- 您现在的位置：买卖IC网 > Sheet目录370 > ZXLD1371QESTTC (Diodes Inc)IC LED DRIVER
A Product Line of
Diodes Incorporated
ZXLD1371
Applications Information (cont.)
Diodes Selection
For maximum efficiency and performance, the rectifier (D1) should be a fast low capacitance Schottky diode* with low
reverse leakage at the maximum operating voltage and temperature. The Schottky diode also provides better efficiency
than silicon PN diodes, due to a combination of lower forward voltage and reduced recovery time.
It is important to select parts with a peak current rating above the peak coil current and a continuous current rating higher
than the maximum output load current. In particular, it is recommended to have a voltage rating at least 15% higher than
the maximum transistor voltage to ensure safe operation during the ringing of the switch node and a current rating at least
10% higher than the average diode current. The power rating is verified by calculating the power loss through the diode.
The higher forward voltage and overshoot due to reverse recovery time in silicon diodes will increase the peak voltage on
the Drain of the external MOSFET. If a silicon diode is used, care should be taken to ensure that the total voltage appearing
on the Drain of the external MOSFET, including supply ripple, does not exceed the specified maximum value.
*A suitable Schottky diode for a switching current of up to about 1.5A would be PDS3100 (Diodes Inc).
Output Capacitor
An output capacitor may be required to limit interference or for specific EMC purposes. For boost and buck-boost
regulators, the output capacitor provides energy to the load when the freewheeling diode is reverse biased during the first
switching subinterval. An output capacitor in a buck topology will simply reduce the LED current ripple below the inductor
current ripple. In other words, this capacitor changes the current waveform through the LED(s) from a triangular ramp to a
more sinusoidal version without altering the mean current value.
In all cases, the output capacitor is chosen to provide a desired current ripple of the LED current (usually recommended to
be less than 40% of the average LED current).
Buck:
C OUTPUT =
8 x f SW
Δ I L ? PP
x r LED x Δ I LED ? PP
Boost and Buck-boost
C OUTPUT =
where:
f SW
D x Δ I L ? PP
x r LED x Δ I LED ? PP
?
?
?
?
Δ I L-PP is the ripple of the inductor current, usually ± 20% of the average sensed current
Δ I LED-PP is the ripple of the LED current, it should be <40% of the LEDs average current
f sw is the switching frequency (From graphs and calculator)
r LED is the dynamic resistance of the LEDs string (n times the dynamic resistance of the single LED from the
datasheet of the LED manufacturer).
The output capacitor should be chosen to account for derating due to temperature and operating voltage. It must also have
the necessary RMS current rating. The minimum RMS current for the output capacitor is calculated as follows:
Buck
I COUTPUT RMS =
I LED ? PP
12
Boost and Buck-boost
I COUTPUTRMS = I LED
D MAX
1 ? D MAX
Ceramic capacitors with X7R dielectric are the best choice due to their high ripple current rating, long lifetime, and
performance over the voltage and temperature ranges.
ZXLD1371
Document number: DS35436 Rev. 1 - 2
31 of 42
www.diodes.com
February 2012
? Diodes Incorporated
发布紧急采购，3分钟左右您将得到回复。
相关PDF资料
ZXLD1374EST20TC
IC LED DVR BUCK BOOST 20TSSOP
ZXLD1937ET5TA
IC LED DRIVR WHITE BCKLGT TSOT-5
ZXLD381FHTA
IC LED DRIVR WHITE BCKLT SOT23-3
ZXLD383ET5TA
IC LED DRIVR WHITE BCKLGT TSOT-5
ZXSC300E5TA
IC LED DRVR WHITE BCKLGT SOT23-5
ZXSC380FHTA
IC LED DRVR WHITE BCKLGT SOT23-3
ZXSC400E6TA
IC LED DRVR WHITE BCKLGT SOT23-6
0-1005447-1
SENSOR PIEZO FILM VIBRA MASS
相关代理商/技术参数
ZXLD1374
制造商:DIODES 制造商全称:Diodes Incorporated 功能描述:60V HIGH ACCURACY 1.5A BUCK/BOOST/BUCK-BOOST
ZXLD1374_11
制造商:DIODES 制造商全称:Diodes Incorporated 功能描述:60V HIGH ACCURACY 1.5A BUCK/BOOST/BUCK-BOOST
ZXLD1374EST20TC
功能描述:LED照明驱动器 60V 1.5A BUCK/BOOST LED DRIVER AEC-Q100 RoHS:否 制造商:STMicroelectronics 输入电压:11.5 V to 23 V 工作频率: 最大电源电流:1.7 mA 输出电流: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:SO-16N
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