude pulses
increase the total RMS current flowing into the input
capacitor, requiring the use of more expensive input
capacitors, and increasing both EMI and losses in the
input capacitor and input power supply.
With 2-phase operation, the two channels of the LTC3701
are operated 180 degrees out of phase. This effectively
interleaves the current pulses coming from the switches,
greatly reducing the overlap time where they add
together. The result is a significant reduction in the total
RMS input current, which in turn allows for use of less
expensive input capacitors, reduces shielding requirements
for EMI and improves real world operating efficiency.
Figure 3 shows example waveforms for a single switching
regulator channel versus a 2-phase LTC3701 system with
(Refer to Functional Diagram)
INPUT VOLTAGE (V)
2
0
I
0.2
0.6
0.8
1.0
2.0
1.4
4
6
7
3701 F04
0.4
1.6
1.8
1.2
3
5
8
9
10
SINGLE PHASE
DUAL CONTROLER
2-PHASE
DUAL CONTROLER
V
OUT1
= 2.5V/2A
V
OUT2
= 1.8V/2A
Figure 4. RMS Input Current Comparison
both channels switching. A single phase dual regulator
system with both sides switching would exhibit twice the
single side numbers. In this example, 2-phase operation
reduced the RMS input current from 1.79A
RMS
to
0.91A
RMS
. While this is an impressive reduction in itself,
remember that power losses are proportional to I
RMS2
,
meaning that actual power wasted is reduced by a factor
of 3.86. The reduced input ripple current also means that
less power is lost in the input power path, which could
include batteries, switches, trace/connector resistances,
and protection circuitry. Improvements in both conducted
and radiated EMI also directly accrue as a result of the
reduced RMS input current and voltage.
Of course, the improvement afforded by 2-phase opera-
tion is a function of the dual switching regulator’s relative
duty cycles, which in turn are dependent upon the input
voltage V
IN
. Figure 4 shows how the RMS input current
varies for 1-phase and 2-phase operation for 2.5V and
1.8V regulators over a wide input voltage range.
It can be readily seen that the advantages of 2-phase
operation are not limited to a narrow operating range, but
in fact extend over a wide region. A good rule of thumb for
most applications is that 2-phase operation will reduce the
input capacitor requirement to that for just one channel
operating at maximum current and 50% duty cycle.
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LTC3701EGN#TR 功能描述:IC REG CTRLR BUCK PWM CM 16-SSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:PolyPhase® 標準包裝:2,500 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:500kHz 占空比:96% 電源電壓:4 V ~ 36 V 降壓:無 升壓:是 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 125°C 封裝/外殼:24-WQFN 裸露焊盤 包裝:帶卷 (TR)
LTC3701EGN#TRPBF 功能描述:IC REG CTRLR BUCK PWM CM 16-SSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:PolyPhase® 標準包裝:2,500 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:500kHz 占空比:96% 電源電壓:4 V ~ 36 V 降壓:無 升壓:是 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 125°C 封裝/外殼:24-WQFN 裸露焊盤 包裝:帶卷 (TR)
LTC3701EGNPBF 制造商:Linear Technology 功能描述:DC-DC Controller Dual Step-Dn 10V SSOP16
LTC3701EGNTRPBF 制造商:LINEAR TECHNOLGY 功能描述: