- 您现在的位置：买卖IC网 > PDF目录20858 > LTC3783IFE#PBF (Linear Technology)IC LED DRVR PWM CONTROL 16-TSSOP PDF资料下载
参数资料
| 型号： | LTC3783IFE#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 9/24页 |
| 文件大小： | 0K |
| 描述： | IC LED DRVR PWM CONTROL 16-TSSOP |
| 标准包装： | 95 |
| 恒定电流： | 是 |
| 恒定电压： | 是 |
| 拓扑： | 回扫，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，通用 |
| 频率： | 20kHz ~ 1MHz |
| 电源电压： | 3 V ~ 36 V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-TSSOP（0.173"，4.40mm）裸露焊盘 |
| 供应商设备封装： | 16-TSSOP-EP |
| 包装： | 管件 |
| 工作温度： | -40°C ~ 125°C |
LTC3783
OPERATION
Main Control Loop
The LTC3783 is a constant frequency, current mode con-
troller for PWM LED as well as DC/DC boost, SEPIC and
flyback converter applications. In constant current LED
applications, the LTC3783 provides an especially wide PWM
dimming range due to its unique switching scheme, which
allows PWM pulse widths as short as several converter
switching periods.
For voltage feedback circuit operation (defined by V FBP ≤
1.23V), please refer to the Block Diagram of the IC and the
Typical Application on the first page of this data sheet. In
normal operation with PWMIN high, the power MOSFET
is turned on (GATE goes high) when the oscillator sets
the PWM latch, and is turned off when the ITRIP current
comparator resets the latch. Based on the error voltage
represented by (V FBP – V FBN ), the error amplifier output
signal at the I TH pin sets the ITRIP current comparator input
threshold. When the load current increases, a fall in the
FBN voltage relative to the reference voltage at FBP causes
the I TH pin to rise, causing the ITRIP current comparator
to trip at a higher peak inductor current value. The average
inductor current will therefore rise until it equals the load
current, thereby maintaining output regulation.
When PWMIN goes low, PWMOUT goes low, the I TH switch
opens and GATE switching is disabled. Lowering PWMOUT
and disabling GATE causes the output capacitor C OUT to
hold the output voltage constant in the absence of load
current. Opening the I TH switch stores the correct load
current value on the I TH capacitor C ITH . As a result, when
PWMIN goes high again, both I TH and V OUT are instantly
at the appropriate levels.
In voltage feedback operation, an overvoltage compara-
tor, OV, senses when the OV/FB pin exceeds the reference
voltage by 7% and provides a reset pulse to the main RS
latch. Because this RS latch is reset-dominant, the power
MOSFET is actively held off for the duration of an output
overvoltage condition.
For constant current/constant voltage regulation operation
(defined by V FBP > 2.5V), please refer to the Block Diagram
of the IC and Figure 11. Loop operation is similar to the
voltage feedback, except FBP and FBN now sense the
voltage across sense resistor R L in series with the load.
The I TH pin now represents the error from the desired dif-
ferential set voltage, from 10mV to 100mV, for I LIM values
of 0.123V to 1.23V. That is, with V ILIM = 1.23V, the loop
will regulate such that V FBP – V FBN = 100mV; lower values
of I LIM attenuate the difference proportionally. PWMIN is
still functional as above, but will only work properly if load
current can be disconnected by the PWMOUT signal.
In constant current/constant voltage operation, the OV/FB
pin becomes a voltage feedback pin, which causes the loop
to regulate such that V OV/FB = 1.23V, provided the above
current-sense voltage is not reached. In this way, the loop
regulates either voltage or current, whichever parameter
hits its preset limit first.
The nominal operating frequency of the LTC3783 is pro-
grammed using a resistor from the FREQ pin to ground
and can be controlled over a 20kHz to 1MHz range. In
addition, the internal oscillator can be synchronized to an
external clock applied to the SYNC pin and can be locked
to a frequency between 100% and 130% of its nominal
value. When the SYNC pin is left open, it is pulled low by
an internal 100k resistor. With no load, or an extremely
light one, the controller will skip pulses in order to maintain
regulation and prevent excessive output ripple.
The RUN pin controls whether the IC is enabled or is in a
low current shutdown state. A micropower 1.248V refer-
ence and RUN comparator allow the user to program the
supply voltage at which the IC turns on and off (the RUN
comparator has 100mV of hysteresis for noise immunity).
With the RUN pin below 1.248V, the chip is off and the
input supply current is typically only 20μA.
3783fb
9
相关PDF资料 |
PDF描述 |
|---|---|
| P51-300-G-S-I36-20MA-000-000 | SENSOR 300PSI 1/4-18NPT 4-20MA |
| P51-3000-S-F-I12-4.5V-000-000 | SENSOR 3000PSI 1/4-18NPT .5-4.5V |
| BAS16W-7 | DIODE SWITCH 75V 200MW SC70-3 |
| REC7.5-4815DRW/H2/A/M | CONV DC/DC 7.5W 36-72VIN +/-15V |
| P51-2000-S-S-MD-4.5V-000-000 | SENSOR 2000PSI 1/4-18NPT 4.5V |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3785EUF#PBF | 功能描述:IC REG CTRLR BST PWM VM 24-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 特色产品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 标准包装:1 系列:PowerWise® PWM 型:电压模式 输出数:1 频率 - 最大:1MHz 占空比:81% 电源电压:4.5 V ~ 18 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-5°C ~ 125°C 封装/外壳:32-WFQFN 裸露焊盘 包装:Digi-Reel® 产品目录页面:1303 (CN2011-ZH PDF) 其它名称:LM3754SQDKR |
| LTC3785EUF#TRPBF | 功能描述:IC REG CTRLR BST PWM VM 24-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:24-WQFN 裸露焊盘 包装:带卷 (TR) |
| LTC3785EUF-1#PBF | 功能描述:IC REG CTRLR BST PWM VM 24-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:24-WQFN 裸露焊盘 包装:带卷 (TR) |
| LTC3785EUF-1#TRPBF | 功能描述:IC REG CTRLR BST PWM VM 24-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:4,500 系列:PowerWise® PWM 型:控制器 输出数:1 频率 - 最大:1MHz 占空比:95% 电源电压:2.8 V ~ 5.5 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:6-WDFN 裸露焊盘 包装:带卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名称:LM1771SSDX |
| LTC3785EUFPBF | 制造商:Linear Technology 功能描述:10V Synch Buck-Boost Controller LTC3785 |
发布紧急采购，3分钟左右您将得到回复。