参数资料
型号: LT3956EUHE#TRPBF
厂商: Linear Technology
文件页数: 14/20页
文件大小: 0K
描述: IC LED DVR BUCK BOOST 36-VQFN
标准包装: 2,500
恒定电流:
恒定电压:
拓扑: 回扫,低端,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
类型 - 次要: 白色 LED
频率: 100kHz ~ 1MHz
电源电压: 4.5 V ~ 80 V
输出电压: 80V
安装类型: 表面贴装
封装/外壳: 36-WFQFN 裸露焊盘
供应商设备封装: 36-QFN-EP(6x5)
包装: 带卷 (TR)
工作温度: -40°C ~ 125°C
LT3956
APPLICATIONS INFORMATION
T SS = C SS ?
T SW ? V LED ( V IN – V LED )
L BUCK =
L BUCK-BOOST =
T SW ? V IN ( V LED – V IN )
L BOOST =
OutputCapacitorSelection
The selection of the output capacitor depends on the load
and converter configuration, i.e., step-up or step-down
and the operating frequency. For LED applications, the
equivalent resistance of the LED is typically low and the
output filter capacitor should be sized to attenuate the
current ripple. Use of an X7R type ceramic capacitor is
recommended.
To achieve the same LED ripple current, the required filter
capacitor is larger in the boost and buck-boost mode ap-
plications than that in the buck mode applications. Lower
operating frequencies will require proportionately higher
capacitor values.
Soft-Start Capacitor Selection
For many applications, it is important to minimize the
inrush current at start-up. The built-in soft-start circuit
significantly reduces the start-up current spike and output
voltage overshoot. The soft-start interval is set by the soft-
start capacitor selection according to the equation:
2 V
10 μA
A typical value for the soft-start capacitor is 0.01μF. The
soft-start pin reduces the oscillator frequency and the
maximum current in the switch. The soft-start capacitor
is discharged when EN/UVLO falls below its threshold,
during an overtemperature event or during an INTV CC un-
dervoltage event. During start-up with EN/UVLO, charging
of the soft-start capacitor is enabled after the first PWM
high period.
it is important to consider diode leakage, which increases
with the temperature, from the output during the PWM
low interval. Therefore, choose the Schottky diode with
sufficiently low leakage current. Table 3 has some recom-
mended component vendors.
Table 3. Schottky Rectifier Manufacturers
VENDOR WEB SITE
On Semiconductor www.onsemi.com
Diodes, Inc. www.diodes.com
Central Semiconductor www.centralsemi.com
Inductor Selection
The inductor used with the LT3956 should have a saturation
current rating appropriate to the maximum switch current
of 4.6A. Choose an inductor value based on operating
frequency, input and output voltage to provide a current
mode signal of approximately 0.6A magnitude. The fol-
lowing equations are useful to estimate the inductor value
(T SW = 1/f OSC ):
V IN ? 0 . 6 A
T SW ? V LED ? V IN
( V LED + V IN ) ? 0 . 6 A
V LED ? 0 . 6 A
Table 4 provides some recommended inductor vendors.
Table 4. Inductor Manufacturers
VENDOR WEB SITE
Schottky Rectifier Selection
The power Schottky diode conducts current during the
interval when the switch is turned off. Select a diode rated
for the maximum SW voltage of the application and the
RMS diode current. If using the PWM feature for dimming,
Sumida
Würth Elektronik
Coiltronics
Renco
Coilcraft
www.sumida.com
www.we-online.com
www.cooperet.com
www.rencousa.com
www.coilcraft.com
3956f
  
相关PDF资料
PDF描述
XLN3640-GL POWER SUPPLY PROGRAM DC 36V/40A
REC8-243.3SRW/H2/A/M CONV DC/DC 8W 24VIN 3.3VOUT
EBC13DRTH CONN EDGECARD 26POS DIP .100 SLD
P51-500-A-R-M12-4.5OVP-000-000 SENSOR 500PSI M12-1.0 6G .5-4.5V
ECC05DRAN CONN EDGECARD 10POS R/A .100 SLD
相关代理商/技术参数
参数描述
LT3956IUHE#PBF 功能描述:IC LED DVR BUCK BOOST 36-VQFN 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
LT3956IUHE#TRPBF 功能描述:IC LED DVR BUCK BOOST 36-VQFN 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
LT3956IUHE-PBF 制造商:LINER 制造商全称:Linear Technology 功能描述:80VIN, 80VOUT Constant-Current, Constant-Voltage Converter
LT3956IUHE-TRPBF 制造商:LINER 制造商全称:Linear Technology 功能描述:80VIN, 80VOUT Constant-Current, Constant-Voltage Converter
LT3957 制造商:LINER 制造商全称:Linear Technology 功能描述:Wide Input Voltage Range