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| 型号： | LT3755EUD-2#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 12/26页 |
| 文件大小： | 0K |
| 描述： | IC LED DRVR HP CONST CURR 16-QFN |
| 标准包装： | 121 |
| 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： | 无 |
| 类型 - 主要： | 车载 |
| 类型 - 次要： | 白色 LED |
| 频率： | 100kHz ~ 1MHz |
| 电源电压： | 4.5 V ~ 40 V |
| 输出电压： | 75V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-WFQFN 裸露焊盘 |
| 供应商设备封装： | 16-QFN-EP（3x3） |
| 包装： | 管件 |
| 工作温度： | -40°C ~ 125°C |
| 产品目录页面： | 1340 (CN2011-ZH PDF) |
LT3755/LT3755-1/LT3755-2
APPLICATIONS INFORMATION
I LED =
V OUT = 1.25 ?
V OUT = V BE + 1.25 ?
V OUT C OUT
100k
–
When V CTRL is higher than 1.2V, the LED current is
regulated to:
100mV
R LED
The LED current programming feature can increase total
dimming range by a factor of 10. The CTRL pin should
not be left open (tie to V REF if not used). The CTRL pin
can also be used in conjunction with a thermistor to
provide overtemperature protection for the LED load, or
with a resistor divider to V IN to reduce output power and
switching current when V IN is low. The presence of a time
varying differential voltage signal (ripple) across ISP and
ISN at the switching frequency is expected. The amplitude
of this signal is increased by high LED load current, low
switching frequency and/or a smaller value output filter
capacitor. Some level of ripple signal is acceptable: the
compensation capacitor on the VC pin filters the signal so
the average difference between ISP and ISN is regulated
to the user-programmed value. Ripple voltage amplitude
(peak-to-peak) in excess of 20mV should not cause mis-
operation, but may lead to noticeable offset between the
average value and the user-programmed value.
Programming Output Voltage (Constant Voltage
Regulation) or Open LED/Overvoltage Threshold
For a boost application, the output voltage can be set by
selecting the values of R3 and R4 (see Figure 2) according
to the following equation:
R3 + R4
R4
For a boost type LED driver, set the resistor from the output
to the FB pin such that the expected V FB during normal
V OUT
operation will not exceed 1.1V. For an LED driver of buck or
a buck-boost 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:
R3
R4
+
R3 R SEN(EXT)
LED
ARRAY
LT3755 37551 F03
FB
R4
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 (150mV, 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 SENSE current
limit — it prevents GATE from going high (switch turn-on)
until the ISP/ISN difference falls below the threshold. If the
load has appreciable series inductance, use of a Schottky
clamp from GND to ISN is recommended for the SEPIC
to prevent excessive current flowing from the ISN pin in
a fault.
LT3755
FB
R3
Dimming Control
R4
37551 F02
Figure 2. Feedback Resistor Connection for
Boost or SEPIC LED Driver
There are two methods to control the current source for
dimming using the LT3755. One method uses the CTRL pin
to adjust the current regulated in the LEDs. A second method
uses the PWM pin to modulate the current source between
37551fd
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| LT3755EUDPBF | 制造商:Linear Technology 功能描述:4.5-40Vin 75Vout LED Controller QFN16EP |
| LT3755EUD-PBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:40VIN, 75VOUT LED Controller |
| LT3755EUD-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:40VIN, 75VOUT LED Controller |
| LT3755HMSE-2#PBF | 功能描述:IC LED DVR HP CONST CURR 16MSOP 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 |
| LT3755HMSE-2#TRPBF | 功能描述:IC LED DVR HP CONST CURR 16MSOP 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 |
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