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参数资料
| 型号： | MIC3263YML TR |
| 厂商： | Micrel Inc |
| 文件页数： | 16/32页 |
| 文件大小： | 0K |
| 描述： | IC LED DRIVER 6CH BKLT 24-MLF |
| 特色产品： | MIC3263 Boost Switching Regulator |
| 标准包装： | 1 |
| 恒定电流： | 是 |
| 拓扑： | PWM，升压（升压） |
| 输出数： | 6 |
| 内部驱动器： | 是 |
| 类型 - 主要： | 背光 |
| 类型 - 次要： | 白色 LED |
| 频率： | 400kHz ~ 1.8MHz |
| 电源电压： | 6 V ~ 40 V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 24-VFQFN 裸露焊盘，24-MLF? |
| 供应商设备封装： | 24-MLF?（4x4） |
| 包装： | 标准包装 |
| 工作温度： | -40°C ~ 125°C |
| 其它名称： | 576-3663-6 MIC3263YML TRDKR MIC3263YML TRDKR-ND |
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?
R ISET =
Micrel, Inc.
The input frequency to the DRC pin can be 100Hz to
40kHz and the internal dimming frequency D R w ill be
determined by R DFS .
The duty cycle of the input frequency at DRC is converted
according to Table 2 for the actual dimming duty cycle.
For direct dimming control, co nnect DFS to V D D and use
the MODE pi n for the input dimming pulse. This method by
passes the internal dimming control and allows f or
dimming control by the external PWM.
DFS Filter
In addition to the R DFS resistor-to-gro un d at th e DFS pin, a
series RC filter is required when operating a t dimm ing
frequencies below 1kHz. The reason is that the DFS pin is
the ou tput of a transconductance differential am plifier. The
differential amplifier has a high-frequency pole.
At low dimming frequencies of around 1kHz R DFS is high
around 100k ? and the differential amplifier po le produces
a phase shift that can cause instabilities in the DFS
control.
Ther efore, a RC filter is required to compensa te for the
lagging phase shift created by the pole by ad d ing a zero
and therefore , a phase lead at the DFS pin. U se a 4k ?
resi stor in series with a 2.2nF ceramic capac itor. When
using a dimming frequency of 2 kHz or less. T h e filter has
no ill effect at higher dimming frequencies.
COMP
Con nect a capacitor and resistor to ground to co mpensate
the boost stage.
DRC
Dimmin g Ratio Control (DRC) is an input PWM dim ming
con trol. The MIC3263 converts this to one of sixteen
dimming ratios that is used to dim the LEDs. T h e dimming
ratio is built on a log scale.
CINT
C INT integrates the DRC input pulse. For a PWM frequency
range of around 1kHz use 100nF. For a PWM frequen cy
range of around 20kHz pulse, use 10nF. Fo r a PWM
frequency range of around 100Hz pulse use 1 μ F.
ISET
Set the LED current of all six channels by this resistor. Use
2k ? for 30mA and 3k ? for 20mA. The R ISET is inversely
proportional to I LED . Use the following equation to find
R ISET :
60
I LED
MIC3263
For the best current matching accuracy design for an I LED
current of 15mA to 30mA.
CRV
Use a 2.2 μ F capacitor at the CRV pin. This is used as the
reference voltage of the boost sta ge. The CRV capacitor is
continually being charged or discharged in order to keep
V OUT at the right level (refer to Functional Diagram
illustration). CRV will be charged t o keep the IO’s at about
1.2V.
IO1 ─ IO6
These are the connections to th e linear-mode current
amplifier in each channel. Connec t the cathode end of the
LED channels to these pins. The control loop will keep this
at about 1.2V. 1.2V insures that t he current amplifier is in
the linear region and therefore can regulate the LED
current.
In cases where there are a differ ent number of LEDs in a
channel, the V(IO) of the channel w ith the fewest LEDs will
have a higher V(IO). V(IO) can be as high as 7.5V before
the fault monitoring circuits will sense that channel as a
short to V OUT .
When there are a different numb er of LEDs in a channel
the IO voltage will be higher in the cha nnels that have less
LEDs in order to keep the LE Ds biased correctly. A
difference of up to 7.5V betwe en channels can occur
because of this. If the circuits th at monitors the IO pins
sees a fault, that channel will turn off and that channel’s IO
pin will be at high impedance. An off channel’s IO pin will
be near or below the booster outp ut voltage. On a channel
that has a shorted LED, that c hannel’s IO voltage will
increase to keep correct voltage drops on the other series
LEDs. It is best to use equal number of LEDs in each
channel but there will always be diffe rences in the LEDs
volta ge drops so all IOs will not have the exact same
voltage. Each channel has its own monitoring circuit
monitoring the IO1 ─ IO6 pins. If any V(IO) drops below
0.5V (if an LED opens), that channel is turned off and the
other channels are unaffected. If any IO goes about 7.5V
(if several LEDs short to V OUT ), that channel is turned off
and the other channels are unaffected.
VSW
This is the boost-stage switch node, the collector of the
internal power switch.
EN
Connect EN high to enable the part, low to disable. Do not
leave the EN pin floating.
VIN
Supply voltage to the part (6V–40V).
January 2010
16
M9999-012110
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MIC3287 | 制造商:MICREL 制造商全称:Micrel Semiconductor 功能描述:1.2MHz PWM White LED Driver with OVP in Thin SOT-23 and 2mm x 2mm MFL |
| MIC3287_10 | 制造商:MICREL 制造商全称:Micrel Semiconductor 功能描述:1.2MHz PWM White LED Driver with OVP in Thin SOT-23 and 2mm x 2mm MFL |
| MIC3287-24YD6 | 制造商:Rochester Electronics LLC 功能描述: 制造商:RF Micro Devices Inc 功能描述: |
| MIC3287-24YD6 TR | 功能描述:LED照明驱动器 2x2mm White LED Driver w/ 24V OVP (Lead Free) RoHS:否 制造商:STMicroelectronics 输入电压:11.5 V to 23 V 工作频率: 最大电源电流:1.7 mA 输出电流: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:SO-16N |
| MIC3287-24YD6TR | 制造商:RF Micro Devices Inc 功能描述: |
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