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参数资料
| 型号： | A6281EESTR-T |
| 厂商： | Allegro Microsystems Inc |
| 文件页数： | 8/11页 |
| 文件大小： | 0K |
| 描述： | IC LED DRIVER PWM CONTROL 16-QFN |
| 产品培训模块： | A6281 Three-channel LED Driver |
| 标准包装： | 1,500 |
| 恒定电流： | 是 |
| 拓扑： | 线性，PWM |
| 输出数： | 3 |
| 内部驱动器： | 是 |
| 类型 - 次要： | RGB |
| 频率： | 5MHz |
| 电源电压： | 4.75 V ~ 17 V |
| 输出电压： | 1 V ~ 3 V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-WFQFN 裸露焊盘 |
| 供应商设备封装： | 16-QFN/MLP 裸露焊盘（3x3） |
| 包装： | 带卷 (TR) |
| 工作温度： | -40°C ~ 85°C |
| 产品目录页面： | 1141 (CN2011-ZH PDF) |
| 其它名称： | 620-1218-2 |
A6281
3-Channel Constant Current LED Driver
with Programmable PWM Control
intended as an external power source. There should be a 1.0 μ F,
10 V ceramic capacitor connected between the VREG pin and
LGND. The capacitor should be located as close to the VREG
pin as possible.
Dot Correction Control
The A6281 can further control the maximum output current for
each output by setting the three 7-bit dot correction registers
with scale data that ranges from 36.5% to 100% of the overall
maximum output current that is set by the REXT resistor. This
feature is useful because not every type of LED (red, green, or
blue, for example) has the same level of brightness for a given
current, and the brightness could be different even from LED to
LED of the same type. By scaling the output currents so that all
the LEDs have matched intensities, the application will have full
color depth when using the PWM counters. The dot correction
current can be calculated by the following equation:
I OUT n = I OUT n (max) × (Scale n / 2 + 36.5) / 100
Where Scale n is in the range 0 to 127, as shown in the following
table:
The actual package power dissipation is:
P D(act) = DC 0 × V DS0 × I OUT0
+ DC 1 × V DS1 × I OUT1
+ DC 2 × V DS2 × I OUT2 + V IN × I IN ,
where DC i is the PWM duty cycle for channel i , and I OUTi is the
output current for channel i , determined by the dot correction
current for that channel and REXT.
When calculating power dissipation, the total number of avail-
able device outputs is usually used for the worst-case situation
(3 LEDs at 100% duty cycle).
Thermal Shutdown (TSD)
When the junction temperature of the A6281 reaches the thermal
shutdown temperature threshold, T JTSD (165°C typical), the
outputs will shut off until the junction temperature cools down
below the recovery threshold, T JTSD – ? T J ( 15°C typical). The
shift register and output latches will remain active during the
TSD event. Therefore there is no need to reload the data into the
output latches.
Undervoltage Lockout
Scale
0
1
2
...
127
I OUT /I OUT (max)
(%)
36.5
37.0
37.5
...
100
The A6281 includes an internal undervoltage lockout (UVLO)
circuit that disables the driver outputs in the event of the logic
supply voltage dropping below a minimum acceptable level.
This prevents the display of erroneous information, a necessary
function for some critical applications. The shift register will not
shift any data in a UVLO condition. Upon recovery of the logic
Refer to figure 5 for the bit configurations for the scalar registers.
The dot correction data in the shift register is latched on a rising
edge of the LI pin. The dot correction data remains latched on a
rising OEI signal. The default output current when the A6281
is powered-up or recovers from a UVLO is 36.5% of the current
set by the R EXT resistor.
Package Power Dissipation
The maximum allowable package power dissipation is deter-
mined as:
P D (max) = (150 – T A ) / R ? JA .
supply voltage and on power up, the internal shift register and all
latches will be set to zero.
Ballast Resistors
The voltage on the outputs should be kept in the range 1 to 3 V.
If the voltage goes below 1V, the current will begin to rolloff as
the driver runs out of headroom. At V OUT above 3 V, the power
dissipation may become a problem, as each output contributes
V OUT × I LED of power loss in the output sink driver. Typically the
power supply nominal voltage is chosen to keep the output volt-
age in this range. Alternatively, series resistors can be added to
dissipate the extra power and keep the output voltage within the
recommended range.
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
8
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相关代理商/技术参数 |
参数描述 |
|---|---|
| A6281KIT | 制造商:Allegro MicroSystems 功能描述:EVALIATION KIT |
| A6282 | 制造商:ALLEGRO 制造商全称:Allegro MicroSystems 功能描述:16-Channel Constant-Current LED Driver |
| A6282AEESTR-T | 制造商:Allegro MicroSystems LLC 功能描述: |
| A6282AELPTR-T | 制造商:Allegro MicroSystems LLC 功能描述: |
| A6282EES-T | 制造商:Allegro MicroSystems 功能描述:LED DRIVER 16 CH CONST-CURRENT 制造商:Allegro MicroSystems 功能描述:LED DRIVER, 16 CH, CONST-CURRENT 制造商:Allegro MicroSystems 功能描述:LED DRIVER, 16 CH, CONST-CURRENT; Topology:Constant Current; No. of Outputs:16; Output Current:51.1mA; Output Voltage:12V; Driver Case Style:QFN; Input Voltage Min:3V; Input Voltage Max:5.5V; Switching Frequency:30MHz; Operating ;RoHS Compliant: Yes |
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