收藏本站
LT3743
APPLICATIONS INFORMATION
( 163 ° C – T A )
( 35 ° C/W ) ? ( V IN – 5V ) ? ( Q GHG + Q GLG )
f S ≤
VoltageRegulationandOvervoltageProtection
The LT3743 uses the FB pin to regulate the output to a
maximum voltage and to provide a high speed overvoltage
lockout to avoid high voltage conditions that may damage
expensive high current LEDs. The regulated output voltage
is programmed using a resistor divider from the output
and ground (Figure 12). When the output voltage exceeds
130% of the regulated voltage level (1.3V at the FB pin),
the internal open-LED flag is set, terminating switching
and forcing both PWMGL and PWMGH signals high. The
regulated output voltage must be greater than 2V and is
set by the equation:
The internal power consumption of the LT3743 is de-
termined by the switching frequency, V IN , and the gate
charge, Q G of the external switching MOSFETs selected.
The 4mm × 5mm QFN package has a θ JA of 35°C/W. The
following equation calculates the maximum switching
frequency to avoid current limit and thermal shutdown at
a given ambient operating temperature, T A :
f S ≤
60mA
( Q GLG + Q GHG )
V OUT = 1V 1 +
R2
R1
LT3743
FB
R2
R1
V OUT
Since the regulated output current flowing into the LED
may be very large, the switching frequency needs to be
carefully considered. Higher switching frequencies will
reduce the large size of high saturation current inductors,
while reducing efficiency and increasing power loss within
the LT3743.
Table 4. Switching Frequency
SWITCHING FREQUENCY (MHz)
R T (kΩ)
3743 F12
Figure 12. Output Voltage Regulation and Overvoltage Protection
Feedback Connections
1
0.750
0.5
40.2
53.6
82.5
Soft-Start
Unlike conventional voltage regulators, the LT3743 utilizes
the soft-start function to control the regulated inductor
current. The charging current is 5.5μA and reduces the
regulated current for both the high and low regulated
current states. The SS pin is latched in a discharge state
until the first PWM pulse and is reset by UVLO and thermal
shutdown.
1.2
1.0
0.8
0.6
0.3
0.2
143
221
Programming Switching Frequency
The LT3743 has an operational switching frequency
range between 200kHz and 1MHz. This frequency is
programmed with an external resistor from the RT pin to
ground. Do not leave this pin open under any condition.
The RT pin is also current limited to 60μA. See Table 4
and Figure 13 for resistor values and the corresponding
switching frequencies.
0.4
0.2
0
0 50 100 150 200 250 300 350 400 450 500
R T (k )
3743 F13
Figure 13. Frequency vs R T Resistance
3743fd
18
发布紧急采购，3分钟左右您将得到回复。

采购需求

(若只采购一条型号，填写一行即可)

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

*型号 *数量 厂商 批号 封装
添加更多采购

我的联系方式

*
*
*
相关PDF资料
LT3745IUJ#TRPBF IC LED DVR 16CH 50MA 40QFN
LT3746IUHH#TRPBF IC LED DRIVER 32CHANNEL 56-QFN
LT3754IUH#TRPBF IC LED DVR 16CH 50MA 32QFN
LT3755EMSE#PBF IC LED DRVR HP CONS CURR 16-MSOP
LT3760EFE#PBF IC LED DVR WHT/CLR BCKLT 28TSSOP
LT3799IMSE#PBF IC LED DRIVER TRIAC DIM 16-MSOP
LT3956EUHE#PBF IC LED DVR BUCK BOOST 36-VQFN
LTC3201EMS#TRPBF IC LED DRVR WHITE BCKLGT 10-MSOP
相关代理商/技术参数
LT3743EFE#PBF 制造商:Linear Technology 功能描述:IC LED DRIVER BUCK TSSOP-28
LT3743EFE#TRPBF 功能描述:IC LED DVR SYNC STEPDOWN 28TSSOP 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
LT3743EFEPBF 制造商:LINER 制造商全称:Linear Technology 功能描述:High Current Synchronous Step-Down LED Driver with Three-State Control
LT3743EFETRPBF 制造商:LINER 制造商全称:Linear Technology 功能描述:High Current Synchronous Step-Down LED Driver with Three-State Control
LT3743EUFD#PBF 功能描述:IC LED DRVR HP CONST CURR 28QFN RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 恒定电流:- 恒定电压:- 拓扑:升压（升压），切换式电容器（充电泵） 输出数:1 内部驱动器:是 类型 - 主要:背光 类型 - 次要:白色 LED 频率:625kHz ~ 875kHz 电源电压:2.7 V ~ 5.3 V 输出电压:5V 安装类型:表面贴装 封装/外壳:10-TFSOP，10-MSOP（0.118"，3.00mm 宽） 供应商设备封装:10-µMAX 包装:带卷 (TR) 工作温度:-40°C ~ 85°C
LT3743EUFD#PBF 制造商:Linear Technology 功能描述:IC LED DRIVER BUCK QFN-28 制造商:Linear Technology 功能描述:IC, LED DRIVER, BUCK, QFN-28
LT3743EUFD#TRPBF 功能描述:IC LED DVR SYNC STEP-DOWN 28QFN 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
LT3743EUFDPBF 制造商:LINER 制造商全称:Linear Technology 功能描述:High Current Synchronous Step-Down LED Driver with Three-State Control