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参数资料
| 型号： | ZXLD1320DCATC |
| 厂商： | Diodes Inc |
| 文件页数： | 9/18页 |
| 文件大小： | 0K |
| 描述： | IC LED DRVR WHITE BCKLGT 14-TDFN |
| 特色产品： | LED Driver Solutions |
| 标准包装： | 1 |
| 拓扑： | PWM，降压（降压） |
| 输出数： | 1 |
| 内部驱动器： | 是 |
| 类型 - 主要： | 车载，闪灯/白光 |
| 类型 - 次要： | 高亮度 LED（HBLED） |
| 频率： | 600kHz |
| 电源电压： | 4 V ~ 18 V |
| 输出电压： | 18V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 14-TDFN 裸露焊盘 |
| 供应商设备封装： | 14-DFN-EP（4x3） |
| 包装： | 标准包装 |
| 工作温度： | -40°C ~ 125°C |
| 产品目录页面： | 1478 (CN2011-ZH PDF) |
| 其它名称： | ZXLD1320DCADKR |
ZXLD1320
Device description
The ZXLD1320 is a buck mode inductive DC-DC converter, with an internal switch, designed for
driving single or multiple LEDs in series up to a total of 1.5A output current. Depending upon
supply voltage (VIN), LED forward voltage drop (V LED ) and circuit configuration, this can provide
up to 24W of output power.
Applications cover both commercial and automotive environments with VIN ranging from 4 to 18V.
?
The device employs a modified Pulse Frequency Modulation (PFM) control scheme, with
variable "ON" and "OFF" time control and adjustable peak switch current limiting.
General device operation (refer to block diagram)
Normal operation
Control is achieved by sensing the LED current in a series resistor (R M ), connected between the
two inputs of the LED Current Monitor. This generates a proportional current (IMON) that charges
the external integrator capacitor C FB . I MON is balanced against a reference discharge current
(I ADJ ) generated at the output of a second voltage to current converter driven from the demand
voltage (V ADJ ) on the ADJ pin. The difference between I MON and I ADJ is integrated by C FB to
produce an error voltage. A comparator takes a summed version of the voltage at the ISENSE pin
and a fraction of this CFB voltage and resets the latch driving the switch when the sum is greater
than 50mV. The switch transistor is turned on by the output of the SR latch, which remains set
until the emitter current in the switch transistor produces a voltage drop Vsense (=50mV nominal)
in external resistor Rsense, defining a preset maximum switch current of 50mV/Rsense.
Operation is such that a rising error voltage on CFB will effectively lower the voltage required on
the ISENSE pin and therefore reset the latch earlier in the switching cycle. This will reduce the
'ON' time of the switch and reduce the peak current in the switch from its preset maximum value.
Similarly, a falling error voltage will reset the latch later and the peak switch current will be
increased. The control loop therefore reduces or increases the energy stored in the coil during
each switching cycle, as necessary, to force the LED current to the set value. This results in high
accuracy, as no error is needed in the LED current to drive the servo to the required region.
The time taken for the coil current to reach the peak value depends on several factors: the supply
voltage, the peak coil current required at that particular LED power and whether the system
operates in "continuous" or "discontinuous" mode. The time allowed for the coil current to
discharge into the LED is fixed by the 'Variable Off Delay' monostable, whose period is modified
by the power demand signal on the ADJ pin. This monostable determines the time for which the
latch remains reset (switch off) and provides a longer "OFF" period at lower power settings,
helping to keep the parameters within an acceptable range.
Note that the "ON" period and the "OFF" period are set by the supply voltage, LED power and
external components chosen. The frequency is therefore determined by these parameters and is
NOT fixed. The 500mV reference voltage defines the nominal VADJ voltage and this defines the
100% output current. For lower LED currents, the ADJ pin can be-driven from an external dc
voltage (50mV<VADJ<500mV) or a low frequency Pulse Width Modulated (PWM) waveform.
Issue 1 - January 2008
? Zetex Semiconductors plc 2008
9
www.zetex.com
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ZXLD1321 | 制造商:ZETEX 制造商全称:ZETEX 功能描述:Boost mode DC-DC converter for LED driving with 1A output and current control |
| ZXLD1321DCATC | 功能描述:直流/直流开关转换器 DC-DC Boost Conv 1A output RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| ZXLD1322 | 制造商:DIODES 制造商全称:Diodes Incorporated 功能描述:BUCK/BOOST MODE DC-DC CONVERTER |
| ZXLD1322DCCTC | 功能描述:直流/直流开关转换器 Buck-Boost DC-DC Con 0.7A output RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| ZXLD1322DCCTC-CUT TAPE | 制造商:DIODES 功能描述:ZXLD1322 Series 15 V 600 kHz 700 mA Buck/Boost Mode DC-DC Converter - DFN-14 |
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