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參數(shù)資料
| 型號： | IRS2540STRPbF |
| 廠商： | International Rectifier |
| 英文描述： | LED BUCK REGULATOR CONTROL IC |
| 中文描述： | 發(fā)光二極管降壓穩(wěn)壓器控制IC |
| 文件頁數(shù)： | 7/14頁 |
| 文件大小： | 456K |
| 代理商： | IRS2540STRPBF |
IRS254(0,1)(S)PbF
Functional Description
Operating Mode
The IRS254(0,1) operates as a time-delayed
hysteritic buck controller. During normal operating
conditions the output current is regulated via the IFB
pin voltage (nominal value of 500 mV). This
feedback is compared to an internal high precision
bandgap voltage reference. An on-board dV/dt filter
has
also
been
used
transitioning.
Once the supply to the IC reaches V
CCUV+
,
the LO
output is held high and the HO output low for a
predetermined period of time. This initiates charging
of the bootstrap capacitor, establishing the V
BS
floating supply for the high-side output. The IC then
begins toggling HO and LO outputs as needed to
regulate the current.
www.irf.com Page 7
to
ignore
erroneous
Fig.1 IRS254(0,1) Control Signals, Iavg=1.2 A
As long as V
IFB
is below V
IFBTH
, HO is on, modulated
by the watchdog timer described below, the load is
receiving current from V
BUS
, which simultaneously
stores energy in the inductor, as V
IFB
increases,
unless the load is open. Once V
IFB
crosses V
IFBTH
,
the control loop switches HO off after the delay
t
HO,OFF
. Once HO is off, LO will turn on after the
deadtime (DT), the inductor releases the stored
energy into the load and V
IFB
starts decreasing.
When V
IFB
crosses V
IFBTH
again, the control loop
switches HO on after the delay t
HO,ON
and LO off
after the delay t
HO,ON
+ DT. The switching continues
to regulate the current at an average value
determined as follows. When the inductance value
is large enough to maintain a low ripple on I
FB
, I
out,avg
can be calculated:
VIFBTH
avg
Iout
=
)
(
RCS
(A)
(B)
F
ig.2 (A) Storing Energy in Inductor
(B) Releasing Inductor Stored Energy
t_LO_on
t_HO_off
DT1
IFBTH
50%
50%
50%
50%
t_LO_off
DT2
t_HO_on
HO
LO
IFB
50%
Fig.3 IRS254(0,1) Time Delayed Hysterisis
The control method is based upon a free running
frequency, in constrast to a more widely used fixed
frequency regulation. This reduces the part count
since there is no need for frequency setting
components and also provides an inherently stable
sytem, which acts as a current source.
A deadtime of approximately 140 ns between the
two gate drive signals is necessary to prevent a
“shoot-through” condition. At higher frequencies, the
switching losses become very large in the absence
of this deadtime. The deadtime has been adjusted to
maintain precise current regulation, while still
preventing shoot-through.
HO
LO
Iout
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| IRS25411 | 制造商:IRF 制造商全稱:International Rectifier 功能描述:LED BUCK REGULATOR CONTROL IC |
| IRS25411PBF | 功能描述:LED照明驅(qū)動器 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 |
| IRS25411PBF | 制造商:International Rectifier 功能描述:IC LED DRVR DIP8 |
| IRS25411SPBF | 功能描述:LED照明驅(qū)動器 600V 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 |
| IRS25411STRPBF | 功能描述:LED照明驅(qū)動器 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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