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参数资料
| 型号： | LT3956EUHE#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 11/20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： | 是 |
| 恒定电压： | 是 |
| 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： | 是 |
| 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
I OUT ( MAX ) ≤ 2 . 5 A
V OUT = 1 . 25 ?
20mV should not cause misoperation, but may lead to
noticeable offset between the average value and the user-
programmed value.
Output Current Capability
An important consideration when using a switch with a
fixed current limit is whether the regulator will be able
to supply the load at the extremes of input and output
voltage range. Several equations are provided to help
determine this capability. Some margin to data sheet
limits is included.
For boost converters:
V IN ( MIN )
V OUT ( MAX )
Programming Output Voltage (Constant-Voltage
Regulation) or Open LED/Overvoltage Threshold
For a boost or SEPIC application, the output voltage can
be set by selecting the values of R3 and R4 (see Figure 2)
according to the following equation:
R3 + R 4
R 4
For a boost type LED driver, set the resistor from the output
to the FB pin such that the expected voltage level during
normal operation will not exceed 1.1V. For an LED driver
of buck mode or a buck-boost mode configuration, the
output voltage is typically level-shifted to a signal with
respect to GND as illustrated in Figure 3. The output can
be expressed as:
For buck mode converters:
I OUT(MAX) ≤ 2.5A
V OUT = V BE + 1 . 25 ?
R3
R 4
I OUT ( MAX ) ≤ 2 . 5 A
ForSEPICandbuck-boostmodeconverters:
V IN ( MIN )
( V OUT ( MAX ) + V IN ( MIN ) )
LT3956
R3
+
V OUT
–
100k
R LED
LED
ARRAY
C OUT
R3
These equations assume the inductor value and switch-
ing frequency have been selected so that inductor ripple
current is ~600mA. Ripple current higher than this value
will reduce available output current. Be aware that current
limited operation at high duty cycle can greatly increase
inductor ripple current, so additional margin may be
required at high duty cycle.
If some level of analog dimming is acceptable at minimum
supply levels, then the CTRL pin can be used with a resistor
divider to V IN (as shown on page 1) to provide a higher
output current at nominal V IN levels.
V OUT
LT3956
FB
R4
3956 F02
Figure 2. Feedback Resistor Connection
for Boost or SEPIC LED Drivers
FB
R4
3956 F03
Figure 3. Feedback Resistor Connection for
Buck Mode or Buck-Boost Mode LED Driver
ISP/ISN Short-Circuit Protection Feature for SEPIC
The ISP and ISN pins have a protection feature indepen-
dent of the LED current sense feature that operates at
ISN below 3V. The purpose of this feature is to provide
continuous current sensing when ISN is below the LED
current sense common mode range (during start-up or
an output short-circuit fault) to prevent the development
of excessive switching currents that could damage the
power components in a SEPIC converter. The action
threshold (335mV, typ) is above the default LED current
sense threshold, so that no interference will occur over
the ISN voltage range where these two functions overlap.
This feature acts in the same manner as switch-current
limit — it prevents switch turn-on until the ISP/ISN differ-
ence falls below the threshold.
3956f
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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 |
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