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参数资料
| 型号： | MAX8608YETD+T |
| 厂商： | Maxim Integrated |
| 文件页数： | 8/11页 |
| 文件大小： | 0K |
| 描述： | IC LED DRVR WT/OLED BCKLT 14TDFN |
| 标准包装： | 2,500 |
| 拓扑： | PWM，升压（升压） |
| 输出数： | 2 |
| 内部驱动器： | 是 |
| 类型 - 主要： | 背光 |
| 类型 - 次要： | OLED，白色 LED |
| 频率： | 770kHz ~ 1.25MHz |
| 电源电压： | 2.7 V ~ 6 V |
| 输出电压： | 26V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 14-WFDFN 裸露焊盘 |
| 供应商设备封装： | 14-TDFN-EP（3x3） |
| 包装： | 带卷 (TR) |
| 工作温度： | -40°C ~ 85°C |
High-Efficiency, 26V Step-Up Converters for Main
and Subdisplays Using OLEDs and/or White LEDs
Table 1. Truth Table for the Enable Inputs
ENA
0
0
1
1
ENB
0
1
0
1
OUTA
Hi-Z
Hi-Z
ON
ON
OUTB
Hi-Z
ON
Hi-Z
Hi-Z
BOOST BIAS
OFF
ON
ON
ON
The fast 1MHz internal oscillator allows for a small
inductor and small input and output capacitors while
minimizing input and output ripple. For higher efficiency
at the expense of larger components, a logic input may
select 500kHz operation. At light loads, the MAX8608
operates in PFM mode to maximize efficiency. A soft-
start gradually illuminates the LEDs, reducing the
inrush current during startup.
The single analog control input allows easy adjustment
of WLED current or OLED voltage. The control input is
internally filtered to allow for either simple analog volt-
age control or direct-PWM duty-cycle control while
maintaining low input/output ripple. In shutdown, sup-
ply current is reduced to a low 0.01μA.
Enable and Output Control
The MAX8608’s outputs are enabled by the ENA and
ENB inputs, which also turn on and off the part’s inter-
nal bias circuitry. ENA is the dominant input. Table 1
shows the truth table for these inputs.
Each output is protected against short circuit to ground
by an internal current limit (300mA typ). If an output
becomes current limited, the corresponding output
switch turns off, the C COMP is discharged to ground,
and the soft-start sequence is reinitiated.
Soft-Start
The MAX8608 attains soft-start by charging C COMP
gradually with a current source. When V COMP rises
above 1.5V, the internal MOSFET begins switching, but
Overvoltage Protection
Overvoltage lockout (OVLO) occurs when V OVP is
above 27V (typ). The protection circuitry stops the inter-
nal MOSFET from switching and causes V COMP to
decay to GND. The device comes out of OVLO and into
soft-start when V OUT falls below 25V (typ).
Ambient Temperature Derating Function
(MAX8608Y Only)
The MAX8608Y limits the maximum LED current of
OUTA depending on the die temperature. V FBA is limit-
ed to 340mV up to +40°C. Once the temperature
reaches +40°C, the maximum V FBA declines by
5.8mV/°C. Due to the package’s exposed paddle, the
die temperature is always very close to the PC board
temperature.
The temperature derating function matches the charac-
teristic in popular WLED data sheets and allows the
LED current to be safely set higher (25mA typ) at nor-
mal operating temperatures, thereby allowing either a
brighter display or fewer LEDs to be used for normal
display brightness.
Design Procedure
Adjusting WLED Current
Adjusting the MAX8608’s output current changes the
brightness of the LEDs. An analog input (CTRL) and the
sense resistor value sets the output current. Output cur-
rent is given by:
at a reduced duty cycle. When V COMP rises above
2.25V, the duty cycle is at its maximum. See the Typical
Operating Characteristics for examples of soft-start
I LED =
V CTRL
5 x R SENSE
operation with WLED and OLED loads.
Shutdown
The V CTRL voltage range for adjusting output current is
0 to 1.65V. To set the maximum current, calculate
The MAX8608 enters shutdown when ENA and ENB are
R SENSE when V CTRL is at its maximum as follows:
low. In shutdown, supply current is reduced to 0.01μA
by powering down the entire IC. C COMP is discharged
during shutdown, allowing the device to reinitiate soft-
start when the device is enabled. Also, the internal
R SENSE =
1 . 65
5 x I LED ( MAX )
switches from OVP to OUTA and OUTB are turned off
so no current can pass to the loads.
Power dissipation in R SENSE is typically less than
10mW; therefore, a standard chip resistor is sufficient.
8
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX8608YEVKIT | 功能描述:LED 照明开发工具 RoHS:否 制造商:Fairchild Semiconductor 产品:Evaluation Kits 用于:FL7732 核心: 电源电压:120V 系列: 封装: |
| MAX8608ZETD+ | 制造商:Maxim Integrated Products 功能描述: |
| MAX8608ZETD+T | 功能描述:LED照明驱动器 26V Step-Up Converter 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 |
| MAX8608ZETD-T | 功能描述:LED照明驱动器 26V Step-Up Converter 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 |
| MAX860C/D DIE | 制造商:Maxim Integrated Products 功能描述: |
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