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| 型号： | LTC3214EDD#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 6/12页 |
| 文件大小： | 0K |
| 描述： | IC LED DRIVR WHITE BCKLGT 10-DFN |
| 标准包装： | 121 |
| 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： | 闪灯/白光 |
| 类型 - 次要： | 白色 LED |
| 频率： | 600kHz ~ 1.2MHz |
| 电源电压： | 2.9 V ~ 4.5 V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 10-WFDFN 裸露焊盘 |
| 供应商设备封装： | 10-DFN（3x3） |
| 包装： | 管件 |
| 工作温度： | -40°C ~ 85°C |
| 产品目录页面： | 1339 (CN2011-ZH PDF) |
LTC3214
OPERATION
The LTC3214 uses a fractional switched capacitor charge
pump to power a high current LED with a programmed
regulated current. The part starts up into the 1x mode. In
this mode, V IN is directly connected to CPO. This mode
provides maximum ef?ciency and minimum noise. The
LTC3214 will remain in this mode until the forward volt-
age (V F ) approaches the maximum CPO voltage possible
in this mode. When this dropout condition occurs, the
LTC3214 will switch to 1.5x mode after a soft-start period.
Any subsequent dropout detected will cause the part to
enter 2x mode.
A 2-phase nonoverlapping clock activates the charge pump
switches. In the 2x mode, the ?ying capacitors are charged
on alternate clock phases from V IN . While one capacitor
is being charged from V IN , the other is stacked on top of
V IN and connected to the output. Alternatively, in the 1.5x
mode the ?ying capacitors are charged in series during
the ?rst clock phase, and stacked in parallel on top of V IN
on the second clock phase. This sequence of charging
and discharging the ?ying capacitors continues at a free
running frequency of 900kHz (typ).
The current delivered to the LED load is controlled by
the internal programmable current source. The current is
programmed by a resistor connected between the I SET pin
and GND. The resistor value needed to attain the desired
current level can be determined by Equation 1.
Thermal Protection
The LTC3214 has built-in overtemperature protection.
Thermal shutdown circuitry will shut down the part when
the junction temperature exceeds approximately 165°C. It
will re-enable the part once the junction temperature drops
back to approximately 150°C. The LTC3214 will cycle in
and out of thermal shutdown inde?nitely without latchup
or damage until the heat source is removed.
Short-Circuit Protection
When EN is brought high, the part will connect V IN and
CPO through a weak pull-up. If the CPO capacitor fails to
charge up to over 1V (i.e., CPO is shorted), the chip will
not be enabled. Similarly, during operation if CPO is pulled
down below 1V, the part will be disabled.
Soft-Start
To prevent excessive inrush current during start-up and
mode switching, the LTC3214 employs built-in soft-start
circuitry. Soft-start is achieved by increasing the amount
of current available to the output charge storage capacitor
linearly over a period of approximately 150μs.
Charge Pump Strength
When the LTC3214 operates in either the 1.5x mode or 2x
mode, the charge pump can be modeled as a Thevenin
R SET = 3570/I LED
(1)
equivalent circuit to determine the amount of current
Overcurrent shutdown mode will prevent damage to the
part by shutting down the high power sections of the chip.
available from the effective input voltage and effective
open-loop output resistance, R OL (Figure 1).
Choosing an R SET value of 5k or greater will ensure that
the part stays out of this mode.
R OL
+
Regulation is achieved by sensing the voltage at the I LED
pin and modulating the charge pump strength based on
the error signal.
1.5V IN
OR
2V IN
+
–
3214 F01
CPO
–
In shutdown mode all circuitry is turned off and the LTC3214
draws a very low current from the V IN supply. The output is
disconnected from V IN and is pulled down by a resistance
Figure 1. Charge Pump Open-Loop Thevenin-Equivalent Circuit
of approximately 43kΩ. The LTC3214 enters shutdown
mode when the EN pin is brought low.
3214fb
6
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3215 | 制造商:LINER 制造商全称:Linear Technology 功能描述:700mA Low Noise High Current LED Charge Pump |
| LTC3215EDD | 功能描述:IC LED DRIVR WHITE BCKLGT 10-DFN RoHS:否 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 |
| LTC3215EDD#PBF | 功能描述:IC LED DRIVR WHITE BCKLGT 10-DFN RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 标准包装:60 系列:- 恒定电流:- 恒定电压:- 拓扑:线性（LDO），PWM，升压（升压） 输出数:8 内部驱动器:是 类型 - 主要:背光 类型 - 次要:RGB，白色 LED 频率:500kHz ~ 1.5MHz 电源电压:4.75 V ~ 26 V 输出电压:45V 安装类型:* 封装/外壳:* 供应商设备封装:* 包装:* 工作温度:-40°C ~ 85°C |
| LTC3215EDD#TR | 功能描述:IC LED DRIVR WHITE BCKLGT 10-DFN RoHS:否 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 |
| LTC3215EDD#TRPBF | 功能描述:IC LED DRIVR WHITE BCKLGT 10-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 |
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