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參數(shù)資料
| 型號(hào)： | ISL97631IHTZ-T7A |
| 廠商： | INTERSIL CORP |
| 元件分類(lèi)： | 穩(wěn)壓器 |
| 英文描述： | White LED Boost Regulator With Integrated Schottky Diode |
| 中文描述： | 0.35 A SWITCHING REGULATOR, 1800 kHz SWITCHING FREQ-MAX, PDSO6 |
| 封裝： | ROHS COMPLIANT, TSOT-6 |
| 文件頁(yè)數(shù)： | 6/8頁(yè) |
| 文件大小： | 332K |
| 代理商： | ISL97631IHTZ-T7A |
6
FN7370.1
December 21, 2005
Components Selection
The input capacitance is typically 0.22μF. The output
capacitor should be in the range of 0.22μF to 1μF. X5R or
X7R type of ceramic capacitors of the appropriate voltage
rating are recommended. The output capacitor value affects
PWM dimming performance. Lower output capacitor values
increase the range of PWM dimming. However, the ripple
voltage will be greater for lower values.
When choosing an inductor, make sure the average and
peak current ratings are adequate by using the following
formulas (80% efficiency assumed):
Where:
I
L
is the peak-to-peak inductor current ripple in Amps
L is the inductance in H.
f
OSC
is the switching frequency, typically 1.35MHz
The ISL97631 supports a wide range of inductance values
(22μH~82μH). For lower inductor values or lighter loads, the
boost inductor current may become discontinuous. For high
boost inductor values, the boost inductor current will be in
continuous mode.
The demo board efficiency bench test results are shown in
Figure 11. The input voltage is 4V and curves are shown for
2, 3, 4, 5 and 6 LEDs (boost inductor L = 22μH).
White LED Connections
One leg of LEDs connected in series will ensure brightness
uniformity. The 27V maximum output voltage specification
enables up to 6 LEDs to be placed in series.
In order to drive more LEDs, series/parallel connections are
used. A current mirror circuit (as shown in Figure 12) should
be used to balance LED currents.
Parallel strings of LEDs may draw significantly different
currents due to manufacturing and temperature differences.
For correct operation of the current mirror circuit, the total
voltage between FB pin and the top of the primary LED
string must be equal to or greater than the other strings. To
ensure this, a small value resistor may be inserted between
FB pin and the primary LED string.
FIGURE 10. LED DRIVER WITH OVERVOLTAGE
PROTECTION CIRCUIT
ISL97631
C1
1μF
L1
22μH
C2
0.22μF
R
SET
4.75
2.7V~5.5V
OFF/ON
LEDs
V
IN
LX
ENAB
FB
GND
V
IN
R1
Dz
V
OUT
I
LAVG
I
V
0.8 V
IN
--------------------------------
=
(EQ. 6)
I
LPK
I
LAVG
1
2
--
I
L
+
=
(EQ. 7)
I
L
V
OUT
OSC
V
V
–
(
)
--------------------------------------------------
=
(EQ. 8)
50%
55%
60%
65%
70%
75%
80%
85%
90%
0
5
10
15
20
25
30
I
LED
(mA)
E
FIGURE 11. EFFICIENCY CURVE WITH 2, 3, 4, 5 AND 6 LEDs
LOAD
22μH, V
IN
= 4V
3LED
4LED
5LED
2LED
6LED
FIGURE 12. LEDs IN SERIES/PARALLEL WITH MIRROR
CURRENT BALANCE
ELVOUT
C1
VDD
ISL97631
LX
ENAB
FB
GND
L1
D1
C2
R
SET
V
IN
2.7V~5.5V
OFF/ON
LEDs
VIN
ISL97631
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| ISL97632_07 | White LED Driver with Digital Dimming |
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| ISL97632IRT14Z-TK | White LED Driver with Digital Dimming |
| ISL97632IRT18Z-T | White LED Driver with Digital Dimming |
| ISL97632IRT18Z-TK | White LED Driver with Digital Dimming |
相關(guān)代理商/技術(shù)參數(shù) |
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|---|---|
| ISL97632IRT14Z | 制造商:Intersil 功能描述:LED Driver with 1-Wire Dimming(3 LED) |
| ISL97632IRT14Z-T | 功能描述:IC LED DRIVR WHITE BCKLGT 8-TDFN RoHS:是 類(lèi)別:集成電路 (IC) >> PMIC - LED 驅(qū)動(dòng)器 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:2,500 系列:- 恒定電流:- 恒定電壓:- 拓?fù)?升壓（升壓），切換式電容器（充電泵） 輸出數(shù):1 內(nèi)部驅(qū)動(dòng)器:是 類(lèi)型 - 主要:背光 類(lèi)型 - 次要:白色 LED 頻率:625kHz ~ 875kHz 電源電壓:2.7 V ~ 5.3 V 輸出電壓:5V 安裝類(lèi)型:表面貼裝 封裝/外殼:10-TFSOP，10-MSOP（0.118"，3.00mm 寬） 供應(yīng)商設(shè)備封裝:10-µMAX 包裝:帶卷 (TR) 工作溫度:-40°C ~ 85°C |
| ISL97632IRT14Z-TK | 功能描述:IC LED DRIVR WHITE BCKLGT 8-TDFN RoHS:是 類(lèi)別:集成電路 (IC) >> PMIC - LED 驅(qū)動(dòng)器 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:2,500 系列:- 恒定電流:- 恒定電壓:- 拓?fù)?升壓（升壓），切換式電容器（充電泵） 輸出數(shù):1 內(nèi)部驅(qū)動(dòng)器:是 類(lèi)型 - 主要:背光 類(lèi)型 - 次要:白色 LED 頻率:625kHz ~ 875kHz 電源電壓:2.7 V ~ 5.3 V 輸出電壓:5V 安裝類(lèi)型:表面貼裝 封裝/外殼:10-TFSOP，10-MSOP（0.118"，3.00mm 寬） 供應(yīng)商設(shè)備封裝:10-µMAX 包裝:帶卷 (TR) 工作溫度:-40°C ~ 85°C |
| ISL97632IRT18Z | 制造商:Intersil 功能描述:LED Driver with 1-Wire Dimming(4 LED) |
| ISL97632IRT18Z-T | 功能描述:IC LED DRIVR WHITE BCKLGT 8-TDFN RoHS:是 類(lèi)別:集成電路 (IC) >> PMIC - LED 驅(qū)動(dòng)器 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:2,500 系列:- 恒定電流:- 恒定電壓:- 拓?fù)?升壓（升壓），切換式電容器（充電泵） 輸出數(shù):1 內(nèi)部驅(qū)動(dòng)器:是 類(lèi)型 - 主要:背光 類(lèi)型 - 次要:白色 LED 頻率:625kHz ~ 875kHz 電源電壓:2.7 V ~ 5.3 V 輸出電壓:5V 安裝類(lèi)型:表面貼裝 封裝/外殼:10-TFSOP，10-MSOP（0.118"，3.00mm 寬） 供應(yīng)商設(shè)備封裝:10-µMAX 包裝:帶卷 (TR) 工作溫度:-40°C ~ 85°C |
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