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參數(shù)資料
| 型號： | ISL97634 |
| 廠商： | Intersil Corporation |
| 英文描述： | White LED Driver with Wide PWM Dimming Range |
| 中文描述： | 白光LED的PWM調(diào)光范圍寬驅(qū)動器 |
| 文件頁數(shù)： | 5/10頁 |
| 文件大?。?/td> | 470K |
| 代理商： | ISL97634 |
5
FN6264.2
April 10, 2007
Detailed Description
The ISL97634 uses a constant frequency, current mode
control scheme to provide excellent line and load
regulation. There are three OVP models for driving 3, 4,
and 6 LEDs and their OVP thresholds are set at 14V, 18V,
and 26V respectively. The ISL97634 operates from an
input voltage of 2.4V to 5.5V and ambient temperature from
-40°C to +85°C. The switching frequency is around
1.45MHz and allows the driver circuit to employ small LC
components. The peak forward current of the LED is set
using the R
SET
resistor. In the steady state mode, the LED
peak current is given by the following equation:
V
SET
PWM Dimming
The ISL97634’s PWM/EN pin can be tied permanently to
high for a fixed current operation. On the other hand, the
ISL97634 can be applied with an external PWM signal to
pulse width modulated the output current. It is well
understood that the LED brightness is a linear function of the
LED current. In addition, the average LED current
corresponds to the duty cycle “D” of the PWM signal as:
V
SET
As a result, PWM signal provides a means to dim the LED
brightness. PWM dimming offers the best LEDs matching
over DC dimming. It is because the LED peak current
operating point is far away from the knee of the diode I-V
curve where part to part variations are high. The PWM
dimming test results are shown in Figure 6 with two PWM
frequencies, 1kHz and 20kHz. The vertical scale parameter
FB is proportional to the current and therefore the
brightness.
For the ISL97634, PWM dimming provides linear dimming
adjustment with low frequency signal, such as 1kHz and
below. The applied PWM dimming signal can be up to 32kHz
FIGURE 7. PWM DIMMING AT 1kHz, D = 1% ZOOM IN
FIGURE 8. PWM DIMMING AT 1kHz, D = 99%
FIGURE 9. PWM DIMMING AT 20kHz, D = 50%
ILED
PWM/EN
LX
V
OUT
V
IN
= 4V
R1 = 4
Ω
L1 = 22μH
ILED
PWM/EN
LX
V
OUT
V
IN
= 4V
R1 = 4
Ω
L1 = 22μH
ILED
PWM/EN
LX
V
OUT
V
IN
= 4V
L1 = 22μH
R1 = 4
Ω
I
LED
--------------
=
(EQ. 1)
I
LED
AVG
–
--------------
D
=
(EQ. 2)
ISL97634
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| ISL97634IRT14Z-T | White LED Driver with Wide PWM Dimming Range |
| ISL97634IRT14Z-TK | White LED Driver with Wide PWM Dimming Range |
| ISL97634IRT18Z-T | White LED Driver with Wide PWM Dimming Range |
| ISL97634IRT18Z-TK | White LED Driver with Wide PWM Dimming Range |
| ISL97634IRT26Z-T | White LED Driver with Wide PWM Dimming Range |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| ISL97634ART26Z-TK | 制造商:Intersil Corporation 功能描述: |
| ISL97634IRT14Z | 制造商:Intersil 功能描述:White LED Driver with PWM Dimming(3 LED) |
| ISL97634IRT14Z-T | 功能描述:IC LED DRIVR WHITE BCKLGT 8-TDFN RoHS:是 類別:集成電路 (IC) >> PMIC - LED 驅(qū)動器 系列:- 產(chǎn)品培訓模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:2,500 系列:- 恒定電流:- 恒定電壓:- 拓撲:升壓（升壓），切換式電容器（充電泵） 輸出數(shù):1 內(nèi)部驅(qū)動器:是 類型 - 主要:背光 類型 - 次要:白色 LED 頻率:625kHz ~ 875kHz 電源電壓:2.7 V ~ 5.3 V 輸出電壓:5V 安裝類型:表面貼裝 封裝/外殼:10-TFSOP，10-MSOP（0.118"，3.00mm 寬） 供應商設備封裝:10-µMAX 包裝:帶卷 (TR) 工作溫度:-40°C ~ 85°C |
| ISL97634IRT14Z-TK | 功能描述:IC LED DRIVR WHITE BCKLGT 8-TDFN RoHS:是 類別:集成電路 (IC) >> PMIC - LED 驅(qū)動器 系列:- 產(chǎn)品培訓模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:2,500 系列:- 恒定電流:- 恒定電壓:- 拓撲:升壓（升壓），切換式電容器（充電泵） 輸出數(shù):1 內(nèi)部驅(qū)動器:是 類型 - 主要:背光 類型 - 次要:白色 LED 頻率:625kHz ~ 875kHz 電源電壓:2.7 V ~ 5.3 V 輸出電壓:5V 安裝類型:表面貼裝 封裝/外殼:10-TFSOP，10-MSOP（0.118"，3.00mm 寬） 供應商設備封裝:10-µMAX 包裝:帶卷 (TR) 工作溫度:-40°C ~ 85°C |
| ISL97634IRT18Z | 制造商:Intersil 功能描述:White LED Driver with PWM Dimming(4 LED) |
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