参数资料
型号: LTC3783EFE#TRPBF
厂商: Linear Technology
文件页数: 16/24页
文件大小: 0K
描述: IC LED DRVR PWM CONTROL 16-TSSOP
标准包装: 2,500
恒定电流:
恒定电压:
拓扑: 回扫,PWM,SEPIC,降压(降压),升压(升压)
输出数: 1
内部驱动器:
类型 - 主要: 车载,通用
频率: 20kHz ~ 1MHz
电源电压: 3 V ~ 36 V
安装类型: 表面贴装
封装/外壳: 16-TSSOP(0.173",4.40mm)裸露焊盘
供应商设备封装: 16-TSSOP-EP
包装: 带卷 (TR)
工作温度: -40°C ~ 85°C
LTC3783
OPERATION
R DS(ON) < 150mV ?
? ? 1 + ? ? ? I OUT(MAX) ? r T
I O(MAX) = 150mV ?
? ? 1 + ? ? ? R DS(ON) ? r T
? I OUT(MAX) ?
? 1–D MAX ? ?
k ? V OUT 1.85 ? ?
? C RSS ? f
Duringtheswitchon-time,theIMAXcomparatorlimitsthe
absolute maximum voltage drop across the power MOSFET
to a nominal 150mV, regardless of duty cycle. The peak
inductor current is therefore limited to 150mV/R DS(ON) .
The relationship between the maximum load current, duty
cycle, and the R DS(ON) of the power MOSFET is:
1–D MAX
? c ?
2
The r T term accounts for the temperature coefficient of
the R DS(ON) of the MOSFET, which is typically 0.4%/°C.
Figure 8 illustrates the variation of normalized R DS(ON)
over temperature for a typical power MOSFET.
2.0
1.5
1.0
0.5
0
–50 0 50 100 150
JUNCTION TEMPERATURE (°C)
3783 F08
Figure 8. Normalized R DS(ON) vs Temperature
Another method of choosing which power MOSFET to
use is to check what the maximum output current is for a
given R DS(ON) , since MOSFET on-resistances are available
in discrete values.
1 – D MAX
? c ?
2
It is worth noting that the 1 - D MAX relationship between
I O(MAX) and R DS(ON) can cause boost converters with a
wide input range to experience a dramatic range of maxi-
mum input and output currents. This should be taken into
consideration in applications where it is important to limit
the maximum current drawn from the input supply, and
also to avoid triggering the 150mV IMAX comparator, as
this condition can result in excessive noise.
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. Since the controller
is using the MOSFET as both a switching and a sensing
element, 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.
The power dissipated by the MOSFET in a boost converter
is:
2
P FET = ? ? R DS(ON) ? D MAX ? r T +
? I OUT(MAX) ?
? 1–D MAX ? ?
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.
3783fb
16
相关PDF资料
PDF描述
LTC3783EDHD#TRPBF IC LED DRIVER PWM CONTROL 16-DFN
REC3-483.3DRWZ/H6/C/SMD CONV DC/DC 3W 18-72VIN +/-3.3V
P51-1500-S-AF-D-4.5V-000-000 SENSOR 1500PSI 9/16-18 UNF 4.5V
GEM11DRTS CONN EDGECARD 22POS DIP .156 SLD
GEM11DRKS CONN EDGECARD 22POS DIP .156 SLD
相关代理商/技术参数
参数描述
LTC3783IDHD#PBF 功能描述:IC LED DRIVER PWM CONTROL 16-DFN RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 标准包装:6,000 系列:- 恒定电流:- 恒定电压:- 拓扑:开路漏极,PWM 输出数:4 内部驱动器:是 类型 - 主要:LED 闪烁器 类型 - 次要:- 频率:400kHz 电源电压:2.3 V ~ 5.5 V 输出电压:- 安装类型:表面贴装 封装/外壳:8-VFDFN 裸露焊盘 供应商设备封装:8-HVSON 包装:带卷 (TR) 工作温度:-40°C ~ 85°C 其它名称:935286881118PCA9553TK/02-TPCA9553TK/02-T-ND
LTC3783IDHD#TRPBF 功能描述:IC LED DRIVER PWM CONTROL 16-DFN RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 标准包装:6,000 系列:- 恒定电流:- 恒定电压:- 拓扑:开路漏极,PWM 输出数:4 内部驱动器:是 类型 - 主要:LED 闪烁器 类型 - 次要:- 频率:400kHz 电源电压:2.3 V ~ 5.5 V 输出电压:- 安装类型:表面贴装 封装/外壳:8-VFDFN 裸露焊盘 供应商设备封装:8-HVSON 包装:带卷 (TR) 工作温度:-40°C ~ 85°C 其它名称:935286881118PCA9553TK/02-TPCA9553TK/02-T-ND
LTC3783IFE#PBF 功能描述:IC LED DRVR PWM CONTROL 16-TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 标准包装:6,000 系列:- 恒定电流:- 恒定电压:- 拓扑:开路漏极,PWM 输出数:4 内部驱动器:是 类型 - 主要:LED 闪烁器 类型 - 次要:- 频率:400kHz 电源电压:2.3 V ~ 5.5 V 输出电压:- 安装类型:表面贴装 封装/外壳:8-VFDFN 裸露焊盘 供应商设备封装:8-HVSON 包装:带卷 (TR) 工作温度:-40°C ~ 85°C 其它名称:935286881118PCA9553TK/02-TPCA9553TK/02-T-ND
LTC3783IFE#TRPBF 功能描述:IC LED DRVR PWM CONTROL 16-TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 标准包装:6,000 系列:- 恒定电流:- 恒定电压:- 拓扑:开路漏极,PWM 输出数:4 内部驱动器:是 类型 - 主要:LED 闪烁器 类型 - 次要:- 频率:400kHz 电源电压:2.3 V ~ 5.5 V 输出电压:- 安装类型:表面贴装 封装/外壳:8-VFDFN 裸露焊盘 供应商设备封装:8-HVSON 包装:带卷 (TR) 工作温度:-40°C ~ 85°C 其它名称:935286881118PCA9553TK/02-TPCA9553TK/02-T-ND
LTC3785EUF#PBF 功能描述:IC REG CTRLR BST PWM VM 24-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 特色产品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 标准包装:1 系列:PowerWise® PWM 型:电压模式 输出数:1 频率 - 最大:1MHz 占空比:81% 电源电压:4.5 V ~ 18 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-5°C ~ 125°C 封装/外壳:32-WFQFN 裸露焊盘 包装:Digi-Reel® 产品目录页面:1303 (CN2011-ZH PDF) 其它名称:LM3754SQDKR