參數(shù)資料
型號(hào): LT3782
廠商: Linear Technology Corporation
英文描述: 2-Phase Step-Up DC/DC Controller
中文描述: 2相升壓型DC / DC控制器
文件頁(yè)數(shù): 10/16頁(yè)
文件大?。?/td> 200K
代理商: LT3782
LT3782
10
3782fa
Power MOSFET Selection
Important parameters for the power MOSFET include the
drain-to-source breakdown voltage (BV
DSS
), the thresh-
old voltage (V
GS(TH)
), the on-resistance (R
DS(ON)
) versus
gate-to-source voltage, the gate-to-source and gate-to-
drain charges (Q
GS
and Q
GD
, respectively), the maximum
drain current (I
D(MAX)
) and the MOSFET’s thermal resis-
tances (R
TH(JC)
and R
TH(JA)
).
The gate drive voltage is set by the 10V GBIAS regulator.
Consequently, 10V rated MOSFETs are required in most
high voltage LT3782 applications.
Pay close attention to the BV
DSS
specifications for the
MOSFETs relative to the maximum actual switch voltage in
the application. The switch node can ring during the turn-
off of the MOSFET due to layout parasitics. Check the
switching waveforms of the MOSFET directly across the
drain and source terminals using the actual PC board lay-
out (not just on a lab breadboard!) for excessive ringing.
Calculating Power MOSFET Switching and Conduction
Losses and Junction Temperatures
In order to calculate the junction temperature of the power
MOSFET, the power dissipated by the device must be
known. This power dissipation is a function of the duty
cycle, the load current and the junction temperature itself
(due to the positive temperature coefficient of its R
DS(ON)
).
As a result, some iterative calculation is normally required
to determine a reasonably accurate value. Care should be
taken to ensure that the converter is capable of delivering
the required load current over all operating conditions
(line voltage and temperature), and for the worst-case
specifications for V
SENSE(MAX)
and the R
DS(ON)
of the
MOSFET listed in the manufacturer’s data sheet.
APPLICATIU
W
U
U
The power dissipated by the MOSFET in a 2-phase boost
converter is:
P
I
D
R
D
k V
I
D
C
f
FET
O MAX
(
2
1
DS ON
(
T
O
O MAX
(
2
1
RSS
=
(
)
+
(
)
)
)
)
2
2
ρ
The first term in the equation above represents the I
2
R
losses in the device, and the second term, the switching
losses. The constant, k = 1.7, is an empirical factor
inversely related to the gate drive current and has the
dimension of 1/current. The
ρ
T
term accounts for the
temperature coefficient of the R
DS(ON)
of the MOSFET,
which is typically 0.4%/
°
C. Figure 4 illustrates the varia-
tion of normalized R
DS(ON)
over temperature for a typical
power MOSFET.
JUNCTION TEMPERATURE (
°
C)
–50
ρ
T
1.0
1.5
150
3782 F06
0.5
0
0
50
100
2.0
Figure 4. Normalized R
DS(ON)
vs Temperature
相關(guān)PDF資料
PDF描述
LT3782EFE 2-Phase Step-Up DC/DC Controller
LTC3731 2-Phase Step-Up DC/DC Controller
LTC3731CG 16-Bit Edge-Triggered D-Type Flip-Flop With 3-State Outputs 48-SSOP -40 to 85
LTC3731CUH 16-Bit Edge-Triggered D-Type Flip-Flop With 3-State Outputs 48-SSOP -40 to 85
LTC3731IG 3-Phase, 600kHz, Synchronous Buck Switching Regulator Controller
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LT3782A 制造商:LINER 制造商全稱(chēng):Linear Technology 功能描述:2-Phase Step-Up DC/DC Controller
LT3782AEFE 制造商:LINER 制造商全稱(chēng):Linear Technology 功能描述:2-Phase Step-Up DC/DC Controller
LT3782AEFE#PBF 功能描述:IC REG CTRLR BST PWM CM 28-TSSOP RoHS:是 類(lèi)別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 特色產(chǎn)品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 標(biāo)準(zhǔn)包裝:1 系列:PowerWise® PWM 型:電壓模式 輸出數(shù):1 頻率 - 最大:1MHz 占空比:81% 電源電壓:4.5 V ~ 18 V 降壓:是 升壓:無(wú) 回掃:無(wú) 反相:無(wú) 倍增器:無(wú) 除法器:無(wú) Cuk:無(wú) 隔離:無(wú) 工作溫度:-5°C ~ 125°C 封裝/外殼:32-WFQFN 裸露焊盤(pán) 包裝:Digi-Reel® 產(chǎn)品目錄頁(yè)面:1303 (CN2011-ZH PDF) 其它名稱(chēng):LM3754SQDKR
LT3782AEFE#PBF 制造商:Linear Technology 功能描述:Switch Regulator IC
LT3782AEFE#TRPBF 功能描述:IC REG CTRLR BST PWM CM 28-TSSOP RoHS:是 類(lèi)別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:4,500 系列:PowerWise® PWM 型:控制器 輸出數(shù):1 頻率 - 最大:1MHz 占空比:95% 電源電壓:2.8 V ~ 5.5 V 降壓:是 升壓:無(wú) 回掃:無(wú) 反相:無(wú) 倍增器:無(wú) 除法器:無(wú) Cuk:無(wú) 隔離:無(wú) 工作溫度:-40°C ~ 125°C 封裝/外殼:6-WDFN 裸露焊盤(pán) 包裝:帶卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名稱(chēng):LM1771SSDX