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参数资料
| 型号： | LTC3453EUF#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 6/12页 |
| 文件大小： | 0K |
| 描述： | IC LED DRIVER PHOTO FLASH 16-QFN |
| 标准包装： | 2,500 |
| 拓扑： | PWM，降压（降压），升压（升压） |
| 输出数： | 4 |
| 内部驱动器： | 是 |
| 类型 - 主要： | 闪灯/白光 |
| 类型 - 次要： | 白色 LED |
| 频率： | 900kHz ~ 1.1MHz |
| 电源电压： | 2.7 V ~ 5.5 V |
| 输出电压： | 4.5V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-WQFN 裸露焊盘 |
| 供应商设备封装： | 16-QFN（4x4） |
| 包装： | 带卷 (TR) |
| 工作温度： | -40°C ~ 85°C |
LTC3453
OPERATIO
Buck-Boost DC-DC Converter
The LTC3453 employs an LTC proprietary buck-boost
DC/DC converter to generate the output voltage required
to drive the LEDs. This architecture permits high-effi-
ciency, low noise operation at input voltages above, below
or equal to the output voltage by properly phasing four
internal power switches. The error amp output voltage on
the V C pin determines the duty cycle of the switches. Since
the V C pin is a filtered signal, it provides rejection of
frequencies well below the factory trimmed switching
frequency of 1MHz. The low R DS(ON) , low gate charge
synchronous switches provide high frequency pulse width
modulation control at high efficiency. Schottky diodes
across synchronous rectifier switch B and synchronous
rectifier switch D are not required, but if used do provide
a lower voltage drop during the break-before-make time
(typically 20ns), which improves peak efficiency by typi-
cally 1% to 2% at higher loads.
Figure 1 shows a simplified diagram of how the four
internal power switches are connected to the inductor,
V IN , V OUT and GND. Figure 2 shows the regions of opera-
tion of the buck-boost as a function of the control voltage
V C . The output switches are properly phased so transi-
tions between regions of operation are continuous, fil-
tered and transparent to the user. When V IN approaches
V OUT , the buck-boost region is reached where the conduc-
tion time of the four switch region is typically 150ns.
Referring to Figures 1 and 2, the various regions of
operation encountered as V C increases will now be
Buck Mode (V IN > V OUT )
In buck mode, switch D is always on and switch C is always
off. Referring to Figure 2, when the control voltage V C is
above voltage V1, switch A begins to turn on each cycle.
During the off time of switch A, synchronous rectifier
switch B turns on for the remainder of the cycle. Switches
A and B will alternate conducting similar to a typical
synchronous buck regulator. As the control voltage in-
creases, the duty cycle of switch A increases until the
maximum duty cycle of the converter in buck mode
reaches DC BUCK |max given by:
DC BUCK |max = 100% – DC 4SW
where DC 4SW equals the duty cycle in % of the “four
switch” range.
DC 4SW = (150ns ? f) ? 100%
where f is the operating frequency in Hz.
Beyond this point the “four switch” or buck-boost region
is reached.
Buck-Boost or Four-Switch Mode (V IN ≈ V OUT )
Referring to Figure 2, when the control voltage V C is above
voltage V2, switch pair AD continue to operate for duty
cycle DC BUCK |max, and the switch pair AC begins to phase
in. As switch pair AC phases in, switch pair BD phases out
accordingly. When the V C voltage reaches the edge of the
buck-boost range at voltage V3, switch pair AC completely
phases out switch pair BD and the boost region begins at
described.
75%
D MAX
BOOST
V4 ( ≈ 2.1V)
PV IN
16
V OUT
13
D MIN
BOOST
A ON, B OFF
PWM CD SWITCHES
BOOST REGION
V3 ( ≈ 1.65V)
PMOS A
PMOS D
D MAX
BUCK
FOUR SWITCH PWM
BUCK/BOOST REGION
V2 ( ≈ 1.55V)
SW1
15
SW2
14
D ON, C OFF
PWM AB SWITCHES BUCK REGION
NMOS B
NMOS C
0%
DUTY
V1 ( ≈ 0.9V)
CONTROL
3453 F01
CYCLE
3453 F02
VOLTAGE, V C
Figure 1. Simplified Diagram of Internal Power Switches
Figure 2. Switch Control vs Control Voltage, V C
3453fa
6
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相关代理商/技术参数 |
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|---|---|
| LTC3454 | 制造商:LINER 制造商全称:Linear Technology 功能描述:1A Synchronous Buck-Boost High Current LED Driver |
| LTC3454EDD | 制造商:LINER 制造商全称:Linear Technology 功能描述:1A Synchronous Buck-Boost High Current LED Driver |
| LTC3454EDD#PBF | 功能描述:IC LED DRIVER PHOTO FLASH 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 |
| LTC3454EDD#TRPBF | 功能描述:IC LED DRIVER PHOTO FLASH 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 |
| LTC3454EDDPBF | 制造商:Linear Technology 功能描述:LED Driver 1A Buck-Boost 3.3/5V DFN10EP |
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