參數(shù)資料
型號(hào)： IRS2540
廠商： International Rectifier
英文描述： IRPLLED1 High Voltage LED Driver using the IRS2540
中文描述： IRPLLED1高電壓LED驅(qū)動(dòng)器采用IRS2540
文件頁(yè)數(shù)： 24/28頁(yè)
文件大?。?/td> 839K
代理商： IRS2540
24
RD-0608
www.irf.com
The ENN filter capacitor was arbitrarily chosen to be 100 nF, this helps slow the rate of switching
during open load conditions.
The IRS254(0,1) was specifically designed to handle low frequency ripples on V
BUS
. Its capability to
handle such ripple makes it ideal for an offline rectified waveform. However if high voltage (on the
order of 5 V to 10 V) high frequency oscillations (greater than or close to the operating frequency) are
present on V
BUS
, it is recommended to implement an input filter. If these high frequency signals are
present on V
BUS
the IRS254(0,1) will still continue to regulate the current through the load, but
abnormal switching of LO and HO may be observed. This poses a problem in terms of switching
losses. As previously discussed, one may need or want to control the operating frequency to control
the systems efficiency, but if LO and HO randomly switch, it may negate all attempts to control the
frequency. Of course the root of this problem can be significantly contributed through PCB layout, but
it is also a function of the load current. If filters on I
FB
and V
CC
are not placed correctly these high
frequency ripples will couple to the chip and appear within the control loop. Also if the load current is
on the order of 1 A or 1.5 A, when HO turns on, the load immediately tries to pull the rated current.
Since the circuit supply is not usually close by, the capacitance of the input wire is not enough to
compensate for this large pull of current, this will result in oscillations or change in potential on the
input line. Since the switching element of the circuit is one cause of these oscillations, it is easy to see
how likely the presence of high frequency oscillations are. To alleviate the circuit of such possible
problems, it is much easier to implement an input filter. The input filter will also greatly improve the
circuits EMC performance.
EMC performance
The IRS254(0,1) demo board has not been EMC tested. Input and output filters can be used to reduce
the conducted emissions to below the limits of the applicable EMC standard as needed. All inductors
may require a powdered iron core rather than ferrite, it can handle a much larger current before
saturating, needs are pending on the load current. If EMC is of critical importance, one may prefer to
use one FET and one diode, in contrast to a half-bridge driver. The reverse recovery time for a diode
is inherently shorter than that of a FET. This will help in reducing transients observed in the
switching elements resulting in better EMC performance.
Layout considerations
It is very important when laying out the PCB for the IRS254(0,1) to consider the following points:
1.
C
VCC2
and C
F
must be as close to the IC as possible.
2.
The feedback path should be kept to a minimum without crossing any high frequency lines.
3.
C
OUT
should be as close to the main inductor as possible.
4.
All traces that form the nodes V
S
and V
B
should be kept as short as possible.
5.
All signal and power grounds should be kept isolated from each other to prevent noise from
entering the control environment. It’s a general rule of thumb that all components associated
with the IC should be connected to the IC ground with the shortest path possible.
6.
All traces carrying the load current need to be adjusted accordingly.
7.
Gate drive traces should also be kept to a minimum.
10.
Design procedure summary
1.
Determine the systems requirements: input/output voltage and current needed
2.
Calculate current sense resistor
3.
Determine the operating frequency required
4.
Select L
1
and C
OUT
so that they maintain supply into the load during t
HO,on
.
相關(guān)PDF資料
PDF描述
IRS4426 DUAL LOW SIDE DRIVER
IRS4428SPBF DUAL LOW SIDE DRIVER
IRS4426PBF DUAL LOW SIDE DRIVER
IRS4426S DUAL LOW SIDE DRIVER
IRS4426SPBF DUAL LOW SIDE DRIVER
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
IRS25401 制造商:IRF 制造商全稱:International Rectifier 功能描述:LED BUCK REGULATOR CONTROL IC
IRS25401PBF 功能描述:LED照明驅(qū)動(dòng)器 Hysteretic Buck LED Drvr RoHS:否 制造商:STMicroelectronics 輸入電壓:11.5 V to 23 V 工作頻率: 最大電源電流:1.7 mA 輸出電流: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SO-16N
IRS25401PBF 制造商:International Rectifier 功能描述:IC LED DRVR DIP8
IRS25401SPBF 功能描述:LED照明驅(qū)動(dòng)器 200V HALF BRDG DRVR LED BUCK REGULATOR RoHS:否 制造商:STMicroelectronics 輸入電壓:11.5 V to 23 V 工作頻率: 最大電源電流:1.7 mA 輸出電流: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SO-16N
IRS25401STRPBF 功能描述:LED照明驅(qū)動(dòng)器 Hysteretic Buck LED Drvr RoHS:否 制造商:STMicroelectronics 輸入電壓:11.5 V to 23 V 工作頻率: 最大電源電流:1.7 mA 輸出電流: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SO-16N
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