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参数资料
| 型号： | SP6683UEB |
| 厂商： | Exar Corporation |
| 文件页数： | 6/14页 |
| 文件大小： | 0K |
| 描述： | EVAL BOARD FOR SP6683 |
| 标准包装： | 1 |
| 系列： | * |
THEORY OF OPERATION
General Overview
The SP6683 is a current regulated charge pump
ideal for converting a Li-Ion battery input for
driving white LEDs used in camera flash or
backlighting color displays in cellular phones,
PDAs, digital cameras and MP3 players. The
SP6683 is able to efficiently drive one 200mA
Flash LED or up to eight 20mA white LEDs in
parallel and maintain a constant brightness over
a very wide operating voltage range (2.7V to
5.5V). The SP6683 operates with an internal
1.2MHz clock, enabling the use of small exter-
nal components. Other features of SP6683 in-
clude PWM dimming control as well as com-
plete input/output disconnect in shutdown. In
shutdown mode the IC typically draws 500nA
current. The output regulation is achieved by
sensing the voltage at the feedback pin and
modulating the switch between the charge pump
and output capacitor.
Theory of Operation
The SP6683 regulated charge pump block dia-
gram consists of four main blocks (Voltage
Reference, Mode Control, Clock Manager, Start-
up and Charge-Pump Switches) and two com-
parators (V MODE Comparator and V OUT Com-
parator).
1) Voltage Reference. This block provides the
315mV and 1.25V reference voltages needed
for the two comparators.
2) Mode Control. An external voltage divider
connected to the V MODE pin will define an input
voltage to the mode comparator which sets the
logic state of the mode selection outputs to the
X1 or X1.5 modes. V MODE is compared to a
1.25V bandgap voltage. For example, if one
makes a 158K/100K divider, the mode will
change at 2.58 x 1.25 V = 3.23V. A comparator-
based cycle by cycle regulation ensures that no
mode change occurs during cycles.
3) Clock Manager. An internal 1.2MHz clock
is generated in this block. Depending on the
mode control, the appropriate clock phasing is
generated here and sent to the startup and charge
pump switches block.
4) V OUT Comparator & Output Control. A
315mV reference voltage is compared to feed-
back voltage to control the V OUT needed for the
application. Output current is set by a bias
resistor from the FB pin to the GND pin chosen
by the relationship:
I OUT = V FB
R FB
where V FB = 315mV.
Date: 3/31/06 RevG
SP6683 1X/1.5X Charge Pump LED Driver for Flash or Backlight
6
? Copyright 2006 Sipex Corporation
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相关代理商/技术参数 |
参数描述 |
|---|---|
| SP6685 | 制造商:EXAR 制造商全称:EXAR 功能描述:700mA Buck/Boost Charge Pump LED Driver |
| SP6685_06 | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:700mA Buck/Boost Charge Pump LED Driver |
| SP6685EB | 功能描述:电源管理IC开发工具 Eval Board for SP6685 Series RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
| SP6685ER | 制造商:Exar Corporation 功能描述:LASER DIODE/LED DRIVER, 10 Pin, Plastic, LCC |
| SP6685ER/TR | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:700mA Buck/Boost Charge Pump LED Driver |
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