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参数资料
| 型号： | ZXLD1374EST20TC |
| 厂商： | Diodes Inc |
| 文件页数： | 16/39页 |
| 文件大小： | 0K |
| 描述： | IC LED DVR BUCK BOOST 20TSSOP |
| 标准包装： | 1 |
| 拓扑： | 低端，PWM，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： | 高亮度 LED（HBLED） |
| 频率： | 300kHz ~ 1MHz |
| 电源电压： | 6.3 V ~ 60 V |
| 输出电压： | 60V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 20-TSSOP（0.173"，4.40mm 宽）裸露焊盘 |
| 供应商设备封装： | 20-TSSOP-EP |
| 包装： | 标准包装 |
| 工作温度： | -40°C ~ 125°C |
| 其它名称： | ZXLD1374EST20TCDIDKR |
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A Product Line of
Diodes Incorporated
ZXLD1374
Application Information (cont.)
a)
Boost and Buck-Boost Modes
A basic ZXLD1374 application circuit for Buck-Boost and Boost modes is shown in Figure 28.
Control in Boost and Buck-boost mode is achieved by sensing the coil
current in the series resistor Rs, connected between the two inputs of
a current monitor within the control loop block.
V IN
R1
Buck-boost
Boost
An output from the control loop drives the input of a comparator which
L1
LX
REF
TADJ
drives the gate of the internal NMOS switch transistor. In Boost and
Buck-boost modes, when the switch is on, current flows from V IN , via
Rs, coil and switch to ground. The switch current ramps up until an
upper threshold value is reached (see Figure 29). At this point the
switch is turned off and the drain voltage increases to either:
C1
RGI2
VAUX VIN ISM
PWM
GI
ADJ ZXLD1374 LX
FLAG
STATUS
SHP NC SGND PGND
SD1
C OUT
or
1) the LED chain voltage plus the forward voltage of D1 in Boost
configuration,
2) the LED chain voltage plus the forward voltage of D1 plus
GND
RGI2
C2
100pF
VIN in Buck-boost configuration.
The inductor current flows via Rs, coil, D1 and LED back to V IN
(Buck-boost mode), or GND (Boost mode). When the coil current has
ramped down to a lower threshold value the switch is turned on again
and the cycle of events repeats, resulting in continuous oscillation.
The feedback loop adjusts the NMOS switch duty cycle to stabilize
the LED current in response to changes in external conditions,
Figure 28 Boost and Buck-Boost Configuration
including input voltage and load voltage.
Loop compensation is
achieved by a single external capacitor C2, connected between SHP
and SGND. Note that in reality, a load capacitor COUT is used, so
that the LED current waveform shown is smoothed.
The average current in the coil is equal to the average of the
maximum and minimum threshold currents and the ripple current
(hysteresis) is equal to the difference between the thresholds. The
average current in the LED, I LED , is always less than I RS . The
feedback control loop adjusts the switch duty cycle, D, to achieve a
set point at the sense resistor. This controls I RS .
During the interval t OFF , the coil current flows through D1 and the LED
load.
During t ON , the coil current flows through Q1, not the LEDs.
Therefore the set point is modified by D using a gating function to
control ILED indirectly. In order to compensate internally for the effect
of the gating function, a control factor, GI_ADJ is used. GI_ADJ is set
by a pair of external resistors, R GI1 and R GI2 . (Figure 28.)
This allows the sense voltage to be adjusted to an optimum level for
power efficiency without significant error in the LED controlled current.
Figure 29 Operating Waveforms
(Boost and Buck-Boost Modes)
ZXLD1374
Document number: DS35032 Rev. 3 - 2
16 of 39
www.diodes.com
September 2012
? Diodes Incorporated
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ZXLD1601 | 制造商:ZETEX 制造商全称:ZETEX 功能描述:ADJUSTABLE DC - DC BOOST CONVERTER WITH INTERNAL SWITCH IN SC70 |
| ZXLD1601H6 | 制造商:Diodes Incorporated 功能描述:LCD/OLED BIAS BOOST CONVERTER SMD |
| ZXLD1601H6TA | 功能描述:开关变换器、稳压器与控制器 Boost Converter for LCD and OLED BIAS RoHS:否 制造商:Texas Instruments 输出电压:1.2 V to 10 V 输出电流:300 mA 输出功率: 输入电压:3 V to 17 V 开关频率:1 MHz 工作温度范围: 安装风格:SMD/SMT 封装 / 箱体:WSON-8 封装:Reel |
| ZXLD1601H6TC | 功能描述:开关变换器、稳压器与控制器 Boost Converter for LCD and OLED BIAS RoHS:否 制造商:Texas Instruments 输出电压:1.2 V to 10 V 输出电流:300 mA 输出功率: 输入电压:3 V to 17 V 开关频率:1 MHz 工作温度范围: 安装风格:SMD/SMT 封装 / 箱体:WSON-8 封装:Reel |
| ZXLD1615 | 制造商:DIODES 制造商全称:Diodes Incorporated 功能描述:ADJUSTABLE DC-DC BOOST CONVERTER WITH INTERNAL SWITCH IN |
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