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参数资料
| 型号： | MAX1984 |
| 厂商： | Maxim Integrated Products, Inc. |
| 元件分类： | LED驱动器 |
| 英文描述： | Ultra-High-Efficiency White LED Drivers |
| 中文描述： | 超高效率白光LED驱动器 |
| 文件页数： | 13/17页 |
| 文件大小： | 333K |
| 代理商： | MAX1984 |
capacitor can be connected from BITB to ground to
increase the total time constant. Use the following
equation to calculate the total time constant:
τ
= 0.2M
C
EXT
+ 0.098ms
where C
EXT
is the external capacitance.
The recommended DPWM duty-factor range is from
20% to 100% for DPWM frequencies between 20kHz
and 2MHz, using the internal 0.1ms filter. For lower
DPWM operating frequencies, use C
EXT
and ensure the
voltage on C
EXT
(BITB), including ripple, remains
above DF
MIN
0.75
V
REF
, where DF
MIN
is the mini-
mum reliable DPWM duty factor of 15%.
In DPWM mode, the MAX1984/MAX1985/MAX1986
enter shutdown mode when the DPWM duty cycle is
below 5% (typ) and BITC is a logical low level.
Analog Control
To use the analog control mode, connect MODE, BITA,
and BITC to IN. Connect BITB to a DC voltage that sets
the LED current. The operational range for the analog
control is from 140mV (15%) to 0.75
V
REF
(100%).
The LED current is given by the following equation:
where K1 = 0.0465, K2 = 0.953, V
BITB
is the voltage at
the BITB pin, V
REF
is the 1.25V internal reference voltage,
and I
LED(FS)
is the full-scale LED current set by SETI.
In analog mode, the MAX1984/MAX1985/MAX1986
enter shutdown mode when both V
BITA
and V
BITB
are
logic low.
Parallel Control
The MAX1984/MAX1985/MAX1986 also support 2-bit or
3-bit parallel control. To use the 3-bit parallel control
mode, connect MODE to ground. BITA is the most sig-
nificant bit and BITC is the least significant bit. To use
the 2-bit parallel control, connect MODE to IN and BITC
to ground. BITA is the most significant bit and BITB is
the least significant bit. In parallel mode, the
MAX1984/MAX1985/MAX1986 enter shutdown mode
when BITA, BITB, and BITC are logic low. Tables 3 and
4 are the truth tables.
I
K
K
V
V
I
LED
BITB
×
REF
LED FS
=
+
×
×
1
2
0 75
.
(
)
M
Ultra-High-Efficiency White
LED Drivers
______________________________________________________________________________________
13
V
IN
38
7.2M
DAC
DECODER
0.75 x V
REF
0.75 x V
REF
3-BIT
LEVEL
SHIFT
10pF
200k
9.8M
MODE
BITA
BITB
BITC
SHUTDOWN
THRESHOLD
SHUTDOWN
TO CURRENT
REGULATORS
IREF
SETI
0.045V
0.5mA TEST
200k
300k
R
SETI
SETI
SETI
V
IN
- 0.7V
18mA DEFAULT
1
100
Figure 5. Brightness Control Equivalent Functional Diagram
相关PDF资料 |
PDF描述 |
|---|---|
| MAX1984ETP | Ultra-High-Efficiency White LED Drivers |
| MAX1985ETP | Ultra-High-Efficiency White LED Drivers |
| MAX1986ETE | Ultra-High-Efficiency White LED Drivers |
| MAX1994ETM | Dual Step-Down Controllers Plus Linear- Regulator Controller for Notebook Computers |
| MAX1816 | Replaced by TMS320VC5506 : Digital Signal Processors 144-LQFP |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1984ETP | 功能描述:LED照明驱动器 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 |
| MAX1984ETP+ | 功能描述:LED照明驱动器 High-Efficiency White LED Driver 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 |
| MAX1984ETP+T | 功能描述:LED照明驱动器 High-Efficiency White LED Driver 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 |
| MAX1984ETP-T | 功能描述:LED照明驱动器 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 |
| MAX1985ETP | 功能描述:LED照明驱动器 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 |
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