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參數(shù)資料
| 型號： | FAN5333ASX |
| 廠商： | FAIRCHILD SEMICONDUCTOR CORP |
| 元件分類： | 顯示驅動器 |
| 英文描述： | High Efficiency, High Current Serial LED Driver with 30V Integrated Switch |
| 中文描述： | LED DISPLAY DRIVER, PDSO5 |
| 封裝： | SOT-23, 5 PIN |
| 文件頁數(shù)： | 7/11頁 |
| 文件大小： | 538K |
| 代理商： | FAN5333ASX |
7
www.fairchildsemi.com
FAN5333A/FAN5333B Rev. 1.0.1
F
Block Diagram
Figure 4. Block Diagram
Circuit Description
The FAN5333A/FAN5333B is a pulse-width modulated (PWM)
current-mode
boost
converter. The
improves the performance of battery powered equipment by signif-
icantly minimizing the spectral distribution of noise at the input
caused by the switching action of the regulator. In order to facilitate
effective noise filtering, the switching frequency was chosen to be
high, 1.5MHz. The device architecture is that of a current mode
controller with an internal sense resistor connected in series
with the N-channel switch. The voltage at the feedback pin
tracks the output voltage at the cathode of the external Schottky
diode (shown in the test circuit). The error amplifier amplifies the
difference between the feedback voltage and the internal band-
gap reference. The amplified error voltage serves as a refer-
ence voltage to the PWM comparator. The inverting input of the
PWM comparator consists of the sum of two components: the
amplified control signal received from the 30m
resistor and the ramp generator voltage derived from the oscilla-
tor. The oscillator sets the latch, and the latch turns on the FET
switch. Under normal operating conditions, the PWM compara-
tor resets the latch and turns off the FET, thus terminating the
pulse. Since the comparator input contains information about
the output voltage and the control loop is arranged to form a
negative feedback loop, the value of the peak inductor current
will be adjusted to maintain regulation.
FAN5333A/FAN5333B
current sense
Every time the latch is reset, the FET is turned off and the cur-
rent flow through the switch is terminated. The latch can be
reset by other events as well. Over-current condition is moni-
tored by the current limit comparator which resets the latch and
turns off the switch instantaneously within each clock cycle.
Over-Voltage Protection
The voltage on the feedback pin is sensed by an OVP Compar-
ator. When the feedback voltage is 15% higher than the nominal
voltage, the OVP Comparator stops switching of the power tran-
sistor, thus preventing the output voltage from going higher.
Open-circuit protection
As in any current regulator, if the feedback loop is open, the out-
put voltage increases until it is limited by some additional exter-
nal circuitry. In the particular case of the FAN5333, the output
voltage is limited by the switching transistor breakdown at
around 45V, typically (assuming that C
diode rating voltage are higher). Since at such high output volt-
age the output current is inherently limited by the discontinuous
conduction mode, in most cases, the switching transistor enters
non-destructive breakdown and the IC survives.
OUT
and the Schottky
However, to ensure 100% protection for LED disconnection, we
recommend limiting V
OUT
with an external Zener diode or stop-
ping the boost switching with an external voltage supervisory
circuit.
Applications Information
Setting the Output Current
The internal reference (V
and 315mV (Typical) for FAN5333B. The output current is set by
a resistor divider R connected between FB pin and ground. The
output current is given by
REF
) is 110mV (Typical) for FAN5333A
Reference
Oscillator
n
FB
FB
Error
Driver
Comp
-
-
+
+
S
Ramp
Generator
R
R
R
Q
S
Current Limit
Comparator
30m
1.15 x V
REF
Shutdown
Circuitry
Thermal
Shutdown
SHDN
4
GND
SW
1
V
IN
5
Amp
2
3
Over
Voltage
Comp
-
+
-
+
-
I
LED
V
--R
=
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| FAN5333B | 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:High Efficiency, High Current Serial LED Driver with 30V Integrated Switch |
| FAN5333BSX | 功能描述:LED照明驅動器 SYSTEM_POWER 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: 安裝風格:SMD/SMT 封裝 / 箱體:SO-16N |
| FAN5333BSX-CUT TAPE | 制造商:FAIRCHILD 功能描述:FAN5333B Series 5.5 V 1.5 MHz High Efficiency High Current Serial LED Driver |
| FAN5333SX | 功能描述:IC LED DRVR WHITE BCKLGT SOT23-5 RoHS:是 類別:集成電路 (IC) >> PMIC - LED 驅動器 系列:- 標準包裝:1 系列:- 恒定電流:- 恒定電壓:- 拓撲:PWM，切換式電容器（充電泵） 輸出數(shù):1 內(nèi)部驅動器:是 類型 - 主要:背光 類型 - 次要:白色 LED 頻率:642kHz 電源電壓:2.7 V ~ 5.5 V 輸出電壓:5V 安裝類型:表面貼裝 封裝/外殼:10-VFDFN 裸露焊盤 供應商設備封裝:10-VSON 包裝:剪切帶 (CT) 工作溫度:-30°C ~ 85°C 產(chǎn)品目錄頁面:1371 (CN2011-ZH PDF) 其它名稱:BD1603NUV-E2CT |
| FAN5336 | 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:1.5MHz Boost Regulator with 33V Integrated FET Switch |
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